Wondering if I can cut outside threads on 2" or 2.5" or 3" steel pipe?
I’m not aware of DMS possessing any NPT taps or dies.
One of the drawers in the tall tool box right outside the wood shop doors is labeled “taps and dies”, I think. Not sure what “NPT” stands for, or whether what’s in the drawer is suitable for your needs…it’s anyone’s guess what’s in there and/or what was originally there. Probably worth a look/see, though…
National Pipe Thread Taper
OK thanks - worth looking at…
I have some taps and dies, but nothing that size.
Don’t get your hopes up. I’m 99.999% positive we don’t have them. I think Home Depot can thread pipe for you, at least, I’ve seen a pipe threading machine there in use. Not sure if they go up to 3" though.
Sooo.
Devil’s advocate here…
A cursory read through of hastily googled materials suggests the Colchester might be able to do this…
1 Like
nice thinking on the Colchester 
tho I’m not sure how much effort this is worth.
thanks all!
Yes, but that requires someone who has the skill.
2 Likes
The Colchester can do threading, though pipe threading is a tapered thread, which is more difficult to do on a lathe. That said, the Colchester is missing a large number of its change gears so we can only do a limited number of fine pitch threads on it right now (think 28 tpi to 80 tpi). So it really isn’t an option for pipe threads.
2 Likes
exactly, requires metal lathe skills, which quickly excludes me But I do appreciate all of the out of the box thinking 'round here !
2 Likes
I believe we have the gears for 14-80 TPI. But 3" is 8 TPI, and I forgot about the taper.
Using the threading chart on the lathe or the manual the coursest thread we can cut is either 28 tpi or 32 tpi, cant remember which.
To cut the courser threads on the standard chart we need the 42 tooth gear we are working on. Pipe threads are typically not on the standard charts, which are for machine threads, and may require some of the other roughly dozen change gears we are missing.
Also pipe threads require threading on a taper (without the threads themselves tapering), so short of a tapering attachment or CNC lathe-taps and dies are really the only option for pipe threads
Wow - great info - thanks! But I think that’s a bit beyond what I was looking to do - so I’ll probably find another path. Thanks a ton though!
I have been told that we have gears V(21T), W(60T), and M(120/100T). Assuming that’s correct, the chart on page 11 of the manual (p 24 of the PDF) shows a range of 14 - 80 TPI. More specifically, 14, 16, 18, 20, 22, 24, 28, 32, 36, 40, 44, 48, 56, 64, 72, and 80.
So are you saying that you believe the yellow circled combinations apply to the yellow arrow column?
If so, then our threading capabilities are much more extensive then I thought. Has anyone actually tried to cut say a 1/4"-20 thread? If not, I believe I will after the steam engine session Saturday.
1 Like
I see you have started another thread so I’m gonna just close this necrobump.
1 Like