Vickie Stirling Engine

[wagnmkr]

Well, you got me interested ...I have printed out the plans and I am studying them ... we'll see.

That front frame looks a bit complicated.

Tom

[b.lindsey]

Jump right in Tom. That front plate isn't as bad as it appears thought there is some rotary table work to it, especially for some of the decorations Jerry added to this design. I am glad to see that Jerry's site now offers plans via download now too.

Bill

[wagnmkr]

Bill, I have a 6" rotary table and a dividing head on it so that should be big enough. I'll check my aluminum to see what is in the bin.

Thanks for the encouragement.

Tom

[b.lindsey]

Tom,
 I was lucky enough to find a short piece of 5/8" thick aluminum from one of the vendors at CF. This was enough to make the three main pieces of the frame with a small scrap left over...$6.00 and no shipping   They have been cut up to rough size now as shown below...though it hardly looks like an engine yet. My RT is only 4" in dia. but I think I can make it work. If not I have access to larger ones.

Bill

[wagnmkr]

I found the required aluminum for all the frame bits. It was covered with dust and cobwebs so it has been there for a while. I will have a go at the front frame and if I can get that done, I will carry on.

It will be a bit before I get a start as I really need to finish cutting several sets of gears. Once that is the mill will be free for a new challenge.

Cheers

Tom

[b.lindsey]

Unfortunately had to work half the day today over at the school, but this afternoon I got the displacer bushing made out of a short piece of bronze as shown in photos 1-4 below. I had also started on grooving the displacer cylinder using the rotary table and a slotting saw on the mill which works out better on these small machines but does take longer. In photo 5 two of the grooves have been cut to depth and a third one started. There will be a total of 9 grooves each to a depth of .400" done in .025" increments so a lot of RT turning. When I get tired of doing that I go back to the lathe and work on some turned parts like the displacer bushing and as shown in the last photo, a start on the rear displacer cap. More on the cylinder and cap tomorrow.

Bill

[b.lindsey]

This morning I finished the rear end cap for the displacer and the displacer rod which actuates it through the bronze bushing shown previously. In the first three pictures, the diameter is turned down to size, a slight relief put in the large end, and the small end chamfered. Though not shown the small end was also drilled .086: as per the plans. Photo 4 shows the cut off operation. Once this was done, the piece was reversed in the chuck, faced to final length and the ID bored and counter-bored to accept the bushing with slight clearance needed for free movement. Photos 5 & 6 show the bushing slipped over the rod and at both ends of its travel. Finally, the last picture shows the whole assembly with the end cap pressed into the displacer piston. Still working on the displacer cylinder fins...more on that later.

Bill

[Dave Otto]

Nice progress Bill,

Do you use any indicators on your lathe? I would like to see a shot of how you are measuring things in the Z axis? I would guess that you are using the hand wheel dial in X?

Also do you leave the compound slide on the lathe most of the time or do you just install it when needed? It seems that rotating the head stock every time you need to cut a chamfer; then having to dial it back in straight would grow tiresome very quickly.

Dave

[b.lindsey]

Dave, I have zero settable handwheels on both lathe axes and just us them generally. Obviously when something needs to be "close" I will stop and measure either the diameter or length. In general, I find that for a machine this size, the handwheels are amazingly accurate.  As for the compound I install it just when needed and you are right, offsetting the headstock every time for that would be a pain!!

Bill

[Don1966]

Bill it seems I missed yesterday's post but caught up. That little sherline sure does some great work for it's size. Well without the operator it wouldn't do anything so nice work buddy. I like the way you cut those fins on the mill with the RT very interesting but a lot of work from what I see. Does it really take longer to do it on the lathe and does it strain it to do it?

Don

[b.lindsey]

Don, on a part this large the main problem is that the tailstock isn't long enough to be able to support the end of the piece which can cause issues. The plans call for the fins to be tapered so I will likely do that on the lathe once the majority of the material has been removed with the slitting saw. It is a slow process though.

Bill

[mklotz]

It is a slow process though.

Have you ever given thought to making a fitting for the RT such that its rotation could be driven by an electric screwdriver?

I keep meaning to do that but never seem to be motivated after doing a job where I could have used it.   The screwdriver seems the right tool; slow speed and plenty of torque.

[Dave Otto]

Dave, I have zero settable handwheels on both lathe axes and just us them generally. Obviously when something needs to be "close" I will stop and measure either the diameter or length. In general, I find that for a machine this size, the handwheels are amazingly accurate.  As for the compound I install it just when needed and you are right, offsetting the headstock every time for that would be a pain!!

Bill

Ah, I had for forgot about the zero settable handwheel also on the Z axis.

Thanks,
Dave

[b.lindsey]

Been thinking about it  more and more Marv But I don't really do it often enough and once done, promptly forget about it again.

Bill

[mklotz]

Been thinking about it  more and more Marv But I don't really do it often enough and once done, promptly forget about it again.

Yeah, that's my problem too.