Jan Ridder's Glass-Cylinder Flame Eater Mk2

[bent]

Well, wish me luck.  This is engine project #3 for me, based on the engine shown here http://www.ridders.nu/Webpaginas/pagina_happer_inw_schuif_mk2_glascilinder/inw_schuif_glass_frameset.htm.  I emailed Jan from his website, and promptly received his drawing set for the subject engine.  Of several flame-eater (flame licker?) engines I looked at, I liked this design because it seems to eliminate any potential issues with lubrication, corrosion, and thermal expansion that all-metal designs might face.  Also, what the heck, I've never tried machining glass or graphite.  Jan's engines are so darn pretty, I think I may be embarrassed to show my version when its done...but I'm more of a function drives form kind of guy, so if it works and runs, I'll be happy.

So, first I've been slowly working through the plans and converting where necessary to US customary units (while I can find metric sized bearings and tubing, they are typically double the cost of near-sized inch equivalents) and threads that I have taps/dies for.

The first actual "machining" work I have done was on some McMaster-Carr 1" borosilicate (pyrex) glass tubing, and is more grinding than cutting.  Jan on his website shows how he built a cute wet diamond saw from a dremel tool.  But, I already own a cheap wet saw and have used it a lot cutting geodes, so gave it a try.  Made a quick little jig from polycarbonate to hold the tube perpendicular (first photo below), and used careful hand feeding...to make some really nasty looking cuts, heavy chipping (3 tubes shown in photo #2 below).  Methinks my tile saw diamond blade is a bit to coarse and/or wobbly (and lower speed? need to check that) to make good cuts on glass.  Also hand feeding is a bad idea, as over-feeding was definitely causing some if not all of the heavier chipping.  One of the best pieces I made was done with very careful, slow cutting, but still had some fairly large chips breaking off the edges.  I could probably sand down the edges to clean them up, but it will be a lot of work.  Will probably pursue a dremel blade and experiment some more.

Next, I checked the i.d. of the McMaster tube with calipers - and saw out-of-round and end-to-end variation of the i.d. of over .005".  Jan uses glass syringes for his cylinders, which have a very closely held precision-bore (+/-.01 mm or .0004") in order to keep the glass plunger of the syringe from sticking/binding.  This makes it much easier for him to get very tight fits with his graphite pistons.  Hm  .  I looked for precision bore glass tubing, and while it's available it only comes in large lots for several hundred dollars per box of several dozen or so.  Unless a bunch of people here start doing these and would be willing to split the costs, I don't think that approach will work for me.  I also googled the patents for precision bore tubing, and found that they make it by vacuum-shrinking hot (softened) glass tube down onto precision-ground mandrels (no, spell checker, not mandrills, that would be cruel).  That's a neat trick, but I don't have a centerless grinder, vacuum pump, gun drill to machine the vacuum port, nor a oxy-fuel torch...but it would be a neat process to watch/perform.

So, more amazon shopping, and hey...managed to find some of the "Fortuna Optima" glass syringes in the right 20 cc size; these are the ones Jan recommends.  There also appear to be similar products for sale from Truth (with an umlaut on the u), made in India but have good reviews.  At $20 a pop, and one cylinder per syringe, this is spendier by far than the commercial-grade pyrex tube, and so am going to need to make up a good jig, and practice on the pieces of tube I've already cut before having a go at those.  Like I said, wish me luck!

[b.lindsey]

So you are going to try and grind the ID's of the tubes to make them round like the syringe tubes? That should be interesting, as well as trying to polish them to clear again. Following along, good luck.

Bill

[Ian S C]

Jan Ridders suggests that you may be able to lap the bore of a glass tube using diamond paste.
In USA there is a company called "Airpot" that makes glass cylinders with matching graphite pistons, these are made for door closers, but they were offering free samples, and they come in a very large range of sizes, from less than an inch up to about 4 inch (I think).  Worth thinking about, I think lapping glass tube could be frustrating to say the least.
Ian S C

[gerritv]

I made a jig to use with Dremel diamond disc to cut the cylinders form my Mk2 Ridders gasoline engine. A dripping water tube kept things lubricated. A bit messy with the glass grit spinning to the back wall but excellent results.

