# Tail Stock Travel



## Mark_f (Dec 26, 2015)

My 9 inch south bend lathe has 1 5/8" tailstock travel. The machine specs are 1 7/8". I am thinking the screw has been shortened a little for some reason at one time. Does anyone know what the length of the screw should be? I will make a new screw if this is my problem. 


Mark Frazier


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## David VanNorman (Dec 27, 2015)

Does your tail stock barrel have set screws or pipe plugs to keep the tooling from spinning?
If so your screw was modified . I modified mine not long ago and I noticed I lost travel.


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## Mark_f (Dec 28, 2015)

David VanNorman said:


> Does your tail stock barrel have set screws or pipe plugs to keep the tooling from spinning?
> If so your screw was modified . I modified mine not long ago and I noticed I lost travel.



Neither. I don't see any modifications. I wonder if along the way if the screw has not been shortened a little for some reason, but don't know that. I do know my maximum travel is 1 5/8" but the markings go to 2". I read an old SB brochure and it specifies 1 7/8".


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## RJSakowski (Dec 28, 2015)

mark_f said:


> Neither. I don't see any modifications. I wonder if along the way if the screw has not been shortened a little for some reason, but don't know that. I do know my maximum travel is 1 5/8" but the markings go to 2". I read an old SB brochure and it specifies 1 7/8".


Mark,  A common problem with lathe tail stocks is the tang on many Morse taper tools and adapters prevent full usage of the lead screw.  My answer to that was to cut the tang off the tooling.  I did that on the chucks for both my Atlas 6" and my Grizzly G0602.  
However it is possible the the PO of your lathe cut the screw instead.  This is not a good solution as it doesn't extend the usable travel of the lead screw; it just moves the point of disengagement of the Morse taper. 

It also might move the point of disengagement of an untanged taper to the point where you can't  pop the taper free which could be a problem.  It is possible that the PO, realizing that error, would have put an extension on the shortened screw but that extension would be unthreaded and would not restore the travel.    The only way to really know would be to pull the lead screw.  

It looks like you may have to find or make a new screw to recover your lost travel.

Bob


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## Mark_f (Dec 28, 2015)

RJSakowski said:


> Mark,  A common problem with lathe tail stocks is the tang on many Morse taper tools and adapters prevent full usage of the lead screw.  My answer to that was to cut the tang off the tooling.  I did that on the chucks for both my Atlas 6" and my Grizzly G0602.
> However it is possible the the PO of your lathe cut the screw instead.  This is not a good solution as it doesn't extend the usable travel of the lead screw; it just moves the point of disengagement of the Morse taper.
> 
> It also might move the point of disengagement of an untanged taper to the point where you can't  pop the taper free which could be a problem.  It is possible that the PO, realizing that error, would have put an extension on the shortened screw but that extension would be unthreaded and would not restore the travel.    The only way to really know would be to pull the lead screw.
> ...



This is what I have surmised. There is no evident modification to the screw or any other parts but that does not rule out that the previous owner did not shorten the screw for some reason. I plan to modify the tail stock with the installation of a graduated dial. I think I might as well make a new screw at the same time and try to get a little more travel. 
    There is a guy that modifies the tail stock to give an extra inch of travel. I have considered this but I would have to send the complete tail stock to him to do it. I kind of hate to do that. I have looked at the photos of this modification but can't understand how it works.


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## David VanNorman (Dec 28, 2015)

I  think you would need a longer barrel and a longer screw. It shouldn't be that hard. I lost travel when I added the plug screws to keep the tanged tools from slipping. It worked well but then I had to cut the screw to then extract the regular center. This cut down on travel. I coul have just drilled the screw and added a pin to the end to fit between the plugs to knock out the center.


