Author Topic: Jan Ridder's Glass-Cylinder Flame Eater Mk2  (Read 847 times)

Offline bent

  • Full Member
  • ****
  • Posts: 35
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

  • Global Moderator
  • Full Member
  • *****
  • Posts: 9811
  • Dallas, NC, USA
    • Workbench-Miniatures
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

  • Full Member
  • ****
  • Posts: 382
  • St Catharines, ON
    • Gerrit's Hobbies
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

  • Full Member
  • ****
  • Posts: 35
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

  • Full Member
  • ****
  • Posts: 827
  • Stirling Engine Maker Darfield Canterbury N Z
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

Online Steamer5

  • Full Member
  • ****
  • Posts: 707
  • The "Naki" New Zealand
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

  • Full Member
  • ****
  • Posts: 35
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...