# Kiwi Mk II



## Richard P (Jan 3, 2022)

Hi there, I recently joined the forum and have been viewing and enjoying some of the content posted by you all.

I have been enjoying getting into the hobby of model engineering for the last 2 to 3 years, mostly making workshop tools and a couple of steam engines. I thought I would take the plunge on a more challenging project and make my first IC engine.

I have chosen the Kiwi Mark II from Hemingway kits as I had had some reasonable success with some of their other (non-engine) projects.  While researching how to go about it, I stumbled across Vince Cutajar's thread in this forum which has been invaluable in helping me make progress.  I started work at the beginning of December and have been investing quite a bit of time in it.

In this thread, my plan is to share some of the major milestones along the way to (hopefully!) producing my first working IC engine!


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## Richard P (Jan 3, 2022)

Here are are some shots of the work on the crank case.


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## Richard P (Jan 3, 2022)

Here is the other side of the crankcase and timing cover.


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## Richard P (Jan 3, 2022)

Finishing off the timing cover.  Milling and boring the cylinder platform.


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## Richard P (Jan 3, 2022)

Machining the engine bearers and getting to work on the cylinder liner.


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## Richard P (Jan 3, 2022)

The cylinder casting was out of spec. so I had to reduce the diameter of the fins quite a bit to fully clean up the casting.


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## Eccentric (Jan 3, 2022)

Wow, you are making quick progress and the engine is looking great.  The Kiwi Mk2 is a classic Westbury and one of my favorites.  I will be tagging along for the ride.


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## Richard P (Jan 4, 2022)

Eccentric said:


> Wow, you are making quick progress and the engine is looking great.  The Kiwi Mk2 is a classic Westbury and one of my favorites.  I will be tagging along for the ride.


Thanks, quite a way to go yet!


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## Saddo (Jan 5, 2022)

I built mine from Hemingway's castings and followed the words and music from Westbury's original articles, it turned out to be an easy starter and good runner. It's a lovely engine to build enjoy.


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## Richard P (Jan 5, 2022)

Saddo said:


> I built mine from Hemingway's castings and followed the words and music from Westbury's original articles, it turned out to be an easy starter and good runner. It's a lovely engine to build enjoy.


Hi thanks, yes I am enjoying using the articles as well as the helpful advice found in this forum. One decision I have is what to do with the ignition as there was no spring steel or tungsten points in the kit.  What did you do?


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## Charles Lamont (Jan 5, 2022)

Richard P said:


> One decision I have is what to do with the ignition as there was no spring steel or tungsten points in the kit.  What did you do?


Many people now use a magnet, Hall sensor and electronic ignition instead of points.


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## Gedeon Spilett (Jan 5, 2022)

yes, electronic ignition with Hall sensor (Rxcel or the likes) is a neat solution, but if you are in a vintage mood, you may found easily on ebay new contact breaker for moped or motorcycle or car, complete, with spring, isolated breaker arm and tungsten points that you install in such way that the cam follower lies on the engine ignition cam...if you already have the ht coil, condenser and battery !


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## Richard P (Jan 5, 2022)

Thanks for the pointers ('scuse the pun) on ignition options.  Here are some shots of the work I did on the cylinder head before Christmas.  I misread the drawings and ended up putting an extra fin on the head, but I think I just about managed to improvise my way around the error.  Hopefully the extra cooling will be beneficial given I had had to trim the fins to under spec because of the casting.


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## Richard P (Jan 5, 2022)

And here are the valves, guides, collars and collets.  I had a bit of bronze spare so upgraded the collars from MS for a bit of bling.  First attempt at machining valves, so pretty happy with how they have come out.  And they seem pretty air tight in their seatings even before any grinding, so all quite positive.











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## vcutajar (Jan 5, 2022)

That's a lot of progress.  You'll be finished in no time.

Vince


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## Saddo (Jan 5, 2022)

I had an old set of car points which I cannibalised, and an old modelec coil purchased years ago. On my Mastiff I've used a magnet and hall sensor with a Minimag setup which is extremely good.


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## methuselah1 (Jan 6, 2022)

As far as points go, Kirk at Hemingway has a stock of the ones ETW specified, but you might not like the price... He also has a stock of tungsten discs if you want to do a home brew. He doesn't advertise these on the website.

If you want to go down the ready-made route, you'll find that Ford model A points are still readily available, and inexpensive.

The Kiwi II is a fun project, and well proven. It does have a bit of a reputation for running hot, though, so you often see pictures of them with an additional fan, to help with this.

When it comes to the cams, you can do them the ETW way, or make harmonic cams. M.E.N has a program to help you do this (camcalc) but because of a coding glitch, you can only use it via internet explorer - not firefox...


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## Vietti (Jan 6, 2022)

Tungsten point discs can be made quite readily by slicing TIG electrodes with a Dremel abrasive disc.


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## methuselah1 (Jan 6, 2022)

Reeves 2000 sell spring steel by the foot. Not much of a selection, but you'll need some for the float bowl cover clip, regardless of making points. It's inexpensive... But getting the bends in the right place for the carb clip is tricky. I made up a simple bending fixture for mine. I punched some holes in it while I was there, for flexibility as well as aesthetics.


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## Gedeon Spilett (Jan 7, 2022)

"Tungsten point discs can be made quite readily by slicing TIG electrodes with a Dremel abrasive disc. "

good to know that, thanks for the tip...
i have failed to cut disks in 3 mm tungsten carbide tool bits !
silver contacts work well with small engine but don't last long.


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## Richard P (Jan 7, 2022)

methuselah1 said:


> Reeves 2000 sell spring steel by the foot. Not much of a selection, but you'll need some for the float bowl cover clip, regardless of making points. It's inexpensive... But getting the bends in the right place for the carb clip is tricky. I made up a simple bending fixture for mine. I punched some holes in it while I was there, for flexibility as well as aesthetics.