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## Waterlooboy2hp (Dec 30, 2015)

mark_f said:


> My 9 inch south bend lathe has 1 5/8" tailstock travel. The machine specs are 1 7/8". I am thinking the screw has been shortened a little for some reason at one time. Does anyone know what the length of the screw should be? I will make a new screw if this is my problem.
> 
> 
> Mark Frazier





mark_f said:


> My 9 inch south bend lathe has 1 5/8" tailstock travel. The machine specs are 1 7/8". I am thinking the screw has been shortened a little for some reason at one time. Does anyone know what the length of the screw should be? I will make a new screw if this is my problem.
> 
> 
> Mark Frazier


I`ve had all the parts for a 9" SB in my basement for 20 years, that I have never put together. I checked the  length of the screw, and it is 2 5/8", from the tip, back to the spacer. I can run the full 2" on the scale + 1/8", before the barrel un-hooks from the screw. --- John in York


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## Mark_f (Dec 30, 2015)

Waterlooboy2hp said:


> I`ve had all the parts for a 9" SB in my basement for 20 years, that I have never put together. I checked the  length of the screw, and it is 2 5/8", from the tip, back to the spacer. I can run the full 2" on the scale + 1/8", before the barrel un-hooks from the screw. --- John in York



John,

Thank you very much for the information. That is the problem. My screw is only 2 3/16" from the end back to the little flange. I guess I need to make a new screw.


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## fastback (Jan 3, 2016)

Mark, do you remember where you saw the tailstock extension setup for the Southbend.  I remember seeing it years ago, but for the life of me can't remember where.

Thanks in advance,

Paul


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## Mark_f (Jan 3, 2016)

fastback said:


> Mark, do you remember where you saw the tailstock extension setup for the Southbend.  I remember seeing it years ago, but for the life of me can't remember where.
> 
> Thanks in advance,
> 
> Paul


 I googled "modifying the south bend lathe tail stock" and it came up in the listings. This guy will do the mod to your tail stock for about $150 but you have to send him your tail stock.


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## fastback (Jan 5, 2016)

Thanks Mark, I plan on giving it a look see.  I have the same problem with my Heavy Ten.  I have to start mine at 1/4" and the shaft disengages at 1 and 7/8'.   This is a heavy duty lathe you would think they would have given a longer quill like 3 inches.  I also have the same problem with my 9B.

Paul


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## fastback (Jan 5, 2016)

Well I checked out the thread.  It appears that guy no longer does this. The thread was old from 2010. By the looks of it he extended the quill and the rear of the tail stock.  The extension may be 1 1/2 or so.  It also looks like the quill has a long key inserted.  I wonder if the acme screw also needs to be extended.

Paul


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## Mark_f (Jan 6, 2016)

fastback said:


> Well I checked out the thread.  It appears that guy no longer does this. The thread was old from 2010. By the looks of it he extended the quill and the rear of the tail stock.  The extension may be 1 1/2 or so.  It also looks like the quill has a long key inserted.  I wonder if the acme screw also needs to be extended.
> 
> Paul


I been trying to figure it out. I know he extended the tail stock housing and the screw, But he said he adds the additional engravings to the original quill. That is the part I can't figure out. how can he still use the original quill?


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## Mark_f (Jan 6, 2016)

fastback said:


> Thanks Mark, I plan on giving it a look see.  I have the same problem with my Heavy Ten.  I have to start mine at 1/4" and the shaft disengages at 1 and 7/8'.   This is a heavy duty lathe you would think they would have given a longer quill like 3 inches.  I also have the same problem with my 9B.
> 
> Paul


On the 9 inch lathe the screw will disengage at 1 7/8" or 2". I found an old South Bend catalog and it specifies the tail stock travel at 1 7/8". I know mine has been shortened and I am going to make a new screw. I also figured out if I modify the tail stock rear housing nut so the spacer retracts into it, I can get an extra 1/4" which will give me 2 1/4 " total travel. I am also going to put a graduated dial on the tail stock to give great accuracy to positioning. within .001"


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## fastback (Jan 6, 2016)

To  me the quill would also have been extended in order to get the support when fully extended.  Its been some time since I disassembled my tail stock so I don't remember how long the original quill is.  I would think that the extension to the tailstock is used to receive the added quill length, that's my guess anyway.  He is getting a full 1.5 inch extra of travel. I'm wondering where and how the extended key comes in to play.  As you know, the original is just a small plug that turns into a key at the end.  The folks that had this upgrade done for $150, got their moneys worth.  Oh, for my gage I used a 4 inch digital caliper from HF.  I cut the caliper ends off and made a holder to attach to my tailstock.  This system is very accurate and can be zeroed anywhere.  The nice thing about this caliper is shut off by it self, but any movement of the quill turns it back on at the setting it went off at.

