Got a dumb question on drill bit sizes.

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Joe Burns

Joe Burns

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Joined
Sep 9, 2011
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Location
Temple Texas
I have a dumb question. I wanted to try the Jr. Majestic kits and received two in the mail today with some other items.

In reading the instructions it says I need a 10.5 drill for the lower tube and a .492 for the upper tube. I have a 10.5 and a 12.5 that I am using to build Jr. Gent IIs and Jr. Statesmen IIs. Is the 12.5 the same as the .492 in the instructions?

Joe
 
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Frequently, a drill bit size other than what is suggested will also work as well, if not better than the manufacturer's suggestion. Here are just a few:

7mm or J
8mm or O
3/8 or V
10mm or 25/64
10.5mm or Z (and 27/64 will work for some applications)
 
Wanna avoid mistakes?? Get a caliper and measure the tubes when you start a pen. Then, take a conversion chart and look for a size that is a hundredth or so larger than the tube.

Fringe benefit: If you happen to grab a brass tube off your bench that you are "sure is a sierra", and the caliper says it is .40"ish, it is the lower half of a triton, atrax, jr gent, jr statesman, etc. The sierra is .412 ish The .40 will not work right!!!! DAMHIKT!!
 
I appreciate it everyone. Im on track now. Was used to seeing drill bit sizes in mm or fractions. Wasnt used to see them expresses as decimals.

Joe
 
Joe Burns said:
I appreciate it everyone. Im on track now. Was used to seeing drill bit sizes in mm or fractions. Wasnt used to see them expresses as decimals.

Joe
Click to expand...

Well Joe, the "big boys" DON'T express these things in thousandths. But it really is the easiest way to compare all the different "standards". How many people know how large a "J" or "O" bit might be? Or even 7mm? When we "resort to" the decimal inch equivalent, at least we all have an IDEA of the size.

Unfortunately, very few things in pen-making are built with a "standard" in mind. So, we need to develop our own way of "best communicating" what we need!!!

Welcome to the (sometimes) very strange world of pen-making!!
 
Ed, I appreciate it. I do understand there. If it wasn't for you and everyone else here to keep me on track Id would definitely be lost in la la land.

Joe
 
The drill bit sizes specified are normally the closest SIZE COMMONLY AVAILABLE. I often find a slightly smaller size is closer to correct. Drill with a size smaller by .050" or so, then step up one drill size at a time until the brass tube just fits in the hole with a sliding slip fit. Write the correct size down on the instruction sheet and stash it in your notebook.
 
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