Cutting 11.5 Tpi On Pm 1127vf-lb

lpeedin

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Do any of you know a change gear combo that will allow me to cut a 11.5 TPI on my 1127Vf-LB? My chart only shows 10 or 11. Any advice would be greatly appreciated. I am trying to cut thread for a small pipe adapter I am working on.
 
You can look at the gears that it takes to cut a thread the same pitch as your lead screw, find the ratio between your lead screw pitch and 11.5, and see if you can put together a combination that will meet or approximate closely that ratio, working from the gears that match the lead screw pitch to what you need for the 11.5. If you have a quick change gearbox on that lathe you can also use those ratios to the lead screw pitch to help reach your goal. Some people have inputted all that information into a computer program for their lathe that gives results in TPI, decimal inches, and millimeters for every possible combination, but that is above my pay grade... Is it a pipe thread? What are you making?
 
My pm 1030 manual shows a gear combo for 11.5 tpi. I don't know if the lead screw and gear box ratios are the same as yours but it might give you a place to start.
 
Dale, if you don't mind, can you tell me or shoot me a pic of the change gear chart for your machine?

Bob, I am actually trying to finish up my coolant mist system and meed to make a reducer bushing. I just realized that I don't actually need the 11.5 TPI, but I still would like to know how since this is a standard for garden hoses and such. I made my kids a water balloon filler last year and just did 11 TPI with only two threads. I would like to be able to do it correctly this year.
 
I don't have a way to send pictures. The gears for 11.5 tpi are Z1 H , Z2 70 , Z4 30 , Z3 46 , L 75 H . Hope that helps. You might be able to get PM to email you a copy of the chart.
 
Dale, I appreciate your response. Is that 46 correct? I know I don't have a 46.
 
You will still need to do the math to see if it will work on you lathe. Different lathes often have different gearing.
 
I'm pretty sure it says 46. some numbers in my manual are hard to see. It could be 40. I have not looked to see if I have a 46 either. My gears are not marked that great either.
 
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