# Triple start die question



## rstought (Jan 18, 2009)

I received my triple start tap and die (from the group buy) yesterday, and noticed something about the die when compared to a "standard" die (or at least the standard ones I've been using up to this point to practice with - I'm not a machinist, so I have not had broad exposure to thread cutting tools...).

The die is not a solid, continuous piece.  There is a break at one point, and the break is joined via a small allen head screw. Does this indicate that there needs to be some sort of adjustment performed before/during threading (e.g. tightening and/or loosening) and, if so, how is this done?

Thanks in advance for any and all assistance and advice...


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## Daniel (Jan 18, 2009)

Bob, I am no machinist either. but I was just looking at the one I have left. As well as I can with it wrapped up anyway. Just a couple of thought on this feature when I noticed it. one would be that the die can be adjusted if desired for a looser or tighter fit of the threads. it also would allow you to adjust the die in case heat expansion became an issue. otherwise it might simply be a means of mounting it in a die holder of some sort.
I do not expect any of the above would become an issue in threading parts for pens.
That is only my ideas of what the gap is for but hopefully somebody who actually knows will impart some wisdom.


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## BRobbins629 (Jan 18, 2009)

It is an adjustment screw.  If you want tighter threads you can open the die a little, if you want looser threads, you can close it up.  I haven't touched mine.  Worked just fine for me as received. Its not designed to be much of an adjustment but it can provide a little movement.


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## me2cyclops (Jan 18, 2009)

the dies that are solid and usually hex shaped are not ment for cutting threads they are for chasing and cleaning threads that have been already cut


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## ldb2000 (Jan 18, 2009)

I have never had a reason to adjust mine , it worked fine right out of the box .


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## CaptG (Jan 18, 2009)

As Bruce said.  You tighten the allan screw to get a larger dia. thread that will make the fit with the mating part tighter.  The two detents on the die 180 degrees apart are for set screws that hold the die in the holder.  If your thread fit is too tight, remove die from holder, back off allan screw a SMALL amount, maybe 1/8 to 1/4 turn, replace in die holder an snug down the two set screws that hold die in place.  You may have to re-adjust several times to get the fit just right, but when it is, you should not need to mess with it again.  Hope this helps.  Oh ya, DO NOT hold the die in pliers, vice grips, channel locks or the like and try to thread with it.  Invest a few bucks in the proper holder and save yourself a lot of grief.


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## CaptG (Jan 18, 2009)

Die holder for the one inch dia. round adjustable die,   McMaster-Carr #25565a21  $8.48


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## rstought (Jan 18, 2009)

I suspected it might provide some sort of adjustment but, not knowing precisely WHAT it might adjust - and not necessarily wanting to experiment with a rather pricey tool - I felt it best to ask the experts.  I thank all of you who have taken the time to respond, and for imparting your wisdom.

CaptG, I'm with you on the die holder.  Several months ago, upon the advice of, I think, rherrell (in another post  - not mine - regarding threading) I invested in the #2MT die holder from The Little Machine Shop, and have been using it with excellent results during my "practice" threading sessions leading up to the receipt of the triple start dies.


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## CaptG (Jan 18, 2009)

Bob, good choice with the #2mt holder, always centered.  The holder I listed above is just a t handle holder for hand use.


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