South Bend 9 center height measurement

juzer99 · Jan 16, 2021

I wanted to make a center height reference tool and needed the dimension.
In the process I discovered that Google does not know what that distance is so I measured it using a method shown by Joe Pieczynski on YouTube (search for "setting lathe tools on center" if you have not seen it). I used a parallel bar between the pin in the chuck and the pin on top of the gage block stack set on the flat part of the ways then swept the parallel across.

I came up with the spindle center height 117.152mm / 4.6228" measured from the flat part of the ways to the spindle center.

I would appreciate if a few SB9 owners verified my result.
I realize the wear on various machines and measurement errors will result in slight variation but I think it would be an interesting exercise to compare results.

SteveBerry · Jan 16, 2021

South Bend put a hash mark on the tailstock quill for setting tool cutter height on my 9 ,Not sure if this helps or if your lathe has the hash mark.
Steve

mcload · Jan 16, 2021

Edge Technology

juzer99 said:
I wanted to make a center height reference tool and needed the dimension.
In the process I discovered that Google does not know what that distance is so I measured it using a method shown by Joe Pieczynski on YouTube (search for "setting lathe tools on center" if you have not seen it). I used a parallel bar between the pin in the chuck and the pin on top of the gage block stack set on the flat part of the ways then swept the parallel across.

I own a 9A, but sorry, I don't have the measurement you're asking for. I did watch the video you referenced;
it was interesting. But off hand, I would think this vertical distance will change depending on how close or
how far away your tool is, and how much wear there is on the ways at you cutting spot.

I purchased a very simple and inexpensive tool from Edge Technology to use predominantly with my
parting (cut-off) tool, and using the "lamp post" tool holder.

You should go to the Edge Technology website and look for the "Pro Lathe Gage 02-000". It is
absolutely great, and always gets my tool exactly on center. (Edge also makes other great products
as well...I have one of their "Tailstock Alignment Bars" too).

There is a video on using this gage you should watch; seems a lot easier than the other
method you are trying to use. (And also if you don't own a mill to precisely cut that block):

Pro Lathe Gage 02-000 - Edge Technology

By the way, in order to use this gage while your workpiece is in the chuck, I think you will
have to put it into a drill chuck in your tailstock. That, or level the tool(s) before you start by
putting it in the chuck (or a collet). The good thing is that it's a very inexpensive tool and works well.

Good luck.

PMc

View attachment 310722 View attachment 310723 View attachment 310724

juzer99 · Jan 19, 2021

The tool should remain at the same height no matter where the saddle and the compound is.
Only the wear on the ways can make the tool "dip".
There are a few fundamental problems with using level to adjust the tool height.
1. Those simple level scales are not very precise.
2. The method relies on the lathe being level, which may or may not always be true.
3. You can't check the tool height while the workpiece is mounted on the lathe. This is the deal breaker for me.

texasgeartrain · Jan 19, 2021

Every lathe is going to be different. You need to run checks to find your best spot a C hair above center line. As already mentioned, the tail stock quill should have an etched line at approximate center line, as a rough gauge.

From HTRL 55th edition:

the link:
South Bend Lathe Works - Publication Reprints - How To Run A Lathe 55th Edition | VintageMachinery.org

The pdf:
http://www.vintagemachinery.org/pubs/1617/17726.pdf

I have made a flat bar gauge previous myself, but the next one will be adjustable somehow, maybe with an adjusting bolt for fine tuning.

To get in the ball park, run facing cuts on something, but a hair low. when you miss the center low, you can use the diameter of what remains and figure out what center is, then adjust for a hair over centerline. Or run your facing cut from slightly low, until you just clear all the material in center and raise a c hair more. With that figured out, set height gauge to whatever height the tip of the tool is.

Before fine tuning your height gauge, I'd level the lathe if you have not already. And check headstock alignment. If you adjust those later, you'll need a new height gauge.

Might experiment with your tools and angles also, to see your best performance and finish on the work.

