Geometric threaders

[swatson144]

In another thread I mentioned Geometric, Rubometric threading, and there seemed to be some interest. I do not want to detract from this thread but I wouldn't mind carrying on a discussion here for those interested.

The geometric threading tool uses "chasers" for each thread diameter and pitch. You would need both a set of 1/4 20tpi and #12 20tpi if you wanted to cut those threads.

It self releases the chasers when the threaders forward movement is stopped. So if you have one setup on a lathes compound you simply close it and stopping the thread feed will release the die for retraction.

Steve

 

[Bill Gruby]

Boy Howdy, I havent seen those mentioned in a long time. The difference being that one gets closer to the shoulder than the other I believe. There may be other differences but that part of my memory is shot. It has been a long time, over 20 years. Is there a pitch difference also ???

"Billy G" )

 

[swatson144]

I'm remembering that the geometrics were awful expensive and the rubometrics were another brand that used the same chasers but were just different enough to escape litigation.

this is the picture from the other thread
http://www.hobby-machinist.com/attachment.php?attachmentid=40257&d=1347237794

The pitch is determined by the chasers. It was mentioned that they appear adjustable, but really no more than a standard round tap. Its real function in life is rapid threading and releasing the workpiece at the end.

Simply put,,, If mounted on the carriage of a lathe you'd set the lathe to feed the same pitch as the chaser set. You can then thread to length and stop release the half nuts (much like single pointing) the dies (chasers) release, the lathe is still turning and nothing is wrecked.

Steve

 

[Tony Wells]

Landis was another maker of die heads. I have a Landmatic 5/8 with a 1" shank and 24 tpi dies in it. It is adjustable over a wider range, as I recall. I'll never use it. I should sell it to someone who needs it. A quick check of ebay shows they seem to be worth quite a bit in some people's eyes. I'll have to check closed auctions to see what they actually went for.

 

[7HC]

The geometric threading tool uses "chasers" for each thread diameter and pitch. You would need both a set of 1/4 20tpi and #12 20tpi if you wanted to cut those threads.
Steve

So, is there anything special about the thread profile it cuts?


M