Nemett Lynx 15 cc 4 Stroke I/C Petrol Engine

[gus]

Excavating the crankcase cavity was a very tedious job with the fear of destroying job with last cuts of the day.
Did not dawn on me to use two fluke end mills. Was using 4-f mills and quill cuts with table hand feed.Cavity cutting took total of 8 hours.The quill feed max out at 10 mm depth. The depth of cavity was hard to gauge.DIY a mini slip gage and adjusted quill
for the cut. Turned out to be OK.
Had to stretch & coax the Sakai,Japan Mill to cut crankcase. Would be great if I still have the BridgePort Mill,Leblonde 12 " Swing Precision Lathe and a big machineshop.Have to adjust and live with mini lathe and mill in a balcony shop.:rant:

 

[Swifty]

You've done very well Gus, all the big parts are nearly done.

Paul.

 

[gus]

You've done very well Gus, all the big parts are nearly done.

Paul.

The crankcase milling was nail biting. One excessive feed,the crankcase gone.
Trying get a crankcase wall finishing as good as yours was just impossible.
Foto shows Cylinder jacket bolted on to crankcase. Outer-Head has yet to drilled/tapped. Am wary of the orientation.Will be next week but I have two days off to do some deep sea fishing.
Bearings bought. Will be working on the bearing housing.

 

[Brian Rupnow]

Looks awesome Gus!!!---Brian

 

[gus]

Looks awesome Gus!!!---Brian

Thanks Brian for the support.

Off fishing this Sunday.Darling Boss wants fish.

 

[gus]

World War 1 MachineShop Technology.

With no DRO and the Rotary Table has yet to be graduated in Degrees. Drilling the bolt holes for the cylinder jacket and outer-head falls back to WW-1 methods---------drill jigs and fixtures. The humble divider to scribe pitch circle and divide holes.
Even my tapping is WW-1 too. Tapmatic Fluid sure helped reduce the friction and gives good shiny thread. About time to DIY an Auto Tapping Machine. Suggestions ,Please.

 

[gus]

Spent entire morning drilling and tapping M2.5,M3,M4,M5 and M6 Holes. All in 22 drilled/tapped holes. Engine supports done but deviated from print. Used 15mm Angle bought from TokyuHands months ago.Crankcase cover done but beefed up to M6 overflow port.
Cylinder Jacket.
See foto. Believed Malcom did same. See shortened Allen Key to fit in.
Decided to use CM6 Spark Plug instead of the humongous Champion Plug.
Outerhead still some details to finish up and from there on to the bearing housing .

Not a very productive morning in terms of number of parts done. But number of parts count is now 7.

 

[Swifty]

Gus, it's coming together nicely, that plug does look better than the other one that you had, the size is more suitable. I have just about finished all my larger parts now, so will be working on the small bits next.

Paul.

 

[gus]

Gus, it's coming together nicely, that plug does look better than the other one that you had, the size is more suitable. I have just about finished all my larger parts now, so will be working on the small bits next.

Paul.

Hi Paul,
Gus had a productive day with nothing for the ''Rag & Bone'' Man. Part count only -----------one.
Took my time to turn the bearing housing and it was 4 hours just the unbored blank. The taper part was done by hand and hence a bit rough but the 1000 grit
Emory Paper did a good job improving the finishing.The Bearing Housing Spigot done with a push fit into crankcase. One bearing went in with push fit.
The front bearing bore will be done tomorrow.Cutting Tools are HSS. No Carbide.
Crankcase now all covered up.
Internal parts will be done from next week. Pretty lot of parts to do and some have unforgiving fits.

 

[doubletop]

Gus

You are going well there. A nice steady productive pace.

Pete

 

[Swifty]

Gus, your doing a great job, you are certainly an inspiration to those with smaller machines and limited work space.

Paul.

