Collapsing twist mechanisms

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tomfree99

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Jan 7, 2014
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Location
Centre, Al
Just finished my first aluminum slimline pen.
Problem: I can't get the twist mechanism to press into the tube. I have collapsed 3 of them attempting to get one to go in all the way. I have tried sanding a little off the mechanism and a little from inside the tube but to no avail. Any suggestions ?
 
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Is there burr or some cured CA or epoxy in the tube? I am sure you ruled those things out - just trying to help.
 
Well I have tried using a taper reamer to ease entrance, sanded inside the tube and even sanded slightly the twist mech. It goes into the tube down to within 1/8 inch of being in correct depth. If I stop to check the depth, it will not continue into the tube. That's when it collapses.
 
Try using dish washing detergent as a lubricant. It could be jamming as the brass tube can't expand enough. The aluminium won't let it expand as much as wood or acrylic.
 
A little light oil worked.Yea!! Used 600 grit sandpaper to give it a cross hatched brushed effect. DSC02112.JPG

DSC02113.JPG
 
What did you use for the aluminum? 6061? Where did you find it?
Can you drill aluminum on a wood lathe(it's all I have)?
Sorry for all the questions... This is one I've been wanting to try for awhile and get pumped every time I see one...love it!
Thanks for the advice.
 
Making an aluminum pen, you run into the same problem as you do when making a casing pen. On a typical wood pen, when you press in the transmission, the brass tube expands slightly. On a solid aluminum pen, the aluminum will not expand. There are a couple of options for casing pens....and it will work for aluminum pens as well:

1. Glue in your lower tube. Let dry, With a 1/4' bit drill out the inside of the tube for the first 3/16 of an inch. Your mechanism will now press in much better.

2. Ream out the inside of your lower tube really good. This method is not as fool proof and you still run he risk of bending the mechanism.

3. Drill your lower blank with a 7mm bit. Re-drill the top 1/4" with a 5/16" bit. Glue your tube in with epoxy....let dry, press in your mechanism after turning. You now have room for expansion of the brass tube.

Hope this helps.
 
Full-metal pen bodies

When I turn full metal pen bodies for 7mm pens my routine is

1. Face
2. Spot with 1/4 stubby drill (so the spot just reaches the 1/4 diameter of the drill, now you have a nice central point for the other drills)
3. Drill an inch or so with a 1/8 stubby drill (this straight hole will make it easier for the larger drills to go straight too)
4. Drill through with 3/16
5. Drill through with D drill (.246)
6. Ream with .248 reamer
7. Ream with .249 reamer

(take out the tube and flip it around)

8. Face the other side and cut it to length
9. Use the .249 reamer again to take off the burr from the cutting and facing. Just let it go in a little bit for the burr.

The reamed .249 hole will allow a normal permanent press fit of the twist mechanism. If there is any run-out your press fit will be loose and you can hope a gluing will rescue the project. You will know by testing by hand, I think.

Likewise a .249 hole will press onto the other side snugly. You might decide that can be .250 instead.

I may be making assumptions on machine capabilities since my lathe is for turning metal.
 
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