Discussion:
Geometric Self Opening Die Heads
(too old to reply)
Bob La Londe
2024-07-13 18:31:01 UTC
Permalink
Geometric Self Opening Die Heads

I've made simple die heads. Some driven by a tommy bar, others by a pin
in the mandrel that can be set up come out of the groove and free spin
when it reaches the stopping distance. recently I started researching
my $350 Lin Huan TL-25 lathe score in the long term plan to getting it
running again.

Its a copy of a Hardinge turret lathe. Jet, Enco, and probably some
others sold it under their own label with some form of "25" in the model
name. I've been watching videos during my connection time with the
brain sucker box while drinking coffee in the mornings. There are lots
of cool tool holders available for the turret, and I have some ideas for
the head stock top mounted parting blade holder to add "one more"
function to it for some repetitive jobs. There are parts I would
probably offer for sale more aggressively if I had this machine running
and a few setup configurations ready to go.

A lot of the "expensive" special tool holders for it are pretty easy to
make, and I may make them as needed or in some cases make batches.

I found only one really good video on setup for one of these machines.
Lots of guys did a short video that was basically "look at my machine,"
and a number of machinery dealers did a short video showing the machine
runs and most of the function work, but there was only one I found so
far that seemed to show the setup and setting up a job. Its about 3o
minutes long, and its a little slow for my taste, but the first 15
minutes shows his setup for a job, some of the limitations, and finally
cutting one piece in the job setup.

Here is where he introduces the part.


The video showed one tool that might very well be a challenge for me to
make. I also looked them up and new ones are fairly expensive. A self
opening die head. One some types of jobs this could really be an
efficiency tool. I am sure I can my shop made simple die heads on the
turret lathe much the same way I use them on the engine lathe, but I
have to stop, reverse, reengage the tool, thread the die off the part,
and then stop the lathe to switch it back to forward. The self opening
die head pops open when it reaches its "limit" which would allow me to
simple back off the turret and use the next tool. At most change the
speed (which is supposed to be shift on the fly). A speed change is
something I would have to do anyway if the next tool demands it.


If you don't want to watch the whole video here is where he runs through
one part.
http://youtu.be/WXoG9uEMIpA

I am sure if I look around I can find a used version of this tool for
less than a brand new one, but I need to ask. Have you used a tool like
this. The self opening die head, not a turret lathe. I am sure lots of
you have used a turret lathe. How easy was it to setup for each job?
How affordable where the thread jaws? Did you find it worked reliably?
Do you have nay other feedback for using one or reasons not to?
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
David Billington
2024-07-13 19:23:05 UTC
Permalink
Post by Bob La Londe
Geometric Self Opening Die Heads
I've made simple die heads.  Some driven by a tommy bar, others by a
pin in the mandrel that can be set up come out of the groove and free
spin when it reaches the stopping distance.  recently I started
researching my $350 Lin Huan TL-25 lathe score in the long term plan
to getting it running again.
Its a copy of a Hardinge turret lathe. Jet, Enco, and probably some
others sold it under their own label with some form of "25" in the
model name.  I've been watching videos during my connection time with
the brain sucker box while drinking coffee in the mornings.  There are
lots of cool tool holders available for the turret, and I have some
ideas for the head stock top mounted parting blade holder to add "one
more" function to it for some repetitive jobs.  There are parts I
would probably offer for sale more aggressively if I had this machine
running and a few setup configurations ready to go.
A lot of the "expensive" special tool holders for it are pretty easy
to make, and I may make them as needed or in some cases make batches.
I found only one really good video on setup for one of these machines.
Lots of guys did a short video that was basically "look at my
machine," and a number of machinery dealers did a short video showing
the machine runs and most of the function work, but there was only one
I found so far that seemed to show the setup and setting up a job. 
Its about 3o minutes long, and its a little slow for my taste, but the
first 15 minutes shows his setup for a job, some of the limitations,
and finally cutting one piece in the job setup.
Here is where he introduces the part.
http://youtu.be/WXoG9uEMIpA
The video showed one tool that might very well be a challenge for me
to make.  I also looked them up and new ones are fairly expensive.  A
self opening die head.  One some types of jobs this could really be an
efficiency tool.  I am sure I can my shop made simple die heads on the
turret lathe much the same way I use them on the engine lathe, but I
have to stop, reverse, reengage the tool, thread the die off the part,
and then stop the lathe to switch it back to forward.  The self
opening die head pops open when it reaches its "limit" which would
allow me to simple back off the turret and use the next tool.  At most
change the speed (which is supposed to be shift on the fly).  A speed
change is something I would have to do anyway if the next tool demands
it.
If you don't want to watch the whole video here is where he runs
through one part.
http://youtu.be/WXoG9uEMIpA
I am sure if I look around I can find a used version of this tool for
less than a brand new one, but I need to ask. Have you used a tool
like this.  The self opening die head, not a turret lathe.  I am sure
lots of you have used a turret lathe.  How easy was it to setup for
each job? How affordable where the thread jaws?  Did you find it
worked reliably? Do you have nay other feedback for using one or
reasons not to?
I've looked at them in the past but haven't had a job where I could
justify getting one as mainly doing low volume stuff so just used split
dies although I did make a double ended die holder with a die for
roughing and the other end set for a finish cut for one job threading
stainless tube. On this side of the pond they're called Coventry die
heads and the heads and chasers are quite common on ebay. If you have a
surface grinder my understanding is the chasers can be resharpened a few
times if they become worn.
Jim Wilkins
2024-07-13 21:13:20 UTC
Permalink
"Bob La Londe" wrote in message news:v6uh55$3mnvk$***@dont-email.me...

