Flame Licker lubrication

[Shipdisturber]

Well once again I screwed up on my machining. I was drilling along the side of the cylinder for my valve linkage when the drill bit decided it wanted to veer off centre. So I left the broken drill bit in place and used a milling bit to make a trough beside the broken drill, so far so good. Got the whole works together and once again my sterling machining ability showed binding between the moving parts. There is not a snowballs hope in Hades that this thing will ever run, so under the bench it went. I now have the Jan Ridder plans for a micro sterling engine which I started this weekend I will start a new thread. One good thing about building small engines is it really puts the spot light on ones skills and equipment! This time I will take my time and not save any sketchy parts.

 

[fcheslop]

Good luck on the new build
Im slowly building a scaled down version and pinched a few bits from Jans design and a few bits from the Duclos engines
It was going to be 3/8 bore but the reamer left a few marks so its now 0.4 with a 1inch stroke dam Chinese reamers although I would normally just bore to size no idea why I decided to use a reamer
cheers

 

[Shipdisturber]

Thanks fcheslop. Where do you locate these tiny reamers?

 

[fcheslop]

The last ones I bought came from Tracy tools and have been poor I should have sent them back but got them at a show and didnt have a receipt so in the bin they went
I normally just bore to size or make D bits or tool makers reamers from silver steel (drill rod) and theyve served me well for many years
I have some smaller reamers bought many years ago that still work correctly
I tend to make the smaller toys so 3/8 is reasonably large for me and if I over shoot by a few thou as long as the piston fits the hole the engine will never know the difference
Well thats my guilty secret out of the bag
I sometimes believe people get tied up with tenths of thous when the reality is as long as the parts fit what does it matter when making toys.
I have worked in production environments and do know there is a time and place for such things but for my simple needs I get by by hook or by crook
cheers

 

[Shipdisturber]

Yes I'm thinking clean up the bores with sandpaper on a dowel and drill. I can always machine the piston to the bore. This small toy thing works because material cost is way down that way. I have also been sharpening lathe bits down to tiny sizes for machining little parts. I'll have to get a build thread going for that little engine.

 

[fcheslop]

I think a bit of wood wrapped in sandpaper maybe a recipe for disaster
I make my Stirling engine/flame gulper and IC engine cylinders by boring to size or a few thou under then lap them using a wee bit of wood turned to dia running in the lathe with grinding compound
The lap must always be softer than the cylinder or you will end up embedding the grinding paste into the cylinder walls this in turn knackers the piston very quickly or at least thats my experiance
In times of desperation Iv used a slot drill to machine a cylinder to size and had pretty good results
The humble D bit has a lot going for it despite its simplicity and have made and used them for a long time and rarely had a problem with them
cheers

 

[Shipdisturber]

I think I have some lapping compound I use for seating valves. Thanks for the tip I'll cross that bridge when I come to it. I sharpened some lathe bits to tiny cutting surfaces so I hope they work OK.