16” SB Spindle Taper

furpo

furpo

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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
 
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:
 
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.
 
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
 
Back when that lathe was made a 4-1/2 morse taper was in use. The large end on it was 1.500".
 
Thanks for the input.
Looks like I’m shopping for MT 4 ½?
Flea Bay!!
 
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.
 
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
 
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
 
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
 
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