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Beware the dreaded Woodruff key!


Gary_Ash

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I needed to remove the clutch release shaft from a 1937 Studebaker President 8 bell housing, discovered that there were two Woodruff keys in the shaft that had to come out to do it.  The outside one was a # 8, 5/32" x 3/4" long, the inside one was a #6, 5/32" x 5/8" long.  They had been in there for 82 years and did not want to move.  The keyways were so deep, there was nothing to grab on to, so I started down the list of "best known methods".  

1.  Put a screwdriver blade under the outer edge and pry up.  Ha!  Nothing to engage the almost vertical surface.

2.  Tap on the end of the key to drive it up on the other end.  Wouldn't budge, just made big divots in the key.  

3.  Use a punch to tap down on one end and rotate the key up at the other end.  Nothing moved and I was starting to mushroom the top surface.  Heated the shaft with a torch to expand it.  Nope.  Heated the key with the torch, squirted on Kroil, repeat, repeat.  Nothing moved.

4.  Drill a hole down into the key and use a nail or punch to rotate the key.  I tried a couple of nail sets, even beat on them at risk of breaking them off.  No joy!

5.  Tap the drilled hole, insert a screw, and pull.  I ran a #36 drill in as far as I dared, ground off the pointy end of a 6-32 tap and got a couple of threads, but the screw eventually pulled out.

6.  Grab the exposed part of the key with ViseGrips or side-cutting pliers.  No, not happening.

7.  The nuclear option:  weld a sturdy piece of steel to the top of the key and drive it upward.  I had avoided this since I had to drag the welder from the other side of the garage and I didn't really want to weld the key into the shaft, but now I was desperate since I'd already invested 4-5 hours on the keys.  I ground a 5/32 wide slot in a scrap piece of 1/8" steel plate, filed the top of the key to clean it, and hit it with the MIG torch.  The first attempt didn't get a good bead on the key, so I tried again with the MIG wire in contact with the key when I pulled the trigger.  A few shots and it was firmly attached.  Tap, tap with the hammer and out came the key.

 

The inner key was tougher to get at as there was only a 1" space for the 5/8" long key.  I cut a slot in a piece of 1"x1" angle iron, welded it on, and had a second success. 

 

So, after 6 hours of frustration, I finally got the two keys out, drove out the shaft with a brass drift, and it's on to the next part of the project.

woodruff key #8 welded.jpg

woodruff key #6 angle iron.jpg

woodruff keys removed-back.jpg

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A man after my own heart.
 

Did you try swearing and throwing tools? I find that sometimes frightens the parts into cooperating. But if that doesn't work, sometimes all you can do is get creative. Nice work!

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I just went through this trying to remove a Woodruff key in a pneumatic sander that I was rebuilding.  Fortunately I did not have to resort to the nuclear option, but now that you've suggested it, I've got it filed away for future reference.  Thanks for the tip.

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If you read the "P" (procedure) pages of a collision crash book (flat rate book for collision shops) you will see the times to R&R parts are based on NEW UNDAMAGED vehicles. Just when was the last time we worked on a NEW UNDAMAGED vehicle to fix damaged parts?😲😯😁😵

 

Great work with the welder!👍

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Another way I learned was to put two lengths of tape alongside the key and run a bead of weld down the top of the key. The weld shrinks the key and it will pull out. Works the same when removing inner tapered races that you can’t get behind. A bead of weld around the face and the race falls right out it shrinks so much. With your key being deep in the shaft, your method of straddling the key with sacrificial metal was probably the best way to go. I do have a tig welder which is very, pin point controllable, and it is perfect for the above process when you can’t risk an “oops!” Great Fix.

Edited by chistech (see edit history)
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1 hour ago, chistech said:

run a bead of weld down the top of the key. The weld shrinks the key and it will pull out. Works the same when removing inner tapered races that you can’t get behind. A bead of weld around the face and the race falls right out it shrinks so much.

I agree;  

This is how I removed the bearing race in my Shaw DuAll Tractor. 

It works like magic!

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