Author Topic: Tailstock hex die holder  (Read 1672 times)

Offline bouch

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Tailstock hex die holder
« on: March 05, 2018, 05:31:25 PM »
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)

<attachment Hex Die Holder 1>

Both the inserts an be seen in

<attachment Hex Die Holder 2>

They’re both an unknown-grade cast aluminum.

I used the existing one 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.  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.

<attachment Hex Die Holder 3>

Here’s the 1” hex end.

<attachment Hex Die Holder 4>

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 the body, showing the knurled body and the holes for the handles.

<attachment Hex Die Holder 5>

Here’s a “family photo” showing both die holders, the two handles, and the taper-shank shaft.
<attachment Hex Die Holder 6>

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.

<attachment Hex Die Holder 7>

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.

Online b.lindsey

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Re: Tailstock hex die holder
« Reply #1 on: March 05, 2018, 06:34:41 PM »
I like that you can handle both sizes in one tool. No reason it can't be done for round dies too as all of mine are round. I especially need to make something similar for the little Cowells but note that on their description it rides on the OD of the tailstock spindle.

Bill

Offline bouch

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Re: Tailstock hex die holder
« Reply #2 on: March 05, 2018, 07:18:39 PM »
Bill, look closer at photo 6.  The first one I made takes 13/16" round in one end, 1" round in the other. The photo shows the 1" end.  I built that about 10 years ago.  Once I started acquiring hex dies, I had to build the new one.

Mike

Online b.lindsey

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Re: Tailstock hex die holder
« Reply #3 on: March 05, 2018, 08:23:49 PM »
Thanks Mike, yes i see that now.

Bill

Offline Chipswitheverything

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Re: Tailstock hex die holder
« Reply #4 on: March 06, 2018, 08:39:03 AM »
Bill, I have the Cowell die holder, as you note, it simply fits over the tailstock barrel , saves some precious length and is sturdier.  Easy enough to make, I'm not sure if it is worth doing other than the 13/16" end in the first instance, as the torque needed to thread the larger 1" die sort of thread sizes may be beyond the resistance of the small chucks.  ( Might be OK with hex bar in a 3 jaw...)
  Mike - are the flats on your hex dies, presumably meant to be turned with a spanner, concentric enough about the central thread to line up axially on the workpiece to be threaded?  Also, the non adjustability of the die nuts seems a bit of a difficulty as compared with the circular split dies.   Dave

Offline Twizseven

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Re: Tailstock hex die holder
« Reply #5 on: March 06, 2018, 11:02:28 AM »
I have the Cowells ME90 and have the tailstock die holders.  I found them to be okay but bit awkward to rotate either the chuck or die to make the thread.

I decided to follow the good lady Jo's advice and made up a mandrel handle which has simplified matters significantly.  Can now easily hold the tailstock die with right hand and just wind the handle with the left hand.

Colin

Online b.lindsey

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Re: Tailstock hex die holder
« Reply #6 on: March 06, 2018, 02:58:05 PM »
Colin, do you have a picture of where/how the handle engages the lathe? I presume the far left end of the headstock but not sure.

Bill

Offline Twizseven

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Re: Tailstock hex die holder
« Reply #7 on: March 06, 2018, 03:34:40 PM »
Bill,

Quite correct at left hand end. Remove the thumbwheel which holds the gear on left hand end of mandrel and screw the adaptor on./

See pictures below.

Regards,

Colin

Online b.lindsey

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Re: Tailstock hex die holder
« Reply #8 on: March 06, 2018, 03:53:45 PM »
Thanks Colin, that shows it well.

Bill

Offline bouch

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Re: Tailstock hex die holder
« Reply #9 on: March 06, 2018, 06:22:09 PM »
  Mike - are the flats on your hex dies, presumably meant to be turned with a spanner, concentric enough about the central thread to line up axially on the workpiece to be threaded?  Also, the non adjustability of the die nuts seems a bit of a difficulty as compared with the circular split dies.   Dave

I can't say I've tried to measure how concentric these dies are.  I suppose now that I have this holder, and errors in concentricity (is that a real word?) will become more apparent.  If I had a part that needed high tolerances with the thread, I would want to single-point thread anyway.  (aside - another tool that I've started making is G.H. Thomas' Retracting Tool holder)

Agreed about the non-adjustability, and some people have suggested that they're only good for repairing damaged threads.  But, I have cut new threads with them, and seeing as how the local sources around me seem to only stock hex dies, this tool should come in handy.

Offline Ian S C

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Re: Tailstock hex die holder
« Reply #10 on: March 07, 2018, 11:02:27 AM »
 :toilet_claw: These Die Nuts are usually used for repairing damaged threads, and usually get run onto the thread with a Crescent wrench, or what ever is to hand.
Ian S C

Offline bouch

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Re: Tailstock hex die holder
« Reply #11 on: March 07, 2018, 09:06:50 PM »
:toilet_claw: These Die Nuts are usually used for repairing damaged threads, and usually get run onto the thread with a Crescent wrench, or what ever is to hand.
Ian S C

AFAIK, while rethreading dies are always hex, not all hex dies are rethreading.  You can get decent sized tap and die sets off the shelf at "big box" hardware stores which come with hex dies, and my local hardware store has nothing but hex dies.  They're not the greatest quality, but they're a) easily available locally b) reasonably cheap and c) good enough for home shop purposes.

And 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" :)