Taping problem

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Tinyjames

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Joined
Jan 14, 2021
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10
Location
UK
Good afternoon all

I'm having a bit of trouble with my threading Acrylic pen blanks.

Size 14mm cap and barrel thread

So I drill with a 12mm drill first to the full depth required to accept the Nib and external thread of Barrel then I drill with a 13mm drill to the depth required for threaded acrylic barrel plus little extra. I place tap Starter and then intermediate into drill chuck add some oil and then pushing on the back of the tail stock holder (banjo I think it's called) and thread my cap I the turn a concave to the end so it will fit with out any obstructions I then turn my attention to the barrel I turn to 14 mm and add my sliding die holder from Beaufort ink fitted with a 14x1 die (writing facing outwards) I then tighten the center grub screw ( as far as it will go) as this acts as I starter thread, I then thread my 14mm tenon. I then untighten my die and tighten the outer two grub screws until they just hold the die in place and finally turn the die around so the writing is on the inside of holder and finish off the threading.

But the trouble I have or think I have is the cap and barrel feel quite lose until it hit the tenon shoulder.

I forgot to say I chamfer and add oil to help thread, I also remove some thread near the tenon shoulder.


So how can I improve the fit of my Cap and Barrel.
 
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skiprat

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Oct 19, 2006
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In a Skip in Wales
I’d try the threads after you did the first cut, with the die ‘stretched’ open .
I don’t know why you reverse the die at all. It’s in reverse as you remove it anyway. So if you ‘ untighten’ it, it will therefore cut more as you remove it the second time.
 
Joined
Aug 5, 2009
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Location
Seattle, WA
When threading acrylic I don't mess with the screw on the dies after I get it to the size I want it to be for fit. The materiel isn't hard enough to require adjusting the die for each cut. Most of my round dies are tapered on both ends so reversing them doesn't have any benefit. Hexagonal dies when reversed can get you a bit more threads closer to the shoulder.
 

duncsuss

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Jun 29, 2012
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Wilmington, MA
As the others have said - this is soft material, you don't need to make it a multi-step process. Just set the die to cut the right dimension and do it once. I've used different lubricants, from spray-can cooking oil to water with a drop of dish detergent to automatic transmission fluid - they all work if you don't rush things.

Side note: I don't remove threads near the tenon shoulder, it looks ugly and weakens the structure. Instead, I remove some of the internal threads in the part that is going to thread onto the tenon. End result is both stronger and aesthetically more pleasing.
 

Tinyjames

Member
Joined
Jan 14, 2021
Messages
10
Location
UK
Much needed advice and thankyou all for replying to my plea. I will give it ago next week. I use food safe oil to Lubricate my tap's and die and they seam to work well.

Keep safe and again thank you for the advice
 
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