Thread: 12-20 Tap

Hi Jack, you've posted in the right place.

I think a lot of us have been in the same situation - love to have one of them there plug taps but the last time I looked the postage was absurd. If some enterprising soul imported 50 of them and kept the per-unit freight cost to something sensible like 5 or 6 $, I'm sure they'd have no trouble flogging them off....

Cheers,

Thanks for the reply. I'm getting a price for postage of some taps and dies. If it turns out to be reasonable on a per-part basis, I'd be happy to pass them on at cost price to whomever needs them.

I was fortunate to have a colleague in the US. I ordered two pairs of 12-20 taps and dies and had them mailed to him, knowing he was coming here to Perth for a certain purpose. I needed to make a new bolt for a #2 Stanley, and make the tote as well from some Brazilian mahogany I actually got in Brazil! Happy times.

Hi CA. I would be interested.

Swifty, did you use Brazilian mahogany, or Br. rosewood? The latter is what would have been on the original, but it's not allowed out of the country as raw wood since the 1990s. I stared at the pic, but couldn't be sure if it was one or the other. Nice handle whichever it is...
Cheers,

Originally Posted by IanW

Swifty, did you use Brazilian mahogany

We were on a geological recon in northern Brazil and came across a bush mill where they were slabbing some logs. I asked if they had any off cuts, so they gave me three pieces of what was described as mahogany. It doesn’t look like rosewood. I brought them back to Australia, duly declared and they got through no problem. It does look like mahogany too!

OK - if the locals said mahogany, then mahogany it is.

I've not seen those prominent growth rings in any mahogany I've come across 'til now, and the pores seemed a bit large, which was why I asked.

Yes, I've brought back several samples of wood picked up in my working trips to Asia & had no problems except the time I brought back a chunk of ebony from Sri Lanka (which took a lot of effort to get my hands on & cost me a good deal more than it was really worth). I stayed at an old colleague's place in Colombo the night before I left & I noticed there was a bit of dirt on one end where the wood was a bit splintered (it looked like a chunk cut off from the felling scarf), so I washed it & put it out in the carport to dry. In the morning, I grabbed my precious wood, wrapped it in a bit of newspaper & stuffed it in my bag. I'd been at a vet laboratory & had to declare that, as well as my bit of wood. Of course the Ag blokes descend on anyone who may have been near farm animals in that part of the world, so I got well quizzed & checked over for that, which I expected.

Almost as an afterthought, he decided to check my lump of wood. Would you believe it, a blasted looper caterpillar had decided that a gap in the splintered end was a good place to hole up for the daylight hours. I had a hard time convincing the young fella that it wasn't a wood-munching critter that was about to devastate our entire woodland! Eventually, I persuaded him that squashing it on the spot would be all that was required to protect our agriculture & environment. Dunno what his training was, but it obviously didn't include much entomology....

Cheers,

I had to repair a thread on a Stanley a long time ago and bought a die that is stamped 1/4 24 NS. I have just tried it on several different planes and it worked on all the threads so I don't know what the difference between a 12 20 and what I have is. I get the 20 is the thread count but what is the 12 supposed to represent?

Originally Posted by Chris Parks

...... I get the 20 is the thread count but what is the 12 supposed to represent?

It's the gauge, Chris. It was once common practise to use numbered gauges for smaller size machine screws. The Yanks are about the only people who've persisted with it 'cos everyone else has gone metric. Twelve gauge = 7/32".

If the studs you tried a 1/4" 24tpi die on were old Stanleys or Records, then you didn't do them any favours. Veritas use 1/4" NC for their studs, & possibly other manufacturers (L.N.?) do too, so if you tried the 1/4 on one of those, it's no surprise it was ok.. But Stanley (& Record up until about 30 yrs ago) used the 12-20 threads on the studs for their bench planes and 1/4" 24 taps & dies certainly don't fit 7/32 20tpi. You could screw it on without much effort, but the threads are never going to match either in depth or pitch & you'll damage them.

As Mr. Biden said, "don't, don't, don't...."
Cheers,
Ian

Ian, all the threads I tried it on were ok and did not suffer from screwing the die onto the thread, beyond that I can't comment. I recall getting the information from someone here but I can't recall what I originally used it on.

Chris, if the studs were from old Stanleys or Records, they would most certainly have had 7/32", 20tpi threads.

Many of the old studs I've come across were cut with very generous tolerances, the outer diameters of the thread lands can be more than a mm under nominal size. I haven't tried it myself (I will next time I pull a handle off one of my old planes), but I suspect you could screw a 1/4"NC die onto one of these studs for several turns given that it would be a very sloppy fit, but after 4 or 5 full turns (or fewer, depending on the wear on the particular stud thread & how sloppy the fit), the mismatch will show & you'll find the die will not go on without at the very least skimming the tops off some threads.

It's not a practice that should be encouraged, in my view, there is simply no point in using the wrong size of tap or die, I can't see what it will achieve in terms of 'fixing' anything. If you need to clean up a burred thread & you don't have the correct die, better to do it with a thread-file, or failing that, a needle file if it's just a turn or two of thread that's damaged. The 60* corners of a file match the thread angle of American threads & if you are careful, you can clean a damaged thread very nicely.

The most common problem I've come across with old tote studs is stripping of the first couple of threads. They have a very tenuous grip in the plane body, barely 2 full turns on the old style that doesn't have the raised nipple for the tote stud. One "fix" for this is to cut or file off the first two damaged threads, which will give the stud a lot more purchase. By that stage of a plane's life, the wood under the nut at the top has been compressed enough that there will still be plenty enough thread exposed for the nut to grip firmly at that end.

If you have a mangled tote or knob stud that is beyond salvage, contact me & I'll make you a new stud for a couple of $$ in postage. I've got a whole packet of nails of just the right diameter & it takes but a few minutes to chuck one in my mini-lathe & cut the correct thread on it...

Cheers,
Ian

Thanks Ian, it must have fixed the original problem but I will keep what you say in mind.

Ian,
I just sat down to ask if anyone had a spare handle stud but after reading your last post
would you be able to make me a stud for a Stanley no5 rear handle 110mm long I have the brass nuts and the front stud but not the stud for the handle.
I would need postage to NSW south coast.
And Swifty if you read this can you let me know the finish on that handle, it looks like the perfect finish for timber handles.

Thanks. Rick

No problem Rick, PM me an address & it'll be on its way,,,,,,
Cheers,
Ian