Hold a gear for cutting?

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Richard Hed

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I made nine gears for the drive and two for the timing. They all worked well except I used the wrong material for one of the timing gears and it was not strong enough so it stripped off some teeth. It was oil impregnated brass which I had in the odds and ends pile and I thought that it did not have much pressure so it would be OK. I made all of the gears, including the one this was to replace using my spin indexer. I could have used the spin indexer again but I had just gotten these dividing plates and I wanted to try them.
I would have wanted to use the new toys too. I got a dividing head years ago but without any plates. I made my own, not perfect, however, I decided that the holes didn't need to be PERFECTLY placed as if a hole were .010 off, left or right, it would translate into being off in the .001-.0001deg of error. Your stuff is very nice. I was looking at the smoke stack, does it actually burn someting? Does it run?
 

Gordon

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I bought the plates on eBay for $35 for the three plates with the crank and sector indicator. I figured that even if they were off a bit it would not be a major problem. As it ended up they seem to be accurate.

The tractor is kind of a rough model of an Oil Pull Rumely tractor which is basically a diesel burning kerosene. My engine is a pretty much standard four cycle gasoline engine of my design. On the original tractor the exhaust was run through the stack which heated the coolant so that it could run hotter to burn the kerosene. My engine did run until I stripped the timing gear. I was in the process of fine tuning the ignition and carburation etc when the gear stripped. I had run it for probably an hour total trying to get things tuned in.
 

Gordon

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Just to clarify: The Rumley used oil for coolant because it has a higher boiling point than water so the engine could run hotter. The oil was circulated through the front cooling tower and the exhaust was discharged into the cooling tower to create air flow to cool the coolant oil. The front tower was basically a radiator.
 

Richard Hed

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Just to clarify: The Rumley used oil for coolant because it has a higher boiling point than water so the engine could run hotter. The oil was circulated through the front cooling tower and the exhaust was discharged into the cooling tower to create air flow to cool the coolant oil. The front tower was basically a radiator.
Wouldn't the exhaust be hotter than the radiator? Or is it mixt with a lot of cooler air? How does this work?
 

Gordon

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Wouldn't the exhaust be hotter than the radiator? Or is it mixt with a lot of cooler air? How does this work?
The exhaust gas was to provide air flow up. The radiator was basically like boiler tubes and cool air was drawn in from the open bottom.
 

awake

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... it was not strong enough so it stripped off some teeth. It was oil impregnated brass ...
I have not heard of oil impregnated brass, but I think the bronze equivalent (oilite) is sintered. I know that sintered metal CAN be quite strong, depending on how it is done ... but I can also imagine that it would be relatively happy to crumble, particularly where stress is concentrated by the cutting of small teeth.

Take all of this with a grain (or maybe a shovel) of salt - I'm going on memory, and that seems to be getting less and less reliable these days!
 

Gordon

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I am not really sure what it is. It looks like brass. I got it from a friend of mine who was running a turbine generator on his property. It was from the 1920's and had some brass/bronze bearings and some wood bearings. When I cut it there was oil coming out of the blank. It was pretty saturated with oil. In any case it broke.
 

Richard Hed

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I am not really sure what it is. It looks like brass. I got it from a friend of mine who was running a turbine generator on his property. It was from the 1920's and had some brass/bronze bearings and some wood bearings. When I cut it there was oil coming out of the blank. It was pretty saturated with oil. In any case it broke.
Maybe it was an old cookie that fell in an oil vat and looked like brass?
 

Gordon

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One good thing came out of this. After all of the problem with the three jaw chuck I ended up purchasing a chuck which holds ER collets. Due to the much lower profile and a better grip it is much more stable than the three jaw. It is also easy to center on the rotary table because I have a 2MT arbor with a 1" round shank and it is merely a matter of putting the arbor in the table and clamping down on the shank with a 1" collet in the ER chuck.

I cut two cams yesterday with this setup and it is much more stable than the three jaw and gave really good results.
 

Richard Hed

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One good thing came out of this. After all of the problem with the three jaw chuck I ended up purchasing a chuck which holds ER collets. Due to the much lower profile and a better grip it is much more stable than the three jaw. It is also easy to center on the rotary table because I have a 2MT arbor with a 1" round shank and it is merely a matter of putting the arbor in the table and clamping down on the shank with a 1" collet in the ER chuck.

I cut two cams yesterday with this setup and it is much more stable than the three jaw and gave really good results.
I have a D1-5 nose which has six pins. So I am makeing ER 32, 40 and 50s for it. Keeping it simple, I simply weld a solid cylinder about the size of the ER nut for each size onto a plate which holds the pins to the D1-5 nose. My first one didn't come out very well as I don't have a mill (yet) and the pin holes were not accurate enough. Oh, they work and barely fit but they are not consistent when I take it off the lathe and put it back. So when I get the mill set up, I will try again. Have you thot of making your own?
 
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