Thankfully I can use an o-ring to seal the piston to glass, else I too would have been looking at lapping the glass interior.

[bent]

Bill,
I thought about honing or grinding the commercial tubing to improve it, but have (since finding a source for the glass syringes) decided they are now just practice pieces to improve my cutting techniques and tooling before actually cutting the more expensive syringes to size. The chipping on the cut edges just doesn't make me happy, it may survive in an engine ok but I'd only see the chipped edges every time I looked at it.  Also, I have little confidence that I could create a honed/lapped bore as cylindrical and smooth as the precision-bore glass that I've seen and used for precision chem lab and rocket testing work (to make very precise sightglass flow/volume gauges), and is what I expect to see with the syringes when they arrive.

Ian,
I have one of the Airpot samples in about a 1/2" bore size, they are neat devices.  But the "fun" here is trying to actually make one of these.  Pretty sure, based on the airpot I have, that they are using precision-bore, i.e. "hot shrunk" glass tubing, as the bore is very smooth and clear, not like ground glass at all.

Gerrit,
I may go the Dremel route, just like Jan shows on his website and as you discussed.  A bit more tooling to build, but may be better to cut glass with as you can vary the wheel speed to get a smoother cut.  After researching things a bit, I found that the tile saw I have is a 5500 rpm nominal wheel speed for a 7" diameter disk, whereas the dremel is about a 1.5" disk at up to 20000 rpm; those numbers put the tile saw at twice the dremel capability in terms of rim speed on the wheel...maybe the tile saw is too high a sfpm, as Jan says he runs his dremel at about half of full speed?  Irregardless of which cutter, I need to control the depth of cut according to an email conversation with Mr. Ridder, a few thou per cut is what it sounds like.  So, to the shop this afternoon to whittle out a lead screw mechanism (cheap and sleazy, not pretty - this is a one shot device to test a theory, but will hopefully get the job done).

[Tennessee Whiskey]

This may sound silly, but, I noticed several "bottle cutters " on eBay. Could something like this work for cutting the tubes

Cletus

[bent]

Cletus,

You mean the kind that scratch a line with a sharp steel or carbide, and then you tap or bend the glass to break it?  Dunno, I thought about the scratch-and-snap method but thought my tubing would be too large of o.d., and thick walled to get a clean/square edge break.  I've snapped 1/4" glass tube before, but bigger stuff was always sawed.  The second problem, for the flame-eater, is that you need a slot in one end for the valve, you can see I was trying to make that slot with the tile saw, and while it cut ok, I got a lot of edge chipping on the inside.

Love your handle, by the way.

[Plani]

I'll be following your build too.

For cutting off test tubes I'm using Dremel tool with a diamond disc too. What I found is, it's important to have a slow feed because most of the chipping occures when the cut comes through on the back side. I'm using then a torch to slightly melt the cut surface again so it won't crack.

Plani

[Ian S C]

One chap I'v had contact with through the Stirling Engine Forum uses a dremel tool and diamond disc mounted on the tool post of his lathe, and clamps the tube (usually a test tube for a hot cap, and a smaller one for the displacer) in the chuck of the lathe.
This person is a school teacher in Belgium, and each year his class does a Stirling Engine as a project.
Ian S C

[bent]

Plani, thanks for confirming my thoughts regarding fine feed control.  I modified my jig yesterday to put a screw feed on it, and the syringes I ordered should be on the brown truck tonight, so...maybe sometime next week I will get a chance to make some fine silica powder.  I'd say this weekend, but family matters will take priority.

Ian, I thought about that approach too, but two things have kept me from it so far - one is that most people recommend using a wet saw for glass to prevent chipping, and the second is not wanting to get silica dust all over my poor abused mini lathe.  Though it's a fallback method if the jig fails.

[Ian S C]

I think he drips water over the tube as it cuts, and he also covers the lathe bed.
Ian S C

[bent]

Ok, that makes sense.  Hm, a waterproof ways apron, and maybe a drip bucket...could work...may think about that some more.  Jan also suggested using turpentine as a substitute for water coolant, and I had thought of using automotive glycol, both would help reduce corrosion concerns on the lathe.

