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werowance

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lol, yeah i should have said it has helped with "SOME" things i was having trouble bending. its certainly not a perfect make everything bend like you want everytime solution. just helped on a thing or 2 that i kept messing up.
 

Brian Rupnow

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I've changed my mind three or four times about what to do for a gear guard. Gear guards on these little engines do more than protect fingers---they cut down a lot of the noise created by the gears. Yesterday I finalized the design of the gear guard, and this morning I bought a piece of aluminum to make it from. We spent part of today returning a visiting grandson to Orangeville, and I got a good start on my guard this afternoon. I have the final shape laid out, but won't finish machining it until tomorrow. I'm trial fitting this part as I go along, because the finished engine always has minor differences from the engineering drawing. So far, it's fitting the way I had planned.
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Hi Brian, Having bent many tubes with a variety of benders - like you have been doing - I think your explanation shows "Why" I have some success and some failures! = "Wrong material" of tubing.
I have filled copper tubes with plumbers' lead solder, (successfully), Candle wax (Good and easy), sand (difficult and needs ends blocking and good compression of the fine sand), and have heard that fine sugar, (Icing sugar? Castor sugar?) works, but not tried it. Also, I was told that caramel works (melted sugar with a dash of water to help it melt). A friend (many years ago, - 1970s?) made me a new exhaust pipe for the bike, and had an hydraulic bender, and used a proprietary "Brown melting gunge" that cooked in a saucepan, and being brittle when cold, it broke-up during bending the thin walled stainless tube (~2" dia) and the dust and broken shrapnel fell out after bending. - Maybe that was caramel? - he blocked one end of the straight pipe just by sticking it in the lawn for an inch, while we poured the gunge into it. After cooling, the whole thing was solid, and the tube bent like in a factory. Slight necking, and surface marks from the dies/rolls in the Hydraulic bender.
But for your job, I think the (external) spring has given excellent results! - better than mine (I have tried the spring inside a tube - not easy to extract after bending!), I must try an external spring next time.
My benders: (The best for 3/16" or 5mm tube is the one next to the springs: Also, note the thick bar instead of flimsy steel strip for the black benders. Makes them much better.).
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Thanks,
K2
 

Brian Rupnow

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Starting to run out of things to make--and that's a good thing. This afternoon I made the main brass turning for the intake manifold---in fact, I made it twice. First try was with some of the mystery metal I bought last week. As I was turning it, I realized that it was bronze, not brass. I don't even know if you can silver solder bronze, but I was willing to try. Then I found that I had misread my own drawing and I had one of the turned down areas too long. At that point I thru it in the can and started over with something I knew was brass.
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Excellent work Brian. To reply to your question... Yes, you can silver solder phosphor bronze. Also, aluminium bronze, although very difficult and needs special flux... I think? Phosphor bronze bushes are commonly silver soldered into copper boilers, threaded for fittings, because brass will de-zincify with the steam and temperature, so must not be used in boilermaking. Similarly, aluminium bronze can lose aluminium with a steam environment, so not recommended.
Just FYI.
K2
 

Ghosty

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Brian,
You were thinking about the grand kids when you designed the micky mouse ears(gear cover), it does look good and cleans up the gear set quite well. It is one area that lets down a lot of great looking engines. Keep up the great work, Still following along.
Cheers
Andrew
 

Brian Rupnow

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Andrew and Steamchick--I'm glad that you are following my build thread and commenting. I have built at least one part per day since starting this build thread, and the end is somewhat in sight. I am getting to the point where I have to actually search a bit to find parts I need to complete this engine.----Brian
 

Brian Rupnow

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Todays offering to the Machine Gods is a cooling fan. The discoloration is from the heat of silver soldering. I wish I had a small sandblaster, but I don't. This fan has been pickled in Citric acid, scrubbed with an old toothbrush and polished a bit with silver polish on a Q-tip. I may just pint it flat black.
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Brian Rupnow

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This morning I made up the flanges which bolt the intake manifold/fan to the cylinder heads. It went well, so I figured a "mock up" shot was called for. Nothing is soldered yet, it's just held up there by the grace of God and tight tolerances. I still have to do some cosmetic work on the fan blade, but it is getting exciting.
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Brian Rupnow

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This afternoon I cut the keyway into the crankshaft and into the starter hub. The flywheel had been keyed back when I first built it. I made a gasket for the inspection hatch in the bottom of the crankcase, filled it with #30 motor oil until oil began running out the overflow pipe, signaling that the crankcase had the correct amount of oil for splash lubrication. A few squirts of oil down the sparkplug holes, and then I drove my engine with an electric motor for one hour. This loosened everything up, and the motor can be easily spun over by hand now. Tomorrow I will solder the intake assembly and flanges together. I have to remake the axles that the hardened rocker arm ends mount on because of some minor clearance issues, and then all that is left are the exhaust tubes and the cams. I leave the cams for last, because they are always the parts I find hardest to make.
 

Brian Rupnow

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Today seen the soldering of the intake manifold and the changes made to the small axles that hold the hardened part to the end of the rocker arms. I'm reasonably happy with this, and tomorrow I will make the exhaust pipes. I built an aluminum jig with the same bolt pattern as the two cylinder heads, and did my soldering on the intake out in the main garage away from the engine.
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Brian Rupnow

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We're getting right down to the last strokes Steve. I'm agonizing about the exhausts right now. The exhausts are close to the gas tank, and I don't want the first run to be the last run. I would stick with my original exhaust design but there is really no good way to put such tight 90 degree bends into 3/8" o.d. tubing.
 

stevehuckss396

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Could a standard brass fitting from the hardware store be machined to accept your tubing? Something like this with the barbs cut off and reamed so your tubing slips into it.
 

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Brian Rupnow

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I think I've designed something that will work. My exhaust ports are threaded 5/16"-18, so there isn't any good way to make sure that the exhaust tube tightens into the thread at the exact moment that the 90 degree section is aimed in the correct direction. My design isn't quite as pretty as a flowing 90 degree bend, but it addresses the problem.
 

Badhippie

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Brian
That girl looks great I really like the design. I can not wait to hear it run. Looks like she is not far from it either
 
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