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Headstock Lock Stuck
Posted: Tue Aug 18, 2020 8:33 pm
by isuras2
I have been using my 510 for a few weeks. The headstock lock handle is very tough to turn. Upon investigation, the front wedge lock (504235) seems to move but binds. The rear wedge lock (504234) is stuck in the headstock and dies not move. I’m fearing the rear and/or threaded rod has stripped threads. I’ve sprayed both locks and rod with pb blaster, but it’s not much better. I’ve used a mallet to try to persuade the rear one to move into the headstock, but it doesn’t. I’ve read the forum that I may have to cut the threaded rod to eventually get the rod and wedges out for replacement. Is there an easier way than that? Roughly how long does it take to replace these locks and rod?
Luckily, the headstock still moves and locks with just the front wedge lock so no down time yet.
Re: Headstock Lock Stuck
Posted: Tue Aug 18, 2020 9:10 pm
by edma194
If you remove the headstock from the way tubes you may be able to free up the rear wedge lock. You should be able to rotate the front lock independently and pull the rod forward to examine the rear lock. I think the rear end of the double-ended screw has the normal threads so you may be able to clean up the threads in the wedge with a tap if you can get it out. If the rear lock is frozen onto the rod I'm not sure if you can remove the rod without cutting it.
Re: Headstock Lock Stuck
Posted: Tue Aug 18, 2020 10:03 pm
by DLB
Only the earliest version must be cut out by cutting the rod. These were pinned in a blind hole so there was no practical way to remove the pin from the handle. Yours is probably 40 years newer than this. Note though that whatever is wrong with yours may make cutting necessary or expedient. The 'easier way' on one that works is to remove the roll pin and handle, then loosen the wedgelocks until the threaded rod and wedgelocks come out as an assembly. I would do this with the headstock removed from the way tubes and the motor removed from the headstock.
I'd estimate replacement is a 30 minute task for someone familiar with the headstock and with parts on hand. Give yourself a bit more time if it is learn as you go, and I'd allow time for some other routine maintenance while you have it partially disassembled. This is not a difficult task and forum members can help if you have problems.
- David
Re: Headstock Lock Stuck
Posted: Mon Oct 12, 2020 12:32 pm
by 1957jimp
I have a similar problem on a new PowerPro headstock. The headstock slipped on easily but the lock does not move either way. Is the first step to remove the headstock? Or, try to force by hitting with a mallet? What should wedges look like when in the proper configuration for the headstock to be put back on? Thanks, Jim
Re: Headstock Lock Stuck
Posted: Mon Oct 12, 2020 5:09 pm
by DLB
1957jimp wrote:I have a similar problem on a new PowerPro headstock. The headstock slipped on easily but the lock does not move either way.
In my experience having the wedges out of position prevents putting the headstock on the tubes.
Is the first step to remove the headstock?
Inspect, or better yet photograph and post here, the front and rear wedgelocks where they are currently in relation to the headstock and the threaded rod they ride on. Fully unlocked the wedgelocks both protrude from the headstock ~3/16" and fully locked they are recessed slightly, maybe 1/16". If you do remove the headstock first thing is see if the lock moves with the tubes now out of the picture.
Or, try to force by hitting with a mallet?
No! I think the handle is just cast aluminum.
What should wedges look like when in the proper configuration for the headstock to be put back on?
Flat side down toward the tube, and both should be somewhat outboard. When I do this I loosen them all the way so they stay put, all the way outboard. Somewhere (Doug Reid video?) it was rumored that a new headstock comes with cardboard tubes to keep the wedgelocks in position.
The photos are the best bet. Someone here will probably be able to tell you what the problem is right away.
- David
Re: Headstock Lock Stuck
Posted: Mon Oct 12, 2020 5:38 pm
by jsburger
DLB wrote:1957jimp wrote:I have a similar problem on a new PowerPro headstock. The headstock slipped on easily but the lock does not move either way.
In my experience having the wedges out of position prevents putting the headstock on the tubes.
Is the first step to remove the headstock?
Inspect, or better yet photograph and post here, the front and rear wedgelocks where they are currently in relation to the headstock and the threaded rod they ride on. Fully unlocked the wedgelocks both protrude from the headstock ~3/16" and fully locked they are recessed slightly, maybe 1/16". If you do remove the headstock first thing is see if the lock moves with the tubes now out of the picture.
Or, try to force by hitting with a mallet?
No! I think the handle is just cast aluminum.
What should wedges look like when in the proper configuration for the headstock to be put back on?
Flat side down toward the tube, and both should be somewhat outboard. When I do this I loosen them all the way so they stay put, all the way outboard. Somewhere (Doug Reid video?) it was rumored that a new headstock comes with cardboard tubes to keep the wedgelocks in position.
The photos are the best bet. Someone here will probably be able to tell you what the problem is right away.
- David
Not a rumor.

My factory built Power Pro head stock delivered in January 2013 had the card board tubes.
Re: Headstock Lock Stuck
Posted: Fri Oct 16, 2020 2:22 pm
by 1957jimp

- Rear wedge now.
- Rear now V2.jpg (46.97 KiB) Viewed 2144 times

- Front now V2.jpg (44.04 KiB) Viewed 2144 times
Re: Headstock Lock Stuck
Posted: Fri Oct 16, 2020 2:30 pm
by 1957jimp
Thanks for the reply. They didn't look like this when I took the head stock off. Not sure what had happened. There were cardboard tubes, but I suspect the wedges were not completely unlocked, because it binded about 3 inches in. Unlocked it, but then would not lock when the headstock was completely on (it moved freely).
From your message, I think that they are in the correct position now?
Thanks much!
Jim
Re: Headstock Lock Stuck
Posted: Fri Oct 16, 2020 2:58 pm
by JPG
The thing missing from this discussion is: are the two wedges correctly positioned on the locking shaft threads? They MUST be in sync(equal distant from the middle of the threaded rod). Albiet they MUST be rotated to allow the way tubes to slip past when putting the heqdstock back onto the tubes.
Yes with the tubes 'out of the way', the wedges can rotate independently and get out of position.
P.S. Are those washers on the threaded rod?????
Re: Headstock Lock Stuck
Posted: Fri Oct 16, 2020 3:26 pm
by DLB
JPG wrote:P.S. Are those washers on the threaded rod?????
Yes. PowerPro feature. There is a spiral wrap to cover the middle portion of the threads. The intent of the washers is to keep that out of the threads. The intent of the wrap is to prevent wire chaffing. (All per the DIY PP install manual.)
- David