SLK001 · Jan 22, 2021

In the back of HTRAL, there is a page called "Tooling Dimensions" that has the info you want.

SteveBerry said:
South Bend put a hash mark on the tailstock quill for setting tool cutter height on my 9 ,Not sure if this helps or if your lathe has the hash mark.
Steve

Also, Steve is correct on the hash mark. South Bend made that mark on every lathe. You can use that as a reference.

juzer99 · Jan 24, 2021

Thank you. This is the first time I came across a recommendation to position the cutter above center line.

juzer99 · Jan 24, 2021

Thank you for that tip. I now looked and did find that mark.

woodchuckNJ · Jan 24, 2021

I just use a scale up against the part.
then fine tune. Facing will give you the measurement you need. get rid of the nub and that's the height.

don't need a tool to do the simple stuff.

woodchuckNJ · Jan 24, 2021

SLK001 said:
In the back of HTRAL, there is a page called "Tooling Dimensions" that has the info you want.

Also, Steve is correct on the hash mark. South Bend made that mark on every lathe. You can use that as a reference.

not on my SB 9A , mine was made in WWII, and does not have a mark, I just went and looked.

texasgeartrain · Jan 24, 2021

Even with an etched line on tail stock quill, I'd use it as an estimate, or in the general ball park.

Not knowing the wear on tailstock, and whether its truly pointing at center. Could be .010 to .020" up or down without operator realizing. Also if any wear on the key that keeps quill aligned, might allow a little back and forth rotation of quill.

SLK001 · Jan 24, 2021

woodchuckNJ said:
not on my SB 9A , mine was made in WWII, and does not have a mark, I just went and looked.

It is in the bevel of the quill, not really on the side. If your quill is heavily marked up, it might be hidden by the damage.

I had a 1934 9" lathe that also had this mark. It was owned (originally) by my grandfather - I always thought that he had made that mark, but later I learned that SB made that mark as part of the lathe check-out prior to shipping.

Here's what they look like:

texasgeartrain · Jan 25, 2021

My quill mark is on the side, but I don't have a bevel either.

In truth I don't find the quill mark all that convenient, as I have to fully extend quill to reach across compound.

But if you don't have anything else, it'll help. If you don't have that mark, you could etch it yourself with a lathe cutting tool. Figure out height by a facing cut. Sharpe point tool, Run compound in till tool touches quill, and use saddle like a shaper, move saddle back and forth while feeding compound in a few thousandths. Cut a line like .005" to .010" deep.

QuickChange · Jan 25, 2021

SLK001 said:
It is in the bevel of the quill, not really on the side. If your quill is heavily marked up, it might be hidden by the damage.

I had a 1934 9" lathe that also had this mark. It was owned (originally) by my grandfather - I always thought that he had made that mark, but later I learned that SB made that mark as part of the lathe check-out prior to shipping.

SLK-- I learned something after reading your post. Just checked MY 9" B Model, it's a WW2 era lathe ( has the WAR PRODUCTION TAG on the front), and it DOES have that "height" mark on the quill. Like some others have opined, I never knew it was there! I guess it's not something you would notice offhand unless you were actually LOOKING for it. I guess it's possible the lathe's original owner (I'm the second) may have stamped it there...but good to know it's THERE if I need it!

SLK001 · Jan 25, 2021

QuickChange said:
SLK-- I learned something after reading your post. Just checked MY 9" B Model, it's a WW2 era lathe ( has the WAR PRODUCTION TAG on the front), and it DOES have that "height" mark on the quill. Like some others have opined, I never knew it was there! I guess it's not something you would notice offhand unless you were actually LOOKING for it. I guess it's possible the lathe's original owner (I'm the second) may have stamped it there...but good to know it's THERE if I need it!

If the quill is original, it should be marked with the center height. If the quill was replaced some time in the lathe's life, a new quill wouldn't have this mark, unless the owner re-scribed the mark once he got it installed.

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