# 16” SB Spindle Taper



## furpo

I’m trying to figure out what the Spindle Taper is on my 1938,  16” South Bend?
All the manuals I find spec. to be  #3 Morse Taper.
Mine measures  1.536” ID on the spindle with the 2 3/8” – 6  thread with the 1 3/8” through hole.
The #3 Morse taper should be 0.9380 on the big end.
Thanks


----------



## pineyfolks

I have an adapter that came with my 16" SB to use #3 mt tooling in. I believe its a shortened #4 to #3 but I'm not sure.:thinking:


----------



## 8ntsane

Usually machines of that size did use a sleeve, more common would be the #5 MT to fit the spindle bore, and the ID would be #3 MT. You might find a quick google search will provide a chart of all the MT sizes with dimentions will  get you sorted out pretty easy.


----------



## sniggler

The old parts manual will show a "spindle sleeve" which reduces the spindle taper to 3mt. I don't think the spindle taper is a morse taper but rather something else. On my 11" the sleeve reduces to a 2mt but with the sleeve out a 3mt goes beyond flush in the spindle and a 4mt is way to big. Measuring the spindle sleeve od should reveal the taper in the sdindle.

Bob


----------



## OldMachinist

Back when that lathe was made a 4-1/2 morse taper was in use. The large end on it was 1.500".


----------



## furpo

Thanks for the input.
Looks like I’m shopping for MT 4 ½?
Flea Bay!!


----------



## furpo

Interesting:  I bought a #4 ½” MT off of FleaBay and it is about .036 too small. 

I tried a #5 MT which the small end will go into the head stock about 1” .

I’m tempted to try turning the shoulder off the #4 ½” MT and let it slide into the head stock further to tighten it up.


----------



## sniggler

As I said earlier in the thread I think the spindle sleeve is a south bend special taper but unless some one has one to measure your idea sound fine just so they are the same rate of taper. You could also make a cast of the spindle tape with cerrosafe alloy. The I believe collet closer setup goes in without the sleeve. Look in the South Bend catalog at http://vintagemachinery.org/mfgindex/detail.aspx?id=1617&tab=3 for the original spindle taper.

Bob


----------



## furpo

Looks like I will put the #4 ½ MT  to 5C Collet up for sale and buy the #5 MT  to 5C Collet 
It will give me more material to work with. Will have to remove  0.164"
Thanks


----------



## sniggler

Just look at the difference in taper rates for morse tapers. Morse tapers 1-7 all have different rates of taper and you need to match the spindle.

Bob


----------



## furpo

I think I have a caliper that that I can reach in and measure the taper. 
Otherwise will try the MT #3 taper. The #5 has plenty of metal to work with.
Will turn 1or10 out of scrap first to get it right.  Will try turning on my 10” Logan so I don’t have to keep removing the 12” Chuck on my SB
Thanks


----------



## pineyfolks

If I remember I'll measure mine tomorrow at least you'll be able to compare it to the chart to see where it falls


----------



## sniggler

Wow furpo, 

Those charts are great. I have the spindle sleeve for my 11" and would like have the collet closer setup but making one is out of my depth at this point, would really like the see the project in progress with the metrology and setup.

Bob


----------



## pineyfolks

This is what mine measures, Large dia. 1.630 /  Small dia. =1.483 /  Length 3.000  Hope this helps some. Mine is a 1942 South bend single tumbler if that makes any difference


----------



## sniggler

Just some more info maybe not all have seen.

http://www.sportpilot.info/sp/Use of Accessories Inside the South Bend Head Stock.pdf


----------

