'Poppin' Flame Licker

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madjackghengis:
Hi Nick, by the by, most of my small screws are salvage from old tape decks, CD players, hard drives and other parts from computers, and they are metric, mostly, but I get some salvage which is American thread on occasion. I do buy when I have to, and usually by the box, as it's far cheaper that way, and there's always another small project. With regard to your drills, I tend to use the mill brake, and stop the spindle to pull out tiny drilled holes, and avoid that odd thread look, but generally only with holes I need dead on size and don't have a reamer for. I try to use either fillister head screws or allen screws as much as possible, as they put the pressure as straight down as possible, with counter sunk heads finding center off the counter sink, and occasionally the head will pull the piece it is in, off kilter because the counter sink is put in separate from the hole, and can pull to the side if allowed.
It's good to see this set of engines coming together, I hope you've got a good bore and good pistons, so they start up fairly easily, and run well. It seems that is the primary issue with the "poppin", as the valve gear seems pretty clear from interfering with the running, unlike the Blazer and some others. It really seems to be very effective and I need to build one sooner or later. Too many around to avoid that responsibility it seems. Nice pictures of the frame, hope to see some of the boring for the cylinder soon. :poke: mad jack

NickG:
Cheers Madjack. I do have a set of metric taps and dies now so I can keep my options more open in future rather than stick down the ba route. I wasn't concerned about the rough finish on that particular hole as it will help grip the bearings. Might need a couple of marks putting in anyway to aid grip but will take yours and arnolds advice in future. I did notice it still taking material off the top hole as i was cutting / withdrawing from the bottom one so the top is probably marginally larger. I didn't have a 5/16 or 8mm reamer though.

Good point about counter sunk screws, I was only going to use those as I found a couple but I forgot to countersink anyway so i'll be better off with hex heads. I think they look more authentic on these old type engines.

I used lessons learnt on my Ridders flame licker and reamed the bores with plenty of oil at a slow speed so I'm fairly confident the bore is good enough. On that I just turned the piston and left it straight from the lathe (it gives a very good finish on a slow speed and feed for cast iron) to retain parallelism. Microscopic grooves are probably good at retaining oil too. However, I might try graphite pistons with the stuff that Ade kindly donated for my tiny stirling. I know somebody on HMEM used a graphite one to good effect.

Ha, that's what I thought - I had just finished my Ridders flame licker and thought those would be out of my system, but I was intrigued too much to attempt this more conventional type to compare the performance of the two!

I know I've just restarted this thread so it may have been forgotten where I was up to - check back at older posts for cylinders and other bits, I'd nearly forgotten myself!

Nick

NickG:
Been quite a long night and still a bit to go as this will take a while to write up!

Continuing with the frame for poppin..

First job was to saw the job from the parent stock.

10 minutes with the hacksaw - I did such a good job I thought I'd just touch it up with a file instead of milling.

Just checking you're awake... I thought I'd try to get it a bit flatter than that so put it in the milling machine and decided to flycut it rather than take loads of passes with a small cutter. Luckily the flycutter was still set up from when I skimmed the block originally.

Then it came back out to get marked up for all the holes. (large one for conrod to pass through, cylinder bolting holes and hole for valve rod) I decided that as the width of the standard was 1" and the cyl. cover 1" it was fairly easy for me to just position the cover and mark the holes through.

Spotting the holes.

Then starting to open the large one up:

Drills getting bigger and scarier!

I decided to finish with the closes thing I had to 11/16", a 5/8" slot drill.

This worked really well and gave a good finish.

I was going to stop there as I would guess 5/8" would be big enough for the con rod not to foul. But then I thought, no, I better stick to the drawing as couldn't be bothered calculating stuff! So I found an old boring bar:

it happened to already have a tool in it. I just had to grind a bit away from the wrong end so it didn't interfere with me trying to measure it to get 11/16". I got as near as damn it to what would give 11/16", put it in the collet chuck and started boring!

At this point I was pretty scared as it appeared to be wobbling about like a good 'un! No idea why it would do that but I think it was to do with the shape of the tool - it was a sort of v shape but with hindsight I think I should have had a virtually straight leading edge just with some rake angle and a slight clearance. The up shot of this was that it gave a rubbish finish. I think it was partly my haste using the tool that was already there and wanting to stop the operation as I thought I was going to ruin my component.

I quit with this while I was ahead (well, while nothing was broken!) with the hole at this point. I'll need to practice this boring lark on some scrap and might re-visit it if I get good results I think, or at least I'll get it right for the next frame.

Next, another scary operation. Milling the slot through the bearing holes to enable the crank to pass through. I thought I'd try out my new slitting saw arbor and one of the saws I cunningly kept from my horizontal milling machine. The concentricity of the arbor or saw must be cr@p as you could visibly see the run out (about a mm or so!). I decided as it wasn't moving up or down it should still be ok and turned it by hand a few times with it touching the workpiece trying to get it into what I thought was the best position. I made sure I wasn't climb milling and that when I'd wound it all the way through it'd cut the slot in one pass.

As I neared the workpiece the tinging noise nearly made me have kittens, I thought it was just going to bend the uprights but I thought with a decent speed (about 400 rpm?) and a slow feed it should be ok. I nearly made a massive booboo though. The slitting saw was 0.1" wide and the slot was to be 0.16". So I started off with the bottom edge 0.080" below the centreline of the bearing holes. Then I'd move it up 0.060 to do the second pass and widen the slot to desired width. If I'd have done that, it would probably have bent the top. Glad I remembered and started at the top first then widened at the bottom where it still had more structural integrity. Sorry, this is getting a bit waffley, anyway, it worked ...

I thought I'd tap the holes next. Another problem here, the 10ba tap is nowhere near long enough to go through the clearance hole and into the portion that should be threaded. It gave me 4 or 5 threads in there max before the shank started to foul - have no clue what to do here. I'll have to read the instructions to see if I've missed a trick.

The last thing to do was to drill the 1/4" hole for the valve rod that meets the cross hole for the valve shaft:

That went well. I cleaned the thing up a little and here is the finished standard or frame:

Actually it's not finished - I forgot to drill any mounting holes in the bottom but was too late to start, don't want to ruin anything due to being too tired!

I really don't want to make another one of these right now. I think I want a change of scenery so to speak so might crack on and make some other parts and come back to the 2nd frame!

Nick

NickG:
Oh, forgot to put this one in, a shot after flycutting:

and I couldn't resist this mock up, this was earlier on before I'd (nearly) finished the frame!

sbwhart:
Looking good Nick, I liked the way you bored the stand to take the cylinder.

Stew

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