Author Topic: Jan Ridder's Glass-Cylinder Flame Eater Mk2  (Read 2694 times)

Offline bent

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #15 on: August 09, 2017, 10:09:32 PM »
Thomas,

I've seen that done, and know it can work, but have shied away from the hot snap or cold snap methods.  One problem is that I really want to make a clean partial cut or slot on one end of the tube to make the flame port, where a graphite valve plug will slide over the i.d. edge.  Obviously I can't do that with the snap-off methods.

Plani, thanks, we'll see if I can keep a steady hand tonight.

Online b.lindsey

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #16 on: August 10, 2017, 12:38:27 AM »
Lots of YouTube videos make it look easy. I never found it to be that way, more of an art for those that have mastered it. I resort to the cut and polish method using the dremel also, but it's slow going. Following along though to see if I can learn something bent. Good luck tonight!!

Bill

Offline gerritv

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #17 on: August 10, 2017, 02:38:12 AM »
When I cut the cylinders for my Ridder Glass (not flame eater) engine I had the glass tube in a vee made of 1" angle iron. The problem that  I saw with the Dremel is that the bearings suck, esp. end float. Along with the diamond wheel having a hole too large for the mandrel there is too much movement (aka chatter) for a controlled cut to the extent that you are looking for.

A Foredom (a real one, not the clones disappointed with my Grobet) hand-piece and flex shaft might be better quality.

Gerrit
Programming is like a Hit-n-Miss engine

Offline bent

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #18 on: August 11, 2017, 02:31:26 AM »
I know what you mean about dremel runout, Gerrit.  I did my best to get a good, smooth piece of polycarbonate for my "v-block", and that helps a bit, and I'm using my little-used home Dremel (the shop Dremel at work is looser than...well, ahem).  All in all, it cuts pretty smoothly, at least compared to the tile saw.

But, with a bit of anti-climax, the cuts last night (and finishing with the valve slot today) went...err, pretty smoothly, pun intended.  ;)

My technique for the crosscuts was to use slow advances 1-2 thou per step, and then slowly rotate the tube several times (in the direction that creates a "climb milling" cut, ie the saw edge is pulling chips from the cutting edge down into the cut).  Iterate that about a dozen times or so, until you can see you are within a kerf-width or less left to go - then advance the saw slowly (.001" or so per several secons) and without rotating the tube, until you can see the saw has penetrated the wall.  Now slowly rotate the tube in the reverse direction, i.e. "climb miling" the i.d. surface.  You still get a few chips, but they are pretty darn tiny and few.

The valve slot, well, I just went for it, and got a first slot cut (a kerf-width, maybe 1 mm or so wide).  Then tried slowly moving the tube axially to grind the slot out to the 3.5mm width shown on Jan's prints, but that wasn't working very well.  So, instead I just made several cuts stacked axially until I had the gap needed.  The ends of the slot are thus a little ragged, but I figure I'm going to sand these down a bit with some wet-dry paper to take off any really sharp corners next to the piston, and polish/buff any big chips. 




Offline Ian S C

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #19 on: August 11, 2017, 03:20:05 AM »
On one site (maybe The Stirling Engine Forum),someone built a simple dam, a woodenond cut off saw, using a Dremel disc, and a motor that they had on hand, a wooden V block with a simple stop to adjust the length.
I'v not done it myself, but the way the end of a cut tube is finished is by "flame polishing", a flame is passed over the end and the surface is melted. Polishing with abrasives maybe another method.
Ian S C

Offline Steamer5

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #20 on: August 11, 2017, 11:35:52 AM »
Hi Bent,
 I've done the flame polishing in the past, works a treat. Just need to "heat" the tube with the flame, so you don't thermal shock it, then heat the cut ends, depending on the glass how much, you then heat until it glows orange, take care as you can take it to far....oh when the glow goes the glass is still very hot!

Cheers Kerrin
Get excited and make something!

Offline bent

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #21 on: August 14, 2017, 06:09:43 PM »
Whittled out the graphite piston and valve this last Sunday afternoon.  The graphite used was a 1-foot length of 1" diameter "conductive graphite rod", purchased from McMaster-Carr; this stuff has a reasonably fine grain (.0004" nominal) without being ridiculously expensive. 