Geometric Self Opening Die Heads
...
I am sure if I look around I can find a used version of this tool for
less than a brand new one, but I need to ask. Have you used a tool like
this. The self opening die head, not a turret lathe. I am sure lots of
you have used a turret lathe. How easy was it to setup for each job?
How affordable where the thread jaws? Did you find it worked reliably?
Do you have nay other feedback for using one or reasons not to?
Bob La Londe
-----------------------------------
https://pounceatron.dreamhosters.com/docs/geometric-die-heads.pdf
Bob La Londe
2024-07-14 17:36:47 UTC
Permalink
Post by Bob La Londe
Geometric Self Opening Die Heads
...
I am sure if I look around I can find a used version of this tool for
less than a brand new one, but I need to ask. Have you used a tool like
this.  The self opening die head, not a turret lathe.  I am sure lots of
you have used a turret lathe.  How easy was it to setup for each job?
How affordable where the thread jaws?  Did you find it worked reliably?
Do you have nay other feedback for using one or reasons not to?
Bob La Londe
-----------------------------------
https://pounceatron.dreamhosters.com/docs/geometric-die-heads.pdf
Great manual. Thanks.
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
Jim Wilkins
2024-07-14 11:04:09 UTC
Permalink
Post by Bob La Londe
Geometric Self Opening Die Heads
...
How affordable where the thread jaws?
...
https://www.travers.com/category/chasers

https://www.wttool.com/516-d-regular-high-speed-chasers
Bob La Londe
2024-07-14 17:39:07 UTC
Permalink
Post by Jim Wilkins
Post by Bob La Londe
Geometric Self Opening Die Heads
...
How affordable where the thread jaws? ...
https://www.travers.com/category/chasers
https://www.wttool.com/516-d-regular-high-speed-chasers
Ah... the cost of the "chasers" is really what I was wondering about.
Thanks. I probably wouldn't buy a new die head at this point, but it
would be nice to have a couple sets of dies "chasers" if I decide its
worth the trouble to integrate into a process.

It looks like they are just referenced by slot size. I wonder how
interchangeable they are.
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
Jim Wilkins
2024-07-15 12:41:05 UTC
Permalink
Post by Jim Wilkins
Post by Bob La Londe
Geometric Self Opening Die Heads
...
How affordable where the thread jaws? ...
https://www.travers.com/category/chasers
https://www.wttool.com/516-d-regular-high-speed-chasers
Ah... the cost of the "chasers" is really what I was wondering about.
Thanks. I probably wouldn't buy a new die head at this point, but it
would be nice to have a couple sets of dies "chasers" if I decide its
worth the trouble to integrate into a process.

It looks like they are just referenced by slot size. I wonder how
interchangeable they are.
--
Bob La Londe

----------------------------------
"Chasers" were originally hand-held chisels with multiple teeth filed into
the end, used to clean up initially filed or hand guided single point
threads cut on lathes that had chisel tool rests like a modern wood lathe.

I have an antique die stock that pressure forms male threads between V
grooves in a floating row of die blocks with straight thread profiles on the
walls, no cutting edges. The thread forms could have been cut into the die
blocks by a shaper or planer. The sizes appear to be 18, 16 and 14TPI.