Thanks for that pointer, are you able to share a photo of your perforated cover clip?


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## Richard P (Jan 7, 2022)

methuselah1 said:


> As far as points go, Kirk at Hemingway has a stock of the ones ETW specified, but you might not like the price... He also has a stock of tungsten discs if you want to do a home brew. He doesn't advertise these on the website.
> 
> If you want to go down the ready-made route, you'll find that Ford model A points are still readily available, and inexpensive.
> 
> ...


Thanks for this.  This will be my first go at cutting cams and is a bit further down the line.  Excuse my lack of knowledge, but what is the difference between cams cut the ETW way vs harmonic in terms of ease of execution and benefits?  Thanks


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## Richard P (Jan 7, 2022)

vcutajar said:


> That's a lot of progress.  You'll be finished in no time.
> 
> Vince


Thanks Vince.  Your thread has been extremely helpful!


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## methuselah1 (Jan 7, 2022)

Cams for engines come in two flavours, tangential and harmonic. Tangential cams have straight sides, and a radius on the lobe- the ramp is vicious! I think the first incarnation of the Kiwi used them; they were common in motorbikes of the period.
Harmonic cams have curved flanks, and the ramp to the lobe is far more gentle. They made the tangential cam near obsolete.
ETW's method produces a good approximation of a harmonic profile; then he approached D.H.Chaddock for further help refining the design, which the Professor did using his lathe and an improvised spindle and flycutter on his cross slide. The plan is to take a cut, then roll the lathe mandrel a couple of degrees, set the cross slide for the next cut, rinse and repeat. Although I have the same lathe, I do mine in a vertical mill with a rotary table. I put a 1/16" keyway in the cam blank, and a corresponding key on the mounting peg. Using a big tee slot cutter, I can mill both profiles in one setting, or if I only have an endmill, I can flip the blank upside down, because of the keyway.
This produces a near perfect harmonic profile, with a series of tiny facets, which are carefully removed with a dead smooth file before hardening.
That's where camcalc comes in. It generates all the figures for you. Keep them tucked away, as ETW used the same cam profiles for several of his other engines too!

Now, I'll try to get some photos of the carb clip to you later, (batteries are charging as I type) but my camera has been poorly, so I'm not going to make any promises!


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## methuselah1 (Jan 7, 2022)

Gedeon Spilett said:


> "Tungsten point discs can be made quite readily by slicing TIG electrodes with a Dremel abrasive disc. "
> 
> good to know that, thanks for the tip...
> i have failed to cut disks in 3 mm tungsten carbide tool bits !
> silver contacts work well with small engine but don't last long.



Tungsten (W) actually machines quite readily. Tungsten carbide (WC) is a different animal. It's a tungsten-carbon alloy. It's produced in powder form, and tool manufacturers add a binding agent and sinter the stuff into the cutters we use. The main problem with tungsten is the cost of the damn stuff, which is why purchased blanks from people like Hemingway can be handy, and car points become favourable!

Andrew UK


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## Richard P (Jan 8, 2022)

methuselah1 said:


> Cams for engines come in two flavours, tangential and harmonic. Tangential cams have straight sides, and a radius on the lobe- the ramp is vicious! I think the first incarnation of the Kiwi used them; they were common in motorbikes of the period.
> Harmonic cams have curved flanks, and the ramp to the lobe is far more gentle. They made the tangential cam near obsolete.
> ETW's method produces a good approximation of a harmonic profile; then he approached D.H.Chaddock for further help refining the design, which the Professor did using his lathe and an improvised spindle and flycutter on his cross slide. The plan is to take a cut, then roll the lathe mandrel a couple of degrees, set the cross slide for the next cut, rinse and repeat. Although I have the same lathe, I do mine in a vertical mill with a rotary table. I put a 1/16" keyway in the cam blank, and a corresponding key on the mounting peg. Using a big tee slot cutter, I can mill both profiles in one setting, or if I only have an endmill, I can flip the blank upside down, because of the keyway.
> This produces a near perfect harmonic profile, with a series of tiny facets, which are carefully removed with a dead smooth file before hardening.
> ...


Thanks for the comprehensive reply, really helpful!  Harmonic cams are clearly the way to go and will use the vertical mill and rotary table option when II get to that stage.


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## methuselah1 (Jan 8, 2022)

Richard P said:


> Thanks for the comprehensive reply, really helpful!  Harmonic cams are clearly the way to go and will use the vertical mill and rotary table option when II get to that stage.



I omitted to mention (as if you hadn't realised) that I key my cams to their shafts on all my engines.

Unfortunately my camera is defunct, so no photos, yet. My Mum wants to visit me next week, and she's got one of those fancy telephones that can take good photos - I'll ask her to help.

I did say that ETW used the same cam profiles in several engines, but when building an A/C Seagull, or one of the others, I had to reduce the cam base circle due to a clearance problem. All hail camcalc! It made that very easy to do. Have you been able to find it?

-Andrew UK


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## H. K. Barrows (Jan 9, 2022)

Hello I make points quite often I use 1/8 Tig electrodes I just slice off 1/16 discs. But more than often I use point sets that where used in a car that was popular in 1950 it"s name was Crosley little Like the Mini. for us colonist Whiteny auto part have them. sets come in two pieces an adjustable threaded point ground. For the points I make, I use .010 tho. feller gages. I engines that I have used for many years. HKB


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## Richard P (Jan 9, 2022)

methuselah1 said:


> I omitted to mention (as if you hadn't realised) that I key my cams to their shafts on all my engines.
> 
> Unfortunately my camera is defunct, so no photos, yet. My Mum wants to visit me next week, and she's got one of those fancy telephones that can take good photos - I'll ask her to help.
> 
> ...


