Drilling Capstrips in Sets

[Glenn Patterson]

This was posted in response to jig drilling spar capstrips. It was suggested to post this in the building tips forum.
" We laid the capstrips on the spar, marked the rib intersections and critical holes then gang drilled all 4 cap strips at one time. Pulled them apart & used the one that goes against the spar as the drill template for the spar. Once the spar is drilled the other three predrilled strips are attached to complete the spar/capstrip assembly. The holes were drilled one size down then were drilled to final size in place. This method simplifies getting the caps strips on both sides of the spar to be located exactly the same.

A trick we learned on the rear spars that would have helped earlier was to install the top capstrips. The we used a chop saw with a stop to cut all the veritcal bars to the exact same length & then laid them on the spar. The bottom capstrps were pushed up tight to the verticals & drilled. This saved all the fussing of trying to get the verticals to fit between the capstrips. If it is off a couple of thousandths it is not critical but it does save a lot of time.

The air drill shown was tossed very quickly & we used cordless drills all the way. Air drills whine, compressor runs & the hose is a PIA. The capstrips were drilled with an 18V cordless that we had but our primary weapon was a DeWalt 12V cordless drill. Light, tons of torque & will drill holes for hours. We got a second one when it came on sale & use both all the time."

A footnote to this conversation: If the set is gang drilled then it may be possible to drill them to their final size on the table and save more work as they are already match drilled as a set. That would just leave drilling the spar & the capstrip drilling is done in one pass.

Glenn

[DRLPatrol]

Glenn,
In the top right corner of each page of the PDF are what appear to be page numbers (105-109). Where can I find the rest of your book.

Doug

[Glenn Patterson]

Doug,
They were pages borrowed from our builders log. The document is on my PC & is not out in the public domain. The routering methods were a combination of excerpts, photos & sketches that were assembled into a separate writing. We have done the odd thing different & I will occasionally use a snippet to illustrate a point to help someone.
Glenn

[DRLPatrol]

Thanks, very helpful
Doug

[Chewie]

I thought I would bump this thread to the top, since it appears some of us are in this stage right now. Or else having bad dreams about it. I also wanted to express my appreciation for this post and the PDF. I know it's been years after you wrote it, but it is hugely helpful now.
I just have one question. On one of the pages, I think 107, you mentioned you deburred the holes before you drilled them out to final size. Is there a reason I couldn't just deburr after the final ream?

[mswain]

When I drilled my cap strips, I made one that became the master for all the others. Clamping them together to match drill, the burrs would get in the way. I chucked a countersink in my drill press and lightly bumped the capstrip to deburr. My arm would have fallen off had I done it by hand.

[DRLPatrol]

+1 on what mswain said. Laid out one then used it as a master. Drilled everything #40, deburred, clecoed spar together, stepped up to size changing one cleco at a time from #40 to final size. That way with the whole spar together with #40s you can recheck till you are happy and then nothing moves while you step up to size.

Doug