Tailstock hex die holder

[bouch]

I took a slight diversion from the project I’m working on to build a helpful little tool for my shop. Years ago, I made a tailstock mounted die holder, which held both 13/16” and 1” round dies, and had a knurled body as well as handles. The tool is about 1 ¼” diameter and 3 ¼” long, and slides on a shaft made from an old taper-shank drill, mounted in the tailstock. I bought the plans for a couple bucks at Cabin Fever probably 15 years ago, and it’s proven to be a very useful little tool

Lately, when I’ve gone to the hardware store, the only dies I could get off-the-shelf were hex dies. I’ve been using a kludge to get these hex dies threaded on straight, but after making about 30 studs for my current project, I decided I just couldn’t kludge things any more. (I probably should have “bit the bullet” BEFORE making those studs, but…)

There are 2 different sized hex dies that I’ve found to be commonly available, 5/8” across the flats, and 1” across the flats. Like the round dies, this new die holder would be able to hold both.
First thing was to take the hex die holders which I had and hack them up into inserts I could then put into a body. I cut off the handles, mounted it in the lathe, and turned it round. Easier to see than describe. Here’s the before and after for 5/8” hex dies. (I bought a small metric and an imperial kit, so I had two handles)



And here’s both the inserts. They’re both an unknown-grade cast aluminum.



I used the one I made years ago as a model, and made some quick drawings. Now that I knew the diameters of the inserts, I knew how big to bore the holes they would be inserted into. I had a 6” length of 1 5/8” steel, and I found that I could use that and still have enough meat around the 1” hex die insert to hold it securely, so that's what I chose as the major dimension. But I thought that that diameter for the full tool would be a bit excessive, so I made the knurled body the same diameter as the one I already had.

I was thinking that I could press these inserts in, and based on the diameter, I wanted about .001” interference between the two. Well, I failed with that, made both ends too loose (I could press them in by hand). So I superglued both inserts in, and then drilled and tapped a 6-32 screw through the body and the insert to guarantee it wouldn’t spin, even under “heavy loads”.

At this point, you’re probably wondering what these things actually look like…

Here’s the 5/8” hex end. Note the set screw used to hold the die in place, so it won’t fall out when handling the tool.



Here’s the 1” hex end.



If you look, you can see that a) I didn’t bother to remove the paint from the inside of the donor handle and b) you can see the filed-off end of the aforementioned 6-32 screw.

And here’s a view of the side of the body, showing the knurls and the holes for the handles.



Here’s a “family photo” showing both die holders, the two handles, and the taper-shank shaft.



In this photo, if you look closely, you’ll also notice that I didn’t bother to fill in the threaded hole in the donor handle where there was a thumbscrew to hold the die in place. Kinda lazy, but since it doesn’t affect the function, It doesn’t really bother me. If it starts to, I may drill and tap and then thread in another screw to fill the hole.

And finally, the tool in the tailstock.



Quick little project, probably took about 4-5 hours of work, and it will be very useful. I also have a small 7x12 hobby lathe, so I need to make a couple of smaller handles, as the ones I have now are too long and they strike the lathe bed. (but that’s also why the body is knurled, so you can grip it with the handles off) But that’ll be quick work.

If you want additional info, drop me a note.

 

[john_reese]

You did a beautiful job.
I thought hex dies were for cleaning up messed up threads, not for cutting new threads. Am I wrong about hat?

 

[bouch]

You did a beautiful job.
I thought hex dies were for cleaning up messed up threads, not for cutting new threads. Am I wrong about hat?

There doesn't seem to be any hard-and-fast rules about that. AFAIK, rethreading dies are always hex, but not all hex are rethreading dies. For example, MSC lists "hex rethreading dies", "round and hex pipe dies", and "round dies".

https://www.mscdirect.com/browse/Threading/Dies-Chasers-Thread-Rolls?navid=12105964

But if you go to Home Depot, you can get a 40 pc tap and die set which is all hex dies (made by Vermont American), here's one example.

https://www.homedepot.com/p/Vermont-American-Metric-Tap-Die-Set-40-Piece-21749-0/202850652

The disadvantage is that they're not adjustable, like most round dies are.

The advantage is I can run down to my local hardware store, or to a home depot, and buy hex dies right off the shelf instead of paying shipping charges and waiting for a week to get a round die.

I've cut more than a few new threads with the hex dies that I have.

 

[bouch]

You did a beautiful job.
I thought hex dies were for cleaning up messed up threads, not for cutting new threads. Am I wrong about hat?

Without beating a dead horse, I took photos of two of my dies. One a 1" hex, one a 1" round. They both look pretty similar. The repair dies I've seen look more like the inverse of bottoming taps to me, where the full thread profile is closer to the face of the die.

and notice two things:
1) Neither is adjustable
2) both say "start this side"

 

[tornitore45]

The hex hole has crisp corners. How did you do it?

 

[wheeltapper]

Read the first post again.

Roy.

 

[bouch]

The hex hole has crisp corners. How did you do it?

I cheated and let someone else make them for me. Look closely at the OP, but the short story is I purchased a handle and removed everything that wasn't a hex shaped hole.

 

[ShopShoe]

Another source for "wrench-sized" hex holes is buying individual imported black-oxide long "impact" sockets. A lot of them cut and machine surprisingly well. I have made custom handles for hex-shafted controls using that approach. In one case I threaded the outside of a long socket to put it into a hand wheel I bored out for the purpose: The result was a removable hand wheel.

--ShopShoe

 

[Wizard69]

You did a beautiful job.
I thought hex dies were for cleaning up messed up threads, not for cutting new threads. Am I wrong about hat?

It depends upon whom manufactured the die from what I can see. Hex dies have some advantages but I don't know of any that are adjustable. Adjustable might be an advantage in certain situations and they do make it easier to do tail stock threading guides.

 

[bazmak]

Very nice knurling. What tool did you use ?

 

[bouch]

Hey Bazmak,

I used a scissors type I bought for $40 at Cabin Fever years ago. Looks a lot like this, but I fairly certain its a knockoff. Came with 3 sets of knurling wheels (1 straight, 2 diamond)

https://www.mscdirect.com/product/details/08657017

The trick I was taught to get a good knurl is to take a VERY light cut and look at the pattern formed. By light, it has to be just enough to make visible marks in the piece. The lines should be a nice pretty hex, and that tells you that the diameter of the piece is the right ratio to the distance between each tooth on the knurling wheels. If it isn't a nice pattern with a light cut, you'll never get a good knurl.

If you don't get a nice pattern with a light knurl then take 1 or 2 thou off the diameter and try it again. Repeat until a light cut gives you a good pattern, and then use a LOT of cutting oil and crank the tool down.