# Thread size for Parker pencil mechanism?



## Cwalker935 (May 17, 2018)

I am trying to figure the right tap for the Parker Style Pencil Mechanism - 0.5mm:

https://www.beartoothwoods.com/catalog/product_info.php?products_id=4996

It’s very close to 7/32 - 32 but not quite it.  I am not versed in tap and die sizing and need some help.  I am thinking an m5.5 or m6 x .5 tap might be the proper tap.  Any help would be greatly appreciated.


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## RobS (May 17, 2018)

following


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## duncsuss (May 17, 2018)

Cwalker935 said:


> I am trying to figure the right tap for the Parker Style Pencil Mechanism - 0.5mm:
> 
> https://www.beartoothwoods.com/catalog/product_info.php?products_id=4996
> 
> It’s very close to 7/32 - 32 but not quite it.  I am not versed in tap and die sizing and need some help.  I am thinking an m5.5 or m6 x .5 tap might be the proper tap.  Any help would be greatly appreciated.



I haven't tried making any of these, so I can't offer an answer -- but have you asked Bear Tooth Woods?


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## Cwalker935 (May 17, 2018)

duncsuss said:


> Cwalker935 said:
> 
> 
> > I am trying to figure the right tap for the Parker Style Pencil Mechanism - 0.5mm:
> ...



They did not know.


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## bmachin (May 17, 2018)

32 tpi is not close to .5mm.  It is much closer to .8mm. (1/32"=.793mm). (.5mm=.020"). (.75mm=.030")

Sorry, but it's the only help that I can offer.  You might take these numbers to victornet.com and check their taps to see if they have any metreic taps that appear close.

Bill


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## Fred Bruche (May 17, 2018)

From Milanspens, the answer is M5.75 x 0.75

https://www.milanspens.com/product-page/1-dsm-2006

Briefly looked but I haven't found any vendor for such a tap.


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## magpens (May 17, 2018)

I trust your word, Cody, but reading your reference to 7-32 caused me some surprise.  I looked up the clearance hole size for that and find it to be something like 0.16", if I am interpolating the reference table correctly.  That is quite a bit smaller than the 5.75mm (0.226") size of the thread stated by Milan.

Even a 7-32 tap is "non-standard".  But Victornet does have them and I bought a couple for a special purpose I have related to using the click mechanism out of a Slimline Pro to make a so-called "kitless" pen.  Turns out that the "stub" of that click mechanism is threaded 7-32 for screwing on a pushbutton.


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## BRobbins629 (May 18, 2018)

Haven't measured that one, but attached is a concept I have used many times.  Measure the OD over the threads and size the tap just a little larger.  Take a picture of the threads next to a steel rule, blow up the picture and count a number of threads that comes close to lines on the rule.  Do some calculations, and it should work.  The attached was from a Pentel Pencil nib and bought the taps on EBay.


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## Cwalker935 (May 18, 2018)

The OD of the threads is exactly 7/32 or around 5.6 mm, using Bruces’s thread counting method I get .75 mm or 34 tpi.  Given that the Milan’s pens info seems to be right.  That solves one problem but raises another- where to find a m5.75 x .75 tap.  I am not having any luck finding one and wonder if a m6 x .75 would work.  Any thoughts?

Thanks for all the help.


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## magpens (May 18, 2018)

I apologize, Cody ... I read your OP incorrectly and now realize my mistake.


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## Cwalker935 (May 18, 2018)

magpens said:


> I apologize, Cody ... I read your OP incorrectly and now realize my mistake.



No problem.


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## Mike V Florida (May 26, 2018)

Wonder why such an odd size?

Try tapco, they make custom taps and dies, http://www.tapcotaps.com/index.html


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