Geometric Die Heads

9finger · May 29, 2019

I noticed while researching Geometric die heads (one of the reasons I finally joined), many people seemed to be looking for manuals. I have two manuals. If anyone needs specific info out of them, I'm happy to take pics or scan pages for you. Here are the two I have.

metalmagpie · May 30, 2019

Just wish your manual would tell me where I can get a few dies in most-used sizes e.g. 5/8-11, 1/2-13 and 3/8-16, plus maybe the equivalent from the fine series.

All I see on the used market are threads I've never used even once.

metalmagpie

lionelt · May 30, 2019

metalmagpie said:
Just wish your manual would tell me where I can get a few dies in most-used sizes e.g. 5/8-11, 1/2-13 and 3/8-16, plus maybe the equivalent from the fine series.

All I see on the used market are threads I've never used even once.

metalmagpie

I was after some Brass Thread dies and found some on Ebay that came from Australia.

Which reminds me, where was that safe place I put them?

Will have to find some more they have completely disappeared.

cyanidekid · May 30, 2019

good on ya mate for the offer! I have one of the EFEM heads, haven't run into any problems yet, but I will keep it in mind.

just wondering, if you have a larger lathe (relatively speaking, I'm talking 15" swing and up), and you are doing a smallish thread such as 10-32, I wouldn't want to drag the tailstock into the work with the die head as is the common practice when using these in an engine lathe. is there a floating holder available with a morse taper tail and a keyed or splined 1" socket for the head?

9finger · May 30, 2019

cyanidekid said:
good on ya mate for the offer! I have one of the EFEM heads, haven't run into any problems yet, but I will keep it in mind.

just wondering, if you have a larger lathe (relatively speaking, I'm talking 15" swing and up), and you are doing a smallish thread such as 10-32, I wouldn't want to drag the tailstock into the work with the die head as is the common practice when using these in an engine lathe. is there a floating holder available with a morse taper tail and a keyed or splined 1" socket for the head?

Well, I have an SB13 and a 19" LeBlond. I have five die heads. I used them once like 13 years ago on the SB in the tailstock just to try them out, and haven't touched them since. My biggest is a 9/16 D head, set up with 1/2-28 chasers, all the others are 5/16. They are a work of art, but if I'm only cutting a few threads here and there, I can have the threads single pointed by the time I remember where I put the heads.

ETA: I skim read your question then answered a totally different question. The only lathe I tested the 5/16 die heads on was the SB, heads in the tailstock in a Jacobs chuck (they are all 5/8" shank) and tried 1/4-20 down to 2-56. It pulled the tailstock just fine, especially if you have a tiny start turned down to the minor, or a chamfer. The smaller ones required a little more help getting them started, but it pulled the tailstock along just fine. That's a fairly small tailstock though. I guess there is a decent amount of weight if you add the chuck and head, but still nothing like the OOOOLLLLDDD Leblond. I'm pretty sure I couldn't lift the tail stock on that thing before I had 20 surgeries...now it hurts to even think about it. It slides like butter though, so I think the 9/16" head would work fine.

In general, if you can slide the TS without much effort, they work fine.

9finger · May 30, 2019

metalmagpie said:
Just wish your manual would tell me where I can get a few dies in most-used sizes e.g. 5/8-11, 1/2-13 and 3/8-16, plus maybe the equivalent from the fine series.

All I see on the used market are threads I've never used even once.

metalmagpie

I probably have 50 sets of chasers, but most are for 5/16 heads. I'll dig through the box and see what's in there.
ETA: You made me curious so I had to go count. I have 126 sets of chasers. A lot of them are standard threads, ha handful of metric, a few left hand, then an assortment or really, really weird threads.

cyanidekid · May 30, 2019

9finger said:
Well, I have an SB13 and a 19" LeBlond. I have five die heads. I used them once like 13 years ago on the SB in the tailstock just to try them out, and haven't touched them since. My biggest is a 9/16 D head, set up with 1/2-28 chasers, all the others are 5/16. They are a work of art, but if I'm only cutting a few threads here and there, I can have the threads single pointed by the time I remember where I put the heads.

ETA: I skim read your question then answered a totally different question. The only lathe I tested the 5/16 die heads on was the SB, heads in the tailstock in a Jacobs chuck (they are all 5/8" shank) and tried 1/4-20 down to 2-56. It pulled the tailstock just fine, especially if you have a tiny start turned down..

