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- Mar 21, 2013
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Got my 98-12 for $45 at a flea market. And a case of butt-burn as the wallet cleared my pocket.
Nice find! I quickly forgot how much I paid for mine, and don't want to remember.
Got my 98-12 for $45 at a flea market. And a case of butt-burn as the wallet cleared my pocket.
I think people are getting the reason for leveling a lathe confused. The lathe itself could be at a 45 degree angle and still cut true. The reason to use a precision level is to take and twist out of the bed from the head stock to the tail stock.
If the bed is twisted and you start a long cut from the head stock and you are dead on centerline of the work piece then by the time you get to the tail stock the cutter will either be above or below the centerline causing the accuracy to be a couple thousands off. Some lathes actually have an adjustment at the tail stock end to twist the bed so you can make sure it is perfect.
Here is a cool pdf file from southbend that has a good explanation of why and how to level a lathe.
Starting at page 16 talks about leveling.
http://www.wswells.com/data/howto/H-3.pdf
It seems to me if the lathe is leveled perfectly in the transverse ( across the ways ) direction it will cut a PERFECT test bar, excluding bed and or carriage wear of course.To clarify I leveled to establish a reference. In theory you can level a lathe but that doesn't necessarily guarantee it will cut a straight cylinder. You need to tweak the leveling feet slightly so that your lathe will cut straight within acceptable limits. This is not my analogy as I read it somewhere else but a great example of not needing to level a lathe is one on a ship. As you know ships are rarely level and if they are they don't stay there very long. So as long as it cuts straight level is irrelevant. Back to my point, level is only a reference and is not necessary to accomplish accurate work. My lathe cuts within .0005" over 8 inches. Plenty close for me. Not trying to be a wise a** just offering up my approach and results.
Tom S
It seems to me if the lathe is leveled perfectly in the transverse ( across the ways ) direction it will cut a PERFECT test bar, excluding bed and or carriage wear of course.
Longitudinal leveling, while not really affecting accuracy, is the "workmanlike" thing to do as this places the lathe in its original " as manufactured" attitude .
I have heard the "lathe on a ship" analogy before and it is usually completely misinterpreted. Lathe setup on shipboard is the same as anywhere else. The LATHE BED must
be totally flat in the TRANSVERSE Plane over its full length. Also, parallel to the spindle of course, but not necessarily " level ". " Leveling " is the easiest and best way of
aligning the bed to a single flat plane. Enough hot air from me, the link placed by 737 mechanic to the W. S. Wells site is a great and clear explanation from S. B Lathe Works,
I recommend reading it through completely ; http://www.wswells.com/data/howto/H-3.pdf …my two cents, thanks.