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Why some SB lathes have graduated dial 0-120
- Thread starter tbone8
- Start date
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- Jan 20, 2018
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- 5,681
120 or 125? How many marks between 120 and 0? Picture?
125 would be 8-tpi lead-screw.
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- Apr 19, 2015
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- 38
Will double check tomorrow but after looking at one on the ebay, like you say, it is probably 0-125. So each hash mark would still be .001 with that 8 tpi screw then? Why was that done, seems confusing...
- Joined
- Jan 20, 2018
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- 5,681
Yes, still .001. I believe early machines had 8-tpi cross-feed lead-screws, back when it was common to think and design in fractions.
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- Jun 7, 2013
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- 10,154
That was before direct reading dials, which had to be larger in diameter, so we knew that .125 on the dial meant .250 on the diameter for the crossfeed.
- Joined
- Apr 19, 2015
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- 38