Can a warped cast iron turntable be flattened?

[JerryVan]

Please! Don't try to bend, heat or straighten it! At best it won't work, at the worst, you'll break it. If it truly is bent, and it's not really a bent spindle shaft, it can be trued up by boring the spindle hole oversize, pressing in a sleeve, and re-boring the hole on a lathe or milling machine which will make the hole perfectly perpendicular to the table surface.

Most wobbles I've seen with cast iron tables were due either to bent spindle shafts, or worn out holes in the turntable that allowed the table wobble loosely on the shaft.

If you want, I'll sleeve the hole for you. Send me the turntable and the spindle shaft, if you wish.

As I reread your title, I've got to ask, does the turntable wobble, as I mention above, or is it not flat? Either way, what I propose above should fix it.

[phonosandradios]

Its funny - when I was awake in the early hours of this morning I was thinking about this and wondered if the problem was not a warped platter but a damaged or worn spindle hole.

[estott]

Its funny - when I was awake in the early hours of this morning I was thinking about this and wondered if the problem was not a warped platter but a damaged or worn spindle hole.

I'd been puzzled a bit from your first post - in my experience cast iron doesn't warp unless it has been exposed to great heat and stress. Yes, there is supposed to be a Malleable Cast Iron, but I suspect the turntables are the common stuff.

[Jerry B.]

I'd been puzzled a bit from your first post - in my experience cast iron doesn't warp unless it has been exposed to great heat and stress. Yes, there is supposed to be a Malleable Cast Iron, but I suspect the turntables are the common stuff.

I acquired the turntable at the APS Expo in Buena Park, CA at the 2018 sale. It was loose on a table and the cost was minimal. Perhaps the turntable was in a fire or ? To be honest I've never had the turntable on a machine. It seemed pointless because the turntable is visually warped. If someone has the skills and willingness to attempt a repair please let me know and I'll send it your way.

Thanks, Jerry

[Daithi]

You can't flatten it but you can center the pivot hole in a lathe and turn or grind the platten and edge by skimming as little as possible from it until it runs true.

[startgroove]

Do you mean that it has a rise to the middle, or the edge? As opposed to a wobble when it spins. If it is a wobble only, it may be possible to align bore the center hole, by lathing it out, and pressing in a brass bushing. If it has a hump, perhaps the hump can be ground down, or lathed down. Cheers, Russie

[Curt A]

Instead of throwing it away, I would opt to correct it by the previously mentioned machining methods. Bore the spindle hole out, put in a new bushing and then true the surface of the platter on a lathe. Machining the surface will be covered up by new felt, so it will never be seen... and it should run like new again.

[Jerry B.]

Here are photos of the Victor 10" cast turntable that is warped. The photos were taken on a flat table. I used white paper to give a better contrast. Jerry Blais

[Curt A]

Jerry,
The warp looks to be fairly significant. It rises off the table approx. the thickness of the turntable, which means that machining the top probably wouldn't work, as there is not enough material to absorb shaving the warp out and making it flat - one side would be thin and the other thick or it would go right through. Typically, if it was some type of steel body panel, you would add material to the side with the warp and then sand or grind it back flat... I'm not an expert on this type of repair, so maybe someone else could give a better opinion about whether or not this can be repaired.

[JerryVan]

Wow. Severe warp! Looks as if it's been through a fire. As others did, I thought we were discussing a wobble. This is more like a wave on the ocean.

Some Model T guys straighten warped cast iron exhaust manifolds by restraining them, then heating to cherry red with a torch or electric furnace, then slowly applying pressure until they are straight. Last, they are let to cool slowly, in the furnace, with the heat turned off. Most find that the electricity or acetylene gas required, outweighs the cost of a new manifold.