For the little bit of tubing work I've been doing, I found that it's a pain in the rear to straighten the 3003 series aluminum tubing that Van's sends you. I posted a question on VAF about whether anyone has any tips or tricks and someone sent a link to a tubing straightener that Jegs sells. Only problem...it's $200. Ouch. I decided to make one of my own. I was going to ask my dad to make me some rollers on his wood lathe, but he suggested that some caster wheels might work. I thought that was a great idea, so I stopped by Harbor Freight and picked up these casters. $3 each. They're not even made in China.

The die grinder made quick work of cutting off one heads of each axle pin.

All five wheels freed from their brackets.

The holes were some odd metric size, like 8.3mm, so I drilled them out to 3/8 inch.

In preparation for cutting a V notch in the face of each wheel, I made some blocks to clamp my die grinder at a 45 degree angle. Also notice the carbide end burr chucked in the collet.

A bolt makes a good mandrel.

It was just a matter of running the drill press, and feeding the corner of the burr into the side of the wheel.

This is a standard way of measuring V grooves. Put a pin in each groove and measure across the pins. I managed to cut the groove in all the wheels to +/- 0.002 inch. Not bad for a crappy drill press arrangement. It's unknown how much runout I've got, though. I'll just hope for the best.

Here's what the V groove looks like.