Very small job but need a 2" NPT pipe tap. Ideas?

[Dadnatron]

I need to clean and refurbish the threads on a diesel tank. There are 6 total holes needing cleaned mainly of rust etc.

I've tried a wire brush to no avail. Only thing I can think of is a tap... but the only taps I can find are online and for sale. While I don't believe anyone should forgo payment for their wares, I just can't stomach a $150 tap to clean out 6 holes. A literal 5 minute job.

Any thoughts? I've thought about getting a 2" nipple, cutting grooves vertically along the threads and using it... but I have no idea whether that will work at all. The metals are going to be roughly the same hardness... maybe even softer than the tank, with galvanized 2" pipe.

Any thoughts would be appreciated. I haven't been able to find a rental. Even Harbor Freight doesn't have one, at least that I can find. The cheapest I can find on Amazon is $88 and they are back-ordered for 2 months.

My goal is quick... I was going to take the tanks to a sandblaster/welder tomorrow evening and have him clean them up. I was removing old fittings this evening, and while there are a couple I can't remove, there are also a few that are acting almost 'cross-threaded' because the threads are so bad.

 

[ultrarunner]

Two thoughts...

I was in the same boat with a 1.5" tap and bought one for $5 at a flea market...

The local rental yards here rent plumbing supplies... otherwise do you have any friends in the trade?

When I bought the 1.5 tap the seller also had a 2" for the same price... in 31 years I have not needed a 2"... but a couple of times a year I use the 1.5 to clean threads.

Maybe Ebay?

 

[LittleBill21]

wire brush in a drill, cut the wheel down to fit inside the hole

 

[bcp]

Cut some grooves in a plug to make a thread cleaner.

Bruce

 

[CADplans]

Cut off the old fitting, weld on a new one. Get 3 pipe couplings, cut them in half, you will have 6. :thumbsup:
The cost will probably be less than $10,,, AND you have BRAND NEW THREADS!!

Any chasing of the threads will make the male fitting go too deep,,
and it probably will not seal.

 

[moriboy]

Cut some grooves in a plug to make a thread cleaner.

This is what I would do, and I own a machine shop.

Since you are dealing with a tapered thread, you won't be able to clean up much past the point where the ID and OD taper meet up. Sanding down the OD of the plug slightly might allow you to screw it in a little further but probably not much. You also could coat the plug with some abrasive paste and work it in and out.

 

[SPYDERLK]

I need to clean and refurbish the threads on a diesel tank. There are 6 total holes needing cleaned mainly of rust etc.

I've tried a wire brush to no avail. Only thing I can think of is a tap... but the only taps I can find are online and for sale. While I don't believe anyone should forgo payment for their wares, I just can't stomach a $150 tap to clean out 6 holes. A literal 5 minute job.

Any thoughts? I've thought about getting a 2" nipple, cutting grooves vertically along the threads and using it... but I have no idea whether that will work at all. The metals are going to be roughly the same hardness... maybe even softer than the tank, with galvanized 2" pipe.

Any thoughts would be appreciated. I haven't been able to find a rental. Even Harbor Freight doesn't have one, at least that I can find. The cheapest I can find on Amazon is $88 and they are back-ordered for 2 months.

My goal is quick... I was going to take the tanks to a sandblaster/welder tomorrow evening and have him clean them up. I was removing old fittings this evening, and while there are a couple I can't remove, there are also a few that are acting almost 'cross-threaded' because the threads are so bad.

Since the threads are not deformed - just rusty I think you can do fine with your grooved thread idea. ... 1st tho, use a toothbrush sized wire brush and Kroil round and round on the inside threads to soften and mobilize the rust. A couple cleanings like that and the threads should look much better. - Then screw in your grooved pipe , back and forth, while still using Kroil to emulsify the rust. Should clean up well. ... Then you can tighten in a regular pipe or plug, etc with antisieze on the threads to finish the reforming. A tap wouldve been spoiled anyway. Rust is pretty abrasive.

 

[Dadnatron]

Brilliant!

My $2 - 2" thread cleaner...

The one on the right was my first try... I didn't think about the direction of threads compared to the 'cutting side'. As soon as I set it on the hole, I knew that wouldn't work. I immediately grabbed another plug and flipped it before the grinder.

 

[Industrial Toys]

Yes, brilliant!

I have been working with 2" bungs for quite a long time and don't recall ever wanting a tap.

Usually just some oil, grease, a good pipe wrench and a pipe on the end.

It's usually only a reducer bushing anyway, and the pump or plugs are smaller.

 

[Fesntkilr]

A literal 5 minute job.

I remember back to my days in construction that there was NEVER such a thing as a 5 minute job.