Retlas

[Jasonb]

Comming along well.

I've just started on a Debolt Allman and that has a very similar eccentric arrangement

[Chipmaster]

Hi Jason, I haven't seen a Debolt Allman so I'd like to know more about it. Does the model use a commercially produced set of castings?
I think Graham Corry referred to Allman engines some time ago so did Alyn foundry sell castings for Debolt Allman engines at some time?

Andy

[Jasonb]

This is a nice one. The Debolt like all there kits was limited in production and has not been made since 1991 so you need to know the right people to get a set of matured castings Having said that I think it would be quite an easy engine to fabricate

It is similar to one of the Allman engines that Graham did but I'm after getting the IF Allman one from him (hint, hint Graham) which ha sa pair of A frames rather than the tuning fork frame

I'll do a build thread on it after the Jowitt build is written up but here are a couple of pics





J

[Alyn Foundry]

Hi Jason, I haven't seen a Debolt Allman so I'd like to know more about it. Does the model use a commercially produced set of castings?
I think Graham Corry referred to Allman engines some time ago so did Alyn foundry sell castings for Debolt Allman engines at some time?

Andy

Hi Andy.

No, Vincent again! Yet another of his scaled from a picture jobs!! This time American Gasoline engines.

The first A&T he built used sqew gears and a hollow side shaft, being hollow allowed him to use a flyball governor with the control rod running through it. Vincent sold that engine a long time ago, it's never been seen since.

The closest to original was the one I built that had a fully functional hit and miss governor mainly thanks to the patent drawings that the later I F Allman were scaled from.

Sorry for the digression, your halftime gear and eccentrics look great, looking forward to your further progress.

Kind regards, Graham.

[Chipmaster]

Carried out some work on the Retlas Exhaust Valve Chest yesterday afternoon.
Here is the plan of the cast iron component.
208 Retlas Exhaust Valve Chest by Andy, on Flickr

My first task was milling the larger surfaces (port face, top, valve guide, stud locations) so that I could decide and mark out where the various holes would be drilled. The large nut in the next picture was the first thing that came to hand to help clamp the casting in the milling vice.
Building Retlas (403) by Andy, on Flickr
Building Retlas (404) by Andy, on Flickr

I glued the valve chest to the port face of the cylinder for drilling and tapping the two 2ba mounting studs.
Building Retlas 407 by Andy, on Flickr
Building Retlas 408 by Andy, on Flickr
Building Retlas 409 by Andy, on Flickr
Building Retlas 410 by Andy, on Flickr
Building Retlas 411 by Andy, on Flickr

The face where the exhaust outlet is to be formed is at 45 degrees to the back of the valve chest so I bolted it to a piece of gauge plate and set the plate at 45 degrees in my milling machine
Building Retlas 414 by Andy, on Flickr

Milled as much of the surface flat as I could, the casting was slightly malformed in this area so I stopped milling the surface when there was a sufficient area to go in with a 3/8" BSP thread.

Building Retlas 415 by Andy, on Flickr

You might notice how the casting slopes away prematurely just in front of the 19/32" drill in the next photo.

Building Retlas 418 by Andy, on Flickr

Starting off a 3/8" BSP tap.
Building Retlas 419 by Andy, on Flickr

Having a go with a modest sized tap holder...
Building Retlas 420 by Andy, on Flickr

I had to use a much larger tap holder to do the job. Notice the red paint here and there - I had an accident stirring paint with a Dremel a few months ago.
Building Retlas 422 by Andy, on Flickr

Exhaust Valve chest back on the cylinder.
Building Retlas 423 by Andy, on Flickr

Coming soon - drilling the pocket for the valve and the port into the cylinder.

Andy

[Chipmaster]

Did some more work on the exhaust valve chest yesterday. I drilled the valve guide hole from the underside of the casting. Having measured up the casting I knew that I would have to machine the boss around the hole to achieve concentricity.

