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View Full Version : how does a H&G threading die head work????



andy_b
08-02-2008, 12:47 PM
i remember some folks posting a while back about threading using a die head, and i think John S. made a holder for his tool post that could hold one of the threading dies in it to use for single-point (well, multi-point in this case) threading. so i was watching flea-bay and scored one not too long ago. it is a size 102, and came with some dies. there is a handle sticking out from one side. how does this thing work? is the handle supposed to move so you can pop the dies out when you reach the end of your thread? any links to manuals or descriptions of operation are well appreciated.

andy b.

Rustybolt
08-02-2008, 02:21 PM
The handle cocks it. it releases by either a button that pushes against the chuck, or by pulling back away from the work. Those are the only two H&G that I've used.

JCD
08-02-2008, 02:23 PM
Try a Google search using "self opening die head" as the search criteria. The patent sight has a good explanation.

Carld
08-02-2008, 02:23 PM
If you go to this site http://www.internationalscrew.com/pages/Distributor/h_and_g.htm you will find the info you want and a manual.

andy_b
08-02-2008, 07:25 PM
The handle cocks it. it releases by either a button that pushes against the chuck, or by pulling back away from the work. Those are the only two H&G that I've used.

when you say "pulling back away from the work", do you mean you grab the handle and when you pull back it releases some mechanism whereby the four dies slide out (like the jaws on a lathe chuck)? i am afraid to apply too much force on any part of this thing because i have no idea what it's supposed to do. i think i need to search YouTube....

andy b.

andy_b
08-02-2008, 07:26 PM
If you go to this site http://www.internationalscrew.com/pages/Distributor/h_and_g.htm you will find the info you want and a manual.

Carl,

i searched that site, but didn't find any manuals, or even any good photos. did you actually see anything of help there, or were you suggesting i give them a call or email? i decided to send an email, so i'll see what they tell me.

andy b.

Rustybolt
08-02-2008, 09:14 PM
No. As the die head is retracted it opens automatically. Very helpful on a turret lathe when your other hand might be busy doing something else.

andy_b
08-02-2008, 10:20 PM
No. As the die head is retracted it opens automatically. Very helpful on a turret lathe when your other hand might be busy doing something else.

what is retracting the die head? you, or some part of the machine? the place i got this from also deals in screw machines, so i'm guessing it can be automated somehow, but the fact i have never seen one in operation means i don't even know what it should look like when running. there is a plunger/bolt of some sort that looks like the end is broken off one one side of the die head. it looks like it is the plunger you mentioned in your original reply. when the die head hits the stop in operation, and this plunger contacts it, does the plunger compress and the four die fingers slide outward? any idea how much force that plunger hits with? what i mean is, can i just push in the plunger with my finger, or do i need to push it in with 30 pounds of force or something?

if i could just see this thing work once i'd have it figured out.

andy b.

Carld
08-02-2008, 10:34 PM
Ahhh, Andy, it's right there on the page that opens when you click on the link. Scroll down the page and they list a manual. You don't have to search their site. I did a google and that and other sites turned up. It's not hard to find parts and manuals for it.

Andy, the way a die head works is it is mounted in a turret tailstock with adjustable stops. You put the dies to cut the thread you want in the head. Then you put the stock you want to thread in the headstock chuck and then you move the tailstock up to the work and extend the ram so the die head goes over the work to the length of the thread you want and set the travel stop on the ram and retract the ram. Then you move the handle to close the dies. When you turn the lathe on and set the rpm for the speed to thread you flood the shaft with oil and move the ram up until the cutters catch on the shaft and then it will be drawn forward and cut threads. When the ram reaches the stop the head will travel a short distance and the head will snap and release the dies and open up. You then move the ram back away from the work and low and behold a thread miracolously appears on the shaft. It's magic.

It takes some modifications to use it in an engine lathe. For one thing it has to be secured to the tailstock quill. another thing is the quill has to move freely from the handwheel while the tailstock is clamped the the bed. Then you have to have a travel stop to set the length of thread you will cut on a shaft.

They are handy but don't expect to just put it in a tailstock of a standard lathe and have it cut threads. It won't happen.