Thanks Andrew!


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## Richard P (Jan 9, 2022)

H. K. Barrows said:


> Hello I make points quite often I use 1/8 Tig electrodes I just slice off 1/16 discs. But more than often I use point sets that where used in a car that was popular in 1950 it"s name was Crosley little Like the Mini. for us colonist Whiteny auto part have them. sets come in two pieces an adjustable threaded point ground. For the points I make, I use .010 tho. feller gages. I engines that I have used for many years. HKB


Thanks for that.  I have ordered a set of points so will see how big they are vs what you mention.  Hopefully they will do.


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## methuselah1 (Jan 9, 2022)

I never thought of using feeler stock! You used to be able to buy it by the roll... How easy is it to shape? The Kiwi ended up getting dyno tested by Prof. Chaddock, and he managed to wring 0.64hp out of his example- at 8000rpm! Do you experience any point bounce?

Although I expect ANY automotive points could be adapted in most cases, (engines like ETW's Seagull must have a custom built breaker 'cos of the design) I mentioned the Ford "A" points because they are one bit, and no larger than the specced item.

Another thing I'd forgotten, is that I've read of people pilfering the tungsten contacts from morse (code) keys. These are handily mounted on threaded tails. There must have been one hell of a glut after the war, as everyone seems to have at least one- even me!


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## Richard P (Jan 9, 2022)

Here is some more progress on the Kiwi.  I've been working on the rockers and other elements of the rocker assembly.  Some sanding and polishing still to do, but overall these components have come out ok.


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## methuselah1 (Jan 11, 2022)

Photos of the float bowl clip, courtesy of mater. Unfortunately, she couldn't quite grasp what I wanted, so whilst they're not as good as I hoped, you should be able to get the idea.

Send me an address to [email protected] and I'll forward them. I can never work out how to upload photos, so if you could do that on my behalf, that'd be great.

-Andrew UK


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## Richard P (Jan 12, 2022)

Thanks Andrew! As requested I've uploaded the photos that show the spring steel clip you made for your Kiwi.

Many thanks

Richard


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## Richard P (Jan 16, 2022)

Spent some challenging hours this week working n my first ever camshaft for the Kiwi.  First struggled to get the Camcalc software to work but was ably assisted by other forum members - thanks!  And then suffered a serious run out problem which I tracked back (eventually) to the baseplate supplied with a cheap import rotary table chuck being way out of square.  I resorted to mounting a collet block holder on the rotary table and got a pretty decent result in the














 end.


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## methuselah1 (Jan 16, 2022)

Well done!!! Very satisfying, isn't it! 

Did you get it right in one go?

Andrew UK


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## Richard P (Jan 17, 2022)

methuselah1 said:


> Well done!!! Very satisfying, isn't it!
> 
> Did you get it right in one go?
> 
> Andrew UK


Yes, very satisfying.  As I mentioned, there was a huge runout error in the baseplate of the chuck I first used, but luckily it resulted in undercutting one side of the cam.  So when I swapped to the collet fixture instead I was able to save the part by recutting it and removing the excess material.  So two goes so to speak, but just the one part!


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## Richard P (Jan 21, 2022)

Been working on the crankshaft this week, but have now pretty much got there.  Just the oil passagway holes to seal.  First time making a crankshaft from solid so fairly nerve wracking as more more and more invested hours are at risk of a c*ck up!  Pleased with final result which spins nicely in the bolted together crankcase.


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## Richard P (Jan 21, 2022)

The bronze balance weights and custom bolts complete the crankshaft assembly...


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## Richard P (Feb 1, 2022)

I've been working on the piston for my Kiwi Mk 2. It is the first time I have machined a piston for an IC engine and had to hit the finer  tolerances required.  Took it slowly and it seems to have come out ok.  Piston rings seat nicely after a little bit of additional fettling.


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## Eccentric (Feb 2, 2022)

Great looking piston.  I can read the word "balanced" in the finish of the piston in the last pic.  Nice lathe work.


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## Richard P (Feb 3, 2022)

Eccentric said:


> Great looking piston.  I can read the word "balanced" in the finish of the piston in the last pic.  Nice lathe work.


Thanks! Yes, pleased with how it came out for a first attempt.  Not quite so shiny now but it’s been going up and down test fitting it in the cylinder for a bit!


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## Richard P (Feb 4, 2022)

This week I have been working on some of the 'shiny bits' namely the oil reservoir and breather assemblies.  Relatively straight forward turning and threading jobs, but quite a lot of them!  I adjusted the design of the oiler so that it mounts directly on to the engine bearer.  Hopefully engine vibration wont be a significant issue.

I think because some of the dimensions are not that critical, I got a bit casual, and so made a few errors along the way.  A few times I got to experience one of my least favourite aspects of machining.... remaking the same part multiple time over!


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## methuselah1 (Feb 4, 2022)

Nice work! Nice to see curves, too... When I make these sort of items (on my engine, the float bowl cap, and the oil and fuel adjustment screws) I always dish the faces with a radius form tool- like the thumbwheels on old microscopes! The "fart valve" cover was too small for that, so I domed it instead...


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## Richard P (Feb 6, 2022)

methuselah1 said:


> Nice work! Nice to see curves, too... When I make these sort of items (on my engine, the float bowl cap, and the oil and fuel adjustment screws) I always dish the faces with a radius form tool- like the thumbwheels on old microscopes! The "fart valve" cover was too small for that, so I domed it instead...


Thanks!  I agree that the little details are worth the effort.  I like the idea of some extra dishing and doming, so will bear that in mind as I proceed further.


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## methuselah1 (Feb 6, 2022)

It appeals to me, though I suspect I might be a frustrated steampunk...


