I've been refurbishing an SB 13 toolroom lathe made in 1971. I'm now working on the last major assembly, which in my case, is the tailstock. I grabbed the only #3MT tool I currently own which is a dead center that I previously used in the headstock of a smaller lathe. I find that when I fully retract the tailstock quill, the tailstock screw does not come forward far enough to "bump" out the center. In fact, the tailstock screw is nearly 1/4" short of making contact with the back end of the center. Now what I want to know is which part is wrong - the center or the tailstock? Should I just buy another center along with a new MT3 shank for my drill chuck or will I need to do some additional work on the tailstock to get things working right?
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South Bend 17 Tailstock Issue - Who's at fault?
- Thread starter mlitzkow
- Start date
- Replies 11
- Views 1,671
texasgeartrain
Titanium
- Joined
- Feb 23, 2016
- Location
- Houston, TX
Its a pity you can't edit title, you will forever have a 17" South Bend now.
If it were me, I'd remove the screw that drives TS quill. Chuck it up and drill and tap the end you want to push center out.
Make a brass or bronze stud/plug of sorts that you can screw into the new hole and give you extra length. Might make a couple of varying lengths in case you have an odd ball in taper.
I suspect it is similar to my heavy 10 and will not eject tapers without a tang on the end. I think you will find that a tanged taper will eject just fine but I have not found a single taper without a tang that ejects. I added a nub to the end of my live center so it ejects. My drill chucks all have tangs and eject fine.
Hope this helps.
Ben
Hope this helps.
Ben
SLK001
Stainless
- Joined
- Feb 8, 2015
- Location
- Coral Springs, FL USA
Tailstock centers for a South Bend are a special item. They require an extension on the end to be ejected by the "ejector". A regular center doesn't have the extension, so it has to be ejected by dismantling the TS and inserting a small metal rod and tapping it out. You can "fix" your current center by either drilling into the end, tapping a hole and putting in an screw or bolt that will contact the ejector. Or, you can build up weld on the end to do the same thing. I used the weld technique to extend a couple of my centers.
I totally agree with that. My policy always was (long ago retired) when at all possible, modify the accessory, not the machine. I would drill and tap a hole in the end of the taper and bottom out a bolt that protrudes the same length as a tang. Next, mill/grind/sand flats on it to fit in the quill slot. To me, it was always worth whatever time it took.
Technical Ted
Cast Iron
- Joined
- Dec 31, 2017
I've had to add extensions to centers and tools that don't eject. I've learned to always very lightly insert a new tool into the taper to make sure it will eject before driving it home....
Ted
Ted
Dobermann
Hot Rolled
- Joined
- Jan 2, 2014
- Location
- North Carolina
The root of the problem goes back to the OEM South Bend Morse taper centers. None of my South Bend lathes will eject a "store bought" center although they will eject an original South Bend center or an accessory with a tang on the end. For some reason, the original South Bend centers sit a little deeper into the taper than anything you can find now. You're left with the decision between extending the accessory or extending the tail stock screw.
Many thanks to all who have replied. I would not have guessed that the OEM centers from SB were different than the ones commonly available today. So apparently neither the lathe nor the center are at fault, but one or the other will need to be modified for them to work properly together. I'm still thinking about which part to modify. I do usually agree that it's best to modify the accessory rather than the tool. However, in this case, I am tempted to make the fix once rather than every time I get a new tailstock accessory.
Dobermann
Hot Rolled
- Joined
- Jan 2, 2014
- Location
- North Carolina
Depending on whether you like an adventure, you might consider making a new tailstock threaded screw that's a bit longer than the original. I did that for my Heavy 10 which was annoying me over this issue. Making a left hand Acme thread is a bit of an adventure but you can do it since you have a lathe! Granted, it's easier to add a short plug to the end of the screw, but think how proud you'll be when you make a new screw.
Dan from Oakland
Titanium
- Joined
- Sep 15, 2005
- Location
- Oakland, CA
Same issue with my 13"- just drill and tap the end of the quill screw and put a button head cap screw in the end of it.
dogfather
Plastic
- Joined
- Aug 3, 2021
- Location
- New Bedford, MA
I use(d) high bond double stick tape to add en extension to my center. It's a quick and dirty low cost "temporary" fix that has lasted longer than expected...no welding or drilling required.
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