Hi I'm new to this forum so mods please feel free to move this thread to the appropriate place if needed. I have been using a Jet 1440-3PGH lathe at work, the only problem is the feed speed/threading chart is missing. I have looked all over the net for a picture of this chart but I can't seem to find one. I have called Jet and they have been no help at all finding a replacement chart or even just a picture of one. For the feed speeds I have spent some time manually turning the chuck and measuring how far the carriage moves. As for threading this has proven to be more difficult. Any suggestions would be welcome.
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Speed and threading chart?
- Thread starter Aqua-Andy
- Start date
Welcome to the H-M.
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More can be found here. http://www.airlinebrats.com/lathe/
Is this what you are looking for:
More can be found here. http://www.airlinebrats.com/lathe/
- Joined
- Jul 2, 2014
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- 7,594
That chart is odd in that it shows straight gearing for metric threads, along with compound gearing for both metric and imperial threads. Is the chart for a metric lead screw or an imperial one? It appears to me to be correct for a metric lead screw. The OP did not say which lead screw he has, but it really does matter!Welcome to the H-M.
Is this what you are looking for:
More can be found here. http://www.airlinebrats.com/lathe/
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- 959
Bob,
The bottom of the chart says 4TPI lead screw, 8TPI feed rod. That chart is kind of confusing to me.
Ted
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- Jul 2, 2014
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Good catch, Ted! It looks like the entire box on the left is for feeds. But then they show compound gearing for both metric and imperial threads. I don't get it...
Thanks for the help with the chart. I tried cutting my first thread today. Well the first did not work out so well, there is a lot going on and that carriage was moving much faster than I was used to. So I cut that part off and tried again. I actually came out with something that resembles a thread and a nut would also screw on to it. Was it pretty? No! But I think this is a good start, when I have more time I will try some more.
Well I finally got time to play with the lathe today. I tried cutting a 12x1.75 thread. I made sure the bit was ground at a 60* angle. set the compound to 29.5* and squared the bit to the part. On this lathe you can't use the threading dial for metric threads so I just stopped the machine, pulled out the tool and reversed until I was at my starting point again. The problem I had was the threads came out looking more like arrows than a nice "V", as in the right side of the thread had a 90* angle and the left side sloped from the peak to the valley. After looking at things I tried again and instead of using the compound to feed the bit in I used the cross feed. So I would make a pass then pull out and then on the next pass turn in the cross feed to where it was plus what I wanted to take off. this last thread came out looking nice, it had a nice "V" shape and a nut fit very nice. All the videos I have seen show using the cross feed just to move the tool in and out but using the compound to dial in the amount to be cut. Not sure what I'm doing wrong.
