Dies to cut bolt threads

[Jim Kibler]

I'm with Dan on the split die recommendation.  They allow for a closer fit and you can open them up to take a bit of a lighter first cut and then close them for a finish cut.  This can help if threading material that has a tendency to tear and pull out.  A sharp die and good cutting fluid also helps a lot with this.

[Hungry Horse]

I have used white vinegar to remove rust, and free up, frozen old bullet molds I bought at yard sales. It works great, but be careful it is acid, and if you forget your project it will resolve it over time.



                             Hungry Horse

[curly]

There is one more very important issue here to be mentioned. Never use a four fluted tap for your initial threading. Always use a two fluted tap. Four fluted taps have less body mass and will break very easily.

Curly

[dannybb55]

Try e bay and find some old madeinusa set that will last a lifetime.

[4ster]

Someone posted somewhere that you can take the plating off (zink/black oxide) by soaking them in vinegar for a bew days. Don't know if it works. Haven't tried it yet. It was in the archives.

I know from experience that vinegar will take chrome off of brass if left submerged too long.  I suspect that it would work well removing zinc.

[4ster]

There is one more very important issue here to be mentioned. Never use a four fluted tap for your initial threading. Always use a two fluted tap. Four fluted taps have less body mass and will break very easily.

Curly

Good, now I know it is not my technique, but using the wrong tool that is the cause of my tap breaking ability. 

[Bob Roller]

I use 2-3 and 4 flute taps with no problems and have fluteless types as well. I had some square taps of French make that are threaded on the corners and even made some years ago. I seldom ever break a tap because I always countersink the hole to the tapped the depth of one thread on both sides when tapping a lock plate. Most of my taps are American made.
Make sure you have a tap/drill chart and use tapping fluid.I use Relton and it works fine. On larger diameter taps.grease can be packed into the flutes to pick up shavings as the threads are cut. This is an old trick I used to retap spark plug threads an not have shavings drop into the cylinder. If a shaving gets under an intake valve on an older car,the ignition can cause a back fire thru the carburetor and start a fire that might destroy a valuable car.

Bob Roller

[kutter]

I've never had any problems with 3 flute taps. The tiny ones I broke were my own fault. Trying to hurry, no lube or an incorrect size hole.
I've  broke a few of the 2 flute off in the 8,10 and 12 sizes. Never did that with the 3fluted taps. I thought they were supposed to be stronger but maybe they have more friction because of the increased contact surface.
Maybe I just don't know what I'm doing sometimes

I've heard of swiping the tap with a bar of soap to fill up the flutes. It's supposed to do the same thing as the grease does in Bob's trick of bringing the chips up and out of the tapped hole.
Never tried it,,never worked on big stuff a lot.
Never thought of it till I was done anyway.

[David R. Pennington]

I buy most of my tools used at flea markets and junk sales. Of course you have to be selective but can find a lot of bargains. Sometimes estate sales have old machinist tools. I have two machine screw sets I picked up at a gun/ pawn shop a few years ago. These are old American made (when we used to make things here). I also found some new old stock taps and dies at the same place for cheap. My truck won't pass a junk sale anymore.