Ripping rear spar caps?

[Phil]

Ribs are done, and after I spend a little time cleaning up and reorganizing my shop space, I'll be ripping the cap strips for the rear spar from a sheet of 0.063. I plan to us my circular saw and have a non-ferrous blade for it, but what do I use for a straight edge cutting guide? What have others used?
Thanks.

[bestbearhawk1231]

Hi Phil, I have a long piece of strap steel that I use when I need to make long straight cuts with a circular saw or jigsaw. Actually I have 3, one is 5', another is 10' and the third is 15'. I think they are 3/16" thick and 1.5" wide. They work great as fences or straight edges. I have also used steel angle as a guide, but you need to find some angle that doesn't have a natural bow in it other wise your saw will bind up.

[N3UW]

Hey Phil, I use a Festool track saw with a fine tooth triple chip blade. Before I got the festool saw I used a 3/4" piece of MDF over a 1/4" piece of plywood. The MDF was about 8" wide and the plywood went under the mdf and the circular saw. Then run the circular saw down the 1/4" plywood and cut it to width. the plywood will then show where the edge of the cut is. Here is a drawing I found of a similar setup

[Phil]

Thanks, I think I'll give the MDF idea a try. But that track saw looks pretty sweet.

[Phil]

OK, after far too long of a hiatus to deal with home improvements and other life issues, I'm back to the Patrol again. I've got plywood and MDF and plan to get the ripping jig built this weekend. Maybe even get the strips ripped before Monday.

Next up, I've got access to a 10' shear and brake through work, so as soon as the cap strips are ripped and finished, I'll be gearing up to bend all the spar channels and stiffeners.

[Steve W]

Phil, I got a small piece of thick aluminum angle 3/4X3/4" 18" long and mounted it to the bottom of a good quality circular saw. After squaring it to the blade, I drilled several small holes through the saw bottom plate and the angle. Confirming it was parallel to the blade, I screwed it together with a couple of #6 screws. With a quality non ferrous blade, I cut all the 1/8" cap strips and the .063 for the Patrol a bit wide than required and finished them of on a router table. Think I used 2 blades to complete the job. The angle acts as a gate/guide and after finishing all the required cuts, the remaining sheet was within 1/32" compared from end to end. I then got the table saw out and ripped two groves in a 12' piece of 2x4 and slid the capstrips in so they could be cleaned up with a vixen file.

[Phil]

Steve
thanks. I've been trying to figure out how to hold the strips for finishing. That looks like a great idea.

[N3UW]

Phil,
I used a file and just clamped them on the edge of my bench. Also I good fine tooth carbid triple chip blade should be able to cut 1000s of feet of aluminum. One thing that helps extend blade life a lot is to used some Of the hard Boelube rubbed on the blade first. Boeing engineer put me onto that stuff.

[Flytaildragger]

I used 3\4 alum. angle. Draw them all out and leave plenty of space between each spar. cut a way from the line with circular saw with fine tooth blade.Each of my strips came out warped like bananas. After sanding the edges to the line with a 12' bench disc sander, the strips all straightened out. 220 paper and finished up with scotch brite pads to a satin finish

[Phil]

I ended up building a jib using 3/4" MDF for the straight edge. I attached 2x4s across my 16' building table, topped with cheap 1/4" ply. Cut 2 lengths of the MDF 8" wide. One factory edge, then used that piece as a straight edge to cut the second piece. I used the sheet of 1/16" aluminum as the straight edge to get the two pieces of MDF lined up. Then screwed them down to the ply and 2x4's underneath. I cut out the corners of the ply away from the cutting edge so I'd have a place to clamp the aluminum sheet. Then made a cut down the length, through the ply and partially through the 2x4's. Then cut spacer blocks on my table saw to set the edge of the aluminum away from the MDF with just over 3/4" from the edge of the saw kerf to the edge of the aluminum. I place the spacer, shove the aluminum up tight to them. clamp it down, pull the spacers and let the chips fly. Photo below after cutting the first test strip.

Edit: I also coated the bottom of the sheet with Boelube along the cut line before cutting.