Any Ideas About This Lathe?

Yes, the spindle bore is 3mt.

On these lathes, the main reason you use a 2mt dead center with a sleeve is for using a lathe dog. The 3mt dead center usually sticks out too far so you have trouble grabbing the work.
 
RandyWilson said:
Page 65 (aka 67 of 92) in the catalog.
Click to expand...
And if you look at the headstock specs on page 39, of the same catalog, it says that the spindle is a MT2 but it is not. MT2 has a large diameter of .7000. The bore of my spindle, inside the 1 1/2-8" end, is about .905. An MT3 taper is supposed to be .9380 at the large end.
 
DoogieB said:
Yes, the spindle bore is 3mt.

On these lathes, the main reason you use a 2mt dead center with a sleeve is for using a lathe dog. The 3mt dead center usually sticks out too far so you have trouble grabbing the work.
Click to expand...

Thank you. That makes sense. I do not understand why all the SB literature I can find states that the headstock has a MT2 bore.
 
As my previous post said, the lathes shipped with a sleeve to adapt the proprietary SB taper, down to MT2. This was done so that your through-hole wasn't limited to the minor bore of MT2. The SB taper is close, but not quite the same, as MT3. This is why an MT3 protrudes too far. Google will find a lot of info on this, mostly on un-named other sources.

If the spindle was supposed to start at MT2, why would they list the sleeve?
 
Thanks to all for the input. After this discussion and checking the chart at http://littlemachineshop.com/reference/tapers.php , as well as measuring the tapers on the tooling I have. The bore of this lathe is an mt3 taper. That opens other possibilities for tooling. It is such a pain to be a newbie at this. :)
 
I've got three SB 9 lathes and they all have an MT3 in the head stock and an MT2 in the tail stock. If it isn't really an MT3 it's close enough so that I never noticed the difference.

I've found it handy to have an MT3 to MT2 adapter sleeve.
 
Hi Jack,

My ~1937 Southbend 9" (catalog number 409R) does have a MT3 in the headstock.
I have used collets, and adapters in it with no issues.

I was hoping you had a male MT3 to check yours with.

I have not heard of a Southbend proprietary "close to MT3, but not quite" taper before.

-brino
 
brino said:
Hi Jack,

My ~1937 Southbend 9" (catalog number 409R) does have a MT3 in the headstock.
I have used collets, and adapters in it with no issues.

I was hoping you had a male MT3 to check yours with.

I have not heard of a Southbend proprietary "close to MT3, but not quite" taper before.

-brino
Click to expand...

I do have an old mt3 drill chuck. I don't remember where it came from, but I still have it. It sits in the spindle beautifully. And solidly. I have to knock it out with the drawbar. The spindle has the same taper rate as a mt3, but I think it's about 1/4 inch short of being the "official" length of an mt3 taper device. That may be why SB had an adapter to hold mt2 shanks. IT still doesn't explain, to me at least, why SB listed the spindle as mt2 when in reality it needs an adapter.
 
The 14.5 and 16 are listed as MT3, because they came with that spindle sleeve. The through hole is much larger. By the South Bend data, none of the spindles are exactly Morse Taper specs, ranging from *almost* to not-even. The 9" is by far the closest, though. The 10" has a shorter taper run with a larger minor diameter. By the time you get to the large spindle 14.5 and 16's, the spindles are closest to Jarno13, even if people insist on hammering a MT4.5 in them (different diameter, different slope). So, yeah, as long as the minor end of the tool doesn't matter, you can use a MT3 in the 9".
 
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