These are extremely glove friendly
https://www.amazon.com/Gloxco-Alumi...+Fittings&qid=1663348556&s=industrial&sr=1-24
https://www.amazon.com/Gloxco-Alumi...+Fittings&qid=1663348556&s=industrial&sr=1-24
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11.5 TPI
- Thread starter Just for fun
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- Oct 7, 2020
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It's a frost-free hydrant that I still need to use to water the chickens. And in the summer, I hook up a manifold system that feeds several water systems.
The summer manifold system.
The summer manifold system.
Hi Tim,
I was traveling when I posted the link to my Threading spread sheet, so could not run it for you at that time. However, I just ran it. Anyway, if you have not found a gear solution yet here is an alternative to the 11.5TPI gearing for the 1236T, which according to the PM web site is the same as the 1340GT.
I think the gears that came with the lathe were 30T, 32T, 40T plus the 120/127T change gear so I used these as possible combinations. If so and my spread sheet works for the 1236T then:
The following gear set up should get you to 11.5175TPI , which is only 0.15% off from the exact 11.5TPI.
Set your gearing as follows: Norton gear box to Seven and B, at the spindle output put the 32T gear in contact with the 120T of the change gear, at the gear box input put the 30T gear in contact with the 127T of the change gear. Make your cut using the lead screw drive.
Let us know if this works for you.
I will attach two pdf copies of the entire set of possible TPI that I think you can make with your machine. They are the same numbers, but one is sorted by increasing TPI values and shows the search for the ~11.5 TPI. The second appears to have random TPI order, but is actually sorted by the gears that are being inserted. There are some duplicates in the spread sheet and there are some places where it calls for you to use the same gear in two positions, but .... It also provides all of the metric threads that are possible plus it also calculates the TPI values you would get if you used the feed bar to drive the saddle rather than the lead screw. (I do not know if that is physically possible on your lathe model but it is on my 1440GT.) The spread sheet macros that is posted allows you to sort the table in various ways as well as to search for TPI values that are close to the one you may want. If you have additional gears you can change the sheets to include these then regenerate the table. (By the way, the feed values that are printed on some of the lathes are not very accurate!)
Including these possible redundancies, the table indicates that there are 1442 possible TPI values that you can cut using the lead screw and if you add the feed drive then the number goes to 1622.
Hopefully this is useful sometime!
Dave L.
I was traveling when I posted the link to my Threading spread sheet, so could not run it for you at that time. However, I just ran it. Anyway, if you have not found a gear solution yet here is an alternative to the 11.5TPI gearing for the 1236T, which according to the PM web site is the same as the 1340GT.
I think the gears that came with the lathe were 30T, 32T, 40T plus the 120/127T change gear so I used these as possible combinations. If so and my spread sheet works for the 1236T then:
The following gear set up should get you to 11.5175TPI , which is only 0.15% off from the exact 11.5TPI.
Set your gearing as follows: Norton gear box to Seven and B, at the spindle output put the 32T gear in contact with the 120T of the change gear, at the gear box input put the 30T gear in contact with the 127T of the change gear. Make your cut using the lead screw drive.
Let us know if this works for you.
I will attach two pdf copies of the entire set of possible TPI that I think you can make with your machine. They are the same numbers, but one is sorted by increasing TPI values and shows the search for the ~11.5 TPI. The second appears to have random TPI order, but is actually sorted by the gears that are being inserted. There are some duplicates in the spread sheet and there are some places where it calls for you to use the same gear in two positions, but .... It also provides all of the metric threads that are possible plus it also calculates the TPI values you would get if you used the feed bar to drive the saddle rather than the lead screw. (I do not know if that is physically possible on your lathe model but it is on my 1440GT.) The spread sheet macros that is posted allows you to sort the table in various ways as well as to search for TPI values that are close to the one you may want. If you have additional gears you can change the sheets to include these then regenerate the table. (By the way, the feed values that are printed on some of the lathes are not very accurate!)
Including these possible redundancies, the table indicates that there are 1442 possible TPI values that you can cut using the lead screw and if you add the feed drive then the number goes to 1622.
TPI Feeds X-Feeds: Generalized Excel file for your Lathe
TPI Feeds X-Feeds: Generalized Excel file for your Lathe Hi Folks, My PM1440GT lathe manual only showed a few of the possible threading values and it appeared to me that the Feed rates were incorrect. They were. Hence, I set about to figure out what all possible TPI could be achieved via...
Hopefully this is useful sometime!
Dave L.
- Joined
- Oct 7, 2020
- Messages
- 2,427
Thanks Dave,
I'm not sure what you're talking about using lead screw vs the feed drive? As far as I know when threading I can only use the leadscrew.
My friend made me three gears one of the gray one is a little too small, the black one fits the shaft really well and seems to mesh with the gears really well. (I need to get one of those 3D printers, that's some cool stuff) I haven't tried anything other than that so far. Thank to @Ken226 for the stl file.
So, after lots of discussion on this subject of cutting 11.5 tpi and the fact that I can't turn a taper. I have decided that @jwmelvin has the best idea and will probably go that route.
I will check out the gears and see if I can cut 11.5 tpi but to implement my plan would not work well considering I need to drain the water out of the pipe as quickly and thoroughly as possible when it is only single digits outside.