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## Richard P (Feb 8, 2022)

I've been working on the Con Road. The central linking part of the casting was a bit crooked relative to the bearing surfaces and so the sides have come out a little bit wonky! Overall though, after a bit of fettling, it's a very smooth running fit on the crankshaft big end bearing














.


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## Richard P (Feb 11, 2022)

I thought I'd have a change from all the fiddly bits, so have been working on the flywheel. Nice to have a bigger chunk of the engine complete!  I have also made the tapered collet but have not shown that here as yet.


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## Mike Ginn (Feb 15, 2022)

Richard P said:


> And here are the valves, guides, collars and collets.  I had a bit of bronze spare so upgraded the collars from MS for a bit of bling.  First attempt at machining valves, so pretty happy with how they have come out.  And they seem pretty air tight in their seatings even before any grinding, so all quite positive.
> View attachment 132590
> View attachment 132591
> 
> ...


Hi Richard
I am about to start the Kiwi build and have a new set of drawings from Hemmingway although the castings and now rather faded drawings were purchased about 20 years ago (don't ask!)
Have you found any drawing errors or dimension errors?
Thanks in advance
Mike - Chelmsford based


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## methuselah1 (Feb 16, 2022)

I didn't consider the cylinder casting useable, as it was undersized. I think Richard found the same thing. So knowing the Kiwi has a reputation for running hot, I made a fresh cylinder muff from HE15, and had it anodised black before skimming the o/d to finished dimensions, to give cosmetic contrast.

Further down the line, after making the rockers (which I put off as long as possible!) I found the exhaust pushrod could foul against the cylinder- I had heard of other builders who had found this.

I simply did a bit of careful clearancing work on the uppermost three fins, with a ball nosed mill to alleviate the problem; it'll be interesting to see if Richard finds the same is necessary on his engine.

The cams, as shown in the drawings, are a good approximation, but not the ultimate solution. I'm sure Richard will share his spread sheet for making better ones.

the points specified are (now) pretty obscure, but I paid a pretty penny and obtained some. There was no way they were going to fit on the casting! Options have been discussed here for alternatives, or you could pinch the simple design used on the Whippet engine, which can be found online. The supplied casting was very brittle and delicate, so I'd suggest milling one from bar stock, instead of trying to use it, to save frustration. I broke two castings.

Andrew UK


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## Mike Ginn (Feb 16, 2022)

Thanks Andrew - I'll mark up the drawings to check when I get to those parts.  I've just finished a Wyvern and now have the time to start planning the Kiwi build, noting the capacity of my available machines .  (Myford S7 with dro, Warco mill with dro, small cnc mill etc).  I guess I will follow the build order of ETW so it's front casting time!
Mike


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## methuselah1 (Feb 16, 2022)

Mike, you've just reminded me! I drilled the 3 and 9 o'clock stud holes and reamed them to accept 5/32" hardened dowels; that way I could firstly split the case halves as many times as I wanted, secondly ( and more importantly) I could put parallels beneath them and wobble off 'em as a reference for getting the top face the right height (and square), and get the cylinder studs in the right place...

My dowels are still in, I might leave them in; but I tapped M4 beneath the reamed holes so I could still fit "false" studs eventually.

Andrew UK


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## Mike Ginn (Feb 16, 2022)

Andrew
Thanks for continuing to think of the issues.  I always find that asking how others did the machining is of great help.  There are a few YouTubers I follow and you can often pick up hints which all go into the pot - actually into a folder on the computer.
The studs seem like a great idea
Thank you
Mike


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## Mike Ginn (Feb 17, 2022)

I would welcome the collective view on my proposed approach to the Kiwi crankcase bearings.  The drawings call for an interference fits for the plain bearing and the ball race.  I really dislike this approach in small brittle Al castings of unknown quality.  I am proposing to do the following:-
Machine the bearing bores in both crankcase halves to a reasonable sliding fit plus 0.002(ish).  I would then Loctite (bearing loc) the plain bearings  with a drill rod in place and the halves bolted/dowelled together.  I would then Loctite the ball races in place in a similar fashion but at a latter date to avoid swarf getting into the races.  The Loctite would need to be correctly applied and my usual practice is to grove the bore or bush.
I think this would be an easier and less risky approach with a fragile casting.  What are your thoughts.

Would ETW have used Loctite?.  Interesting question - but it wasn't available when the design was published for the second time in 1960

Thanks for your comment in advance
Mike


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## methuselah1 (Feb 17, 2022)

Hello again! I went for a light press fit; I can't remember if I cooked the castings in the oven before fitting the races or not...

Either way, there is so much support from the front face, you'd need to be completely ham-fisted to split the casting. Half a thou shy of 7/8" should be ample. DROs or not, using a lathe made in 1941 meant that boring to this accuracy was quite daunting, but I did have very good measuring tools, and a trick up my sleeve...

I set my topslide to 6 degrees. That done, one thou of advance of the topslide progresses the tool one tenth on the X axis; it's an approximation, but not a bad one, so all was well.

On a different note, whenever I build an engine, I buy "proper" drawings which I copy for workshop use; in the case of the Kiwi, I had the magazine articles. I wasn't worried if they got oily (they did!), and I annotated them as I went... Angles, errors, everything- as you progress, tell me the part in question, and I can scan across anything that I made a note about, if you wish.

