CHUK2 - Alyn Foundry Flame Gulper

[Twizseven]

The inlet valve is made from a Stanley knife blade, with the edges ground off.  Ideal opportunity to use the Stent T&C.  The Stent needs quite a lot of TLC, but works quite well as a mini surface grinder.  Excuse the rudimentary wheel guard, its how it was when it came to me.

The little linkage parts for the valve were fun to machine and get the holes in the right places so as to keep free movement.  Then came the bit I was dreading.  My second ever foray into silver soldering.  The first attempt several weeks ago on a job for someone I abandoned and reverted to the oxy-acet rig.

When I did the cam follower end I milled a slot in the small block on the end, so I could push the two parts together to give myself a reasonable chance.  This worked ok.  The tiny link piece on the valve only has a solder area of 2mm x 6mm.  I knew I did not have enough hands, torch, solder, blade and link piece equals four hands, only having two caused a problem.  In the end I found some thin wire and threaded it through the holes and round the blade and twisted the end together,  It still move around a bit so made two more littel loops to go at right angles one either side of the link piece but about 10mm away.  Got it warm, flux melted touched it with solder which rad nicely but the piece moved about 1.5mm out of square.  B....r..    Got it hot again and when solder melted was able to push straight with a scriber.

Made 4mm  link rod with 4BA threads at each end.

Whilst this was going on I was testing the new kiln with the replacement crank web.  Warmed it up to 820 degrees Cent. let it soak for 30 mins and then switch off and allowed to cool for rest of afternoon.

Today I wanted to make the guide bracket for the link rod.  Scribed the shape I required onto a 6mm piece of brass and also scribed the radius of the bearing yoke to which it is to be fitted.  Milled the 4mm slot in it and then filed the bearing yoke radius.  Use the Die Filer for this.  Ended up with a pinched fingers a couple of times, but at least it all comes out square.  Once that was the correct shape, milled the rest to shape and drilled/counterbored for 6BA screws.

Tomorrows task is to try and fit it central and square to the bearing yoke.

Colin

[Twizseven]

Couple more pics.

[Jo]

  That reminds me of something 

Jo

[Twizseven]

Thought it might.  Due to final location of the bearing housing I have had to put a washer between the housing and the cam follower lever.  Luckily I had parted off one of the bosses and have used that.  My guide has come out a little further than yours or so it looks.  I have a feeling that I might end up soldering a small washer to the link rod below the guide bracket and fitting a small spring from a biro or similar to aid in the lowering of the valve.  Just need to remake the crank web now, and possibly the lower link on the rod.  The walls are rather thin.

Trying to line the guide up and drill the holes in the bearing yoke will be entertaining.

Colin

[Twizseven]

Link rod drilled for split pin to support washer and hence spring to aid closing of valve.

Cylinder drilled for support/guide bracket.

Underside of base drilled to fit three small feet (when made).

New crank web appeared out of replacement casting.  Little bit more meat on this one, but still going to shorten the stroke by 1mm to leave a bit more meat on end of web. Piston will still just stick into the valve aperture, by about 0.5mm.
Scrappy drawings to check my dimensions.

Colin

[Alyn Foundry]

Good morning Colin.

If you're concerned about the same thing happening again why not reduce the thread size? There's little force on the crankpin anyway.

Alternatively a drilled and reamed hole with a locknut from behind. This method allows you to run the engine in either direction without the risk of the pin  unscrewing.

Cheers Graham.

[Jo]

I would also suggest you slightly countersink the thread on the crankpin side so that the pin will go flush without having to over tighten it. (The threads nearest the pin will probably not be full depth which accounts for the force you needed last time  )

Jo

[Jasonb]

The alternative is to cut a run out groove at the base of the thread if you want the shoulder to sit nicely against the web. Works for die cut as well as screw cut threads

If not threading the hole you still want to chamfer the edge to ensure any internal radius left by the tip of the tool does not touch first.

[Alyn Foundry]

Jo and Jason.

Wise suggestions, from the seasond practitioners point of view, all done as a matter of course.

Cheers Graham.

[Twizseven]

Thanks, Jo, Jason and Graham.

When I made this one I did put an undercut at end of the thread.  I will see whether I can put little countersink in the crank.

Managed to make some feet for the base and get several coats of paint on the base, cylinder and flywheel.  I knew the cylinder paint was a matt finish, but nowhere on the can did it say the black enamel was a matt finish. Still it is what it is.  Im's sure once its been run (assuming it runs) it will get pretty sooty so maybe not so bad afterall.

Just need to shorten the 4BA fixing bolts for the base, shorten the bearing housing studs slightly, and shorten/find suitable grub screws for the flywheel and cam.

So it may look complete by tomorrow, other than flame generation system.

Colin

[Alyn Foundry]

Hi Colin.

The Matt finish looks good to me.

It's always a good idea to cover the Iron with some form of protection prior to the " oily " stage as it ( the paint ) never seems to stay put afterwards.

Looking forward to seeing it run.

Cheers Graham.

[Twizseven]

Well its a runner - first ever.    Thank you Graham for your assistance in this.

The paint said it needed to be cured, so each part went in kiln for 1hr in case of the matt black and 1.5hrs for the matt red.

[youtube1]https://youtu.be/2r4wGR8y1yc[/youtube1]

Just needs its own flame generation system rather than propane torch.

[Kim]

Very nice, Colin!   It runs great!  Now it's time for the happy dance! 
Kim

[Twizseven]

Thanks Kim,  I'm pleased its my first engine other than a pair of Elmers No.19.

I can start another set of castings now.

Colin

[cnr6400]