Reducers in reverse ?

[mmcmdl]

I've run die grinders , air grinders on the BP in the past when high rpms were needed . I pulled out old gear boxes 5 to1 ratio , 3 to 1 etc . My thought back then was to use these instead of the elaborate setup involved . My question would be can I run these in reverse ? These are expensive and don't want to damage the internals . What are your thoughts ?

 

[extropic]

Are you talking about something like shown in the link?

If so, my only concern is to get the cutter turning in the correct direction. I think these are straight cut spur gears, so direction doesn't matter.

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[pontiac428]

Reversing the input and output will make an underdrive into an overdrive. Whether it would work depends on if the bearings/oiling can take it. The rotational forces for planetaries go up quite a bit depending on the mass of the planet gear carrier, etc., so there are limits.

 

[mmcmdl]

Parkers . Straight and 90 degree . This was just a thought back then .

 

[Flyinfool]

As long as there are no spiral cut bevel gears it mechanically should be fine.
With that said you need to be sure that while running it backwards your output does not exceed the rpm rating of the reducer.
Also is the output shaft rigid enough to take side loads of a cutting tool? They are not usually designed to handle any side load on the input which is now your output. Pay attention to how long it will be by the time you add a tool and a tool holder, the sides forces will be multiplying pretty high.

 

[mmcmdl]

As long as there are no spiral cut bevel gears it mechanically should be fine.

I'm better of with selling these on the bay as NOS .

 

[benmychree]

Good plan!