- Joined
- Oct 7, 2020
- Messages
- 2,427
I gave it a little test run today, running 40-127 and 120-46 with the Norton gear box in B2. I took a few light cuts of .005 and then a couple .002. It looks like 11.5 TPI and the gear still looks like new. I just grabbed a piece of mystery metal just to see if I could cut 11.5.
@B2 Dave, I have not tried your gear setup yet, next time I get achance I'll try it and let you know.
Somewhere I read with that gear setup to use B8, but they may have been talking about a PM1340, maybe there is a difference. At any rate B8 was more like 18 TPI.
Here is a photo of my test piece.
@B2 Dave, I have not tried your gear setup yet, next time I get achance I'll try it and let you know.
Somewhere I read with that gear setup to use B8, but they may have been talking about a PM1340, maybe there is a difference. At any rate B8 was more like 18 TPI.
Here is a photo of my test piece.
Last edited:
Good Morning Tim,
Looks like you have a good solution! I have never tried the 3D printed gears, but I suspect that they work fine, but maybe wear out after a lot of usage. I always wanted one to convert to metric threading for my old SB lathe. Maybe one of these days I will make one on my 3D printer, but I an not for sure why now that I have the 1440GT.
I am not for sure about the 1236T vs the 1340GT, but I think they have the same gear box etc. In fact, just by looking at the PM web site it appears the 1340 just has a longer bed and the 13 inch swing, plus you get a stand. The Feed rod runs parallel to the lead screw, and is just below it, but only has a slot in it, not threads. This slot turns and engages with the saddle gears. On the spread sheet that I posted to you, if you look at the 4, 5,and 6th columns you will see the feed rates. Printed labels that come on the lathes are not very accurate as to xfeed rates and in come cases they are just wrong. If I recall the arrow knob just to the right of your Norton gear box handles determines if the feed rod is engaged. You will notice that by using the feed to cut threads you can get some very high TPI values. My old SB would generate these just via the Norton gear box, but the 1440GT is limited. The only time I ever needed TPI greater than 100 was when I needed make some very precise/delicate devices. This was for an optical systems where I wanted to move a lens along a threaded rod by only 1 or 2 microns. (1 turn of a 100TPI thread is 0.01 inch or 254 micron.)
When I was working on the spread sheet I went through the 1340GT settings with @Ischgl99 . He is very knowledgeable about the 1340GT lathe gearing and we worked out the details of the xfeed gears in the saddle. Anyway, on my PM1440GT the X-feed rod can be used in a manor similar to the lead screw to cause the saddle to move down the lathe. Hence, it can be used to cut threads. However, this maybe not be as precise as using the lead screw. My old SB 10 Heavy does not have a feed rod, one just uses the lead screw to do x-feeds.
I look forward to hearing if my proposed gear settings generates the calculated 11.5175 TPI value, although measuring anything more accurate than 11.5 maybe be very difficult.
Dave L.
Looks like you have a good solution! I have never tried the 3D printed gears, but I suspect that they work fine, but maybe wear out after a lot of usage. I always wanted one to convert to metric threading for my old SB lathe. Maybe one of these days I will make one on my 3D printer, but I an not for sure why now that I have the 1440GT.
I am not for sure about the 1236T vs the 1340GT, but I think they have the same gear box etc. In fact, just by looking at the PM web site it appears the 1340 just has a longer bed and the 13 inch swing, plus you get a stand. The Feed rod runs parallel to the lead screw, and is just below it, but only has a slot in it, not threads. This slot turns and engages with the saddle gears. On the spread sheet that I posted to you, if you look at the 4, 5,and 6th columns you will see the feed rates. Printed labels that come on the lathes are not very accurate as to xfeed rates and in come cases they are just wrong. If I recall the arrow knob just to the right of your Norton gear box handles determines if the feed rod is engaged. You will notice that by using the feed to cut threads you can get some very high TPI values. My old SB would generate these just via the Norton gear box, but the 1440GT is limited. The only time I ever needed TPI greater than 100 was when I needed make some very precise/delicate devices. This was for an optical systems where I wanted to move a lens along a threaded rod by only 1 or 2 microns. (1 turn of a 100TPI thread is 0.01 inch or 254 micron.)
When I was working on the spread sheet I went through the 1340GT settings with @Ischgl99 . He is very knowledgeable about the 1340GT lathe gearing and we worked out the details of the xfeed gears in the saddle. Anyway, on my PM1440GT the X-feed rod can be used in a manor similar to the lead screw to cause the saddle to move down the lathe. Hence, it can be used to cut threads. However, this maybe not be as precise as using the lead screw. My old SB 10 Heavy does not have a feed rod, one just uses the lead screw to do x-feeds.
I look forward to hearing if my proposed gear settings generates the calculated 11.5175 TPI value, although measuring anything more accurate than 11.5 maybe be very difficult.
Dave L.
- Joined
- Oct 7, 2020
- Messages
- 2,427
I found the original thread where the decision was cutting 11.5 TPI on a PM1340. In post #4 @davidpbest recommended 40-127 120-46 and the Norton box position B8 would get you 11.503. I was not able to reproduce that. In position B8 I was getting closer 18 TPI.
https://www.hobby-machinist.com/threads/pm-1340-gt-threading.84388/
https://www.hobby-machinist.com/threads/pm-1340-gt-threading.84388/
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