Kiwi Mk2 Engine

[vcutajar]

Some good news. Yesterday I sent Hemingways an email on a different email address and today Kirk responded saying that the gear has been dispatched today.

This encouraged my do do something with the gears that I have. I decided to increase the hole in each gear to the required diameter, namely 6mm for the 40T gear and 8mm for the 20T gear. To do this I held the gears in the milling vice between soft jaws (to protect the teeth) on a couple of parallels. I made an arbor for the gears which fits tightly in the original hole so that I can locate it under the drill chuck. Drilled the hole on 0.5mm increments and reamed it.

Made a trial fit of the gears to see if they mesh correctly and was pleased that they actually do and turn smoothly. The 20T gear is the one which is undersize in thickness. Maybe next time I will machine the 40T gear.

 

[vcutajar]

Today I did two things.

I milled the tappet guide reducing the height by about 1.5mm. 1mm would have been enough but just to make sure I went down to 1.5mm.

The other thing I did was break the Z axis locking handle on my X3 . The handle is slipping on the splines of the stud (photo 1). At first I thought I could use one of the handles for the X or Y axis but they are different. So I made a temporary repair by removing the stud and handle and replaced it with an 8mm allen head bolt (photo 2). Phoned the guy from where I bought my mill and asked him to order two handles. He said it should not take to long to get them, but as a last resort I think Arc Eurotrade has them also.

 

[vcutajar]

Today I received the pinion gear from Hemingways and started work on both gears.

Started with the spur brass gear and used the 6mm expanding mandrel to machine it to size. Used a profile tool for some bling.

 

[vcutajar]

I then worked on the pinion steel gear and used the 8mm expanding mandrel I had previously made to machine it to size.

The timing gears are now finished. The pinion gear will be pinned to the crankshaft at a later stage and the spur gear and also the cams will need to be broached for a keyway when I manage to get my hands on a 2mm keyway broach. There is an outlet in the UK that is selling a metric keyway broach set but it has been out of stock for a while and I am keeping my eye on it.

 

[ronkh]

Hi vc,

Have watched this from the word go and it is very nice and informative.
I might of asked this of you in an earlier post (but I can't remember)!, so I will ask just in case I didn't. Is it easy to obtain material in Malta or do you have to source from abroad? How do you obtain your metal/steel/brass etc? Naval base maybe?

Kind regards,

Ron.

 

[vcutajar]

Hi Ron

Thanks for checking in the Kiwi build diary.

I tend to find most raw materials locally but not everything. For example, steel, we get bright mild steel and structural steel (what they use in the building industry). I do not ask which type because nobody knows. Aluminium only one type. We find stainless 303,304 and 316, some cast iron, phosphor bronze and aluminium bronze, copper and brass (but not gun metal). If I happen not to find a particular metal that I need I generally replace it with something else.

The only time I needed to source something from abroad is during this build when I needed a piece of tufnol sheet and I could not find a suitable replacement for it.

 

[vcutajar]

Thought I would start work on the connecting rod but spent all the time in the garage sitting and staring at the conrod bronze casting trying to figure out from where to start and how to start. I had a look also at rhitee93's PM Research No.1 build log to give me some inspiration. Brian did the conrod from a casting but his casting looked much better than mine. I also read that some people ditch the conrod casting and do it from bar stock because it's easier. Suspect that tomorrow is going to be another sitting down session as I still have not figured out anything.

 

[vcutajar]

I think I have a plan. Not sure if it works out but it's the best I could think of. There are no flat surfaces and nothing is parallel on this casting so I need a flat surface to use as a reference.

Started out by roughly marking out the centre line of the beam of the conrod. Clamped the conrod on the mill table and shimmed the beam with feeler gauges to bring the centreline as much as possible to be parallel with the mill table (Photo 1 & 2).

I then slowly milled the big end and the small end to have a flat surface as a reference (the big end was about 1mm higher then the small end) (Photo 3).

With the conrod having two flat and parallel surfaces, I put it on the granite plate and marked out a centreline around the conrod. From this centreline I marked the big end and the small end for 0.5" width. Also marked the conrod beam for the correct width (Photo 4).

 

[vcutajar]

Today I milled the beam, big end and small end of the conrod.

