M9 X .75 OK for section threads for #6 nibs?

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Dan_F

Dan_F

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Using the triple start 12mm cap threads, is it ok to use the M9 X .75 tap and die for section threads with a #6 nib? I thought so, but ran across a thread in this forum that said that wouldn't work for the larger nib.

I have used El Grande sections (10x 1), but now want to make my own section using Meister Nib #6 assemblies, and thinking that the smaller tap and die would provide a little more security in the tenon that the cap screw on to.

What has been your experience? Thanks much.

Dan
 
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For The Meister nib #6 thread is m7.4 x.5 so you should have about 1.6mm divided by two or .8 (.032) between threads. Depending on the material your making them out of it will depend on the results. Metal your good to go, but pr im not so sure.
 
For me I switched to a 10x.75 from my usual 9x.75 for #6 nibs. My problem was coming from there not being enough thickness on my section's tenon after threading the outside & inside and drilling the relief for the converter. I kept breaking them off during turning. Now that I've switched to the 10mm threads I haven't had any issues turning.
 
Brooks803 said:
For me I switched to a 10x.75 from my usual 9x.75 for #6 nibs. My problem was coming from there not being enough thickness on my section's tenon after threading the outside & inside and drilling the relief for the converter. I kept breaking them off during turning. Now that I've switched to the 10mm threads I haven't had any issues turning.
Click to expand...

Were you using PR or another material? .032 is about what an El Grande measures, but it doesn't have to hold up to the forces of turning, so maybe that's the deciding factor. I wonder if acrylic or alumilite would work better, being less brittle than PR.

Dan
 
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As an option you could increase the length of the section so that the feed housing doesn't go past the main body (as to not overlap where the tenon is for the M9x.75 threads), just increase the depth of the 6.4mm hole that holds the convertor in place.

This obviously is a design decision that could affect the look of the pen. But it would allow the use of M9x.75 threads for any size feed housing.

This is the idea (shown for a Bock #5 feed housing)

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I thought about that too, looks like it would increase the section length by about a quarter inch, which shouldn't look too bad, especially if the section matches the barrel.

Jonathon --- How were you holding the work when it failed, and where on the work did it fail?

Thanks,

Dan
 
Dan, I pretty much do it as shown on George's tutorial. The section is screwed into a holder and the live center is holding the other end with light pressure. Where it's fails is the threads that are inside the holder. They either break off or strip out. Some of it is me but I think the thickness of the tenon has alot to do with it too. Since going to 10mm threads I've yet to lose one.
 
Brooks --- So either the external threads on the tenon strip out, or the tenon itself breaks off?

External threads on the tenon stripping shouldn't have anything to do with the thickness of the tenon at that point, the tenon itself giving way would however. I wonder if sacrificing a feed housing to serve as a stabilizing plug would help prevent damage to the section as it was turned? Inserting it before shaping the section should add stability, fill with epoxy and center drill to get a true surface for the live center to mate with.

It was George's tutorial that made me think that the 9mm set could be used for all nibs, as that's what he says he uses. It was his reasoning about wanting more beef in the cap tenon that got me going on this, as that is the weak link in a 12mm cap pen.

Dan
 
Both.

The stripping is from the tool catching and stopping the section while the holder still spins. It doesn't happen often, but it has happened.

Best thing I can say is to try them both and see what works best for you. I'm not saying it can't be done, I'm just saying I don't do it that way anymore.
 
Brooks803 said:
Both.

The stripping is from the tool catching and stopping the section while the holder still spins. It doesn't happen often, but it has happened.

Best thing I can say is to try them both and see what works best for you. I'm not saying it can't be done, I'm just saying I don't do it that way anymore.
Click to expand...

Thanks, appreciate the input. I think I'll pick up both 9 and 10 mm sets and see what happens.

Dan
 
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