5/8ths 12 left hand tap needed

I need to chase the rust out the brake adjuster screw holes on an old Eaton truck rear end mid 70's vintage. Local suppliers got no sources. No luck on my sources on internet so far. I know there's one out there for me. I'm thinking about making one cause I need it right now. Anybody got any ideas? Thanks. WWQ

In the past (probably future also ) I have put some gashes in the end of the screw and pretended that was a tap. Dave

Make the tap from 01 drill rod. You can make a very effective tap by grinding the end several ways: 1. Grind the end square. lots of antique taps made that way. I use them all the time when I'm repairing an antique with non standard threads. 2. Grind the end triangular. 3. Grind the end down to 1/2 dia. Let the grind taper away to nothing. On a tap that big,I'd lwet the grind taper out to nothing in 1" or a little more. Then,grind a taper down to thread depth at the start end of the tap. Make it taper out about the same length as the flat grind.Make sure you grind some relief into this taper,or the tap will not cut. The last way makes the strongest tap and best cutting edge. Heat to orange,quench in clean oil,or ATF flluid. Polish an area,and draw to a dark brown.Some even go to purple. This is a quick way to make taps for short runs.

Are you sure it's really 5/8-12 ? 11 tpi is standard.
That sounds unlikely, and darn close to M16 x 2.0 if you do the conversion.

Left-hand metric standard wouldnt be too hard to find.

Taylor tool in cambridge ont.

If thread is rusty and not damaged,
I would first try a shotgun bore brush and some bore cleaner.
Drive the brush back and forth with a reversible hand drill.

Ted

BecksM If I had something I could screw into the hole, I would, but in the process of removing the rusted-in adjuster screw, all I have is fragments. I don't want to take a new screw and force it in there either. The rust is tougher than the steel.

Gwilson, Best advice i'll probably ever get. Now I have to sit down and read it a few times to make sure I get it right.

Ferrous, I knew someone would put that in there. You don't know how much I wanted that thread to be 11. I checked with my metric gage. No match for 2mm. No match for anything metric. It's 12. Now all I have to do is find the engineer who designed the brake adjuster and ask him why he did such a damphool thing as that. Then find his manager's chair and put a tack on it.

Steve, I wonder how much that would cost? I just need to chase some rust out there. I will save for future ref. Thanks.

Ted. I don't know why, maybe it's the alloy, it's a forging that rings pretty well when you hit it, but the rust is tougher than most rust I've encountered. Kinda like Audi exhaust stainless.

This will be my very first left handed tap.

5/8" 12?

Are you quite sure it's 12 and not 11. I have a 5/8 11 LH tap for when I was making SS turnbuckles for a sailing sloop. Never seen one with a 12 pitch. Peter Mine is made by Dormer

OK here are a couple pix. No trix.

http://i92.photobucket.com/albums/l10/WWQuaday/Itsa12.jpg

http://i92.photobucket.com/albums/l10/WWQuaday/No2mmmatch.jpg

MSC lists them, #04848051 for bottoming tap
re
Herm