I have finally completed my project to rebuild a 1985 4 1/2 foot hardened bed SBL 10L. I bought it in the Spring of 2009 and have been rebuilding (maybe better stated "re-manufacturing") for more than six months. Paid $500.00 for it and have spent probably another $3,000.00 (which includes a Bison 3-jaw and a Buck 4 jaw(from Ted Pflugner aka SBLatheman) as well as precision bed way regrind(took 0.010" off) and precision fitting and scraping of NOS apron. Along the way I replaced most of rotating parts with either new or new old stock ( NOS) as well a making a new tailstock spindle, modifying the TS to travel 3 1/2 inches instead of 2 inches, and building a electronic variable speed feed screw drive. I will attach a photo of the parts I discarded. When I purchased the lathe it had a 0.0045" dip in the bed at the wear sweet spot. I knew that when I bought it, but as it had a flame hardened bed and the price was right, it was a "no never mind to me".

I tried to rebuild the 10L to tool room specs. This included such items a re-cutting the apron cross slide dovetail and scraping them to get zero tolerance cross slide travel (90 degrees to bed ways), rebuilding the headstock, complete rebuild of apron will new parts and so forth. Re-fitting cross slide and compound via re-machining and scraping. The original tailstock was a basket case but I did not replace the tailstock with new or NOS but found one in very good condition from C. Donges which I shimed to zero tolerance using my South Bend headstock test bar.

Some of the results of the rebuild are: (1) using my South Bend test bar inserted in the headstock taper= ZERO run out of front side of test bar (see photo) from one end of test bar to other end traveling the carriage with a dial indicator mounted; (2) ZERO runout on top of test bar with carriage traveling after shimming/rebuild tail stock; (3) inserted a 13 inch long 1 1/2"(a bit under sized) dia. 1020 steel bar in the 3-jaw chuck with 9 1/2 inches extended from chuck(unsuported by tailstock) and took a 0.025" test cut which resulted in the same diameter (1.443") the entire length of the bar (see photo); (4) 3/4 inch dia bar between center gave results of same diameter(measured to 0.0005" scale) and finally the heavy heavy heavy weight test to see if the lathe bed could take a lots of strain, I put a 30 inch long 2 inch diameter 1020 bar between centers and took a cut--the result was (measured about each six inches in length of the bar reading from headstock to tailstock: 1.9495" 1.9495" 1.950" 1.950" 1.950" 1.950" (see photos).

I am surprised that a South Bend 10L can cut to the tolerances I have encountered now. They must have been a lot more accurate lathes when new than what many of us thought--especially the tool room models. I have not done enough testing to determine if it will cut to +/- ).00025", but I believe it will be near that. Of course I have to give major credit to Machinery Solutions, Inc. of Lexington, SC to the precision regrind and machining and scraping the NOS apron to fit the reground bed. It was a real find when Milacron gave me their name and address.

Ted Pflugner. Will you comment on whether the accuracy I am encountered with my "new" 10L is to what you saw in really new tool room 10L when you were at South Bend Lathe Co.?

Next is my Oct 1941 9B with 4 foot bed and 0.008" dip in the bed sweet spot. Shipped to USA Treasury Dept originally.

I hope some of my experiences and photos will help others.

You will notice that I changed out the good Baldor motor. I changed it to a rubber mounted new motor in order to reduce vibration and noise. Reducing any amount of vibration helps increase accuracy and noise reduction helps reduce fatigue of operator.

Regards;
Steve

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Here are some more photos

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More photos

These photos show final rebuilt apron and fitted and scraped saddle ready to be installed.

Also show gluing the serpentine belt when I re-installed the headstock. These belts reduce vibration greatly and therefore increase accuracy.

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Steve,

A real beauty, for sure. Could you tell us who did the bed grinding and what it cost?

Ryan

This test was done in accordance with Harry Beckley instructions on the Monarch lathe site of PM.

Also photo of lathe after painting and rebuild, but prior to adding the new tailstock 3 1/2 inch travel modification and before adding the electronic variable speed feed screw control. The last two photos are the tailstock modification and feed screw modification. The last 3 photos are also prior to bed regrind.

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Ryan;

Machinery Solutions, Inc. of Lexington, SC did the lathe bed work. Cost is $100/ft for bed regrind and $90.00/hr. for scraping and fitting.

Steve,
Nice work!
You have seen the test card that South Bend used, they always met those specs. They were pretty darn good. Yours is too!
Ted

Where did you buy the belt? what brand belt? what glue did you use? Would that belt work on a 1984 10k underdrive model?

Auto Zone; Dayco; See photo attached for glue--use either; Yes.

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You don't happen to have next weeks lotto numbers do you???

