Gear alterations

It may be. What sort of loadings/RPM are we talking about? For some loads, epoxy will work just fine to stick it back together.

Smokeyone wrote: (clip) Is is possible/viable to cut out the centres on a lathe ^^^^^^^^^^ That sounds like a lot of work. What about swapping the splined shaft ends?

Thank you both for the replies, I had not thought of epoxy, I was thinking of mechanical means but perhaps there are extra strong industrial epoxyies around. I cannot easily swap shafts around because other gears use the same shaft & splines. You are going to say - no way but we are talking around 80hp - 2000 rpm - 160 lbs torque on the driven gear.

Smokeyone

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Good epoxy bonding cleaned, etched surfaces can achieve 5000psi lap shear strength at room temperature. Since you didn't give dimensions, I can't calculate your chances of success but if you work out the bond area and the force that your torque represents at that radius, you can figure whether epoxy would work.

How about silver solder (brazing)?

Ted

I am not a machinist, but I wonder whether you could cut the centers out of the gears by "parting" at an angle, so you have conical mating surfaces when you reassemble. That way, by offsetting each core, you could eliminate the clearance without the need for a spacer. Then you might be able to silver solder or braze.

You'd have to part at a steep angle to avoid excessive offset of the center in the gears when you reassembled them. A shallow taper cone would sink very deep into the matching gear before it locked up. I've never tried to core out a cone with a parting tool. Seems to me that unless the radius is very large, the parting tool would bind as soon as it got deeper than the front relief. Wire EDM might do it.

Gary

Thank you both for the replies. I will have to double check the exact measurements myself but from a friend the measurements are - one gear

Smokeyone

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I might try something like this (if I had to).

Shoulder bolts interference fit, 3 (or more) each, centered on the inner and outer seams of the filler bushing ID and OD lines.

WB ...............

I wouldn't think epoxy would hold at 80 HP, but I may be wrong... I would think that if you inserted a "new" center into the gear, you could drill through the seam (centered) in several places and press in pieces of drill rod to "lock" the inside piece to the outside piece. Parts should fit pretty snug before you start. Ken.

Thanks very much for the help everyone. Just out of interest does the drawing connect with an engineering site.....

Thanks again

Smokeyone

This drawing is from from the feeble grey stuff under my hat, definitely not what would be considered an engineering site. I drew it with MS Paint, and saved it as monochrome, to minimize the bmp file size.

WB ....................

Thanks again

Smokeyone

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