In general, if you can slide the TS without much effort, they work fine.

yes, understood, but if you did want to reliably and without drama thread say a 4-40 on a 16" lathe in brass, is there such a splined arbor available?

sfriedberg · May 30, 2019

You can probably adapt a tension/compression tap holder, usually used on mills without rigid tapping, for this purpose. It's exactly what they are for, and all you'd need to do is change the shank or grab it in a MT-mounted drill chuck or something like that. These things have limited travel, so you would still have to advance the tailstock ram, but you'd have the whole range of tap holder travel as a tolerance on your ability to advance the ram in sync with the thread being cut.

Given a choice between sliding the tailstock and applying a slight pressure toward the headstock on a Geometric-style die head by manually screwing out the tailstock ram, I would choose the latter without hesitation. I use these heads on a manual turret lathe, where tool advance is purely by hand and sense of touch/pressure. While the work can't exert backpressure through a tailstock ram screw in quite the same way, you'd quickly pick up the ability to keep the die head engaged (not pulling off) while not forcing it onto the work faster than the threads cut allow.

9finger · May 30, 2019

I think it would be pretty easy to make a spring loaded shank (picturing a slide hammer with a compression spring) for using a heavier tail stock. I run a prototype shop though, so I just haven’t had to need to use them. Doesn’t mean I won’t waste time making stuff to use them with....just means there won’t be a point and it’ll be a waste of time when I do. Actually, I never will. But I’ll think about it and maybe start, I just won’t ever finish.

9finger · May 30, 2019

cyanidekid said:
yes, understood, but if you did want to reliably and without drama thread say a 4-40 on a 16" lathe in brass, is there such a splined arbor available?

I can honestly say I’ve never looked in to it, but I bet you could make one in less time than you could find a suitable one online. It would only be 3-4 simple parts.

cyanidekid · May 30, 2019

9finger said:
I can honestly say I’ve never looked in to it, but I bet you could make one in less time than you could find a suitable one online. It would only be 3-4 simple parts.

thanks for the feedback, yes, I’ve rigid tapped by feel, but was looking for a “robust” solution for small stuff. Could of corse make a holder, but as you know it’s always a trade off. “ I could have made one by now” Vs “why the hell didn’t I just buy one”

9finger · May 30, 2019

sounds like mounting it in the carriage may be an option.....I make boring bar holders all the time by putting a piece of stock in a tool holder, and a drill in the chuck, bang, perfectly centered tool holder.

If you want to borrow one to experiment with, you can.

metalmagpie · Jun 1, 2019

9finger said:
I probably have 50 sets of chasers, but most are for 5/16 heads. I'll dig through the box and see what's in there.
ETA: You made me curious so I had to go count. I have 126 sets of chasers. A lot of them are standard threads, ha handful of metric, a few left hand, then an assortment or really, really weird threads.

I have a 1D die head. Want to sell me some chasers? - metalmagpie

9finger · Jun 1, 2019

metalmagpie said:
I have a 1D die head. Want to sell me some chasers? - metalmagpie

What threads are you looking for?

MC Parts Kid · Jun 2, 2019

9finger said:
What threads are you looking for?

1.125-24 for 1.250D and 1.375-24 for 1.750D. Thanks for asking. Bob

ratbldr427 · Jun 2, 2019

Why not see if you can take the crank handle of the tail stock and make a screw on rod that is small enough od to slide through the rear bearing.Make it long enough and put a knob on the end so you can retract it and start it.That way only the spindle barrel would move.Just depends on the size and construction if it would work.

Never tried it but seems possible.

john.k · Jun 3, 2019

The sharpening fixtures and gauges are the hard things to find.....every old guy worked capstans seems to have taken a sharpening kit home with him when he retired,and when he passes,the rellies just throw them away.

9finger · Jun 3, 2019

john.k said:
The sharpening fixtures and gauges are the hard things to find.....every old guy worked capstans seems to have taken a sharpening kit home with him when he retired,and when he passes,the rellies just throw them away.

I just made my own....sharpened the two dull ones I had to see if it worked. Totally unnecessary, but I seem to have a habit of doing things because I want to, not because I need to.

9finger · Jun 3, 2019

ratbldr427 said:
Why not see if you can take the crank handle of the tail stock and make a screw on rod that is small enough od to slide through the rear bearing.Make it long enough and put a knob on the end so you can retract it and start it.That way only the spindle barrel would move.Just depends on the size and construction if it would work.

Never tried it but seems possible.

What’s funny is an old machinist friend of mine said he kept a lathe with a ridiculously sloppy tailstock just for that reason. So I’d bet you are right. There’s a good 1.5” of play in it.

9finger · Jun 3, 2019

MC Parts Kid said:
1.125-24 for 1.250D and 1.375-24 for 1.750D. Thanks for asking. Bob

Unfortunately I don’t have any that large. Story of my life. Sorry.

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