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

OK Thanks guys, yes thats what I am going for, no change gears for inch threads from 4-56 TPI or so. I just wanted to make sure I wasnt missing anything obvious thats finer than 56TPI. A few cases came up, but nothing that I see thats too common. Just checking my thinking against others for a bit. I've done a lot of difficult things in a machine shop, worked on some pretty difficult jobs. But I am not sure if I would be able to make a #1 screw. Heck even a 4-40 is tiny.

There will be change gears for Metric, the gearbox to do that without change gears is just way too big for these smaller machines. We are just working on shrinking down a gearbox like the one from the 1340GT that cuts them all without a change gear, so it can fit on a smaller machine. My goal is a 10/11" Lathe with a quick change gearbox, no change gears for any common inch threads. At a reasonable price. None exist that I've ever found.
 
That sounds great! Any idea when something might be available? I'm likely a couple months out, but I suspect this project of yours might take longer than that. :)
 
RandyM said:
I have been wondering about this. Seems it could be quite fussy.
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They do make micro threading tools. I have seen them in the catalogs at one point. I imagine they are pricey, as I don't remember anything other than seeing them. You put that in the back of your brain for reference if you need it... ya know.
 
Depends on the factory, but I'd say about a year or so, it takes some time. Nothing is 100% yet, if its going to cost as much as a 12", then there is no point, but we will see.
 
Just one guys opinion but if a 12x36 costs $3,000 plus and a high quality feature rich 10x22 could be had sub $2,500 I think you would have a winner. I don't think it needs to be in the $1,500 range like other 10x22 machines that are lacking features. The features I would go for include larger bore than normal for this size, say 1.25" or more. Extend the spindle just enough to drill it for spider screws. An apron with the features of the 1340GT. QCGB like the 1340GT minus a couple gears. With gear changes the 1340GT can likely get in the 250TPI gear range anyway. If this little guy could do 4-40 TPI without a change that would be great. Change the drive and driven gear from 40-40 to 30-60 and you double the capability and get 80TPI. Use 120/127 for the idler gear instead of the 86/91 used by many lathes to get dead on accuracy with metric threads rather than close enough. Thread the mounting holes for adjustable feet for use on a bench. Throw in a little extra mass so it is rigid for its size. Sorry, now I'm just rambling. Sounds like a great lathe that would fit on a work bench.

Best of luck in your pursuit,
Dave
 
qualitymachinetools said:
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.
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If it is a smaller lathe, why not eliminate some of the coarse thread pitches. I don't know much about lathes but if someone were to purchase a smaller lathe perhaps they would be doing finer threading work. If I were working on instruments and needed a lathe I would want one that is super smooth and quite with tollerances to handle fine work. Is it practical to thread 8 TPI in steel on a 1 HP lathe?
 
bretthl said:
If it is a smaller lathe, why not eliminate some of the coarse thread pitches. I don't know much about lathes but if someone were to purchase a smaller lathe perhaps they would be doing finer threading work. If I were working on instruments and needed a lathe I would want one that is super smooth and quite with tollerances to handle fine work. Is it practical to thread 8 TPI in steel on a 1 HP lathe?
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If you need that high find a watch lathe. Generally the swiss make watches on lathes that have no power, they hand turn the spindle.
Consider that most of the lathes old and new fit what is generally needed for the size. And the higher threads might be considered fine, or super fine.
 
Is 60 TPI possible? What is the diameter of an iron atom? ;)
Robert
 
I've had to do 40tpi a bunch, but never finer in 38 years.
 
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