Paul


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## Mark_f (Jan 6, 2016)

fastback said:


> To  me the quill would also have been extended in order to get the support when fully extended.  Its been some time since I disassembled my tail stock so I don't remember how long the original quill is.  I would think that the extension to the tailstock is used to receive the added quill length, that's my guess anyway.  He is getting a full 1.5 inch extra of travel. I'm wondering where and how the extended key comes in to play.  As you know, the original is just a small plug that turns into a key at the end.  The folks that had this upgrade done for $150, got their moneys worth.  Oh, for my gage I used a 4 inch digital caliper from HF.  I cut the caliper ends off and made a holder to attach to my tailstock.  This system is very accurate and can be zeroed anywhere.  The nice thing about this caliper is shut off by it self, but any movement of the quill turns it back on at the setting it went off at.
> 
> Paul



Yes, I thought the quill needed extended also, but what confused me was he said he added the additional travel numbers to the original quill. So I don't understand how he lengthened it. I'm not sure what you mean about an extended key. The key in the front would still be sufficient and the key way in the original quill is long enough for the extra travel. I was trying to understand this setup more out of couriosity. After I finish repairing my tail stock, I will have 2 1/4" of travel and that will be good enough for me. I will be making a new screw to accomplish this and modifying the rear nut slightly. The only visible change will be the addition of the graduated dial.

I had also made a caliper setup much like you did but didn't care for it , so I made a dial indicator to mount on top of the tail stock. I'm looking forward to having the dial much like the cross slide does.


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## fastback (Jan 6, 2016)

I may have read into it a little more that I needed to.  I checked his pictures again.  It looks like the later model tailstock (the one without the lube well) uses a full length key under the quill where the older ones have the pressed in key and is just a short one, maybe 3/16 x 1/2 (I did not measure it).  I think that the way quill was extended was to maybe turn a short shoulder on the existing quill and turn a 1 .5 in extension with a step turned to slip over the quill  I think that this extension could be bored larger than the threaded rod (since the rod will also be longer by 1 .5 inches (the extensions could be longer maybe even 2 inches). The setup could be silver soldered, brazed or welded.  The pictures only show the original quill extended to about 3.5 inches.  When the quill is all the way in it would need to slide into the tailstock extension, so this would be bored to the quill diameter but only to a limited depth.  The side facing the hand wheel would be left with only a hole that is the rod bore.  Now I am not planning on doing this project myself, but the pictures do make you wonder.

As for the tailstock reader I would have used a dial gage like I have on my cross slide, but I wanted something with depth.  I only have 1 inch dial indicators around, a 2 inch would be better.  If the quill were extended, a longer reach would be needed like a 4 inch caliper.

Paul


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## ogberi (Jan 17, 2016)

A bit late to this conversation, but I just got done giving my SB9A a thorough cleaning, and I have a full two inches of travel of the tailstock before it disengages.  Maybe an extra 1/8", because it can pull the tailstock spindle in a bit past the zero mark.  

Mark, you do need me to take the screw out and provide measurements?


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## Mark_f (Jan 17, 2016)

ogberi said:


> A bit late to this conversation, but I just got done giving my SB9A a thorough cleaning, and I have a full two inches of travel of the tailstock before it disengages.  Maybe an extra 1/8", because it can pull the tailstock spindle in a bit past the zero mark.
> 
> Mark, you do need me to take the screw out and provide measurements?


I would very much appreciate it. Thank you.


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