Stuck turntable

[gibsonj]

Hey folks,

Any suggestions for freeing up a stuck turntable? Unless someone can correct me, I'm reasonably sure that DD turntables were designed to just lift off the spindle. But, the one I'm working on is really stubborn. I've tried the usual flooding it with penetrating oil, and even tried bumping the spindle lightly with a brass punch and hammer while letting a friend pull up on the turntable. I see no indications that it's budging at all.

Not wanting to cause damage due to my ignorance, I wanted to ask the experts.

Thanks for any suggestions!

John

[maroongem]

Hi John,

The TT is lifted off in the manner you mention. My guess is that it has rusted to the spindle. I think perseverance is the key here. Have the second person that is lifting it up while you tap it give a bit of wiggle as they are pulling it up. Heat with a torch would probably help, but you run the definite risk of setting your TT felt ablaze!

Bill

[phonogfp]

John,

One word of caution: A/B/C-60 machines and A/B-80 machines have turntables that are fixed to the spindle. No amount of heat or tapping will remove it from these models.

George P.

[gibsonj]

Mar 14, 2009 8:08:16 GMT -5 phonogfp said:

John,

One word of caution: A/B/C-60 machines and A/B-80 machines have turntables that are fixed to the spindle. No amount of heat or tapping will remove it from these models.

George P.

George,

That's very interesting. As I recall, on these models, the turntables were belt-driven. Are the turntables pressed onto the spindle, or welded (did they even know how to weld back then?), or maybe a set screw? Hard to believe there wasn't some way to remove/replace.

Thanks.

John

[maroongem]

John,

Is the turn table that you are trying to remove from the A-200 (as I believed) or from one of the earlier machines that George mentioned?

Bill

[gibsonj]

Mar 18, 2009 20:06:25 GMT -5 maroongem said:

John,

Is the turn table that you are trying to remove from the A-200 (as I believed) or from one of the earlier machines that George mentioned?

Bill

Bill,

Yes, the machine I'm working on is the A-200. I tilted the bedplate enough that I could pear underneath the turntable with a flashlight. Looks like there is a roll pin throught the spindle shaft that a slot in the underside of the turntable casting engages to keep the turntable from free-wheeling. Other than that, I'm assuming that there's nothing else holding the turntable in place, other than "rust weld".

I was thinking that I might have a long shaft screwdriver that might slide under the turntable to provide a little leverage to encourage it. Just don't want to scar up the bedplate.

John

[matty]

It sounds like you might just have to be a little more heavy handed with the hammer while a second pair of hands lifts the turntable.
If you put a piece of brass or aluminium on the spindle you shouldn't damage it.
If you start trying to lever the turntable centre, you run the risk of bending the shaft.
A bit of WD40 & a few quick sharp blows directly down on the spindle and it should suddenly let go.
For stubborn TT's, I'll usually start of with a fairly gentle tap, and hit it a bit harder each time until it pops off. As long as you've got someone lifting the turntable with fairly even pressure from both sides, it's highly unlikely you'll damage anything.
Sometimes you've just got to hit them like you're driving a 4" nail into hardwood

[phonogfp]

John,
Shane and the other guys are right. An A-200 turntable should come off with long-term application of penetrating oil (as in WD-40), and tapping the spindle while a friend holds the turntable edges. I would caution against using a screwdriver beneath the turntable. The risk isn't worth the questionable benefit. Shane's advice above is spot-on.

George P.

[gibsonj]

Thanks, guys. I think as Bill said earlier, patience and perserverance is likely the key. Sometimes, I definitely don't have the patience part. I'll keep at it and let you know. I just wasn't sure how much of a blow the spindle could take without causing some other problem. I'll continue using my brass punch between the spindle and the hammer, but just get a little more deliberate about it.

Thanks for all the advice.

John

[dddave]

I wonder if there isn't some way you could rent a large gear puller from an auto supply store and use that to pull it off?
Dave

[diggr]

I would respectfully recommend against a gear or wheel puller. Assuming you could find one with fingers small enough to get under the TT you would still be pulling on the edge of a casting and pushing on the center. Likely outcome is a broken TT. There are other penetrating oils out there besides WD-40 that may give you better results. Thrust is the first one that comes to mind.

If I were you I would go at it as follows:

Collect 3 or 4 wedges (like door stops), either a fairly hard plastic or hardwood (oak for example). Tap them in equally spaced on the OD of the TT to exert some upward pressure on the TT. Apply the penetrating oil and then heat. I would use a heat gun or a hair drier, possibly over several heat-cool cycles, but definitely not a torch. The idea here is that the steel post and the cast table expand/contract at different rates and may help to break the rust bond and possibly let the penetrating oil work better. Then, making sure you have reasonably equal upward pressure from the wedges, get your brass drift and a standard hammer and give the center-post a single sharp pop and see what happens. It may not come all at once but you should see some results sooner or later.

Good luck.

Diggr

[gibsonj]

Hey everyone,

Well, just a little patience to allow the Deep Creep to do its work, and a little harder rap with the brass drift and hammer did the trick. Thanks for all the great advice and encouragement.

John