Does anyone know of a backing plate casting for a 13" SBL w/ 1-7/8x8tpi spindle?

IsleofManFan · May 16, 2020

I am not looking for a threaded plate but a casting that I can machine to fit my spindle. I need an 8"+ diameter casting with a small hole or no hole..Everything I am seeing is a hole of 1.88" which doesn't help my application...I have been told to buy an 8.25"x 2.25" round..has anyone seen the price of CAST IRON round lately! Thank you...IOMF

garyphansen · May 16, 2020

Most of the time what I am about to say is a bad idea but sometimes it works out fine. Bell bar weights are made of cast iron, usually they have hard spots and can't be machined easily but sometimes they machine nicely and can be made into a good back plate or face plate. At yard sales they can be picked up cheaply. Good luck!

Rudd · May 16, 2020

What in the world on a 13 requires an 8" backplate? Granted, I just saw advertised some import chucks with the bolt holes way out on the perimeter of the chuck, and then thought, "why did they do that? That would take a stoopid big backplate." Most chucks are not like that. In fact, I'd never seen that before.
I've got an 8" 4 jaw and a couple of 6" three jaws, which was std. sizes for the 13. On all of them the backplate sits in a recess on the back of the chuck, so they are much smaller in dia. than the chuck body.
Can you post a photo of the chuck, or whatever it is?

Rudd · May 16, 2020

If that is what is required, well, this *might* work. 1.75 is going to be about minor diameter for your thread.

RDX Back Plate for 11" Lathes

Edit - when ordering from these folks, *call* and make sure they have it in stock before you order. Don't trust "in stock" on the web page.

iwananew10K · May 16, 2020

the 1-1/2-8 backplates from Shars have enough meat to open them up and rethread them.

IsleofManFan · May 17, 2020

I looked at the back of the 4-Jaw chuck and the recessed area where the plate will mount is 7" the hole pattern is 4", that makes a bit more sense! Thank you.

k3vyl · May 23, 2020

Another source of CI is old pump shaft couplings from industrial pumps.The pump side of it will have the smaller bore.Beware of double setscrews when retrieving one.

mandmj · May 26, 2020

I used one of these on a buck 6 jaw that I picked up pretty cheap. It took a lot of machining, and I imagine many might throw a fit that I put a 7" chuck on a 10k, but works really well...

https://www.mscdirect.com/browse/tn...MI7b-suO3R6QIVy8DACh07vAWWEAYYASABEgL0LvD_BwE

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Does anyone know of a backing plate casting for a 13" SBL w/ 1-7/8x8tpi spindle?

IsleofManFan

Plastic

garyphansen

Titanium

Rudd

Stainless

Rudd

Stainless

iwananew10K

Diamond

IsleofManFan

Plastic

k3vyl

Stainless

mandmj

Plastic

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