Andrew UK


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## Mike Ginn (Feb 17, 2022)

Andrew.  Thank you for that kind offer.  I have a set of drawing sheets and I have cut each component out and placed them in plastic pockets - mainly to make the drawings manageable (Original is A1 size).  I like your 6deg trick - hadn't thought of that.  Although I didn't mention it in my earlier posts I have previously found that using a plug gauge (undersize) to assess the bore diameter can be an issue as it can become stuck!  
So I am still thinking of the Loctite approach
My measuring tools are a set of Moor & Wright internal telescopic gauges and digital micrometer.
Thanks
Mike


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## Richard P (Feb 18, 2022)

Mike Ginn said:


> Hi Richard
> I am about to start the Kiwi build and have a new set of drawings from Hemmingway although the castings and now rather faded drawings were purchased about 20 years ago (don't ask!)
> Have you found any drawing errors or dimension errors?
> Thanks in advance
> Mike - Chelmsford based


Hi Mike, 

Good luck with building your Kiwi, I've enjoyed the process so far!  

Judging by Andrew's answers already, he took a much more methodical and annotated approach to his build, so I'm sure he will be able to share many pearls of wisdom as you proceed. I'm sure you have already seen Vince Cutajar's jars post which is a very step-by-step record of his build. I have found that extremely useful and he has carefully chronicled any difficulties that he encountered with each part, including any modifications to measurements.  I followed Westbury's magazine sequence, but often used Vince's approach to each component as they were very well set out and made sense to me.

I confess that I sometimes focus a bit more on speed of progress than the absolute accuracy of every dimension.  I am very careful in nailing the critical dimensions of an individual part, but then am a bit more relaxed at tolerances for some of the less important aspects, or where there is a bit of license to change the design a little for aesthetic effect.

I did find the cylinder jacket casting smaller than spec, but persevered with it, adjusting the dimensions of the fins a little. The supplied cylinder liner cast iron was also under spec but again I worked with it and adjusted the recess in the cylinder head slightly. I haven't yet worked on the ignition timing casting but it is pretty feeble, so will probably make something from bar stock.  And I didn't like the supplied float chamber casting so have made that out of brass which looks quite attractive. I have not yet decided whether to go for a fully functioning float chamber design or convert it into a small fuel tank as Vince did.

Cheers

Richard


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## Richard P (Feb 18, 2022)

This week I've been working on the carburettor, which has a lot of awkward parts. It will be the first time I have made one, so fingers crossed!


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## methuselah1 (Feb 18, 2022)

Nice work, Richard! I fabricated mine- nothing wrong with the casting, but I got to use brass against copper, for "bling"! I also made a brass float bowl, for the same reason... I made my tank from some 1+5/8" copper tubing that started life as the outside waste pipe from my Dad's kitchen sink; (and people wonder why I never throw stuff away?) so by the time I'd made a pair of spun copper end caps, a brass filler, and an outlet and stop valve, it looked OK, and it was fun to make.

What are you going to do for the jet screw needle?

-Andrew


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## methuselah1 (Feb 18, 2022)

Any pearls of wisdom that I can provide may be the result of cracking many oysters full of cock-ups... Which you won't hear so much about... 

At least some of the time, that will be why I made notes in the margins. After sequence planning, there is nothing particularly methodical in the way I go about making stuff!

-Andrew


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## Majormallock (Feb 20, 2022)

A wise person once said" he who has not made scrap has not made anything"

Really nice looking casting. Like Andrew i hewed mine out solid. Put it on a Hoglet.


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## Mike Ginn (Feb 20, 2022)

Thanks Richard and Andrew.  Yes I have seen Vince's excellent build write-up and of course yours Richard.  I also intend to follow ETW's sequence since it seems logical.  I have just started machining the crankcase and noted the warnings about coring errors which are to be expected.  I did a quick measurement and found that it would be very easy to have a "one" sided spigot.  The approach and jig I made is shown in the photo.  I am not aware that this approach has been taken by others but it does seem to work.  Now to machine the bearing recess - I know if it all goes wrong I can fall back to Loctite 603!
Mike


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## Charles Lamont (Feb 20, 2022)

Mike, as you say, that set-up looks very hairy. Could you not have used the faceplate?


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## Mike Ginn (Feb 20, 2022)

Hi Charles
Not sure how the face plate would help.  The initial cut was with the casting secured in a 4 jaw with a center.  The second cut used the 1/4 inch thick disc in the 3 jaw to make a very light cut.  My concern was movement of the disc which could have been Loctited or had paper between the surfaces.  I could have used a thicker disc but 1/4 seemed ok.  I think a faceplate would have needed a lot of setting up and clamps and I wouldn't really know where the spigot would be when the casting was reversed - that was the beauty of the disc!.
It worked and was quick!
Mike


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## Steamchick (Feb 21, 2022)

Hi, I am getting my head around this one. Without thinking too deeply about this...
I would have followed the following process:
Hold acting in a 4 -jaw chuck to create the datum face. Or set-up on the miller and mill it flat. Whatever suits available tooling.
If possible, without changing the set-up, drill and bore/ream the shaft hole from the inside of the casing. That way, the shaft hole is exactly where you want it relative to the casing interior. Also define and ream the dowel holes on the flange for whatever goes on the open casing. The all the datums are defined in a single setting.
To main the OD of the spigot, mount the casting on a mandril, set true in the lathe, using the bore. I think this is essentially what you have done, but why use the disc? A shouldered shaft as a mandril sold have been enough I think?
Any better ideas, I am here to learn!
K2


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## Mike Ginn (Feb 21, 2022)

Steamchick said:


> Hi, I am getting my head around this one. Without thinking too deeply about this...
> I would have followed the following process:
> Hold acting in a 4 -jaw chuck to create the datum face. Or set-up on the miller and mill it flat. Whatever suits available tooling.
> If possible, without changing the set-up, drill and bore/ream the shaft hole from the inside of the casing. That way, the shaft hole is exactly where you want it relative to the casing interior. Also define and ream the dowel holes on the flange for whatever goes on the open casing. The all the datums are defined in a single setting.
> ...


