Trent's RV14 Build: 6-04: VS deburring

Page 6-04 Step 3 - “Disassemble all parts and deburr”

8 hours of work later..

The process I seemed to find worked the best was as follows:
- Start with the rib flange edges or the skin edges. They all seem to have some “steps”, presumably from the stamping process. I tried removing these with the edge scraper tool, but all this does is scrape the edges and maintains the steps. I found the best way to remove the steps was with a vixen file to flatten the whole edge. Once this is done, for rib flanges I gave a quick gentle pass with the scraper tool and then onto the scotchbrite wheel. For skins (which are too big to take to the scotchbrite wheel), after the vixen file, a smooth file to smooth it off some more. Then a 120 grit flap wheel seems to work better than a 1” scotchbrite. Finally the edge scraper tool gently, and some 400grit and maroon scotchbrite pad - all edges now done. You really need to go easy on the edge scraper tool - it's very easy to take to much and end up with a faceted edge.

Edge Deburring Tool

- After the edges, I found 400 grip aluminium oxide paper wrapped around a square of maroon scotchbrite pad works really well on the gaps between the flanges.

- Finally, all holes are deburred with the countersink tool - either the normal one, extra long one or a small one that I spin in my fingers. After the hole tool, a quick pass along all hole areas with a scotchbrite pad gets any remaining tiny burrs.

- Once this is done, I check over for any large scratches, and if there are any, sand them out with 400 then 600 grit aluminium oxide paper, followed by a rub with maroon scotchbrite.

Below are some images of the front edges of the VS-705 and VS-706 ribs and how I needed to adjust them so they fit the skins.

VS-706 Tip Rib - didn't need too much removed, and it was the flanges which were interfering with the skin. These were initially bent out of the way a little, and then filed to a profile. A small amount was removed with the snips - edge distance was not an issue at all.

VS-705 Root Rib - this one needed quite a bit removed - it was the flange/web corner which was interfering with the skins. I ended up knife edging the corner of the flange and web, so ended up marking the minimum edge distance, and snipping the end off. After this everything was rounded and sanded to prevent cracks. Came out ok i think.

VS-705 on the left, and VS-706 on the right.

Once 6-04 Step 3 was done (took 8 hours!), I moved onto step 4 - dimpling the skins. I started by carefully taping over all the holes which did not get dimpled in both the skins and the ribs, and i recking i checked this 50 times.

Lessons learned here:

- The DRDT2 works better on my large wide worktable, rather than the side bench, as i have more depth to move the side tables around. It works fine even if not screwed or clamped down.
- The folding mechanism on the side tables was poorly designed - i needed to whack in a chipboard screw to secure them so they didn't collapse as they require quite a bit of moving around to support the skins.
- Tape needs to be applied to the top of the dimpling mechanism, otherwise it really scratches the top skin (this needed a bit of sanding to get the scratches out - once i taped the skin, no problem).
- the laser really helps to find the holes.
- You really need to lift the skin when moving it, or you scratch the outer skin surface with the male dimple.
- It takes some creating maneuvering to get to all the inside dimples, but i doable with one person easily.
- The remaining edge dimples, which i could not get to as the skin was too tight near the leading edge, were done with the pneumatic squeezer.

The side bench depth is not enough to successfully dimple large skins here. The side tables work very well once the legs were secured with a screw.

All dimples done - skin ready for cleaning, etching and priming.

Once the skin was done, all the corresponding holes in the flanges of the ribs were also dimpled. I was using the Cleveland Substructure Dimple Die set to dimple the flanges, but they just didn't look right to me. The dimples seemed under formed. I was scratching my head about it, until i realised that i had the substructure male die mating with the normal female die. All was good once i redid all the dimples with a matching set of dies.

Moving onto 6-04 Step 5 - i used a practice piece and setup my countersink cutter in my hand held electric drill. I considered using the drill press, but the VS-808PP Spar Doubler was a long piece which would need supporting (stands), and i thought i could do it just freehand with the drill. Each hole was half done with light pressure and slower speed, the cutter cleaned out and the shavings removed from the piece, then the full speed and full depth cut made. I think it turned out ok:

This step also included dimpling the corresponding holes in the VS-803PP aft spar that the VS-808PP doubler gets rivet to. (the flush rivets at the bottom of this piece are there so the whole assembly bolts flush to the aft fuselage bulkhead(s). The holes we leave open are tooling holes - later on, the aft bulkheads are cleco'd and aligned to the spar assembly using these holes, then using holes in the bulkheads, bolt holes are match drilled to the spar assembly - effectively aligning the VS with the bulkhead, before it is riveted into the fuse). The holes in the VS803PP spar were dimpled with the pneumatic squeezer and the longeron yoke easily.