Hints For Homebui lders
A "Holey" Tip Cutting holes accurately
By Cy Galley
Hole saws are great; they don't kick back and can be used in a handheld drill. But wouldn't it be nice to use the cut-out disk without the ugly cen- ter pilot hole? We could cut a disk for a disk brake pad. Use the saw to cut inspection holes without wor- rying that the pilot drill will damage something behind the surface we're cutting, like a gas tank, fuel lines, or control cables. Other uses would be to cut gussets for wing ribs and inspection covers.
However, you cannot just remove the center pilot drill, as it locates and stabilizes the saw. We need something to hold the saw from "walking" and wandering; some- thing to locate the hole.
The solution is to drill a hole through a piece of thin plywood, such as a scrap of paneling, with the pilot drill in place. Then use the hole in the
plywood as a guide by clamping or taping the plywood where you want the hole. Use the lines to center the guide. Then use the hole saw without the centering drill. Some hole saws use the drill as a drive shaft; if so, you'll have to use a shortened drill.
The previously drilled hole in the plywood will provide all the posi- tioning necessary to drill your new hole or create a disk without a hole in the center. Because you are using an outside guide, you even can saw less than a semi-circle.
If you are making several disks and have a quality hole saw, make the guide from 1/8-inch aluminum. How- ever, if you are just making disks, stack enough layers and each layer will guide the next. Use a slower speed when cutting larger disks. A metal-cutting hole saw would make the job easier on aluminum.
Hints for Homebuilders Videos
EAA has produced hundreds of hints for homebuilders videos. You can view them all here, www.eaavideo.org/channel.aspx?ch=ch_hints. Here's a sampling of the videos that are available.
Cotter Key Installation-Standard Method
Brian Carpenter, of Rainbow Aviation in Corning, California, demonstrates the standard method for installing a cotter key on a castle nut. Here's the video.
Cotter Key Installation-Alternate Method
Brian next demonstrates the alternate method for installing a cotter key on a castle nut. Here's the video.
EAA EXPERIMENTER 27