PM-1054TV Mill with broken worm shaft - help needed

[nvetro]

First time poster! I picked up a PM-1054TV Mill and 1640TL lathe which was recently delivered and I am setting up. Unfortunately when I loosened the 4 front bolts on the mill head and tried to turn the worm gear to tilt the head up from its shipping position (while having someone support it and assist) I sheared the worm gear shaft off inside the head, it broke at the weak part in the middle where it necks down.

Now to my first problem, the head is still tilting in a downward shipping position. I know I need to remove the head to replace the shaft and potentially the worm gear(s), I would like to get the head vertical first and use a mill head removal tool i have to assist while using the table. Is there a way to get the mill head vertical without the worm gear? I attempted to test pulling on the head (with 4 bolts loosened) with an engine hoist and it wasn’t moving.

 

[davidpbest]

Turn the head facing top down. Raise the knee and use it to support the J-head as shown below. Then you can pull the head off the knuckle and ram.

I completely disassembled my PM-935 (same basic design, identical head) to strip and re-paint the mill. My build log is here with tons of photos dealing with all aspects.

 

[nvetro]

@davidpbest thanks for the reply. How do I turn the J head to get it in that position if the worn shaft is broken off?

I tried to move the head with the 4 bolts loose in the front and pulling up on the head with a engine hoist and it wouldn’t budge, it lifted the machine.

 

[markba633csi]

I think I would take the motor off at this point

 

[7milesup]

@davidpbest thanks for the reply. How do I turn the J head to get it in that position if the worn shaft is broken off?

I tried to move the head with the 4 bolts loose in the front and pulling up on the head with a engine hoist and it wouldn’t budge, it lifted the machine.

The 4 bolts in front are for rotating the head left and right. The 3 on the side bolts are for tilting the head.
Loosening the four bolts on the front will not let the head move to vertical, you need to loosen the 3 bolts on the side. I'm guessing that is why you broke the shaft.

 

[7milesup]

I think I would take the motor off at this point

No, don't do that. He just needs to loosen the correct bolts to get this to work.

 

[nvetro]

Bad choice of words my mistake. I am trying to rotate the head without the worm shaft (since it broke) not tilt the head back.

How do I rotate the head if the worm shaft is broke ?

Maybe the worm gear is jammed?

 

[7milesup]

Ah! Ok, now I get it. I was confused.

Look at David's first photo. I believe that you are going to have to completely remove the four bolts on the front of the head.

I would bet that your summation of the worm gear being jammed would be correct.

Edit: I believe that you could take that worm drive out, rotate the head to vertical, tram it, and continue to use the machine while waiting for parts.

 

[nvetro]

@7milesup any recommendation on how to get the shaft out? I thought you cannot get the shaft out with the head on because of the drift key that holds the worm gear on the shaft as well as the Allen head cap screw?

 

[7milesup]

@7milesup any recommendation on how to get the shaft out? I thought you cannot get the shaft out with the head on because of the drift key that holds the worm gear on the shaft as well as the Allen head cap screw?

I'm afraid that I don't have an answer for that. I would suggest looking through @davidpbest's photos (which are excellent) along with the parts diagram in the manual to determine the best approach for the head removal.