Jim Caudill
08-02-2008, 10:44 PM
I am assuming this works the way most other die heads work. There is a knob of some sort that rotates the head and causes the chasers to close. Once they are closed you are ready to feed the rotating stock into the stationary head, by using either the carriage or tailstock (whatever you have the head mounted on). Once the head starts cutting, it will want to "self feed" and pull the tailstock, carriage, or whatever forward towards the headstock. Now, you can stop this forward motion using different techniques; the easiest is to stop carriage movement by grabbing the handwheel and holding it or giving it a sharp jerk backward. You could also use a carriage stop to block the carriage from advancing past the "set point". In any case, when you stop the head from advancing, the chaser portion will still try to continue towards the headstock, this results in a tension being applied to the head, which will cause the chasers to pop or snap open. Now you crank the carriage back, clean out the chips, change the barstock, and rotate the head to close the chasers back up and you're ready for the next piece. I cut threads at around 400 rpm in my chucker (should be slower for some of the tough stuff) and it work fine. There's more to all this, but this should get you started. You can do roughing and finishing passes, set the chasers for the "fit", etc. Some heads can be set to "pull off" and some are set to "push off". Don't know much about H&G, try looking at some Geometric info, if you can't find your brand.

Andy, don't feel bad, I couldn't find it either. I've gone back several times to their website and searched all over, still couldn't find any manuals.
If you got a high speed connection, you might want to download this manual:
http://toprake.com/index.php?module=documents&JAS_DocumentManager_op=viewDocument&JAS_Document_id=14

Here's a quick cheat sheet:http://toprake.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=36

andy_b
08-03-2008, 10:04 AM
Ahhh, Andy, it's right there on the page that opens when you click on the link. Scroll down the page and they list a manual. You don't have to search their site. I did a google and that and other sites turned up. It's not hard to find parts and manuals for it.


Carl,

i must be losing my mind. the page that opens when i click your link does have a list of H&G tools, but no manual. in fact, the page that opens for me does not even contain the word "manual" anywhere in the text on the page. here is the link to the page that opens when i click your link:

http://www.internationalscrew.com/pages/Distributor/h_and_g.htm

i clicked every link on that page and not a single one goes to a manual or link to a manual. the page does appear to be loading correctly, but my firewall may be preventing something from popping up.


andy b.

andy_b
08-03-2008, 10:06 AM
Andy, don't feel bad, I couldn't find it either. I've gone back several times to their website and searched all over, still couldn't find any manuals.
If you got a high speed connection, you might want to download this manual:
http://toprake.com/index.php?module=documents&JAS_DocumentManager_op=viewDocument&JAS_Document_id=14

Here's a quick cheat sheet:http://toprake.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=36

Jim,

THANKS! that does give me some info to go on. the one in your pdf file looks a little different, but i'll see what i can figure out.

andy b.

Carld
08-03-2008, 10:45 AM
My mistake, maybe it's just a catalog. They may have or know where to get a manual if you ask them.

Sorry 'bout that.

andy_b
08-03-2008, 08:20 PM
well i had to play around with the die head some more. NOW i see what happens. yes, there is a plunger (as i mentioned, the end is broken off), and when i push on it with a punch, the die fingers pop open. then you grab the handle sticking out of the side of the head and rotate it and the fingers pop back in and lock. a very interesting tool. it is an H&G 0-1/2" Model DSA.

what i'd like to do is make a holder for it to mount to the cross slide. i would then set the carriage feed to the same TPI as the dies in the threading head, and thread that way. basically just using the threading head to cut threads in a single pass instead of multiple pases with a single-point tool. i got the head cheap, and it came with a bunch of dies (maybe 50 or 60 sets), otherwise i wouldn't bother.

i also want to make up a holder to hold a single die and try some threading that way. just some projects to play around with.

andy b.

Jim Caudill
08-03-2008, 08:34 PM
You would not want to use any type of powerfeed for the carriage when using the head. You can use the handfeed to help the carriage along, but let the head determine the rate and you just keep a little pressure against it with the hand feed wheel.