Nib Fit "Tips"...

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JoeyPerot

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Aug 7, 2016
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I have been turning for several months now and all in all feel like I've gotten myself through most of the hurdles I've come across.

One area I continue to struggle though is what I'm calling "Nib Fit" on my slimline and funline kits.

I've just not developed a consistent process that gives me a proper fit where my pen nib and blank meet. Most of the time it's dead on but I still have a few pens that either have a small lip or a small dip where these two parts press together.

So...what do you do that provides you with a consistent fit each and every time? What do you typically account to lose when sanding? What do you expect to "gain back" when applying CA?

I look forward to your expert advice!
 
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thewishman

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Mar 9, 2006
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Reynoldsburg, Ohio, USA.
It is so frustrating when you finish a pen and it isn't quite right - we've all been there. Two main things make the fit a bit tricky:

First is the bushings used - most bushings I have seen for slims are fairly generic, and if you are using kits from different suppliers and in different styles (regular vs. funline) there is no way the same bushings could be perfect for all (or any) of them.

Second is the source of the kits - if you are using kits from different sources, or of different styles, the parts will vary in size. Add in different platings and there are even more variables.

To get the fit right, measure the pen parts where the barrels will be attached, then use that measurement, and not the bushing size, to get your barrels to the right final dimension. It takes more work, but it will get you much better results.:)
 
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magpens

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Feb 2, 2011
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It is pretty hard to get a perfect fit "each and every time".

Before I complete the turning, I measure both the blank and the nib (and finial) very close to where they will meet, using a digital caliper. . I measure several times (say 5) and take an average of the measurements because it is unlikely you will get the same value every time.

Then I turn the wood to 0.002" smaller in radius than the size of the nib where it will meet the wood.

Remember that your caliper measures the diameter not the radius so you will be constantly making adjustments for that fact.

I try to avoid sanding close to the ends of the wood where it will meet the metal.

By undersizing the wood at the ends by 0.002" (radius) this allows me to put on about 5 or 6 coats of thin CA (of the brand that I use) to raise the wood to about the nib size. But I usually put on about 8 coats of thin CA and then sand it back down to size. . Fewer coats for medium CA

In my opinion, it does not matter if the resulting wood + CA is a little oversize, but I do not like it to be undersize compared to the nib.

All comes down to your own materials, experience, and a bit of luck.

You will have to rely on trial and error ... and you will make mistakes, but eventually you will develop a technique that works for you most of the time.

If you want to sand your whole blank then you will have to take into account how much material the sanding takes off. . Make a trial pen and measure the important areas before and after sanding. . It should be an actual pen (not just a round rod) because when you are sanding, you will usually take off more at the ends than you do in the middle of the blank. . Keep written records of wood type, sanding grit, how many sanding strokes, what part of the blank the measurement was made at, etc.

When I am sanding, I always have the lathe turned off and I always sand in the lengthwise direction of the blank, turning the lathe headstock slowly by hand as I am sanding. . If you sand with the lathe on you don't have good control of how much material you are taking off, AND you will be sanding circumferentially which leaves scratches around the blank that are hard to get off later. . Sanding with the lathe on is OK for roughing to size, but the fine sanding should be done with the lathe off and always done lengthwise.

You can buy a decent digital caliper at a tool store for around $30. . I would not buy anything priced under $20. . Try it out before you buy it to check that it operates smoothly and do not buy one that has a capacity of less than 6.000". . (you will want to measure tube and blank lengths sooner or later) Make sure that the battery in it is a type that is readily available at more than one store because you will need to replace it at some time.
 
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corgicoupe

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Mar 9, 2016
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Smoke Rise, GA
You surely measure the "diameter" with the calipers. I'm wondering how you determine the "radius" to be 0.002" smaller than the metal kit parts. Did you mean the turned "diameter" is 0.004" smaller than the nib? Or did you mean "diameter"?
 
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leehljp

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Feb 6, 2005
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Tunica, Mississippi,
You have had suggestions to use a caliper to measure. I don't see how anyone can consistently make EVERY one fit perfectly withOUT calipers.

BUSHINGS ARE CONSUMABLES. They wear out. DON'T measure the finished pen diameter by the bushings! PERIOD. Some people will say that you can and even get offended by suggestions to the contrary. These will be people who say that "it is good enough". Since you want consistency, you will only get it by measuring each end with calipers and turning to size (or .002, .003 smaller) and finishing with enough finish to bring it up to size. I always finish with excess of CA and sand back down to size.

There is less of a (feel) difference if the blank is finished with CA .001 or .002 LARGER than the nib then round the end over lightly and smooth. The difference is more noticeable if the blank is finished (with CA or other) .001 or .002 smaller than the nib/center band, and the hand can feel it too.

The idea of building the blank up larger and rounding over does well when the CB or Clip end or nib are ornate and sizing varies depending on where it is measured.

The reason for Calipers is this: Not all nibs of the same pen style are the same. Get a new batch and you may find the new nibs may vary .001 or .002 from previous ones, or even one nib from another; the same for center band or clip end.

The hand can feel differences that the eye cannot necessarily see. Use Calipers. I used to recommend this to everyone starting out, but people are more interested in finishing a pen than accuracy in the beginning. For some reason, it it hard to get people to understand that bushings start wearing down from the first use - due to nicks from the chisel or from sand paper. Don't measure the finished blank by the bushings. Measure them with calipers according to what it is going to mate against.
 
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