Shop Made 5/16 X 12 Acme Tap will it work?

[Old Iron]

I made this this morning and figured with out looking that I had a smaller end mill than a 1/8 But I didn't.

I know it should have 3 flutes but that wouldn't have left any threads so I only did 2. All I'm going to use it for is to tap 2 or 3 brass nuts for that small Lathe I'm working on.

So let the flaming begin.

Paul

 

[Uncle Buck]

Why would someone flame you? I applaud your effort. You took a piece of raw material and machined a tool that will add value to your project. Well done.

 

[Old Iron]

Paul,
Not a chance.

Looks good to me, are you going to harden and temper it, or just use it as it is?


DaveH

Thanks Guys! Its A-2 Tool Steel A2 Drill Rod so I'm going to oil harden it. But first I need to put a square on the end.

Paul

 

[terry_g]

Looks good to me Paul. Here is a 10mm x 2 acme tap I made to make a new compound feed nut
for a metric SouthBend lathe I once owned. I made it from 1/2" W1 drill rod and hardened and tempered it.
I should have made it longer with more taper and made the flutes wider. You can see how much twist it developed.
I was worried that it was going to break but it did the job and that is what counts.

Terry

 

[pdentrem]

Good job! I made a tap for my 3AT collet drawbar. Since it was cutting steel I did harden with Kasenite and it only had to cut one thread it worked fine. Since yours will only be cutting brass it could work as is. Are you going to make your minor diameter in the brass .010" larger then the root diameter?

 

[Tony Wells]

As long as you used the dimensions for the internal thread limits, there should be no problems using it. Normally, taps are "backed off", by relieving the OD behind the cutting edges. If you threaded a rod to the correct dimensions, and it isn't backed off, it will drag on the OD. In brass, and with lube, that should only manifest itself as the need for what may seem to be abnormal effort needed to turn. Unless it is so severe as to risk breakage, you'll actually get a burnishing effect from it. Go for it. Make sure the minor diameter of the hole is not less than the minor diameter of the tap. It's tough to get a tap to cut in that area. I'd try to harden it before use.

 

[Old Iron]

Good job! I made a tap for my 3AT collet drawbar. Since it was cutting steel I did harden with Kasenite and it only had to cut one thread it worked fine. Since yours will only be cutting brass it could work as is. Are you going to make your minor diameter in the brass .010" larger then the root diameter?

That was my thinking I hope were right.:headscratch: I will also be making the screws so maybe it will work out.

Paul

 

[churchjw]

Looks good to me Paul. Here is a 10mm x 2 acme tap I made to make a new compound feed nut
for a metric SouthBend lathe I once owned. I made it from 1/2" W1 drill rod and hardened and tempered it.
I should have made it longer with more taper and made the flutes wider. You can see how much twist it developed.
I was worried that it was going to break but it did the job and that is what counts.

Terry

Holly C^$P that twisted that much. I was going to ask you how you got the cool twist in it LOL. Still it looks great.

Jeff

 

[Old Iron]

When I first retired I bought an old sail boat and went to the western Caribbean. While in Guatemala I had a breakdown and could not get a 12 millimeter tape. so I took my little 4 and 1/2 grinder with a cut off wheel and carved one out of a 12 millimeter grade 8 bolt. It worked surprisingly well with lots of oil and forward and backing. Mac

Now thats one I'd like to see!

Paul

 

[Old Iron]

Paul,

So have you used yet?

Was it OK?

DaveH

Haven't had a chance, Been working on SWMBO drill press. But soon!:whistle:

Paul