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Quick chaange GB for 1910 13 in. South B.

philippine john

Plastic
Joined
Mar 8, 2018
Hello, this my first post on this forum.

My question is.
I own a 1910 13 in Southbend Lathe that does not have a quick change GB. I would like to have the convivence of the QC GB. I have the opportunity to purchase a 1906 single tumbler GB from a 16 inch lathe. Does anyone know if this will go on my 13 in. lathe. Because gears are so expensive to purchase I am thinking even if I have to cast a new gear case {which I can do} to install the gear setit would be better than purchasing individual items.

In my study I have realized that a two tumbler GB is maybe more practicle if I have to recast the Gear What do you Guys think, and thanks for any input you can give.
 
There was a member recently that used a 10" gearbox on his early 13...it worked out good because the early 13 had a 8tpi leadscrew.

IIRC - it was dcstang67
 
You could buy a parts lathe to get what you need, then sell excess parts to recoup some of the costs.
 
SB did not have a gearbox until 1920ish, and that one was a simple three-speed affair. Whatever gearbox you get, you will need some gears for the end of the lathe, to turn the gearbox at the right speed. What is the pitch of your leadscrew?

allan
 
thanks Guys for the info. I am in Texas at the moment but live in the Philippines. So buying a parts lathe in not practicle due to shipping cost. May my best bet is to get a two tumbler box so if i have to do repairs at least i could get parts or fabricare myself. I like the looks of the single tumbler box but the splined tumbler shaft scares me. Are all the two tumbler boxes the same dimension from the bottom of the bed where thr box mounts to the centerline of the output shaft
 
the double tumbler boxes vary in size with the size of the lathe and its age. The double tumbler (and later single tumbler) machines tend to have the leadscrew further outward from the front of the bed, allowing for a larger apron. There are no absolutes here. You'll need measurements off your current machine, including the leadscrew pitch.

allan
 
thanks Guys for the info. I am in Texas at the moment but live in the Philippines. So buying a parts lathe in not practicle due to shipping cost. May my best bet is to get a two tumbler box so if i have to do repairs at least i could get parts or fabricare myself. I like the looks of the single tumbler box but the splined tumbler shaft scares me. Are all the two tumbler boxes the same dimension from the bottom of the bed where thr box mounts to the centerline of the output shaft

I just bought a 1943(guessing by serial number) 13" south bend to part. Has a single tumbler box. IMG_20180304_172958166.jpg
I can get pics or measurements. I can ship parts to Texas, but not out of the USA.just trying to help.
 
I would be interested in this GB. What would be the price for the GB along with the lead screw gear, banjo and input shaft gears. I have another GB i am looking at and its cost is $125.00 plus shipping but does not include the banjo or any gears. Can we confirm that this box is truly a 13 inch. I may need some measurements if the price is right.
 
on the gear box feed chart what does the most upper line say? "before South Bend there is a number I think. that may indicate the lathe size {maybe|
 
It's a 13" can you pm me a phone number that we I can text you more pictures?
 

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i finally got the info on the lead screw. It is 8 TPI. Can you tell me what the tooth count of the lead screw is. And also the gearing tooth count on the banjo. Or even better would be a simple hand drawn sketch of the gear train for the input end of the gear box. Thanks so much for your help on this issue.
 
Lead screw gear is 24.
In the picture...red gear has 64 and 22. Green gear has 24 and 66. Blue gear has 66.
 

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You can use a gearbox from a lathe with basically any leadscrew pitch, you just have to turn the gearbox slower or faster to match your leadscrew.

The 6TPI single tumbler machine shown in jay's picture uses an 18 tooth stud gear. If you put an 8TPI leadscrew on that box, the threads it cuts will be finer than those on the chart by a factor of 8/6 (or 4/3). So, we need to speed up the input to the gearbox by the same ratio to correct it. In this case, put a 24 tooth gear in place of that 18, and you will turn the gearbox at 24/18 (or 4/3) of its normal speed.

The number of teeth on the leadscrew gear is not really changeable, since it does not have variable center distance.

allan
 








 
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