Actual diameter of 13/16″ die holder in wrench

[Frank SmallParticipant @franksmall87776]

[Frank SmallParticipant @franksmall87776]

Hi

I am trying to thread an 1/8″ shaft with a 5ba split die. Checking the net this seems to be correct, I just cant get the die to start on the shaft. I made the die holder myself which is a very snug fit on the die. I think the problem is probably that it too tight to allow the die to ‘spread’ to start threading. My question is:

What should be  the actual diameter of of the die receiver on the wrench when the diameter of the die is 13/16″ 

Looking forward to your help

Thank You

[Geoff TheasbyParticipant @geofftheasby]

Hi Frank,

 

I have never had to “spread” a die to start a thread, but it can be difficult to start if the shaft is not slightly tapered to allow the die to get an initial grip to start cutting.

 

I do most of my tapping in the lathe, but even with everything well lined up, and a die in a tailstock holder, it often won’t start to cut without a little help.

 

1/8 inch is right for a 5BA tap.

 

[Richard ParsonsParticipant @richardparsons61721]

 

Unless the die says otherwise with words like ‘Start from this side’ stamped into it, ALLWAYS start from the side where the details are written ie the maker’s name, the die size etc. 

You only use the ‘wrong side’ of the die if you want to ‘get close’ to a ‘face’ or ‘flange’ at the end of your thread

P.S. Your die may be a 21mm not 13/16ths. That could be your trouble.  As my friend Mr Wun Thou Wong (the chinese inspector says ‘No gettee right allee time.

p.p.s please excust the change in typeface -things are running amoke 

Edited By Richard Parsons on 11/08/2010 08:14:46

[KWILParticipant @kwil]

“Wrong side” use is only as a chaser, having cut the bulk of the thread first from the correct side.

[DMBParticipant @dmb]

Hi Frank,

All my various sized / makes dies fit in the various makes diestocks with space to spare – sort of slack fit. Also my double -ended tailstock die-holder from GLR, holds dies with a bit of room to spare.

My usual method is to chamfer end of rod/bar in 3 jaw. I tighten central screw which opens up die and loosely screw up the 2 side screws. Threading jollop on end of work and start the threading. After  say 3 turns, unscrew die from T/S holder, release from chuck and mount work vertically in bench vice and fit Die Stock to die to continue. After removing die from work, try screwing work in to female thread or try fitting a nut. If good fit, job done. If to tight, slack off centre screw and tighten 2 side screws and start again using Die – Stock.

Sorry if this sounds long-winded but I have only explained in  minute detail my successful method which is small improvement on what I was taught at school.

Hope this helps.

John 

[Paul BoscottParticipant @paulboscott25817]

Hello All

 

I am also intrested in the answer to the original question as I made a tailstock die holder with what must have been to much clerance as I spread a die it cracked in two

 

Paul

[KWILParticipant @kwil]

There is an article in an earlier MEW by David Piddington about making  tailstock die holders , the type where you leave the die mounted for quick interchangeability without the need to set up the die each time. He gave suitable sizes.

[KWILParticipant @kwil]

MEW147 onwards

[The Merry MillerParticipant @themerrymiller]

Frank,

 

I’ve just measured mine and it is 0.819″.

Give it size  to -2 thou. and you should be O.K.

 

Len. P

[Frank SmallParticipant @franksmall87776]

Hi Guys,

 I got the shaft threaded due to ur help

Many thanks

 

Regards

Frank

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