Those specs don't strike me as surprising. When I finished the rebuild of my 10L, I cut an ~8" (it's been 4 years, don't remember the exact length) bronze bar of 1.75" diameter, 0.002" DOC, 0.0007" IPR feed, no tailstock support. The bar was of uniform diameter to 0.0003" over the entire length, being large at the unsupported end (deflection possibly?).

I think it was and is normal for machines that are aimed at industry hold tolerances like that or better. Those numbers are only impressive because we are all used to clapped out machines on the used markets, or trashy imports which are marketed to people who don't know the difference between holding 0.0001", 0.001", and 0.010". Look at the tolerances on even low-end CNC machines like a Haas, and suddenly it seems a machine which doesn't hold +/- 0.00025" out of the factory is abnormal, not the other way around.

You've done a very nice job, but I do wish to clarify a point regarding the cross slide alignment test.
Below is a picture of the set-up for the cross slide alignment test that I think you are referring too. It is from post #117 of the "Another New Toy" topic on the Monarch forum. The parallel is approx 1" X 2" X 12". It was chosen because that is the biggest parallel I have. Please note that it is held in 4 jaw chuck. The chuck is rotated 180*, and checked for 0-0 indicator readings, if it isn't 0-0, adjustments are made until it is 0-0. Note that I had to use a shim on one of the jaws. Of course it also has to be vertically square, or you will get false readings. Next the cross slide is slid across the cross slide ways, noting the changes in the indicator readings. The maximum deviation is .0005"/6" concave. The above procedure is from Connelly's book "Machine Tool Reconditioning".

Harry

Harry;

Thanks for commenting on the cross slide alignment. I could have been more clear in what the two photos were illustrating. The two photos show the actual travel of the point of the indicator from front to rear of the 1-2-3 block using a indicator with a 0.0005" scale. There might have been 0.0002" concavity. I need a dial indicator with a 0.0001" scale to illustrate better. I had a bit of luck on my test as the SBL 10L headstock spindle I have is a D1-4 and when I bolted/placed a precision 1-2-3 block on the front of it, I only had to fiddle and turn the spindle a few degrees one time in order to get the dial indicator to a 180 degree 0-0 reference point--did not have to shim one side. The front of the D1-4 spindle has a precision ground surface where I could place and bolt the 1-2-3 bock. If the spindle had been the typical threaded South Bend one, it would have been much more trouble and I would have had to use a 4-jaw chuck. And of course 3 inches of travel is about all I get with my 10L cross slide so I could use a 1-2-3 block and not a 2-4-6 block. Ted Pflunger says that the craftsmen at the South Bend Lathe Co. had an adjustable protractor that they inserted into the front of the headstock to perform this test. It took me the best part of a day to mill the saddle dovetails and scrape them to get the cross slide into proper alignment. It was a much larger task than I had expected. However, I had to do it as it was .006" off alignment front to rear. The scrapeing of the gib was a bit of chore as well. I learned a lot from you tutorial on the Monarch site.

Sincere kindest regards;
Steve

It is good to know that talented and skilled craftsmen such as you look in on us rank South Bend Lathe amateurs from time to time.

No, and I did not have last week's lotto numbers either. Thanks for pointing out the typo. I have not been down to Australia for a 6 or 7 years (last time to Tasmania). I hope the summer has been pleasant and that the fires do not happen this year. Such a beautiful country and such wonderful wine. I can't afford even a bottle of Grange though.

Hi Steve,
I just read your post on the rebuild of your 10L. I was very impressed with the work. I also have a 1979 10L with D1-4 spindle, long bed and flame hardened ways. I have been working on mine for about 18 months. My question for you is do you know the original specifications for the D1-4 spindle journal diameters? Any information would be greatly appriciated.

Mike

Some might be aghast at my suggestion but couldn't you just take a light cut on the spindle nose with a carbide tool to square it up before disassembly? This would provide a nice reference surface for squaring up the cross slide, no?

Joe

Mechatgsk;

I don't remember what they are just now. But Ted Pflugner, late of South Bend Lathe Co. can tell us. Maybe he will read this and respond. Both of my journals were under by 0.0005", so I just polished them and installed new sleeve bearing that I bought from Ted. If yours are too far undersized, you could send the spindle to Miller Machine and let him build them up for you. You can find Miller Machine's contact info on the "sticky" about parts and so forth.

The spindle original size will be the next standard bearing size "whole" number(s) up from what your spindle journal measure. For example (I am just picking a number) if they measure 2.121" then you could expect the original size to have been 2.125"

Best Regards;
Steve

No. it would not provide a nice reference surface, because you do not know if the saddle dovetails are perfect 90 degrees to the spindle then. Even if the dovetails are only off by 0.0005' in two inches of travel, they are not a perfect zero to zero that you must have with an adjustable protractor or setting up a 1-2-3 block or something similar to get to a zero to zero condition.

Front 2.2490/2.2495"
rear 1.8740/1.8745"

same for the 2 1/4-8 and the LOO spindles
Ted