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Need Help: Shaft & Keyway machining
- Thread starter 4caseih
- Start date
Here are some better pics if they help of overall project. 
The gear and shaft im repairing mesh with gear off of motor.
There is a cover w bearing and seal that encloses it then pulley assembly goes onto shaft that needs reworked.
Another bearing in the top housing holds top side of pulley assembly. Entire setup actually mounts opposite of pictures and the 3 holes on the top are where it slides for belt tension when mounted on mill.
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The gear and shaft im repairing mesh with gear off of motor.
There is a cover w bearing and seal that encloses it then pulley assembly goes onto shaft that needs reworked.
Another bearing in the top housing holds top side of pulley assembly. Entire setup actually mounts opposite of pictures and the 3 holes on the top are where it slides for belt tension when mounted on mill.
Sent from my iPhone using Tapatalk
- Joined
- Apr 23, 2011
- Messages
- 2,476
Thanks for the extra pics, they always make guessing a repair so much easier :thinking:
In this pic
As to your gear it may be a high tolerance shrink fit and you will never get it off, or it may be a forging, or less likely, a casting. Like chuck noted thats a lot of chips if its turned from a billet.
And depending on your lathe that pulley is gunna be a bugger to chuck up!
Cheers Phil
In this pic
Are we looking at the bottom of this big pulley?
Turn a bush to nominal size, (OD a bit larger than what you will need to bore out of your pulley to get rid of the damage). Bore the bush and cut a keyway, then I would look at turning a press fit collar that will go over the exposed end of the protruding part, this to provide some support for when you machine the old keyway out. (This will depend on how deep the keyed section is, If there is plenty of material up in the pulleys' then the collar may not be neccessary but if the keyed section is relatively short then you might need to consider adding some "meat" Bore the pulley to accept your new keyed bush. Press it in. Depending on access you may be able to drill cross wise (or close to it) to secure the new keyed bush to the pulley, or use a "dutchman". Or weld.
As to your gear it may be a high tolerance shrink fit and you will never get it off, or it may be a forging, or less likely, a casting. Like chuck noted thats a lot of chips if its turned from a billet.
And depending on your lathe that pulley is gunna be a bugger to chuck up!
Cheers Phil
- Joined
- Mar 31, 2014
- Messages
- 607
I'll just offer this up as a suggestion/option before you start making a bushing, for the most part the pulley looks in good shape and there seem to be very little material that needs to be removed to clean things up, how far is the pulley bored out beyond what is necessary for the shaft? is there relief in there from when they cut the original keyway?
You would be taking so little out of that keyway to clean it up that you would not be facing the same issues (chip build up) as starting with cutting a blind keyway from scratch, if there is no relief in there now from when the original keyway was cut it could be easily created with an internal grooving tool, it's just a thought and might save you quit a bit of work.
As for the shaft that the gear is on it looks as though you have some room between where the bearing goes and the face of the gear, it might be possible to make a shaft with a flange on it that could be bolted to the gear with socket head countersunk screws.