How To Concentric pins

[Matthew Morvant]

This is my first post here and my first foray into making a blade. I use blade very loosely, I am making letter openers. This way I can dip my toes in without having to figure out heat treating.

Short version:
What is the best way to secure a 3mm copper rod inside of a 5/32" tube (1/8" ID)?

Long version:
The letter opener I made was intended to use 1/8" brass pins cut from a standard brass rod. Technically it was supposed to use 3mm brass pins, but my only 3mm bit broke and I couldn't locally source a 3mm bit. I don't have a drill press and drilled one of the holes out of square. It was far enough out that the scale broke when I tried to fit it in.

To fix the problem I decided to re-drill the hole to 5/32" and use a brass rod with a 3mm copper rod. The ID of the rod is 1/8" (3.2 mm). I used two-part epoxy (Gorilla Glue brand) and did my best to coat the pin. I made up the pins before inserting them into the tang. This part went as expected. However, when I went to file down the pins flush with the scales, one of the pins came loose from the outer rod. Since the outer part was already epoxied and I didn't want to start over I just used a roll-pin punch to try and peen out the copper. I was still about 1/16 proud of the scale surface. I was able to complete the filing and sanding process without the pin coming out. I just don't know how stable it will be moving forward.

Is there a better way than epoxy to secure the pin inside of the rod? I contemplated CA glue, but I felt the heat from the cut-off wheel and filing would break the bond.

 

[David Schott]

I would just peen it and not worry about it. Brass and copper are both soft. Take a ballpein and tap around the edges of the inside pin on both ends. Even a TINY swell will lock it in place. Think about how much that small out of round hole caused the pin to bind. THere's no way that inner pin will be able to slide out if you make its ends wider than its normal OD and wider than the ID of the outer tube. Normally youd do this with the ends proud a bit and peen down into the hole that would be slightly tap but one or two light taps on the pin in the right spots should still spread the pin enough to lock it. Don't overdo it or you'll crack the scales again. You'll need to sand down through any hammer marks when youre done too.

 

[Stacy E. Apelt - Bladesmith]

The hole through the tang should normally be a tad larger than the hole through the scales anyway. Drill the tang holes out with any available size drill bit that enlarges the holes and just use your 3mm brass pins through the scales. It doesn't matter how ugly the tang holes are.
Use a .120" bit as a substitute for 3mm bit when drilling the scales for the 3mm brass. If the fit is a bit too snug, sand the brass rod a bit ... which is a good thing anyway.