Hi K2.  I think we are saying that there is more than one way to skin a cat!  When I first skimmed the chucking piece and reversed the casting I found that, when machined, the spigot would be very lopsided.  My solution was to define the spigot position without much setup and to then re-skim the chucking piece and carry on machining from there using a collet.  I did flatten the face on a surface plate - not much spare metal.
Mike


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## Richard P (Mar 2, 2022)

It has been a while since I've posted due to various distractions. However I have now been able to get on and finish all the fiddly bits for the carburettor, as well as give it a bit of a polish up.  Quite pleased with how this has come out for a first attempt at a carb from what was quite a rough casting. Hopefully it will work!View attachment 134664


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## Richard P (Mar 2, 2022)

It has been a while since I've posted due to various distractions. However I have now been able to get on and finish all the fiddly bits for the carburettor, as well as give it a bit of a polish up.  Quite pleased with how this has come out for a first attempt from what was quite a rough casting. Hopefully it will work!


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## Steamchick (Mar 2, 2022)

Look good to me!
K2


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## Jojo (Mar 2, 2022)

Very nice work!


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## methuselah1 (Mar 3, 2022)

Nice work, as we've come to expect! Two things (for anyone who hasn't made their needles yet) first is that Dremel sell a polishing wheel, #425, that'll shine up a needle after grinding, just like one out of the wife's sewing box. Second, it's nice to see that you took the trouble to make the spherical o/d to the banjo. Did you use the tube trick?

Andrew UK


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## Richard P (Mar 3, 2022)

methuselah1 said:


> Nice work, as we've come to expect! Two things (for anyone who hasn't made their needles yet) first is that Dremel sell a polishing wheel, #425, that'll shine up a needle after grinding, just like one out of the wife's sewing box. Second, it's nice to see that you took the trouble to make the spherical o/d to the banjo. Did you use the tube trick?
> 
> Andrew UK


Thanks Andrew.  I started with an oversized shiny needle and then used the Dremel to grind the taper.   It was all a bit Heath Robinson on the lathe but seemed to have worked ok.  I wasn't very happy with the strength of the thin knurled wheel, so added another threaded ring that butts up against it to add some strengths.  Seems to work! 

What's 'the tube trick?' If I did use it it would have been by accident!


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## methuselah1 (Mar 3, 2022)

The tube trick is a good one. I first saw it at the 1981 M E Exhibition, then George H Thomas wrote a chapter on it in "The Model Engineer's Workshop Manual". It can be used on steel, but it works best on brass- turn your ball blank to its eventual length, turn the o/d plus a thou or two, and rough to a ball-ish sort of shape. Mark the o/d with a permanent marker. Then take a piece of round steel, not much bigger than the ball you want, face it, drill and ream it to a size smaller than the ball you want, and case harden it.

Euclid- Any section through a sphere is a circle...

Spin the lathe up, and present your new tool to the work with your hands. Roll it around the blank, and the excess material will be shaved off. Roll it around between your fingers as you go. 

***This is a golden opportunity to slip and punch the chuck, so be careful!*** 

When the marker ink is shaved off, you've reached finished size, and a perfect sphere. A quick rub with fine scotchbrite (read- worn out scouring pad) and you're done.

Unbelievably, I can find no reference to this method on the internet; just lots of people selling expensive attachments.

For bigger radii, I use two other methods too- I'll explain them when you need 'em.

-Andrew UK


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## Richard P (Mar 4, 2022)

methuselah1 said:


> The tube trick is a good one. I first saw it at the 1981 M E Exhibition, then George H Thomas wrote a chapter on it in "The Model Engineer's Workshop Manual". It can be used on steel, but it works best on brass- turn your ball blank to its eventual length, turn the o/d plus a thou or two, and rough to a ball-ish sort of shape. Mark the o/d with a permanent marker. Then take a piece of round steel, not much bigger than the ball you want, face it, drill and ream it to a size smaller than the ball you want, and case harden it.
> 
> Euclid- Any section through a sphere is a circle...
> 
> ...


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## Richard P (Mar 4, 2022)

Oh now I get it! When I first read your description I thought you meant holding up a flattish plate with a hole in it which sounded rather scary against a fast running chuck! But I can see how a hardened tube would work.

I actually made mine using the Hemingway 'sensitive' ball turning tool that I made up some time a go.


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## Richard P (Mar 4, 2022)

I have been cracking on with the float chamber for the Kiwi, making it up from brass bar stock as I thought that would look better than the aluminium casting supplied. 

I made the clip from a spare feeler gauge that I tempered first so that I could work with it and then re-hardened after shaping, to give it back its spring. Seems to do the trick!


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## methuselah1 (Mar 4, 2022)

Nice work on the spring- it's a fiddle, isn't it! So are you going for the full float carb, or the mini fuel tank approach?

-Andrew


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## Richard P (Mar 6, 2022)

Hi Andrew,

I have decided to go with the full float chamber approach. I am going to see if I can make the float itself from very thin-walled turned aluminium. It remains to be seen whether I can make something light enough to actually float!


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## Richard P (Mar 17, 2022)

I’ve now made progress on the float assembly, making it out of very thin walled turned aluminium.  It just about floats! But whether there will be enough closing pressure to seal the valve remains to be seen!  If it doesn’t work I can always revert to a cork or bale afloat.  





Your browser is not able to display this video.


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## Richard P (Apr 11, 2022)

Delighted to say that I've pretty much finished the Kiwi Mark II and it is a runner!  The thin-walled aluminium float seems to work well and maintains a steady level of fuel in the float chamber. I went with the ignition points casting that was supplied although I had to fettle it quite a bit to make it work, and  have twinned with a mini mag ignition system.

There are a few photos of the finished engine and a link to a YouTube video that shows it running! I need to fabricate an exhaust and sort out a proper base etc.  but the back is definitely broken on this project!





