[bent]

Well, I've learned some things.  The tile saw just doesn't make a clean cut, no matter the feed rate.  Quality of cut improved, but never approached the quality of the factory cuts, just too many big chips along the edges.

But got in some dremel-type diamond saw blades, and had a try - much better.  This method has a couple of advantages - the saw power is much lower so over-feeding is easily detected and corrected.  Also the grit used on the blades seems quite a bit finer than the tile saw - I tried a few dry cuts and collected the swarf produced on a paper towel, and the dremel blades produce a fine dust vs. chips/shards from the tile saw.

So, built up a "rig" to make wet cuts, see photos below.  The "drip can" is a typical tomato can repurposed.  Drilled a 3/16" hole and soldered a short length of brass tubing into it.  The tube was tapped 6-32 on one end, and a hacksaw cut made about 1/8" from the end.  Stuck a 6-32 ss cap screw into the the threads, and presto, a variable-drip rate valve (second photo).

In the third photo, I am using the tile saw base again, but with a dremel tool clamped to the table and braced against the tile saw blade.  The drip can filled with water sits atop the tile saw motor, and the screw adjusted to about 1-2 drops per second.  Dremel set to the slowest speed, and my custom-built screw-feed mechanism slowly advanced until the saw is just kissing the surface of the tube.  Rotate tube slowly thru a couple turns, advance the screw (1/4-20 thread, but turnning a big fat knob about 1/10 turn or less per step, so figure .002" typical cut).  The saw produces a clean, chipless cut on the o.d., but when the last .005" or so of  i.d. is being cut through, the edge tends to break away leaving a slightly chipped surface.  Not too bad, and should be easy to sand smooth with some wet/dry paper.

Fourth photo is a blurry pic (sorry, used the phone instead of my good camera) of the various practice cuts made.  The left tube top edge is factory-made, the middle is a dremel wet cut, and the left tube with the tile saw; you should be able to see the difference of the former two to the latter.

Fifth photo is a picture of what else I've been doing - squaring up and sizing the stock for the flywheel and piston supports, and base plate, after plasma cutting a big chunk of extruded 6061 Al (18" x 24" x .350 thk and warped/twisted pretty badly) down to manageable chunks.  Lots of swarf.  Should have taken pictures of the mill covered in chips, but I keep leaving my camera at home when at work, and at work when at home . 

Last photo is a picture of one of two Fortuna Optima 20cc syringes, these are definitely worth the price.  I tried the Indian competitor syringe (Truth with an umlaut) and returned them as unusable - too much variance in the i.d. to form a consistent air-tight seal.  The Optima syringes can be held inverted, thumb sealing the outlet, and the plunger will not slip downwards; without sealing the outlet the plunger freely slides out.  Variation of the un-ground i.d. surface of the cylinder is less than .0002" on the diameter, using a bore mic with that precision.

So, tonight I will mark the tubes and start cutting.  And remember to take my good camera with me.

[Ye-Ole Steam Dude]

Bent, a friend of mine used to make drinking glasses from wine bottles. She would make a "ring mark" with a glass cutter set in a wood fixture where it was to be parted. Then she would wrap a piece of cotton twine real tight along the groove/mark. Add some lighter fluid to the string, set it on fire and after (guessing) 30 seconds or so, tap it with a wood mallet. Slick as can be, the top would snap clean off. Then she would polish the edge on a wet wheel.

Don't know if that would work with your item?

Thomas

[Plani]

Bent, to me it looks like you have the glass cutting process prety much down 
Good luck with the syringes!

Plani

[bent]

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.

[b.lindsey]

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

[gerritv]

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

[bent]

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. 

[Ian S C]

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

[Steamer5]

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

[bent]

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...

[bent]

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.     

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.

[Ian S C]

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

[bent]

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. 

[b.lindsey]

That is just the fit you want Bent. Sounds like you are headed for a nice runner there

Bill

[bent]

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.

