1"-18 Straight Thread for fluids
1"-18 Straight Thread for fluids
(OP)
I have an old pump (1980's) I'm redesigning and found a very strange threaded part on it. The pump has an oil sight glass and another port which adapts to a pipe thread. Both are 1"-18 (straight thread). Both ports are wrapped with Teflon tape and pipe dope even though they are not tapered. I've never seen anything with this thread before, and after looking through all my fittings catalogs, I've come up empty handed.
Do you know of any pipe fittings, pipe plugs especially, that are designed for a 1"-18 straight thread?
Do you know of any pipe fittings, pipe plugs especially, that are designed for a 1"-18 straight thread?





RE: 1"-18 Straight Thread for fluids
As for the dope and tape, I wouldn't make any assumptions - I've seen a lot of dope and tape where there should be none.
RE: 1"-18 Straight Thread for fluids
This would be very close to 1"-18, and could be easily misgauged if you are using a simple comb gauge.
Straight pipe threads are generally intended to be used with o-rings, gaskets, or crush washers of some sort, and should not rely on thread interferance for a seal.
Good adapter site:
http://www.adaptall.com
RE: 1"-18 Straight Thread for fluids
Regarding the lack of O-rings or other types of gaskets, I thought that was pretty funny myself. Seems like some farmer must have put this one in. Maybe it matched something on his John Deere tractor. <sigh>
RE: 1"-18 Straight Thread for fluids
It's possible to have come mixed ports from the pump mfg.
Looks like it's up to you to make it right, and get rid of the pipe dope.
Charlie
www.facsco.com
RE: 1"-18 Straight Thread for fluids
h
RE: 1"-18 Straight Thread for fluids
RE: 1"-18 Straight Thread for fluids
Is the 1"-18 the actual thread size (1" O/D) or a pipe thread size (approx 1.327" O/D)?
RE: 1"-18 Straight Thread for fluids
RE: 1"-18 Straight Thread for fluids
Hey lbmakem, Is there anyone that makes fittings with that size thread? In particular, I need a couple of plugs. Also, does that fitting use some kind of gasket? I'm thinking there should be.
RE: 1"-18 Straight Thread for fluids
It could be a unified special thread (UNS), but then you can make any diameter or pitch thread you want and call it UNS as long as you follow the thread profile and tolerance standards. It's certainly not a "standard" unified thread, like UN, UNC, UNF, or UNEF.
If they were true "pipe threads", then they would be made with a major diameter that is equal to a standard pipe size. The closest pipe to this is 3/4" which has an OD of 1.05, but the tpi is still way off (14).
I once came across some really bizarre threads on an Italian hydraulic four-slide machine, years ago. As I recall, the diameter was metric and the pitch was in threads-per-inch. What really distinguished them was the fact that they were of Whitworth form! Can you look with a magnifier and see whether the teeth have rounded crests?
Don
Kansas City
RE: 1"-18 Straight Thread for fluids
www.parker.com/quickcouplings/QCD/3800_G_03_02.pdf
www.parker.com/brassprod/cat/3501E/3501-D.pdf
RE: 1"-18 Straight Thread for fluids
If you have ever specified a non-standard thread, you know that UNS is a catch-all for any size combination you might desire that doesn't fit under the standard sizes (UN, UNC, UNF, UNEF). That's what the "S" is for: "special", as opposed to "standardized".
I used to design large reprographic imaging cameras that had large, high-grade lenses with all sorts of bizarre diameters. You simply pick a nominal diameter and tpi, list the critical dimensions and tolerances in your call-out and call it a UNS thread. This covers the unified profile.
Another good example is the threads used for AFBMA bearing lockwashers. A 25 mm bore bearing, for example, calls for an N-05 locknut, which requires that you thread your shaft with 31/32"-32 UNS-3A threads.
Don
Kansas City
RE: 1"-18 Straight Thread for fluids
They also make these windows with BSPP threads, but at 18 the pitch is off.
RE: 1"-18 Straight Thread for fluids
Thanks again.
RE: 1"-18 Straight Thread for fluids
only to keep any moisture out would be my guess.
You might be able to find the glass port from
one of the lube fitting manufacturers. It must
be a standard somewhere for those who make these
sight glasses or ports.
RE: 1"-18 Straight Thread for fluids
h
RE: 1"-18 Straight Thread for fluids
ht
http://www.ernstflow.com/eindex.html