Saturday, August 27, 2016

More Tooling

It was another warm weekend and another great opportunity to spend time in the downstairs shop while I waited out the drying time on the flap primer. There have been two things that while I was building out the right flap that I figured I would build a jig for to make life a little easier when completing the left flap.

The first jig was a good way to machine countersink joggled flanges. The problem with doing this by hand is that even a small micro-step countersink has clearance problems getting into the angle of the joggled flange. That is, the cage hits the angle thus giving an uneven surface to countersink off of.

For this I took some 1/8" 1x2 rectangular 6061 and milled a .060 inset into it. From there I milled a 1/4 slot into that inset to accept the #40 holes (and thus the countersink pilot) from the joggled flanges.



With that done, I was able to remove the cage from the micro-step countersink and use the DRO of my mill to set a zero and accurately countersink each hole to a defined depth.



The results were just what I was looking for! Excuse the scratches in the flange bracket, this was a piece of scrap.




The second jig is for the countersinking of the Trailing Edge (TE) wedges. The TE wedges need to be drilled and countersunk perpendicular to the centerline of the wedge. This is kind of annoying because well, its a wedge. You end up drilling a lot of holes and it would be nice to do this in the drill press rather than with a hand drill in order to keep all of the angles as they should be.

I started with a piece of 1/2" x 2" 6061 bar. After facing the top surface with my SuperFly I milled a 1/2" slot 1/4" deep into the bar. 



Within the main slot I put another .020 deeper slot stopping roughly .250 from each end. The idea here is that I wanted to use a piece of the trailing edge itself set into the base of the slot in order to get the angles correct. Mainly, I didn't feel like re-tramming my mill after this project so rather than set the 10 degree slope with the cutter, I cut a 0 degree slot and used a short piece of trailing edge to be used as the base of the jig.



From there, I made a little cutout to accept the micro-step countersink, hand filed the radius of the base TE corners (to accept the 1/8" radius that was left from my end-mill), and finally drilled a hole through the TE to give some clearance for the pilot of the countersink.


With that complete I was able to take the TE that I needed to countersink and set it into the jig (with the wedge in the reverse direction of the base wedge). This brings the face of the surface I need to countersink perfectly perpendicular to the countersink!


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