I was thinking just do it as a separate path and just highlight that single path  and post process the single path. It was just that you have all the setup, model and previous metal removed in teh earlier CAM so it knows what has already been removed, the new file need not include any of that previos 250k

I have to do that all the time as I can't run multiple tools due to using the free version. Separate Post Processing for each tool used.

So far the frame parts for the engines have been coming together very quickly. Here is where it slows down again!  The Marion engine rear bulkhead has a very large radius curvature where it goes round to the bearing blocks. In this picture, the Marion is the one at the lower right. You can see the curved wall just to the right of the crankshaft, its around a 5/8" radius, and overlaps the opening to the crosshead guide tube. So, this one will need to be pieced up rather than just being made from flat sections like the others.

Just spent some time laying things out, and what I think will work is to turn a piece of brass round bar, about 1-1/4" OD (or whatever the actual measurement is, need to check the plans) with a 3/4" or so bore through it. Then I can mill flats down the length to separate it into quarters with flanges to let me screw it to the straight sections. Those 5 parts can then be silver soldered together to form the rear bulkhead, corners, and straight sections down the sides. Will be a little fiddly, but not too bad. On the smaller engines for the Marion 91 I  built, the whole frame was carved from solid blocks of steel (1144 stressproof I think? Have to look that up). This larger version will be pieced up instead. I could always get it 3d printed/cast, but this is more fun!  I also need to round over the corners on the front bulkhead, right now its a rectangular block.

The crosshead is finished using what was provided and Chris's description is very true, it does look like cheese, cottage cheese!

Looks like they cast that one with some old Cheddar cheese!  I'd send them pics and see what they say.

This is a very fiddly little engine (well for me anyway), but I'm enjoying learning about the new bits and pieces even if the materials are somewhat dubious

Congrats Kim, that has got to be a great feeling!

Dave

Last week I found time to put the Mery on the workbench for careful examination and concluded that the exhaust valve timing was out. Perhaps something had slipped, the eccentric is secured with a grub screw and the tappets also needed adjustment despite having locknuts. Now I am confident the exhaust valves are performing on time. The inlet valves are atmospheric so they suit themselves. That left ignition timing, I needed to revise and improve the contacts which had been adjusting themselves and probably performed erratically.

I couldn’t resist trying to start the engine again and surprise surprise it started after a few tugs on the flywheel and kept running. As there was no cooling it was limited to short runs.
 
The gas supply was still direct from the regulator on the propane cylinder to the needle valve in the engine’s mixer. Using a small Monument manometer I found that I could lower the variable regulator’s outlet pressure down to two inches water column but the slightest movement caused large variations in pressure. Over the last few days the engine has been perfectly reliable, easy to start and with an improvised cooling system has run for up to five minutes. The needle valve and throttle in the engine’s mixer are also sensitive.

IMG_2974 by Andy, on Flickr

I have limited the duration of runs because I’m not confident how long a dose of oil in the cylinder’s lubricator will be sufficient.

An over oiled engine and you can see the result in this video on my Flickr channel.
Mery with a cooling system by Andy, on Flickr

IMG_3043 by Andy, on Flickr
IMG_3044 by Andy, on Flickr

I’m not keen having a constant flow of gas and having to use a gas cylinder that’s heavier than the engine. So I will check and clean the demand valve and try using it again. Ultimately I want to use a C500 size disposable cartridge supplying gas to the engine, the same as my other gas powered engines.

Thanks for your input MJM460 I hope to acheive positive results with the gas supply over the next fortnight.

Here’s a YouTube video of the engine running at a fairly steady pace this afternoon.

<a href="https://www.youtube.com/watch?v=5LAjhHZmA_w" target="_blank">http://www.youtube.com/watch?v=5LAjhHZmA_w</a>

Andy