Here is the link to the YouTube video of the engine running!


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## vcutajar (Apr 11, 2022)

Congratulations Richard on a nice runner.

Vince


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## Vietti (Apr 11, 2022)

Richard,

Very nice!!  

An idea is to replace the oil drain with a one way check valve, the check valve is hooked up to the oil reservoir via a clear hose.  Viola, you have a circulating oil system, don't forget to vent the top of the reservoir.  Did it on a Wall 30, very similar to the Kiwi.  Also if you ever decide to use a needle valve in your carb, be sure to get one with a Viton tip.

Congrats, a good working, small carb is no easy thing in my experience.


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## Richard P (Apr 13, 2022)

vcutajar said:


> Congratulations Richard on a nice runner.
> 
> Vince


Thanks Vince!

I feel like I've been following in your footsteps!

Time to start thinking about the next project...

Richard


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## Richard P (Apr 13, 2022)

Vietti said:


> Richard,
> 
> Very nice!!
> 
> ...


Thanks!  Interesting idea about the circulating oil system, I might have to try that!

Re your comment on the needle valve, did you mean in the float chamber?  The steel needle adjustment into the actual carb seems to work fine.

Richard


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## Vietti (Apr 13, 2022)

Yes, the needle I was referring to is the fuel needle valve controlled by the float.  I made a carb that needed a needle valve and none of the ones I made or purchased worked until I got one with a Viton tip.  I am assuming you are using the polished ball on a stem for a valve?

The oil system I described does work well and it is rewarding to see the oil moving back to the oil reservoir.  Let me know if you have any questions.

John


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## methuselah1 (Apr 29, 2022)

Do you have any further details (even better, photos) of your recirculating setup, John? Did you make drawings, or was it a scribble pad job?

Andrew UK


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## Richard P (Jun 10, 2022)

I decided to spend some time making a good quality stand for my Kiwi and ended up getting a bit carried away!  The engine is quite tall and so I designed a quite high fuel tank based on some other examples I had seen online.  I also designed and built a compact fuel tap around a couple of small viton o-rings I had spare.  Pleased with how that turned out and it actually works and does not leak!


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## Richard P (Jun 19, 2022)

I found a nice piece of thick off-cut walnut for the base of my Kiwi.  I got it from a local specialist hardwood supplier in West London that supplies materials to bespoke furniture makers.  I was able to mill out some neat enclosures for the Minimag ignition and battery to keep everything neat and tidy, and I turned up a nice thick brass washer to set off the inexpensive toggle switch!  A short rod of polycarbonate allows the Minimag LED to shine through so that I can still set the timing.  Almost finished...


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## Steamchick (Jun 20, 2022)

My brother lined the cabin of his yacht with wood he "rescued" from scrap furniture. It is well seasoned after a lifetime in someone's house, so very stable from further warping with age. And a lot of the wood is fine grained hardwood. (Not like the softer Walnut you are using) - typically, Beech, Mahogany, Oak, Teak, etc. But the Walnut does have that curious, curly, knotty grain beloved of those who veneer it. Should look good!
K2


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## Richard P (Jun 23, 2022)

And here a link to a Youtube clip of my fully finished Kiwi!


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## Mike Ginn (Aug 1, 2022)

Guys
I am struggling!!!
I am trying to machine the Kiwi crank and so far I have failed to find the correct cutter.  The picture shows the tools I have used all of which have an overhang of around 35mm.  The tipped parting tools seem to "wobble" and I fear the carbide insert will spring out.  The parting blade isn't really suited to the task and the tool in the rear tool post chatters badly at all speeds.  I have cut a relief into the center of the cutting edge.  I have tried the tipped parting off blade in the read tool post but it wasn't stable.  I believe the tool height is correctly set.

I am sure it can't be that hard but so far I have failed to find a workable solution.  I don't know the grade of the rolled mild steel but it came from a very reliable supplier some years ago and was used for general machining is a development model shop.  I annealed it before use.  It drills very easily.

Any insights would be appreciated.

Many thanks

Mike


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## Steamchick (Aug 1, 2022)

Hi, I understand the problem. I have been there. 1/2" deep tools cannot cope with more than 1 in projection. So I used a tool blade 30mm deep x 4mm wide , clamped where the tool post would fit. Then I managed a stiff enough tool at 2 in projection to make it work. I'll  try and set up some photos and sketches tomorrow.
K2


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## phred (Aug 1, 2022)

I've not used it but have seen a supporting post mounted under the front end of the cutting tool to stabilize it in the vertical direction.
It might help solve your problem.
Fred.


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## animal12 (Aug 1, 2022)

phred said:


> I've not used it but have seen a supporting post mounted under the front end of the cutting tool to stabilize it in the vertical direction.
> It might help solve your problem.
> Fred.


I've seen some guys use a small machinist jack under the  tool / holder . I wonder if using a big HSS tool might be suitable for a job like this , like a blank that's 1/2" x 1" . May have to make a tool holder but maybe having the mass in the tool will help ?
animal


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## Steamchick (Aug 2, 2022)

Hi Mike, A toolmaker advised me that for a "proper" tool, to make a parallel big end journal, you need a tool ground like this:


Essentially:
It needs to be just less than the half width of the journal,
It is ground with a few thou or so or relief in the middle, 
Corners are ground to make the radius required in the corner of the journal where it meets the web.




In use, a small cut is made, and the tool transited sideways across the full width of the journal and back, which ensures that the tool is cutting only a small side-cut, not a full face-cut. 
This ensures that the most forward cutting point between the side radius and the centre relief forms a point contact at the tool and cuts across the journal to give a line of cut set by the alignment of the lather, not the precision of setting the tool. (if you had used a flat-fronted parting tool).