First photo below is the bar being whittled down to size (photo #1), it took me a couple of tries to get it "just so", snug fitting to the cylinder bore (which I spent an hour or two sanding the cut edges of the night before - photo #2).

Once sized, it was pretty quick work to drill for a #6 tap (photo #3), and then cut the counterbore with my smallest boring bar (photo #4).  Both parts finished and parted off (photo #5) and slipped them back in the cylinder (photo #6) - still a tight fit, will hand lap to get them to a more slippery condition.  But the parts are pretty airtight, from finger testing.

Then spent about 20 minutes sweeping up most of the graphite dust.  There is still a nice slippery coating all over the workbench.  Next time I machine graphite (I'm thinking of using it instead of bronze for the valve rod guides) I'll put down some newspaper to hopefully collect all the dust for use as dry lubricant around the house/shop.  Ah well, hindsight...

Offline bent

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #22 on: September 06, 2017, 05:42:48 AM »
Back home from visiting my in-laws in Virginia (they grow real tomatoes there, something about the warm night temperatures that we don't get outside of a greenhouse here in the Seattle area).  12 days spent lounging by the pool, eating fresh pico de gallo, gazpacho, BLT sandwiches, and just plain sliced tomatoes....slurp!  Deelicious.

It's been hot here at home, so hard to get motivated to spend time in the garage or the shop at work, neither air conditioned.  But I spent some time last week on the milling machine at work, getting the crankshaft bearing supports and the cylinder supports laid out, holes bored, and edges milled (photos 1 thru 4, below).  Simplified the parts slightly with some chamfers where Jan had filleted corners.  Not shown is drilling and tapping the bases of the parts to #6-32.  The last picture is a group shot of the 4 pieces.  What's that?  5 pieces?  Oh...yeah.  4 good pieces and one "oops" - spotted the valve rod hole on the marks made for the corner chamfer, about 1/4" north of where it should have been.  That'll teach me to press on without looking at the print.     :embarassed:

Today I found a chunk of 2-3/4" diameter 303 stainless laying about the shop.  A colleague used up most of it, thinking it was tool steel (he did not see the faint stamp impression on the drop end, which this is).  Chucked it up in the trusty Rockwell lathe, after we spent an hour or two replacing some oil seals on the drive selector (last photo).  A good machine, and has a 3-jaw chuck big enough to grip this in one go.  Faced the end, and turned the o.d. to size.  Started to try to part it off to near length (about .05-.10 inches longer than final dimension) but the boys wanted to close the doors, and we have a policy of not having people running machines without somebody else there to hear the screams and call the medics.  So, off for home, through the ash fall and smoke from the mountains burning down to the east, to find a decent IPA in the fridge.  Tomorrow I need to double check the speed and feed for 303 stainless, and see if I can keep from creating a cloud of oil smoke when parting this with the HSS tool.  Bad enough the wood smoke making us all feel like pack-a-day addicts, don't need to add to it.

Offline Ian S C

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #23 on: September 06, 2017, 12:53:26 PM »
Don't know if its been mentioned, but finishing the last 1/10th of a thou on the outside of the graphite piston is best done with a strip of paper, the piston rotated in the lathe, and the paper looped over it as you would with abrasive cloth on steel. Copuer paper seems to be good.
Ian S C

Offline bent

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #24 on: September 06, 2017, 03:54:50 PM »
Ian,

Yes, somebody here had mentioned it, and I did use that method to finish the parts.  But it cuts very slowly, so I actually switched to a piece of crocus cloth, then shifted back to the paper once I had the fit within a tenth or so.  Pistons now fit butter-smooth, dropping thru the cylinder under their own weight, but stay in place if I seal the end of the tube with my thumb. 

