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key "stuck" in shaft

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bpress54

Plastic
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Dec 6, 2018
This is the driveshaft from my Delta bandsaw. I'm trying to replace the bearing, but this key appears to be stuck. I tried tapping it with a small chisel but it only moved a little bit. I also tried grabbing it with vice grips but that didn't help, either. I don't want to mess up the shaft or the key if I can help it. I can't drive the bearing off in the other direction because there's a shoulder behind it. Any ideas?20210516_115002.jpg
 
Do you have a milling vise with smooth jaws? If you do clamp the key in the vise and see if that will give you enough purchase to get it out. If not use side cutters to grab one end and lever it out. You will have to dress the key up with a file after the side cutter trick, but it usually works, especially if you already got it to move with a hammer and punch.

-Brian

Sent from my SM-N976U using Tapatalk
 
As Brian noted, sharp side-cutters and some leverage will get that little sucker out, pronto. You'll have to hold your mouth just right for that procedure to work though!:)

Stuart
 
Hit key with a small blunt punch 90* to the shaft at one end of the key. That is probably a Woodruf key rather than a square key. Woodruf keys have a rounded bottom and doing it this tends to cause the key to rotate out of it's seat. they can be a bitch!!
 
I have had a woodruff key that was so tight I could not get it to budge with heat, or anything else I tried. In the end I just filed the key off smooth, took the shaft out and recut a woodruff key slot
 
It appears to be a woodruff key, so one solution is to use a brass or aluminum drift to drive one end down into the shaft so it will roll itself out.
If you get lucky....

Mike

..like John said! I type slow.
 
Protect the threads with electrical tape and go after one end with a single sided chisel from the end.
There is also the weld a helper or lever on top method and hit that with a big hammer.

I you do know it woodruff tapping (banging) down one end sometimes gets it to rock and the higher end will then more like a chisel.
Worse case is drilling holes in it. This allows the sides to collapse with some persuasion. This IMO last resort as a whole lot of work and nailing all in position hard to do. (start small, work up}
It is a piece of silly metal arguing in a machine shop, eventually it will lose the battle.

If using vise grips which is great make sure they are new or grind the ends as not much to grab here.
Most my vise grips have rather poopy ends or tips from abuse.
Here not pull out force applied which will never work a but twist or in reality hammer the vise grips sideways (lengthwise) tilting the key.

More insane is die grinder or cutoff wheel taking out most of the mass but not hurting the shaft.

I'm sure I have only touched the so many ways in a metal cutting or fab shop.
And then there is heat...

Think of it as not problem but a challenge and the joy of winning.
Bob
 
It certainly looks like a Woodruff key going off that photo. Like some others have said my technique was to wallop one end of the key with a hammer and a brass drift. That usually brought enough of the other end of the key out for you to grip it in a vice to remove it. I’d ground the jaws of my vice smooth so I could grip stuff like keys without damaging them.

Regards Tyrone.
 
I repaired a small pump that had a tiny woodruff key in it. I don’t think the shaft was 1/2”, maybe 3/8”, in diameter. The key was worn half way thru. None of the methods mentioned above worked for me. I ended up tig welding a piece of scrap to the key and driving a chisel between the shaft and the scrap. The key came out with little effort, and the replacement when back in just fine!
 
Another method is to drill through the key until you hit base metal and bottom tap the hole as close to the bottom as possible. Then drop in a loose ball bearing and use a bolt to crank it on out. You can also hand grind or turn the threads off the bottom of the bolt to give it more travel.
 
IMO the aspect ratio is wrong for that to be a standard Woodruff key. It may be an extended Woodruff where the ends are straight and overhang each end of the keyseat. In this instance hammering will distort the shaft raise your ire.

I would weld a lever to the key, and pry the lever up. If your welding equipment isn't up to the task, my next choice would be to take a size narrower woodruff cutter and cut out the center.
 
Another method is to drill through the key until you hit base metal and bottom tap the hole as close to the bottom as possible. Then drop in a loose ball bearing and use a bolt to crank it on out. You can also hand grind or turn the threads off the bottom of the bolt to give it more travel.

I had one on a BP ball screw that would not come out even with this method, pulled the threads right out.

I ended up removed the ball screw, put it in another BP, took a narrower keyseat cutter, and went right through the middle, relieving enough side tension that the old key came right out. Wish I would have took a pic of it, but highly recommend it.
 
As this thread is not really in line with what this forum is for I will be locking it. Also I think we have exhausted most of the good ideas for removing a key. Thanks to all who contributed.

Charles
 
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