 

[gus]

Got out of the rework mess I created for myself. Counter bore for Mini CM6 plug done so socket spanner can be used to tighten/loosen plug.Can now go after the misc. parts.
Intake and exhaust ports done.
Main shaft done except crank disc.M8 thread done with DIY Thread Die. Somehow the modern thread dies give us well form/cut threads. Shaft material was Grade 5 Hex Bolt which can be hard to thread die.Whereas in Trade School,all we got was very bad threads with the dies drawn from tool room. The taps were not any better and tends to break in our trade school projects.Can only guess they were badly worned.
Next week will see more and more parts turned out.

 

[Brian Rupnow]

Gus--that is looking really good.---Brian

 

[Swifty]

Gus, I counter bored my cylinder head today to suit the 1/4x32 plug that I bought, although I think that your 10mm thread plug may be a better size. I can always change later on.

Paul.

 

[gus]

Gus, I counter bored my cylinder head today to suit the 1/4x32 plug that I bought, although I think that your 10mm thread plug may be a better size. I can always change later on.

Paul.

Hi Paul.

Please be cautious. Malcom's dimensions etc are very tight and not much room to mess with. Felt like kicking myself for getting out of line.That's my nature-----going against convention. For a while I thought the Outer-Head would be a goner.:wall:Used a modified fly-cutter to counter-bore.Had earlier skimmed down 14 mm socket spanner to fit. But later found a Taiwanese Spark Plug Spanner that I could not resist. We can compare engine performance i.e. 1/4'' v/s 10 mm. Very much relieved the O/Head
was not ruined.In fact from ugly darkling to ''Swan''

Looking for tools nowadays is so convenient with the ToolMaker's Chest and Tool Cabinet.
No longer hunting high and low.

 

[GailInNM]

Looking really nice Gus.
Gail in NM

 

[Swifty]

Gus, I think that your engine making ability is coming along great, when you are able to recover from mistakes, change the plans to suit yourself etc, it shows that you are more confident in what you are doing and your abilities are increasing.

Paul.

 

[gus]

Gus, I think that your engine making ability is coming along great, when you are able to recover from mistakes, change the plans to suit yourself etc, it shows that you are more confident in what you are doing and your abilities are increasing.

Paul.

Thanks , Paul.

I tend to misread plans. The Cylinder jackets fins ended up as 5 mm deep/high but should be 2 1/2mm. The bearing housing ended with 7 holes instead of 8.How did I miscount. Hopefully Gus will improve with the next engine with zero goofs.The next engine would be the Jaguar but I prefer the Australian Model Engineering Magazine Jan/Feb 2013 version with fabricated crankcase. This will be in 2015. Two engines per year ,I get burnt-out.
Next week will be exciting. No distractions other than the R.C. Church repairs
with breakers going on and on. By mid June it will reopen for Sunday Mass.
Meanwhile mass is said in the canteen which I dread.

 

[gus]

CrankDisc done but some mishap happened. The return scroll spring for the quill broke after 10 years of faithful service.:wall:
Sure hate to give to the ''Rag n Bone Man'' who is sure to tear it pieces.Nobody would want to buy a broken down drill press. Did a ''Bush Engineering'' repair. Looks like Gus just won't dump the drill press after all. A bit of improvement will make m/c look great and unusual.th_wav

The parting off 50 mm CrankDisc was nail biting,took my time with plenty of Tapmatic dobs and tool withdrawal to clear chips.
Cutting the profile with the Bandsaw was labour savings. Cut on next close the marked lines and clean up with some filing.
Will do crankpin tomorrow.

 

[gus]

The Cam-Box looked very simple make but to my surprise ,I spent entire morning from 8-----12 noon plus another 2 more hours
to drill&tap and mount on outer-head. Must put table stops so as to avoid overshot cuts. Had to rework and skim with 6 mm roughing mill to trim to satisfaction.
There is a mountain high of mini parts to machine. Other than rant/dread,I might as well enjoy doing every part and make them good looking.