HK Porter Washout Plugs

Rick Rowlands · **Posted:** Thu Oct 08, 2015 11:45 pm

The washout plugs on the 58 are roughly 2" diameter and 12 threads per inch. What was the standard taper for these plugs?

David Dewey · **Posted:** Fri Oct 09, 2015 12:41 am

I thought boiler standards were 14 TPI, but I could be mistaken!

aswright · **Posted:** Fri Oct 09, 2015 12:42 am

Rick,
According to the 5th edition of Machinery's Handbook published in 1916,
freely available in Google Books, on page 1062 at the top,
it's 1¼" per foot taper.

Adam Wright

Rick Rowlands · **Posted:** Fri Oct 09, 2015 7:24 am

Thanks Adam. That is exactly what I'm looking for.

Kelly Anderson · **Joined:** Tue Sep 14, 2004 7:52 am **Posts:** 2477

Frisco1522 · **Posted:** Fri Oct 09, 2015 10:20 am

I would have thought they would be 3/4"-1' also Kelly. However, Porter may have had a different idea. The sharp V thread is important.

Dave · **Posted:** Fri Oct 09, 2015 11:06 am

Please also test the pitch. My Baldwins had 11.5 TPI, the Limas 12. I damn near fired one guy because he decided on his own to use the wrong one despite my telling him specifically which to use where.......

QJdriver · **Posted:** Fri Oct 09, 2015 12:46 pm

Rick,

The two Porter plantation engines I once owned, both used bronze 1 1/2" NPT pipe plugs, except for their belly plugs, which were the same threads and taper, but a longer plug !!! They had both been reboilered by Erie City after WWII, don't know if this arrangement was factory. Like the man said, better check real good.

Take Care & WORK SAFE

Rick Rowlands · **Posted:** Fri Oct 09, 2015 2:46 pm

The machine shop next door is going to make a tap to match the thread and pitch of our washout plugs. I've already told him to base it off of the existing plug, but I also want to provide him with some additional info. to help in the design. All this info. helps.

David Dewey · **Posted:** Fri Oct 09, 2015 3:05 pm

Be sure the shop understands that the threads do not have the normal rounded root, but are "sharp".
I see my 14"TPI memory was WRONG, good to know! Not that I'm going to be making plugs at anytime (that I'm aware of!)

steamfinder · **Joined:** Sun Aug 22, 2004 6:06 am **Posts:** 24

The one thread previously warned about measuring the taper. This is important because our locomotive drawings specified 3/4 taper on the erection drawings. It was actually 1 1/4 taper when I actually sat down and measured it. I need to mention this was the plug for the valve spool. Be warned someone may have changed the taper from construction to present time.

Bob Milhaupt · **Joined:** Sun Jun 07, 2009 5:20 am **Posts:** 35

Related, but perhaps somewhat off-topic...

I vaguely recall that there are some standards or requirements relating to the length of a tapered washout plug and the amount which it may penetrate the sleeve into which they are installed. I'm thinking I was told that the plug must not extend too far past the inside surface of the sleeve (perhaps excessive insertion could impede circulation?), that there must be some minimum number of plug threads beyond the inside surface of the sleeve (for a strong mate to the sleeve?) and that there must be at least so many full threads on the plug that remain outside of the sleeve (to ensure proper strength of the plug?).

Can anyone point me to such a standard or requirement, in a publicly-available document, relating to the above? I do not find any specific requirement in 49CFR230, just the typical "must be maintained in a safe and suitable condition" phrase, and the requirements for removal of plugs and and inspection of the plugs and sleeves and their threads.

In the absence of a publicly-available reference document, a description of "conventional wisdom" or "good shop practice" would be appreciated.

Bob Milhaupt
Occasional Volunteer,
Illinois Railway Museum Steam Shop

M Austin · **Joined:** Sat Feb 05, 2005 1:05 am **Posts:** 488

Of the 3 Baldwin plantation locomotives on Kauai, the small one KAIPU has 14 TPI plugs, the other 2 bigger ones have 12 TPI plugs. Could not tell you the taper but there were taps in the tool room for both sizes. It should be noted that the blowdown connections were NPT while the washouts were 12 or 14 TPI boiler standard.

Dave's repatriated Baldwins probably got a modification to NPT which is 11-1/2 TPI while speaking Spanish.

Always Measure! I have seen:
Blind Baldwin dome stud holes which are bolt thread chased with tapered stud taps.
Through Baldwin dome stud holes which are tapered chased which straight bolt taps.
Fusible plug holes which are NPT chased with stud taps. Always leaked until drilled for oversized NPT.

ASME has always required 4 full engaging threads in a tapered threaded connection. 5/16" plate doesn't cut it. Corner plugs usually have a riveted reinforcement on the inside.

As far as the longer plugs in the belly, this was so, when lagged, they could be reached with an open end wrench and not a socket.

General rule that I see broken all the time:
IF you can't make the plug tight with a 14" long wrench, the threads are worn out and new plugs need to be made.

The ASME Code requires non-ferrous plugs.
PG-44 When a threaded opening is to be used for inspection
or washout purposes, it shall be not less than 1 in. (25 mm)
pipe size. The closing plug or cap shall be of nonferrous
material except for pressures of over 250 psi.

J.David · **Posted:** Sun Oct 11, 2015 8:52 am

Greetings:
Matt is correct in re-four threads in engagement (one reason for the use of 14TPI plugs).
This answers Bob's question in re-how far the plug should go in. Since these plugs are tapered, they must go in at least 4 threads and when they screw in so far that you don't have 4 threads left, the plug is finished.
As per 49CFR Part230.60(c), plugs and the openings they screw into must be inspected every 31 Service Days. In addition to cracks and worn threads, another thing to look out for is for the plug becoming deformed (belled) due to repeated over tightening. Matt is correct (again) in the length of wrench used to apply the plugs.
At Valley Railroad, we use 3/4" Teflon tape as a sealant plus Teflon paste on the front firebox corners which are curved and prone to leakage per se.
It is amusing to consider that "in the steam era" boiler washing was left to the lowest ranks of roundhouse laborers, now we are so far removed from their basic good workmanship practices that we must discuss it here.
J.David
PS: Bob: I think that if you go out and check your LS&I No.35, you'll find a mixture of 14TPI and 12TPI washout plugs used.
PS: David I have seen washout plug taps which are "V" thread (sharp edge thread) and also "USF" and Whitworth threads (rounded edge thread). JDC

David Dewey · **Posted:** Sun Oct 11, 2015 1:09 pm

Interesting that you use Teflon Tape, I was taught to never use it around steam as the bit of tape that isn't caught in the threaded area can come loose and travel through the system to mess up valves, etc. I was told of one place (I've forgotten where) that would fire you on the spot of any Teflon tape was found in your toolbox. I'm a Rector Seal fan myself. "Old school" I guess!! :)
Whithworth profiled threads, eh? Veedry Interestink! ( For those that might not be familiar with such stuff, the root and tip profiles are slightly different than SAE, USS & UNF standards. All of this is too long ago and far away for me to remember it all--I will have to admit to having a Lucas-wired human memory unit! :) )