Does anyone ever need to thread anything finer than 56 TPI?

[qualitymachinetools]

Reason I am asking is that I am working on a smaller machine and trying to eliminate change gears. But there is only so much room. So if we just left off anything 60 or higher, wanted to see if there was anything common that I was missing. The 1340GT and others we have go up to 112TPI without a change gear, but I am trying to simplify for a smaller machine. Its nothing too fancy, working on maybe a 10" to 12" smaller hobby lathe with a better gearbox. The hard part is that it has to fit on the machine, these lathes are not that big.

 

[ttabbal]

Reason I am asking is that I am working on a smaller machine and trying to eliminate change gears. But there is only so much room. So if we just left off anything 60 or higher, wanted to see if there was anything common that I was missing. The 1340GT and others we have go up to 112TPI without a change gear, but I am trying to simplify for a smaller machine. Its nothing too fancy, working on maybe a 10" to 12" smaller hobby lathe with a better gearbox. The hard part is that it has to fit on the machine, these lathes are not that big.

Very interesting. I've been seriously considering a 1030 from you guys. For what I'm thinking to use it for, I don't see topping out at 60 TPI to be a big issue. Things like telescopes can use finer threads, but if I couldn't get a die for that I could also look into gearing or just farming that part out. As someone that might be considered part of the target market, I don't think I'd look down on a machine that couldn't go finer, particularly if it gets me no change gears for the rest and other features/equipment/price were in my range.

 

[Doubleeboy]

I would think for the market you are after Matt 56 tpi would be fine. I know watchmakers and telescope makers use finer threads, but compared to how many of those people you would loose a sale to you could afford to loose those if you could make a great little lathe that would appeal to the larger market. I think something the size of a Myford with a good gear box, rigid ways and VS would be a great seller, especially if you could get good quality from China factory to keep price down compared to Taiwan machine.

 

[Ulma Doctor]

personally, i haven't cut threads finer than 32 tpi, but i work on industrial equipment.
IMO a lathe that switches easily from metric to imperial threading easily would be a major plus.
my shenwai 1236 cuts from 4 to 112 tpi without any gear changes-
metric threading i gotta change gears.

 

[pdentrem]

I know that there are some lathe that have a simple gear box and with a simple gear change that cuts the feeds by half with a compound gear. That would work for most users perhaps?
Pierre

 

[whitmore]

Hey guys, working on some updated models of some small lathes, and every once in a while, I get people who ask me why a lathe does not thread any finer than 56 or 60 TPI.
What would anyone make that would be finer than that, anything common?

Not really. #1-72 and #0-80 are down in the eyeglass-hinge size range.
Used taps/dies and off-the-shelf hardware, but never a lathe, on those.
If a real need for smaller adjustment screws came up, a differential screw with
20 tpi and 25 tpi generates a virtual 100 tpi effect, and is a LOT less difficult
to cut. Except that '25 tpi' apparently isn't available in standard taps/dies.

 

[rzbill]

Would this machine have change gears in addition to a gearbox? If so, alternate threads might be available to the specialized user by buying a couple of gears extra. Others would use the range up to 56 or 60 as suggested.

EDIT>Ah, I see that was already suggested 2 post above. Sorry about that.

 

[jim18655]

I made a "center dot" adapter for an Ambo adjustable iris" that was very fine threads. I forget what size thread but I had trouble getting a fine enough point on the treading bit to make a nice cut.

 

[RandyM]

I made a "center dot" adapter for an Ambo adjustable iris" that was very fine threads. I forget what size thread but I had trouble getting a fine enough point on the treading bit to make a nice cut.

I have been wondering about this. Seems it could be quite fussy.

 

[mksj]

Reason I am asking is that I am working on a smaller machine and trying to eliminate change gears.

I think there would be have a significant market in a smaller lathe without/minimal gearbox change gears, I can't see needing anything beyond 56 TPI in this size lathe. As others have pointed out, it is possible to sell a set of change gears, or possible flip the input and output gears for a different set of ratios. But the market for anything beyond 56 TPI is very limited, and I believe there is much greater value to not having to deal with change gears for the most common threads. Below is an example of a 11x26 lathe which covers up to 56 TPI, but a major disadvantage is that you need a pile of change gears. I often suggest to small lathe buyers going with the next size larger lathe, so they do not have to deal with a mess of change gears, and it also gives them more feeds without flipping gears. The other day I was cutting metric threads, and just dealing with re-gearing to 120/127 and back to imperial reminded me of what a PTA it is to deal with gear changes. Really made me appreciate a full range imperial gearbox w/o change gears. Other wish lists would be variable speed with 2 or 3 speed ranges, so something like the PM1022V or PM-1127VF-LB with a full range gearbox I think would be a killer combination, but the latter would be very similar to the PM-1228VF-LB.