[bent]

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.

[b.lindsey]

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

[bent]

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

[b.lindsey]

Bent, just a comment....15/32" leaves .03125" to be reamed. That is a lot for a .250" finish size. A letter "C" drill would get you much closer or if you don't have letter drills a 31/64" would help also. Don't want to dull that nice new reamer prematurely.

Bill

[Bluechip]

Bent, just a comment....15/32" leaves .03125" to be reamed. That is a lot for a .250" finish size. A letter "C" drill would get you much closer or if you don't have letter drills a 31/64" would help also. Don't want to dull that nice new reamer prematurely.

Bill

If he's reaming 1/4" through a 15/32" hole he won't have much swarf to get rid of.   

He says 15/64", which gives some 16 and a bit thou I think.

I usually use 6.1mm. Long ago gave up with "inchy" drills. A good set of 1 - 12mm by 0.1mm increments and the rest are redundant IMO ..

Dave

[b.lindsey]

Dave, 15/32" leaves .0156" per side to cut. That is more than normal practice would dictate (as I was taught anyway). The letter "C" drill at .242" or your 6.1mm at .240" would both be more appropriate leaving .004-.005" per side to ream.

Bill

[bent]

15/64, or .235" roughly.  But with the runout on the mini lathe, I think the bore ended up closer to .238 or .240, thus I was reluctant to go to any further.  But I get what you are saying, keep it as close as possible to the final size to reduce wear on the reamer.  I did spend a couple extra $ for a cobalt one, figuring I'll be using it on stainless at some point. 

I really need to take the advice y'all were giving to another newbie, and put down some money on a set of stub drills; going from the short spotting drill to the longer jobber's length drills means the drill doesn't center in the same place, because I have to shift the tailstock to fit the longer bit.   Any tips for making sure the reamer runs on center?  I was thinking of setting the part in the mill, and using a center finder, rather than trust the mini lathe tail stock again.  Also thinking it may be a good idea to invest in adjustable reamers?  I.e. start undersize and work up?  Finally, also realizing that I need a good set of pins, or swipe the ones from work, to use when boring for bearing races and similar close tolerances.  And patience, need to stock up on that when boring to size also    Oh well, it's a learning experience, I keep telling myself that.

[bent]

The new reamer showed up, and between building parts for equipment at work, I found time to finish off a couple of parts.

Set up the crank in the mill vise, and located the center using a combination of center finder and "eyeball", then reamed to .250 for the shaft <photo #1>.   Then shifted the part .56" and drilled the piston rod bearing pin hole. <photo 2>

Before changing out the drill chuck, I also set up and reamed the bearing hole for the piston rod, also at .250 to fit its ball bearing outer race. <photo 3>

Then changed out to a 1/2" roughing mill, and started thinking about how best to hold the crank while profiling the edges.  Decided to whittle out a block of aluminum with a hole in it large enough to pocket around the bearing boss, and the two faces milled parallel to one another.  This is shown clamping the crank in the vise prior to milling <photo 4>.  The nearly finished part (need to weld in the piston rod bearing pin) is shown on some coarse sandpaper in <photo 5>.

Also spent some time on the lathe at home, turning down a piece of the 7/8" graphite rod to make some 1/4" o.d. x 1/8" i.d. bushings for the valve pusher rod <photo 6>.  A piece of paper towel laid on the ways helped to capture most of the graphite dust, as seen in <photo 7>.  I poured the dust into a little snap-lid container, figuring it will come in handy for lubricating something down the road.

Now just need to weld the crank to the crankshaft, the piston bearing pin to the crank, and the valve clip to the end of the valve push rod (Jan Ridders used solder joints for these, but I made the parts from carbon steel so's I could have an excuse to fire up the TIG welder).  Also need to cut a slot in the little-end piston rod pin that I turned on the lathe.  Then some fitup work, pressing/setting bearings, and determine the final locations for the mounting plate bolt holes and finish that part.  And make an alcohol burner, and find some wicking material for it (may rifle the china cabinet and see if we have any alky burners for the wife's chafing dish lying around...she wouldn't mind if I borrowed them for science, would she?)