It generates the required radius in the corner, to relieve the natural fatigue stress raiser in the corner of the journal.
Incidentally, many single replaceable-blade parting tools have a tapered ground top face, which develops side forces and at the actual end where the cut is taking place the cut is "skewed" to the true line at which you want the journal to be cut for a parallel journal. 
Hope this helps?
K2


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## Steamchick (Aug 2, 2022)

Another arrangement of mounting a parting blade for a very rigid mount, is to clamp a parting blade on the back of the cross-slide for "reverse" running:
as per:



Hope this is clear enough?
K2


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## Steamchick (Aug 2, 2022)

But the mounting/large parting blade I used was mounted like this:





I hope the sketch explains how I used a "huge" parting blade on my small lathe? - I removed the 4-way tool post etc. and mounted a suitable parting blade directly on the face where the tool post would mount, so I could get the right height of cutting point. My tool post takes 1/2" tool, but the blade was 30mm (or thereabouts) deep, and with a bit of judicious shimming I managed to fit it...
I had bought the Industrial sized parting blade in the £1 box at my second-hand tool shop - now long since gone, and missed!
K2


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## Mike Ginn (Aug 2, 2022)

Guys - thank you for your thoughts.  Unfortunately I can't use any form of jack since the space between the cheeks is only 1/2inch which is the same as the journal I am trying to cut.

Ken I really like your vertical cutter.  I was proposing to purchase a 7/8 deep parting off tool blade but that would still have "fresh air" under it which would compromise rigidity.  The cutter shown below could be cut to the correct length/shimmed and clamped which would really make for a solid setup.  The forces would be directly down from the cutting edge to the cross slide and then to the carriage all of which is in the correct direction.

All my other cranks have been fabricated but with the oil holes I decided to take the plunge but I have to say I thought this would be easier then it is!

Many thanks

Mike


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## Mike Ginn (Aug 2, 2022)

Ken
I have just made a few measurements and I can't see that there is sufficient space for clamps using the vertical configuration.  There is just under 5/8 clearance between the journal cheeks and the cross slide.  One solution would be to weld 2 pieces of MS to the tool and then tidy up the dimensions in the mill.  The MS pieces probably need to be 90deg rotated from what the photo shows to allow for Tee bolt holes to be close together.

I still like the vertical arrangement but the setup will be tricky.

Mike


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## Steamchick (Aug 2, 2022)

Hi Mike, I got the vertical blade idea from the web, so try a bit of a search to see if you can find it - and details of how it is arranged and clamped. 
I have been browsing, and as an aside, found this "vee-notch" addition to parting tools that really works. I bought a parting tool with blade - that now lives in the back tool post - and the blade has a long Vee in it.
This video shows the "Quick re-grind" you can do to any tool you have...

K2


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## Richard P (Aug 6, 2022)

Mike Ginn said:


> Guys
> I am struggling!!!
> I am trying to machine the Kiwi crank and so far I have failed to find the correct cutter.  The picture shows the tools I have used all of which have an overhang of around 35mm.  The tipped parting tools seem to "wobble" and I fear the carbide insert will spring out.  The parting blade isn't really suited to the task and the tool in the rear tool post chatters badly at all speeds.  I have cut a relief into the center of the cutting edge.  I have tried the tipped parting off blade in the read tool post but it wasn't stable.  I believe the tool height is correctly set.
> 
> ...


Hi Mike, having recently built this engine I've just had a look in the workshop and found the cutter that I used. In the end I went for a pretty sturdy and solid parting blade rather than using an insert cutter.  I shaped the edges to give the stress relieving corner radii and then created the central notch with a diamond hone.  

By working the cutter from side to side with each cut only a small area of the blade is cutting at any point in time time.  I first roughed out the material and then was able to get a very good fine finish cut with this method.


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## Mike Ginn (Aug 7, 2022)

Hi Richard
Thanks for the info and indeed all the other Kiwi photos you have posted.  I did find this crank small end bearing difficult to machine.  I should have removed more material on the mill to reduce the interrupted cut which was my main issue.  I found that I needed to use the rear toolpost to provide rigidity and I ground the 5.5mm wide tool to have 2 spurs about 1mm wide.  Using small cuts and traversing I was able to get to an even cut when the journal was less than 0.5 inch.  I then used a tipped parting tool with an overhang of 35mm to complete the journal.  I very lightly ground the top off the insert to provide a sharp edge (maybe controversial but it worked).  Thanks for the picture of your parting tool.  I tried to get a similar profile but I completely failed to grind the shape using either a Hemmingway grinder or a drimmel.  I also could not get the 2 cutting points to be square with the shank of the tool.

How did you achieve the profile????

I now need to machine the main journals and I will try to mill as much material away as possible before cutting on the lathe.

Thanks for your help

Mike


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## Mike Ginn (Oct 15, 2022)

So you retire – in my case at 75 – and rekindle your interest in model engineering. Maybe resurrecting that model you started 10 years ago. It’s all very relaxing and time slips by!

Then I have to make the crank shaft for the Kiwi. Seems simple but has taken ages with every operation having the potential to wreck the work to date. I normally fabricate the shaft but this time, as per ETW words and music, I started with a bar of unidentified steel. I have finished the shaft and it runs smoothly in the crank case but I have to say that drilling the 2.3mm hole through the shaft to a depth of over 2 inches was stressful to say the lease.  It probably wasn’t helped by the radio discussion about the UK economy - which is a very British disaster!

I used a new Dormer long series drill at the Myford S7’s top speed of around 2000rpm and using the Cowell rack tail stock I was able to quickly retract the drill about every 0.25mm to brush on cutting oil.

I wouldn’t describe it as fun but at least I didn’t break the drill!  I am now letting the headstock bearing cool down while I finish the bottle of wine.

A relaxed Mike


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