Thu Mar 25 2010

Fabricating shims

First thing for today was to fabricate the 0.016 inch thick shim that goes under the left side spacer under the forward spar of the horizontal stabilizer. After cutting this out on the shear, I rounded the corners and match drilled holes.

Then I noticed that my inboard two holes for the forward spar weren't drilled perpendicular to the aft deck. Here's a drill bit stuck in one of the holes and you can see that it's angled somewhat.

It's angled in the other direction, too. Obviously I'm not very good at drilling straight using the angle drill.

I called Van's and talked to Scott about the situation. He recommended I make some thin washers that are angled to compensate for the tilt. That's a good idea, but it really frustrates me that I screwed this up. Nothing to do but fix it. After measuring the tilt of these two holes I found that one hole was tilted 5 degrees and the other was tilted 4 degrees. I trimmed the ends of a piece of scrap oak to 4 and 5 degrees.

The block was used as backup for a small piece of scrap aluminum being sanded on the disc sander.

Unfortunately the 0.032 thick material wasn't thick enough to get a full bevel, so I cut up some 0.063 scrap.

Got the tabs sanded to 4 and 5 degrees and only sanded one knuckle in the process!

Here are the washers after making them round and drilling the #12 holes for the bolts.

They work very well. The bolt head seats down nicely.

Later, I decided to check the rest of the holes I had drilled. You're not going to believe this, but every hole was angled some degree. I measured all the angles and made a plethora of angled washers spanning from 1 to 4 degrees. Gah I'm so pissed with myself. If you're building one of these things, be sure to use a drilling guide when drilling through thick material.