[Ian S C]

It's worth setting up a vacuum cleaner with it's nozzle just behind the tool so that the graphite dust goes direct to the cleaner, and no where else(including up your nose).
Ian S C

[bent]

Achoo!  I did ok (just dusted the lathe, not the whole garage), but did have to keep the speed down to "dead slow".  Wish I had a shop vac still, Ian, but SWMBO threw it out and replaced it with a handheld vac (no hose) for cleaning out vehicles.  We'd uhm, "redefine our marriage" if I used her good vac to suck up graphite dust!   

[bent]

So, after looking around for something to make an alcohol burner of the right height, I finally found a lump of brass that would work, though it would require some machining.  Managed to get the piece I wanted parted off in the mini-lathe without severing any limbs, and so bored it out, starting with a letter J drill and using a dial indicator to hold the depth to point to get a .06-.07 back wall <photo 1>.  Then bored to same depth with a 1/4" end mill, so I could have a flat bottom for the boring bar <photo 2>.  Bored out to a 1/16" wall (roughly 1.24 i.d.), and so have a cup/container, but no lid (yet) <photo 3>.

Tried parting off a short length, but because the piece was odd size, and had to hang the bit I wanted far out from the chuck, I couldn't get the parting tool to cut without dislodging it from the chuck.  Resorted instead to using the hacksaw, turning the part slowly in the lathe.  When finished, I was intrigued by the pattern that the saw cutting on the turning part made, <photo 4> and so kept it with only a light sanding to knock down the burrs.  Drilled holes for a 1/4" tube to hold the wick, and a 1/16" hole opposite for a vent, and viola, mostly done <photo 5>. Have to find a piece of 1/4" thin wall tube now, I'm fresh out of it after making putt-putt steam boats for the kids years ago, and have only some heavy-wall copper left.  Also have to figure out the wick - Jan suggests cotton, but I think the more typical wick is glass fiber?

[Ian S C]

Got my vacuum cleaner dumpster diving, I'v actually got 2 in the workshop. A garage sale cleaner would be ok.
Ian S C

[bent]

Getting there.  Welded up the crank pin to the crank, and tried to press the bearing on...to find that the pin was oversize, and the bearing was cogging rather than smoothly rotating.  So, removed the bearing (destroying it in the process) and re-worked it by hand to the right o.d. by micrometer readings.  The new bearing was still a tight fit, and more hand work got it to be a snug press fit. 

The crank bearings were fairly loose fits in their aluminum supports, so tried to snug them up with Loctite 603.  Two tries, and no success at getting the stuff to cure, so went full scientist on them: found that the cure requires a low oxygen diffusion rate, i.e. a tight fit or a low oxygen environment, and that the cure is enhanced on some alloys (stainless and chrome steels) with primers.  So - used some primer carefully applied to the outer races, then put both bearing/housing assemblies carefully into a canning jar, dropped in a flaming piece of scrap paper and popped the sealing lid on tightly.  Waited over a weekend, and the parts were nicely cured when removed.

And...found that the flywheel had a wobble, which wouldn't straighten up with basic shimming.  Tried tapping some offsetting set screws to hold it in alignment, just to break another tap.  Grr.  So, now am building a new one, this time leaving it in the lathe at work after turning the chunk to size, will bore and ream tomorrow.  Hopefully this will be straighter than attempting to turn the od at work, and get it to align properly in the home lathe.

In the meantime, put the finishing touches on the brass piston pin and valve pin (photo of piston pin is #1 below).

Then, some assembly and fitting, tweaking the valve pushrod and piston/valve pin lengths to get the valve piston to just uncover, and then just cover, the flame port on the side.  (photo #2).

So, another day or so, and should have this ready to fire up.  Fingers crossed.  In other (good) news, my efforts to gin up a nice in-line hop infusing filter for my homebrew worked a treat.  A 12" long by 2" diameter spool piece with sanitary fittings on each end, clamps and gaskets, and two end caps - bored them to size and fitted/welded on some hose barbs.  Delicious IPA now in the mini fridge beneath the lathe.