Looking at older ways to form screw threads shows why we had advanced little
beyond the Romans until the thread cutting lathe became available around
1800. With it the improvements came very quickly, steam powered travel
almost immediately and autos, aircraft and radio in a century.
https://mb.nawcc.org/threads/inch-screws-sizes-in-english-clocks.175136/
Bob La Londe
2024-07-16 21:09:01 UTC
Permalink
Post by Bob La Londe
Post by Jim Wilkins
Post by Bob La Londe
Geometric Self Opening Die Heads
...
How affordable where the thread jaws? ...
https://www.travers.com/category/chasers
https://www.wttool.com/516-d-regular-high-speed-chasers
Ah... the cost of the "chasers" is really what I was wondering about.
Thanks.  I probably wouldn't buy a new die head at this point, but it
would be nice to have a couple sets of dies "chasers" if I decide its
worth the trouble to integrate into a process.
It looks like they are just referenced by slot size.  I wonder how
interchangeable they are.
Looks like I may have been wrong. They appear to be referenced by
maximum thread size.
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
Jim Wilkins
2024-07-16 23:33:27 UTC
Permalink
Post by Bob La Londe
Post by Jim Wilkins
Post by Bob La Londe
Geometric Self Opening Die Heads
...
How affordable where the thread jaws? ...
https://www.travers.com/category/chasers
https://www.wttool.com/516-d-regular-high-speed-chasers
Ah... the cost of the "chasers" is really what I was wondering about.
Thanks. I probably wouldn't buy a new die head at this point, but it
would be nice to have a couple sets of dies "chasers" if I decide its
worth the trouble to integrate into a process.
It looks like they are just referenced by slot size. I wonder how
interchangeable they are.
Looks like I may have been wrong. They appear to be referenced by
maximum thread size.
Bob La Londe

---------------------------------
Turret lathe tooling is beyond my experience. I have enough trouble picking
up a thread to extend it, perhaps from the wear and play uncertainty of my
old lathe. I have six 3/8" x 5" Grade 8 bolts to modify with another 1/2" of
thread, because the store doesn't stock the 4-1/2" long bolts that would fit
better. The supplier was there taking inventory when I looked and we
discussed which area stores had more room for larger selections, but I had
recently checked one of the best and not found 4-1/2" Grade 8 there either.
At least threading is indoor work, out of the East Coast "heat bubble" of
tropical humidity.

I'm upgrading my hoisting equipment for the 4500 Lb log in queue for the
sawmill. Weighing it at both ends (2570+1930) damaged the tripod baseplates
and pushed the rest close to its rated limits, so I bought G100 overhead
lifting rated chain and fittings to upgrade. Apparently the difference
between G80 or G100 alloy and G70 transport chain is better shock overload
capacity, carbon steel chain may be more brittle. I've seen (from a safe
distance) falling logs break equipment.

The new tripod baseplates are 14 gauge CRS steel remnants hammered into
shallow bowls over a depression in wood, with their corners turned down and
a flanged hole in the middle that serves as a socket for the ball or acorn
lower end caps on the tripod legs. They dig in at the flange rim and corners
without seriously damaging the lawn and 14ga was probably the thickest steel
I could hammer to shape neatly on the wooden 'stump' and my anvil. The bowl
shape stiffens them and causes them to sink straight into soft soil instead
of twisting.
Bob La Londe
2024-07-16 23:43:47 UTC
Permalink
Post by Bob La Londe
Post by Jim Wilkins
Post by Bob La Londe
Geometric Self Opening Die Heads
...
How affordable where the thread jaws? ...
https://www.travers.com/category/chasers
https://www.wttool.com/516-d-regular-high-speed-chasers
Ah... the cost of the "chasers" is really what I was wondering about.
Thanks.  I probably wouldn't buy a new die head at this point, but it
would be nice to have a couple sets of dies "chasers" if I decide its
worth the trouble to integrate into a process.
It looks like they are just referenced by slot size.  I wonder how
interchangeable they are.
Looks like I may have been wrong.  They appear to be referenced by
maximum thread size.
Bob La Londe
---------------------------------
Turret lathe tooling is beyond my experience. I have enough trouble
picking up a thread to extend it, perhaps from the wear and play
uncertainty of my old lathe. I have six 3/8" x 5" Grade 8 bolts to
modify with another 1/2" of thread, because the store doesn't stock the
4-1/2" long bolts that would fit better. The supplier was there taking
inventory when I looked and we discussed which area stores had more room
for larger selections, but I had recently checked one of the best and
not found 4-1/2" Grade 8 there either. At least threading is indoor
work, out of the East Coast "heat bubble" of tropical humidity.
I'm upgrading my hoisting equipment for the 4500 Lb log in queue for the
sawmill. Weighing it at both ends (2570+1930) damaged the tripod
baseplates and pushed the rest close to its rated limits, so I bought
G100 overhead lifting rated chain and fittings to upgrade. Apparently
the difference between G80 or G100 alloy and G70 transport chain is
better shock overload capacity, carbon steel chain may be more brittle.
I've seen (from a safe distance) falling logs break equipment.
The new tripod baseplates are 14 gauge CRS steel remnants hammered into
shallow bowls over a depression in wood, with their corners turned down
and a flanged hole in the middle that serves as a socket for the ball or
acorn lower end caps on the tripod legs. They dig in at the flange rim
and corners without seriously damaging the lawn and 14ga was probably
the thickest steel I could hammer to shape neatly on the wooden 'stump'
and my anvil. The bowl shape stiffens them and causes them to sink
straight into soft soil instead of twisting.
Yeah, at a little over 2 bucks a piece for the cheapest ones in the
right size I'd modify hardware store bolts too.

