Agree with your first comment.
Re running a test at 8 tpi, hasn't it already been shown that a 16 tpi setting has only given 15 revolutions per inch?
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Agree with your first comment.
Re running a test at 8 tpi, hasn't it already been shown that a 16 tpi setting has only given 15 revolutions per inch?
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The OP’s opening post pretty much proved the thread dial that’s now on the lathe doesn’t match the leadscrew that’s now on the lathe. That being the case, that thread dial is useless for cutting threads of any type on that lathe as is.
As I said earlier, setting the gear box for 16 TPI and getting a 15 TPI thread indicates that the gear train was designed and built to drive a leadscrew with 3mm pitch. The lathe probably had a 3mm pitch leadscrew when new. That combo of gears with an 8 TPI leadscrew will give you 15.1 TPI when the gear box is set for 16 TPI. That's why I suggested earlier to set the gear box for a 1.5 mm pitch thread and see if it makes a 16 TPI thread. If it does, that will prove that the gear box was assembled with gear ratios to drive a 3mm pitch leadscrew.
Another way to look at it is, when the gear box is set to cut 1.5 mm threads with a 3mm pitch leadscrew, that's a 2:1 ratio between spindle and leadscrew. When the spindle turns 2 revs, the leadscrew will turn one rev. If the leadscrew has a 3mm pitch, the carriage will advance 1.5 mm for each rev of the spindle, cutting a 1.5 mm pitch thread in the work piece. But, if the leadscrew is changed to an 8 TPI (1/8" pitch), then the carriage will advance 1/16" for each rev of the spindle, cutting an 16 TPI thread in the work piece. I hope the OP gets to run that test soon. Will answer a lot of questions.
Tom
As I said earlier, setting the gear box for 16 TPI and getting a 15 TPI thread indicates that the gear train was designed and built to drive a leadscrew with 3mm pitch. The lathe probably had a 3mm pitch leadscrew when new. That combo of gears with an 8 TPI leadscrew will give you 15.1 TPI when the gear box is set for 16 TPI. That's why I suggested earlier to set the gear box for a 1.5 mm pitch thread and see if it makes a 16 TPI thread. If it does, that will prove that the gear box was assembled with gear ratios to drive a 3mm pitch leadscrew.
Another way to look at it is, when the gear box is set to cut 1.5 mm threads with a 3mm pitch leadscrew, that's a 2:1 ratio between spindle and leadscrew. When the spindle turns 2 revs, the leadscrew will turn one rev. If the leadscrew has a 3mm pitch, the carriage will advance 1.5 mm for each rev of the spindle, cutting a 1.5 mm pitch thread in the work piece. But, if the leadscrew is changed to an 8 TPI (1/8" pitch), then the carriage will advance 1/16" for each rev of the spindle, cutting an 16 TPI thread in the work piece. I hope the OP gets to run that test soon. Will answer a lot of questions.
Tom
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Yes, set it up to cut a 1.5 mm pitch thread. That is, set the adjustable lever on the end gears for metric and set the gear box for 1.5 mm. I'm thinking that will make a 16 TPI thread with the 8 TPI leadscrew that's on the machine.
Tom
Tom
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Hukshawn
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I will try to do it tomorrow morning before I leave if I have a few mins. I'll go get it set up right now and just run it in the morning. Too loud this late and my kiddos bedroom is right above the garage. My wife would be none too pleased.
IF it's supposed to have a metric lead screw, and if by some marical I can find one to instal, will that mean I'll be able to use metric and imperial properly? As this lathe seems to advertise. I don't know metric threading at all, and can't say I'm terribly interested to learn it.
I'll also note, India (where this lathe was made) uses the metric system... that would support this being a metric lathe.
IF it's supposed to have a metric lead screw, and if by some marical I can find one to instal, will that mean I'll be able to use metric and imperial properly? As this lathe seems to advertise. I don't know metric threading at all, and can't say I'm terribly interested to learn it.
I'll also note, India (where this lathe was made) uses the metric system... that would support this being a metric lathe.
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Understood. No sense playing with fire.
If it's all set up to go, it shouldn't take much time in the morning. You only have to make one pass to be able to measure the thread pitch. If you do make multiple passes, leave the half nuts engaged.Tom
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Hukshawn
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So I did the test. Set the gears to metric, set the gear box to 1.5..... guess what it cut...?
A 1.5....
16 didn't fit
Edit - I just hand cranked the lathe in front gears.
A 1.5....
16 didn't fit
Edit - I just hand cranked the lathe in front gears.
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Hukshawn
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So I'm freezing in my underwear in the garage...
I set up to cut a 1.5, a 2.0, a 2.5, and a 3.0. All match perfectly in the thread gauge.
I set up to cut a 1.5, a 2.0, a 2.5, and a 3.0. All match perfectly in the thread gauge.
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Hukshawn
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So I guess that means... Hello, Mr Huk! Welcome to the metric system....
I'm relieved... at least I can cut a thread and replicate it. I'll figure out the thread dial another day and figure out how to use it in metric. maybe now I can finally finish my project, albeit, in metric now.
I'm relieved... at least I can cut a thread and replicate it. I'll figure out the thread dial another day and figure out how to use it in metric. maybe now I can finally finish my project, albeit, in metric now.
Good job Mr. Huk, have a hot eggnog on me
Tom, thanks for guidance. I'm learning from this too and looking forward to the next installment.
A question comes to mind; if the lathe cuts metric threads according to the settings provided on the charts, doesn't that mean that the lead screw is O.E.M.?
Tom, thanks for guidance. I'm learning from this too and looking forward to the next installment.
A question comes to mind; if the lathe cuts metric threads according to the settings provided on the charts, doesn't that mean that the lead screw is O.E.M.?
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