Building Retlas 424 (2) by Andy, on Flickr

Building Retlas 428 by Andy, on Flickr

Building Retlas 429 by Andy, on Flickr

On to the pillar drill to drill the valve pocket.
Building Retlas 433 by Andy, on Flickr
Building Retlas 438 by Andy, on Flickr

Building Retlas 436 by Andy, on Flickr

I'll bore a passage from the exhaust outlet through to the valve pocket and the port from the cylinder today.

Andy

[Chipmaster]

Worked on the exhaust valve chest this afternoon. The plans show circular a 1/2" diameter exhaust port through the cylinder to meet up with the 5/16" high by 9/16" wide horizontal slot milled in the valve chest. I fancied milling a matching slot in the cylinder which was a bit awkward owing to the depth of the slot and my 5/16 slot drill being too short. Anyway I got there using a long 1/4" slot drill and a file.
Andy

[Jasonb]

Looking good Andy, just quietly following along.

[Chipmaster]

To complete the valve chest casting I made a 45 degree piloted seat cutter, it was 0.6" diameter heat treated silver steel held in my 3/4" chuck...I mistakenly made it an anti clockwise - left handed tool. However, it did the job and probably won't be used again.
Building Retlas 450 by Andy, on Flickr

Valve seat,
Building Retlas 456 by Andy, on Flickr

View of the exhaust outlet showing the 1/4" hole drilled through to the valve pocket.
Building Retlas 455 by Andy, on Flickr
Andy

[Hugh Currin]

Andy:

You mention "Notice the red paint here and there - I had an accident stirring paint with a Dremel a few months ago." Far better than "Notice the red blood here and there - I had an accident stirring paint with a Dremel a few months ago." Sure glad it's the former.

I've made two special single purpose tools in the last couple of weeks. The first, as yours did, came out a left handed tool. And even after that experience the second came out, you guessed it, left handed. I suspect you've learned and I hope I will one of these days.

Very nice work on the engine. Thanks for posting the build.

Hugh

[Chipmaster]

Yes Hugh, it looked like the Texas Chainsaw Massacre, 500 cc of red paint over everything at waist height. It went straight  through my clothes and was very difficult to get off some of my parts ! Initially my appearance gave my wife a laugh but it took a couple of weeks to get rid of the red hue on my midfield area. At 3,500 rpm the centrifugal force bent the 3mm shaft of my home made stirrer then the fun started.

The lesson: stir paint by hand or make sure the Dremel isn't set at its highest speed when you put the stirrer in the paint and turn it on - and put the paint pot in a box or something to contain the paint if it goes wrong.

Andy

[Myrickman]

Late to this picnic...but now staying to watch. Andy, this is a really neat vertical....I like verticals! Being from across the pond, I was unaware of the Gardner vertical or reasonable facsimile. The valve gear is clever. Like the way you bored the cylinder casting on the lathe. Fascinating engine and build. Paul

[Chipmaster]

Hi Paul, yes this engine will be unusual. As you can read in an earlier post there may be a couple of surviving engines that the model is based on but no photographic evidence. Anyway, so far so good making steady progress working on the castings just the inlet valve chest and the piston then I can have a break from machining iron and work with cleaner metals.
Andy

[Jasonb]

This is a photo of the vertical Gardner

[Chipmaster]

I started work on the inlet valve chest by cleaning up the flat surfaces using my milling machine.
211 Retlas Inlet Valve Chest by Andy, on Flickr

Building Retlas (286) by Andy, on Flickr

The two studs holding the inlet valve chest to the cylinder had to be closer together than planned because  the casting tapered inwards towards the back where the mounting studs pass through.  I had to position them carefully to avoid the drill breaking out through the sides of the casting. This is just a cosmetic thing and I'll probably blend the casting in with the cylinder using a die grinder later on or perhaps I can use some sort of metal filler.

Today I got as far as mounting the inlet valve chest on the cylinder.
Building Retlas 472 by Andy, on Flickr


Building Retlas 476 by Andy, on Flickr
Building Retlas 475 by Andy, on Flickr
I should be able to form the valve pockets and ports by using my pillar drill except for milling the connecting port through to the inlet port in the cylinder..
Andy