https://www.mcmaster.com/products/bolts/fastener-strength-grade-class~sae-grade-8/thread-size~3-8-16/length~4-1-2/
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
Jim Wilkins
2024-07-17 02:30:47 UTC
Permalink
"Bob La Londe" wrote in message news:v770jj$1fv4f$***@dont-email.me...

On 7/16/2024 4:33 PM, Jim Wilkins wrote:

Yeah, at a little over 2 bucks a piece for the cheapest ones in the
right size I'd modify hardware store bolts too.

https://www.mcmaster.com/products/bolts/fastener-strength-grade-class~sae-grade-8/thread-size~3-8-16/length~4-1-2/
Bob La Londe
--------------------------------
I gave the approximate length for simplicity, actually they are threaded
just far enough to keep all shear loading on the full diameter shank with
only enough axial clearance to minimize cantilever loading and avoid binding
when the locking flange nut is snugged. I may have to leave more shank to
fit the stronger chain. The Grade 2 4-1/2" bolts didn't have quite enough
shank length and one showed thread damage when removed.

This is more fussing than I would design into a commercial product unless
higher performance justified it. I've been the tech doing that custom
adjusting, like cutting coax cables to length to match the propagation
delays, the timing error tolerance was equivalent to around 1/16". They were
for a machine that tested computer memory chips for speed and errors before
they were cut from the wafer.

At the start of WW2 when we took on the manufacture of foreign designs, the
Merlin engine and Bofors AA gun, we found that hand fitting was still common
in Europe.
Bob La Londe
2024-07-19 22:08:22 UTC
Permalink
Post by Bob La Londe
Geometric Self Opening Die Heads
<SNIP>
Post by Bob La Londe
If you don't want to watch the whole video here is where he runs through
one part.
http://youtu.be/WXoG9uEMIpA
I am sure if I look around I can find a used version of this tool for
less than a brand new one, but I need to ask. Have you used a tool like
this.  The self opening die head, not a turret lathe.  I am sure lots of
you have used a turret lathe.  How easy was it to setup for each job?
How affordable where the thread jaws?  Did you find it worked reliably?
Do you have nay other feedback for using one or reasons not to?
Another groups take on the subject:
https://bbs.homeshopmachinist.net/forum/general/2095061-geometric-self-opening-die-heads#post2095515

After reading all the comments I have concluded that geoseismic button
taps are bad for single point reaming.
--
Bob La Londe
CNC Molds N Stuff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
Jim Wilkins
2024-07-20 00:27:44 UTC
Permalink
Post by Bob La Londe
Geometric Self Opening Die Heads
Another groups take on the subject:
https://bbs.homeshopmachinist.net/forum/general/2095061-geometric-self-opening-die-heads#post2095515

After reading all the comments I have concluded that geoseismic button
taps are bad for single point reaming.
Bob La Londe

--------------------------------
"For that matter, at one time, not so very long ago, in terms of history,
NOBODY had made such good threads. But somehow, those poor crawling and
ignorant cretins (who would not be allowed by the forum police here to even
discuss the matter), managed to make very accurate threads, despite the fact
that they had no prior experience making them, and had never even seen such
an accurate thread until they made one. And they made good micrometers that
had those threads.
I will guarantee that none of them used dies or dies heads to make those
threads. More precise methods were needed."

Holtzapffel described the early crude and precision threading methods in
detail. It turned out that an angled knife blade carving a spiral on a
rotating rod was about as good a method as any other. The simple way was to
tin a brass rod and wind a clean brass and black iron wire side by side
around it, press then together and dip in solder, that wouldn't stick to the
black iron which was unwound afterwards, leaving the brass wire spiral.
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