South bend 13” - Can a small bore spindle be swapped for a large bore ?

[Dukemaster]

Hi. I am new here . I have recently acquired a 13” lathe . It has the small bore spindle with 1-7/8”x8 threads for mounting the chuck. I have found that the selection is very limited on purchasing chucks . Can the spindle be swapped out for one with the 2-1/4”x8 threads? Please forgive me if this has already been covered. Thanks in advance!

 

[texasgeartrain]

There's a Heavy 10, pretty sure a 13" is just a 13 though.

Do you have a serial number, serial card, or some pics we can better identify. A 13" as far as I know takes a 2-1/4-8 threaded spindle nose.

Just an fyi too, you don't need a chuck with threads. You need threaded backplates. Then fit whatever chuck you want to the backplate. Normally run a facing cut to backplate for a boss that chuck sits on, then 4 allen head bolts pass through chuck and secure it to backplate. Something like this:

HHIP 3900-3322 Backplate for 6" 3 or 4 Jaw Chucks 2 1/4"- 8" for sale online | eBay

Find many great new & used options and get the best deals for HHIP 3900-3322 Backplate for 6" 3 or 4 Jaw Chucks 2 1/4"- 8" at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[Dukemaster]

There's a Heavy 10, pretty sure a 13" is just a 13 though.

Do you have a serial number, serial card, or some pics we can better identify. A 13" as far as I know takes a 2-1/4-8 threaded spindle nose.

Just an fyi too, you don't need a chuck with threads. You need threaded backplates. Then fit whatever chuck you want to the backplate. Normally run a facing cut to backplate for a boss that chuck sits on, then 4 allen head bolts pass through chuck and secure it to backplate. Something like this:

HHIP 3900-3322 Backplate for 6" 3 or 4 Jaw Chucks 2 1/4"- 8" for sale online | eBay

Find many great new & used options and get the best deals for HHIP 3900-3322 Backplate for 6" 3 or 4 Jaw Chucks 2 1/4"- 8" at the best online prices at eBay! Free shipping for many products!

www.ebay.com

I guess I just assumed that the 13 was also called “heavy“ because it looks almost just like my heavy 10 which does have the 2-1/4x8 threads. I can’t even find backplates with the 1-7/8x8 threads. I would like to change the spindle to the later 2-1/4x8 if possible so that I can easily interchange chucks with my heavy 10.

 

[kitno455]

My understanding is that the small bore 13 has a smaller OD on the spindle. So, changing to the bigger spindle requires changing the headstock too.

 

[Dukemaster]

My understanding is that the small bore 13 has a smaller OD on the spindle. So, changing to the bigger spindle requires changing the headstock too.

Okay, that makes sense. Thanks for clearing that up for me. I guess I am going to attempt to make some backplates if I can’t find a source that sells new ones.

 

[wheels17]

Unfinished backplates can be purchased at https://www.victornet.com/category/Unfinished-Lathe-Chuck-Back-Plates/375.html . No association with the company.

It is just a rough casting with a hole.

 

[kitno455]

Easiest way to get backplates in your size is to get 1 1/2 x 8 plates and open up the hole just a bit. You do have to pick up the existing thread, but it is coarse, so pretty easy.