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- Feb 1, 2015
- Messages
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tpi = 25.4 / mm pitch
thds/inch = thds/mm x 25.4 mm/inch = 25.4 /pitch, mm/thd
thds/inch = thds/mm x 25.4 mm/inch = 25.4 /pitch, mm/thd
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Craftsman thread chart
- Thread starter rockyrude
- Start date
- Joined
- Dec 25, 2011
- Messages
- 10,513
rockyrude,
I don't recall whether you have a 6", 10" or 12" lathe but if being able to cut threads is important to you (it doesn't necessarily follow that it is), you should first concentrate on acquiring the additional dozen or so gears called for by your standard threading chart before you worry about whichever transposing pair of gears you need to cut the most metric threads. And get used to the fact that given an inch lead screw, all metric threads are going to be a compromise. Or another way of looking at it is that although theoretically possible, in practice you cannot make an accurate metric lead screw on a machine with an inch leadscrew or vice-versa because you don't have enough space on the banjo for the number of inch-based gears required. Or vice versa.
I don't recall whether you have a 6", 10" or 12" lathe but if being able to cut threads is important to you (it doesn't necessarily follow that it is), you should first concentrate on acquiring the additional dozen or so gears called for by your standard threading chart before you worry about whichever transposing pair of gears you need to cut the most metric threads. And get used to the fact that given an inch lead screw, all metric threads are going to be a compromise. Or another way of looking at it is that although theoretically possible, in practice you cannot make an accurate metric lead screw on a machine with an inch leadscrew or vice-versa because you don't have enough space on the banjo for the number of inch-based gears required. Or vice versa.
- Joined
- Dec 25, 2011
- Messages
- 10,513
OK. In any case, were it mine I would spend time and money first on completing the system including the standard set of gears. And acquire a copy of Version 5 of the MOLO in which among many other things Chapter 7 - Thread Cutting covers threading on the 101.07403. One of the tables covers the more common metric threads.
- Joined
- Dec 25, 2011
- Messages
- 10,513
There is now a PDF copy of Atlas MOLO 1937 V5M3 1942.PDF in the Atlas-Craftsman folders in Downloads. Once you have opened the A-C folder, look for the MOLO folder. The file includes Chapter 7 (pp 62 and following) which covers the 101.07402 and 101.07403. It has a copy of the threading chart for those models and a few pages on has a metric chart in a slightly different format. Note that access to Downloads requires Donor status (any level).