Protecting high-dollar blanks during assembly

[thewishman]

After a few issues with cracking blanks while pressing parts together, I tried a few things. The best way that I found was to reduce the inside diameter of the brass tube. (Sanding the male pen parts causes way to much risk of damaging the plating.)

Sure, a Dremel can do the job, but the wheels are expensive, and they need to be replaced often. I wanted a solution that I could repeat quickly and with a low cost.

Using a transfer punch and a small piece of Abranet (I'm using 120 grit, because that's what I have on hand) I can abrade enough of the brass to create a slip fit for the pen parts quickly. I mount it in a jacobs chuck.


After testing the idea, the best way I have found is to take an inch wide strip of Abranet and taping the first 1/4" to the punch, wrapping it carefully in the direction it will spin. Wrap it around a couple of layers thick, I use electrical tape to attach it to the punch. Be careful that there is no overhang Abranet, make the end flush with the punch.

I found that having a couple of punches set up in different diameters can cover most of the pens I make. My next step is to get a second set of transfer punches and prepare a few sanders so I can quickly switch them out as the Abranet wears.

 

[Sabaharr]

The only blanks I ever had crack on me were when I first started and was pressing the parts in while in a hurry to see what the result was. If they were going a little crooked I kept pressing with the idea that they had to straighten out. That was when the cracks would happen. Now I take my time and press everything in straight and slowly with a machinist vise that I screw to close so I have minute control over parts insertion. I had used a pen press that limited the control I had by using a lever to transfer the force. I haven't cracked a part yet going slow and straight. Oh, and plugging the tube ends with dental wax while gluing also helps keep epoxy out of the tube that could cause excess expansion of the brass leading to cracking of the blank. Guess I have been lucky.

 

[mredburn]

you could also take a 1/4 dowel of aluminum or brass and cut a 1 inch deep slit in the end with a hack saw and make a sanding mandrel. Lets you change out grits easily and you just tear off the worn ends as needed.

 

[stonepecker]

Another great idea from the IAP and mind process of Chris.

Thanks

 

[magpens]

Chris, another way to remove metal from the inside of the tube is to use an adjustable reamer. I have been using these for a couple of years now. I started using this technique when I had a problem with some 30 Caliber Bolt Action blanks breaking during assembly due to excessive plating on the male parts, especially for the gold plating.

The reamers are not overly expensive. I buy them individually ($20) and in sets ($80), from KBCtools.com

If you are not sure what I mean, here is a link. Grizzly sells them in different size sets and maybe individually.

Shop our H5942 - 11 pc. Adjustable Reamer Set at Grizzly.com

 

[ed4copies]

If you are all using a "loose fit and glue", what glue is your favorite?
How long have you been using it? ( A thinly disguised way of asking--do you know it holds through customer "use"?)

 

[JohnU]

I use Loctite 242 medium strength when I can find it. Its made for metal adhering and can still be disassemble later if needed. It also sets up pretty quick. I've used it on many of my own pens and never had an issue with it coming apart unwantedly.

 

[Skie_M]

I haven't tried this type of method yet .... the only blanks that have given me any trouble at all were my alabaster ones cracking during assembly.

I'll certainly have to remember the tip with the aluminum rod and strip of abranet or sandpaper... I'm sure that will do wonders for me!

 

[SteveG]

Chris, I have been using nearly the same solution to this problem for a year or two, but never thought to post it up here as you have done. Thanks for getting the idea out. Once I had bought the second set of transfer punches, I have found a number of uses for the "pick your size" rods, ready to use for dedicated tasks, without leaving "holes" in the punch set. This is a very useful idea. I do not necessarily take the tube-to-kit-part down to a slip fit. I just know that if I remove some material, I will get a fit that works.

My answer to Ed:My adhesive of choice is the RED threadlock. The final fit for the finial is the most important, since it is what keeps the clip from rotating some time down the time line. If I find that I have gotten a true slip fit (more looseness than I really wanted), then I use epoxy. But most of the time I prefer a joint that is still a bit tight, and like the threadloc, since any unwanted squeeze-out and/or Steve-slop during assembly is easy to just wipe away.

 

[magpens]

Ed ~

I use 5 minute Epoxy and try not to think of the possible need to disassemble.

So far (2+ years) there has been no instance of unintended "disassembly" !!