[Ye-Ole Steam Dude]

Hi Bent,

I have found that 603 cures a bit different than 648 and 680. I will use it when I need a little more time to set up.

Your project is looking real good.

Thomas

[bent]

Thanks Thomas, I will look into those alternatives.  603 is what we had laying around the shop...

[Plani]

Looking good, bent 
I'm looking forward to see it run.

Plani

[bent]

Ok, it's running  .  I had to take some time off to go car shopping (new Mazda MX-5, yahoo! ), and teaching the youngest to drive  ...and, well, I had trouble with the engine on my first try.  The burner wick was not able to be placed close enough to the cylinder port.  After reworking the burner, it runs...but now I have to build a base to keep the engine from sliding away from the burner...but enough, here's the video.

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

[Ye-Ole Steam Dude]

Congratulations Bent on a job well done.

Thomas

[Kim]

Very cool, Bent! It runs quite well.  Should make you feel pretty good to see it running like that
Kim

[b.lindsey]

Nicely done Bent. One thing you might try is using pipe cleaners for a wick, the wire in them will let you bend them more easily towards the port and they will stay put!!

Bill

[Plani]

Congratulations Bent!  That's a nice runner. I especially like the see through cylinder.
Maybe you could also make a longer pipe holding the wick in order to get the flame closer to the port?

Plani

[bent]

Thanks Thomas, Kim, Bill and Plani!

I did notice last night that the engine began to slow down, and eventually quit running.  Couldn't figure out why until I noticed that the threaded pin on the valve piston had worked its way back out under the repeated impacts of the power piston pushing it open.  This results in the valve piston not fully opening the flame port.  Threading the pin back in solves the issue, but I will need to try some threadlocker (wonder how well it will work on graphite?), or put a jam nut on the back side of the piston.

Pipe cleaners - awesome idea Bill!  Plani, your idea is how it looks like Jan built his original - with an angled tube; I'd have to mill off the tube I soldered and re-jigger it, but it would work.

I bolted the whole thing to a plank of wood I found in the back of the shop here at work, and I'll put a drop of 603 on the piston pin, then bring the camera in tomorrow and see if it will run through a full tank of gas alky.

[Ian S C]

Bent, try using a bundle of fine iron, or stainless steel wire, I use a wire that is use by florests in flower arranging.  I'v used this type of wick in sizes ranging from 1/8" dia  up to 3/8".
Ian S C

[bent]

Thanks Ian, another good idea.  I assume you just twist a bundle of the wires together to form a "wick"?  Pretty sure I have some fine stainless wire around, either here at work or at home.

[Ye-Ole Steam Dude]

Good morning Bent,

I just sent you a PM.

Have a great day,
Thomas

[NickG]

Well done, these are tricky to get running! I made the metal version and it takes a long time to eat warm enough to run! Once you get it in the right position you can hear it take off exactly like yours. Mine being the cast iron piston it also likes oil to help it run, it’s messy and needs cleaning out but believe it or not I think the oil prevents build up of combustion residue on mine. They are temperamental to say the least but unique and intriguing to watch once they get going! My other two flame eaters use graphite pistons and are much more reliable - definitely the way forward. I wonder whether your DNA has absorbed a bit of moisture as the flame does look quite orange.


Sent from my iPhone using Tapatalk

[bent]

Hi Nick, thanks for the comments.  Jan did reply to my video, and made similar comments about the cylinder needing to be warmed up before the engine will start/run continuously.  After mounting the engine to a piece of wood for a base, which prevents the engine from moving away from the burner, it starts much more reliably.  About 3 or 4 starting spins, then off it goes.  But yes, as the flame burns down and gets more and more yellow/diffuse (more and more water content?) the speed drops and eventually it just stops.  Not a big deal, it runs about 5 or 10 minutes on a fill, so I'm happy with it.  And it is a good way to use up my crappy can of alky .

[NickG]

That’s good going. I do keep planning to replace the iron piston and valve with graphite some day and need something to stop the burner moving as you said, flame position is critical on this design.


Sent from my iPhone using Tapatalk