1. Home
  2. ⏣ General Metalworking
  3. thread identification

thread identification

Hi,

I am restoring a old Bailey #3 handplane and have run into some threads I can't identify.

One is 20tpi and measures 0.222 on the crests of the screw threads. (some wear but definitely not 0.250).

The other is 24 tpi and measures 0.278 (little wear). I was wondering if metric but don't have thread gauges. They fit the 20 & 24 tpi gauge perfectly.

It was made in Canada but I think pre metric days.

I won't even ask about the 24 tpi left hand thread.

The reason I want to know is to chase the threaded holes after removing most of a broken screw. I think I will have to drill out to 1/4" * 20tpi.

Thanks Glen

Reply to
glensmith
Loading thread data ...

You might be supprised - go and glance through the MSC catalog under 'special thread' taps and dies. I think they may have it.

If you can do use a finer thread than 20, as that's a bit coarse for a plane adjusting screw. I had to make my own brass nut for one plane, and it was easy enough to single point the thread for the left hand, 28 tpi.

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

Reply to
jim rozen

Stanley used odd-sized threads on some of their planes. Taps are available. I'd suggest you check with one of the tool collector newsgroups. It's a common question for them.

John Martin

Reply to
JMartin957

I ran in to a somewhat similar problem. I live in a small town and tend to be somewhat impatient so when I needed an odd tap, I made it instead of waiting for it. It worked *very* well.

formatting link
Ted

Reply to
Ted Edwards

...

A couple of days ago I was annoyed (but not seriously surprised) to find that my 5mm x 0.8 tap from a cheap carbon-steel set wouldn't cut into mild steel. Being impatient and only needing about 7 threads I instead used a #10-32 HSS tap, which worked out fine. 0.8mm is pnly .00025" more than 1/32" - not much of a problem in 7 threads. The #10 nominal size of 0.1875" is a good bit smaller than 5mm (.197") but this was no problem since I wanted a tight fit anyway.

-jiw

Reply to
James Waldby

Re. the drop box article on making your own taps: A good way to temper one after quenching is to put it into a 350 degree oven for 45 minutes. It avoids possible confusion "reading the colors". Place the tap in the oven immediately after quenching and before it has had time to cool off enough that you could touch it.

Bob Sw>

Reply to
Bob Swinney

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.