# Fun with aluminum tubing...



## MattTheHat (May 3, 2012)

I happen to have about 10 miles worth of various sizes of .058" wall drawn 6063-T832 seamless tubing in various sizes from .375" up to 2.125". I won't bother with the details of why, but it's there, just taunting me for whenever I get around to using some of it to make some manner of pen. Problem is, depending on the pen I'd like to build, the inside diameter and outside diameter of the various sizes I have just won't quite cut it for a given kit, or for the few designs I've come up with for a kitless version. So having all that aluminum stock has largely been a "Water, water, every where, nor any drop to drink" situation...

Until tonight...

It finally dawned on me to just glue up a few tubes. They're designed to have a fairly decent fit from one size to the other with a total difference of approximately .009 inches. I'd never really though about it, but with half of that clearance on each side of the tube, that's only .0045" which is just a smidge over .1mm. Hmmmmm.

That clearance is such that a 6" hank of three sizes are just shy of a light press fit, depending on the tolerance of a given batch (and all the sizes are generally from different batches). So I cut a piece of .375", a piece of .500" and a piece of .625", each about 6" long and CA glued one inside the next. Each one started easily enough but the last inch or so became a pretty tight press fit. That fact was promising. 

I then chucked the resulting hank o' aluminum in the lathe and turned off just enough to true up the outside diameter. If you look at the picture, you can just barely see the joint line betwixt sizes. It's not much wider than the mill marks left from facing off the end.

This obviously won't work for a closed-end pen (though I have a plan for that), but it sure gives me lots of other options. 


-Matt


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## MattTheHat (May 3, 2012)

*Meh...*

It seemed like such a good idea until I started turning it this evening. I suppose it would be fine depending on how much final thickness there is on the outer tube. When it gets too thin it does what I can only describe as a very slow motion blow out. 

Oh well.


-Matt


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## frank123 (May 3, 2012)

Have you considered making a mandrel in the shape you want in the size of the ID of the pen you are designing and using a roller type of tool like a smooth knurling tool (or maybe just a rounded end rod and lots of oil) to "spin" it to the shape and length you want?

Forming it over the end of the mandrel and using a touch of aluminum welding rod (actually a solder, zinc based I think) such as is sold at HF to close the remaining hole could make a closed end pen.  .058 wall thickness should work easily enough and remain thick enough as long as you didn't put too much linear stretch on it during the process.


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## PTsideshow (May 3, 2012)

If you are going to spin aluminum on a mandrel. DO NOT USE OIL! you will cause yourself a whole lot of headaches, not to mention mess. Use a dolly that is soaked with beef tallow type grease (you can get it at eastwood.com in pound containers) it is used in leading auto body solder work.
You could use a hardwood dowel shaped end as a turning tool, or one made of HSS.
Also check out PSI for their free DVD on metal turning, Terry vid's are the greatest. You can go to smart flix.com and rent his dvd's and most of the wood turning ones too.
There are a number of PDF or knidle based books on metal spinning that are downloadable Internet Archive: Digital Library of Free Books, Movies, Music & Wayback Machine some are here and of course google books.
:clown:


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## MattTheHat (May 8, 2012)

I never thought much about spinning. Hmmmmm...

Thanks for the tip.


-Matt


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