# what is the acceptable limits for a c2 seig lathe and how do you use a mt3 test bar in setup ?



## DavidOulton (Jan 23, 2013)

Do you have any information ?


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## Richard King (Jan 23, 2013)

I wish you would ask your question in more detail.   Do you own one and have questions?  Looking to buy one?   Acceptable limits for what?  swing?  C to C or torque?   What test bar are you referring too?  Those are questions you should ask a distributor or on the Web-Site below:
http://www.siegind.com/products_det...=comp-FrontProducts_list01-1325832996354.html


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## tripletap3 (Jan 23, 2013)

This might help you if you are doing some research. 
http://littlemachineshop.com/Info/MiniLatheUsersGuide.pdf

And as far as I know a Morse taper test bar is only used to check headstock and tailstock alignment. It is a bar that mounts in the spindle taper and is assumed to be perfectly straight allowing you to run a DI down it to check headstock alignment with the bed/ carriage. It will also align the tail stock to spindle center. I have never used one and I don't think most people do. I have only done the "dumbell" or "Rollies dad's" method.


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## Richard King (Jan 23, 2013)

tripletap3 said:


> This might help you if you are doing some research.
> http://littlemachineshop.com/Info/MiniLatheUsersGuide.pdf
> 
> And as far as I know a Morse taper test bar is only used to check headstock and tailstock alignment. It is a bar that mounts in the spindle taper and is assumed to be perfectly straight allowing you to run a DI down it to check headstock alignment with the bed/ carriage. It will also align the tail stock to spindle center. I have never used one and I don't think most people do. I have only done the "dumbell" or "Rollies dad's" method.




That's a great site Triple, thanks for linking it.  I know what the test bars are, but was wondering why David was asking.  Does he have one and did it come with his machine?


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## DMS (Jan 23, 2013)

A test bar is used to test the spindle alignment and runout as others have said. The MT3 versions are fancy, and expensive; nice, but not needed. You can do basically the same thing with a piece of drill rod mounted in the chuck, and there are methods for dealing with inaccuracies in the chuck. Basically (and you should google for more detailed directions). You mount the test bar in the chuck or taper, mount a dial indicator (or better yet, a dial test indicator) on the carriage with the indicator on the bar. Rotate the spindle by hand, and check runout. Move the carriage down the length of the test bar, and check for alignment. 

Another method for doing this is to chuck up a fairly stout piece of stock, and then turn it down so that you just clean up the surface. Take a micrometer and measure at the end farthest from the chuck, and the end nearest to the chuck. If the values are the same, your alignment is dead on. If the values are different, then you are off. You can adjust the headstock to bring things into alignment. With patience you can get things very close. I never bothered to do this on mine, I think it was out about 0.001 over 10 inches.


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## DavidOulton (Jan 29, 2013)

Thanks for your replys , I have the answer thanks to the response of a kind lady called Daisy .


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## Building Something (Feb 5, 2013)

David you have sparked my interest.  I am in the market for a Chinese lathe and would find your info from Daisy very valuable; I have found the responses to your initial question very valuable as well.

Full disclosure:  I would prefer to refirb a piece of Old Iron, however, I want to jump in and start making chips so it looks like Chinese for me to start.


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## Rbeckett (Feb 5, 2013)

Absolutely nothing wrong with a chinese or tiawanese tool.  They have greatly improved in qualtiy over the last few years and a good carefull dissassembly and thorough cleaning with proper reassembly will pay dividends for the life of the machine.   Once you have a machine you can  take your time and get a good old big piece  of American iron to rebuild and have a blast doing it too.  So do jump in and get to chipping as soon as possible, you won't regret it in the long run.
Bob


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## DavidOulton (Feb 6, 2013)

Richard King said:


> I wish you would ask your question in more detail. Do you own one and have questions? Looking to buy one? Acceptable limits for what? swing? C to C or torque? What test bar are you referring too? Those are questions you should ask a distributor or on the Web-Site below:
> http://www.siegind.com/products_det...=comp-FrontProducts_list01-1325832996354.html



Thanks again for all your replys . I own a Seig Cummings 7x12 lathe . I had several times not fully engaged the low /  high shift leaver , with the result of stripping the nylon gears. The head stock was removed to replace the gears with a new Metal gear on the spindal and a new nylon on the selector gear. At the same time I replaced the ball bearings with Tapered Roller bearings . Upon replaceing the head stock I wanted to check to see if it was in correct alingment and that the bearings that were replaced and any cleaning that was done had not effected the lathe.  In order to verify the specifications I had to get the test setup used and limits of the manufacture to check my results against. The run out of the was simple enougth to verify against the chuck race. I got the Factory sheet with all the information on it for my C2 lathe. ( By the way a test bar can be gotten fron UK for < 60$ or 38 pounds. Not nessary only required if you remove the head. )

David Oulton


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