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Engine basics => Engine set up tips => Topic started by: Steve Hines on March 23, 2015, 08:07:12 PM
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What do you do to get a back plate to fit. Can you grind down the collet to make it flush.
Thanks Steve
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What do you do to get a back plate to fit. Can you grind down the collet to make it flush.
Thanks Steve
Um, engine back plate?
Or the drive washer that sits behind the prop?
I suspect its the drive washer that you are referring to here and it is not sitting back far enough onto the collet? The best way is to turn down both the taper of the split collet and the engaging inner diameter of the drive washer without changing the angle on your tool post to achieve parallel surfaces.
I have seen it done that way on a lathe and it allows the collet to sit further into the drive washer giving greater surface contact and alignment, providing of course that the collet does not show through the front.
I assume the cause is a too shallow a cut into the drive washers back?
Cheers.
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can u give us a little more info on what u are trying to do???
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Before I went and whacked metal off of a motor like that, I'd find about 100 ways to ask myself "is this problem due to the design and workmanship of the engine, or is it me?"
Just sayin' -- even with cheap Chinese crap I've gone and "fixed" nonexistent problems, to my ultimate dismay.
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What do you do to get a back plate to fit. Can you grind down the collet to make it flush.
I think you are referring to a spinner backplate, correct? If so, ream the spinner to 3/8", (or use a Tru-Turn without a sleeve) and that is what centers it up. You could probably grind the end of the crankshaft down but the existing method and a 3/8" hole works better.
Another alternative is a "Lyle Washer" that puts another ~3/32" behind the collet and pushes the thrust washer forward, but that makes the spinner gap bigger.
Brett
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I have also used a large plastic washer with the 3/8" hole to be a spacer behind the spinner backplate. Don't use rubber or wood.
Dave
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Sorry, it is the spinner back plate . I have never seen this before. The collet comes out past the thrust washer. It makes it hard to face the nose ring.
Brett do you then step the hole in the prop.
Thanks steve
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Sorry, it is the spinner back plate . I have never seen this before. The collet comes out past the thrust washer. It makes it hard to face the nose ring.
Brett do you then step the hole in the prop.
No. It only sticks out about 1/16" above the face the thrust washer, so once you get the spinner backplate on, the prop can have a conventional 1/4" hole. The part that sticks out is a perfect fit for the Tru-Turn. Many spinners come with a 3/8 hole and sleeves to make it fit 5/16 or 1/4 shafts, in this case, you just don't need the sleeves.
This may seem like a silly arrangement, but once you nose it into the blacktop and only have to replace the prop stud instead of the entire crankshaft, you will see the beauty.
Brett
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If the collet sticks "proud" of the prop driver and interferes with the spinner backplate, I'd slip it onto a dowel of some sort and sand a small amount off the small end of the collet on a belt or disc sander, until it isn't a problem. This would keep the end "pretty square", and won't cause runout of the propdriver or spinner. Deburr both inside and out, of course. You might put a dab of flower clay on the area when you trial fit the assembly to make sure there's a little clearance. y1 Steve
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If the collet sticks "proud" of the prop driver and interferes with the spinner backplate, I'd slip it onto a dowel of some sort and sand a small amount off the small end of the collet on a belt or disc sander, until it isn't a problem. This would keep the end "pretty square", and won't cause runout of the propdriver or spinner. Deburr both inside and out, of course. You might put a dab of flower clay on the area when you trial fit the assembly to make sure there's a little clearance. y1 Steve
It's not the collet, it's the end of the crankshaft. The RO-Jett has a stub crankshaft that is not threaded on the outside. It has a 1/4" stud that threads into the crankshaft. For whatever reason, the very end of the crankshaft sticks out proud of the thrust washer.
Brett
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It's not the collet, it's the end of the crankshaft. The RO-Jett has a stub crankshaft that is not threaded on the outside. It has a 1/4" stud that threads into the crankshaft. For whatever reason, the very end of the crankshaft sticks out proud of the thrust washer.
Brett
Well, if that's the problem (not what the OP stated), then a shim could be the way to go. Probably what I'd do, if I didn't want to counterbore the spinner backplate. I'd look for a 1/4" ID washer that would do. Depending on what specification they are, the bore can be different enough to be appropriate or not worth a darn. Edit: Meaning to put a shim behind the collet to shim out the prop driver.
Mike Haverly sent me a PM and said not to grind the collet, which puzzled me. A collet can't be that expensive. Brett's info sorts that out. No, grinding the end of the crank wouldn't be appropriate. n1 Steve
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Because it is the end of the crankshaft, not the collet!
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Just to be clear here, the issue is the pictured purple crank shaft (2) sticking out through the red drive washer (7)?
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Because it is the end of the crankshaft, not the collet!
Yeah, that's what Brett said. You didn't say that until just now. :! Steve
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Thanks everyone. Had it set up with a Brodak Spinner. drilled part way thru and it works,
Thanks all Steve.