Online b.lindsey

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #25 on: September 07, 2017, 12:07:20 AM »
That is just the fit you want Bent. Sounds like you are headed for a nice runner there :)

Bill

Offline bent

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #26 on: September 07, 2017, 03:24:46 AM »
Thanks Bill.  I need some cheering up after messing up my nice piece of stainless steel flywheel.  That sucker was really hot when I went to turn it around to finish cleaning up the back side -  too hot to hold, and had to drop it, bouncing off the ways and onto the concrete floor at work put some nice little dings in the surfaces I'd just finished cleaning up.  Grr.  Then struggled some more with parting it off, and finally ditched the parting tool and just whittled down the junk saw-cut end, reducing it to straw-colored chips (a surprising number of which seemed to find every crevice in my shirt).  To just top off my day, I tried profiling the dish in one of the faces of the wheel, and marred the darn thing some more when the tool holder bumped against the face of the part (not used to the thicker holders we use on this machine).  Not my best day.  Brought the darn thing home, since the o.d. is mostly finished, to see if I can do a better job on the mini lathe.  Maybe tomorrow, right now a finger of Talisker whiskey is sounding better than making more swarf out of perfectly good stock.  It may soon be only good for another Elmer machine, if I drop it a couple more times.

Offline bent

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #27 on: September 12, 2017, 11:38:27 PM »
Finished the flywheel, less a tapped hole for a set screw.  Finished the profile on the mini lathe at home, with somewhat better results, though still had to fight some tool chatter.  (photo #1)

The flywheel design calls for a 6-hole bolt circle pattern, which I've debated keeping.  Putting holes in a circle pattern hasn't been easy to do for me by the layout and drill method, so I decided to figure out how to use a rotary table instead for putting the holes through the web...which meant I had to move the milling vise to make room for the rotary table on our mill-drill at work.  Then find some 5/16" bolts to fit the table's T-slot nuts.  Then buzz out some toe clamps to hold the flywheel on the table.  And cut some pieces of 3/8" tubing as shims/step blocks to hold up the other ends of the toe clamps (Photo #2)

Then a stopper moment - how am I going to align the table to the mill axis, and then align the part to the same axis, prior to offsetting the mill table for the bolt circle radius?...hmm.  Then had a bright idea moment - I turned a 1" od x 3/8 id bushing out of some handy PVC rod stock, the od sized to fit the central bearing hole on the rotary table, and used a center in the drill chuck to move the mill table to align to the 3/8 i.d. of the bushing, thus zeroing (fairly well) the mill and rotary table axes.  Locked the mill table down, then clamped the part lightly to the rotary table, and kissed the center hole of the flywheel with the same center, and tightened up all the clamps.  Then moved the table for the bolt circle offset, and chucked up a spotting drill... (photo #3)

After drilling the first spotting hole, realized that I had not left any clearance under the part, so could not complete the 1/4" thru holes.  Doh.  Finished spotting all 6 holes and moved back to the mill vise, and carefully centered and through-drilled each hole, and chased one side with a 90 deg. countersink, then flipped and counter-sank the back side...and realized I was off about 0.01" or so on the profile on the back side, so the countersink left some gouges on the profile (photo #4).  Sigh.  Not a big deal, but it's a mistake that will bug me and I'll see it every time I look at it.  Maybe tonight I will re-chuck in the mini-lathe and recut the profile, or maybe I'll ignore it and press on.

Online b.lindsey

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #28 on: September 13, 2017, 01:08:09 AM »
Hi bent, despite your trials and tribulations it looks good to me. I think if your re-profile that back side you can get rid of the mark made by the countersink and not have to fret over it. Still following along and liking it :)

Bill

Offline bent

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Re: Jan Ridder's Glass-Cylinder Flame Eater Mk2
« Reply #29 on: September 19, 2017, 03:31:07 AM »
Spent last Friday whittling down some bar stock and making the clips for the ends of the valve push rod.  Also sawed off a piece of 1117 stock to make the crank from, facing one side and then turning a 1/2" diameter spud to hold it with on the mini lathe at home.  (photo #1)

Today at home, turned the o.d. to size and faced the flat side to set the crank web thickness (photo 2).  Then reversed the part and re-chucked in the inside jaw set, facing the spud to length and cutting a taper, so that it can act as a standoff from the crank bearing inner race (photo 3).  Then spot drilled and thru-drilled at 15/64" in preparation for reaming to .250 (photo 4).  Came back inside and checked on the delivery of a new 1/4" reamer I ordered...and the brown truck won't arrive til tomorrow.  Ah well, time for dinner and a nice scotch whiskey (the rain has finally arrived in Seattle again, though will spend the next few days coughing back up all the soot we've inhaled over the last couple of months :)