 

[vcutajar]

Well today spent nearly half a day in the shop to drill and tap two 3mm holes in the conrod. :-[

80% of the time to setup and 20% to mill, drill and tap.

Used an angle plate on the granite plate. With a toolmaker clamp held the conrod lightly to the angle plate and nudged it vertical using an engineer's square (photo 1). I then used a clamp on the small end (photo 2). Checked again it was still vertical and used another clamp to the big end (photo 3).

I then transferred the setup to the mill table and squared it up. I had previously marked the position of the holes on the conrod. Using the needle point of the wiggler I put the spindle over both holes and wrote down the X and Y readings for each hole. Using a 6mm slot drill I milled both flats where the bolts will rest. Then using the previously recorded coordinates I drilled and tapped for 3mm (photo 4).

Next operation is to saw the big end but I am still not certain how I should do this and keep both ends aligned. Hope I have not missed a step.

 

[BBQHOG]

Great work. I'm new here and have been following along. Reintroducing myself to machining with a new(1939)lathe and a new Grizzly mill. And no the "head timekeeper" doesn't understand why I have to keep ordering this and that and I tell her it's because I saw you guys using it and therefore to further my knowledge of model machining I must have the tools to do it with.(thanks). Your statement 80% setup and 20% machine time reminds me that the first shop teacher told me , spend 80% on setup, 15% on clean up, and in the other 5% you can run the machine and smoke and have a cup of Joe. I'm gonna be watching this one. And again great work

 

[ProdEng]

Interesting setup on the conrod, look forward to seeing the next steps.

Jan

 

[vcutajar]

Hi BBQHOG and Jan. Thanks for checking in.

We all learn from each others ups and downs on this forum. I might have overdone it with the clamps on the conrod but wanted to make sure the thing did not move :big:.

Vince

 

[vcutajar]

Yesterday I setup the conrod in the vice sandwiched between two sets of parallels. The parallels were holding the conrod between the small and big end (photo 1).

Today decided that the setup was good enough but just to make sure that this sucker does not move I applied a toolmakers clamp on each side of the parallels (photo 2).

I did the cut with a 1.5mm slitting saw at 300 rpm and a depth of cut of 0.2mm. I was not taking any chances. Eventually (after 64 passes) I finished the cut. Photo 4 showing the two cut pieces before cleanup.

 

[arnoldb]

There you go Vince.

You certainly erred on the side of caution there

When you're out and about, collect people's business cards (or any other thin cardstock for that matter; the business cards are always free ). The stiff cardboard ones are great for helping to reliably hold parts where it's not easy to get good purchase on or that are shaped a bit irregularly, and prevents the vise from marring a surface as well.

IMHO, if you had clamped the conrod with paper adding the extra friction, you could have easily slit the end off in a single pass or two.

Kind regards, Arnold.

 

[vcutajar]

Thanks Arnold for the tip. I actually used it when I set it up on the angle plate to drill the two holes. For some reason I forgot to use the same trick to do the cut.

Yes I admit I went overboard again in the clamping of the conrod :big: but I was still having Simon's photos at the back of my mind.

Vince

 

[vcutajar]

Some more progress with the conrod. Drilled 3mm clearance holes in the big end cap. Cleaned both mating surfaces of the big end and bolted them together (photo 1).

I then clamped the conrod to the mill table and drilled and reamed 10mm the big end (photo 2) and 6mm the small end (photo 3).

Now I need to skim the faces of the big end and small end and clean up the beam of the conrod. Maybe tomorrow.

 

[arnoldb]

Coming along well Vince Thm:

:big: I wasn't referring to the clamping - it's always better to clamp down a bit more. It's the 64 passes that got me - I'd bet you had a sore crank-arm after that!

Kind regards, Arnold

 

[vcutajar]

I was using my temperamental mill table power feed.

Vince

 

[vcutajar]

Hand fitted the conrod to the crank. Took a bit of elbow grease but got it where I wanted it (photo 1). After I finish the rest of the work on the conrod I will give it a final hand fitting session.

I also put the cranksaft with the conrod in both halves of the crankcase to see if there is any interference. Found that it touches slightly with the front crankcase (photo 2). To tell the truth, I did not do any machining on the inner walls of the crankcase. A slight touch with the Dremel should fix it.