RV-10 HS Spar Attachment Brackets

I made the HS spar attachment brackets tonight. When cutting with the band-saw, I went just a touch too far and cut slightly into the protrusions which distinguish the brackets between left and right. I did the same thing on both brackets but on one I was able to polish out the little ditch with the scotch-brite wheel. The error on the other bracket went a bit deeper and I don't feel comfortable polishing away any more material. There is still a little more smoothing to do on it but before I continue working on this bracket, I'm trying to decide if I need to scrap it, order a new length of angle, pay for shipping, wait a week for it to arrive, etc., etc., and eventually redo it. Or if it's safe the way it is.

I'd like to hear your opinions on the seriousness of this little ditch. Is it going to be a matter of safety, or does it just look bad. You can get a pretty good sense from the pictures how deep the ditch is and where it is on the bracket.







Thanks in advance,

Joe,

Those are beyond polishing and need to be replaced.

I believe the raw materials for building the brackets were around 6" long, I'd suggest getting a few more inches on your reorder so you have enough to crank out another one or two if you need them in an emergency. It won't cost much.

An alternative is to get a pair of HS-1008's machined ($25) by Steve DiNeri at IFLYRV10.com.

Phil

Agree with Phil, those are scrap. If you look carefully at Figures 3 and 4 on page 8-3 in the plans, you will see that that cut should have been made at an angle to match the flange, which would have prevented your problem. I did mine using a chop saw set to the right angle, just a single cut for both flanges. I find that a chop saw or a table saw makes nicer straight cuts than a band saw anyway. While I admit Steve's machined parts are beautiful and not that expensive, this kind of bracket is really easy to fabricate by hand. I really recommend his trim tab anchors, though, and am looking forward to using his door hardware.

Also, looking at your picture, you are deburring way too much. You just want to remove the burr, not actually chamfer the holes.

Joe,
Just like Phil and Patrick said, that bracket is scrap. For what it's worth, it took me 3 tries to fab acceptable brackets. On the holes you don't need more than 2 turns of the deburring bit and light pressure to get the job done.

Phil said:

Joe,

Those are beyond polishing and need to be replaced.

Phil

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Ho hum. I suppose deep down inside I knew it all along and was hoping for someone to tell me it's fine. Thanks guys. I think I'll see about getting the parts from Steve DiNeri. Thanks for the tip on that.

flion said:

Agree with Phil, those are scrap. If you look carefully at Figures 3 and 4 on page 8-3 in the plans, you will see that that cut should have been made at an angle to match the flange, which would have prevented your problem.
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Also, looking at your picture, you are deburring way too much. You just want to remove the burr, not actually chamfer the holes.

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Thanks for the tip on this. Might be nice if this were explained in the plans. Oh. And thanks for mentioning the deburring on the holes. On the thicker pieces, for some reason, I have a tendency to over do it.

Good advice

The responses you got were right on.

Just remember, the way Vans does things, you are still early in the learning stage of the build. IMHO, you should make your own brackets, and keep at it till you get it correct.

While the premade units are nice, you are going to be shortchanging yourself when it comes to developing needed skills.

Like Stein says ----- "my $.02"

I remember those holes too and if I recall correctly my first set of brackets looked pretty similar. That aluminum seemed harder and more difficult to drill cleanly and that required quite a bit of material removal to get rid of the burrs.

A reamer would have be the perfect tool for a clean hole. If you don't have one, just creep up on the correct size in 1/16" increments. When you go through the last time just be sure to use plenty of speed and move through the material slowly.

I'm going to dig mine back out and look at them again. It's been a few years and I want to make sure mine aren't aggressively deburred still. At that stage in the kit my 'touch' deburring wasn't too refined.

Phil

Remember...

When drilling soft material like aluminum use high speed and low pressure. Too much pressure causes greater burrs. Less burr means easier clean-up.

Thanks Everybody

I appreciate all the advice everyone. I decided to order from Steve at this point. I spent so much time getting it wrong that I need to make some forward progress. Thanks to all of you, I'll be more prepared on what to expect and how to proceed when it's time for the next fat bracket to make.

I am not familiar with this particular part, but typically the key to whether the piece is salvagabe or not is the hole-to-edge distance. From the center the hole, to the edge of the material must be no less than two times the diameter of the hole. This is the minumum distance allowed. There are rare cases where the 2D minumum can be violated (2 1/2 D is even better), however in your case, since the part can be fairly easily duplicated, and your peace of mind is important, I would not disregard the 2D rule.

Just for clarification...

I'm not an engineer, so take this with a large grain of salt, but I think that 2D requirement is for rivet spacing and does not necessarlily apply to bolts, which is the application in this case. Not saying that 2D wouldn't be a safe way to go if in doubt, but I also don't think that's the correct answer. Maybe one of the resident VAF engineers could chime in...

If you were at the assembly point, and knew where those little brackets go, and what all attaches your tail to your fuselage, you wouldn't even question re-doing those parts...you'd probably cringe and want them to be made of titanium.
Tim

I messed up one of the measurements on mine, and had to redo them. It is a good practice in fabricating parts. On my second set, I got something to be proud of.

TimO said:

If you were at the assembly point, and knew where those little brackets go, and what all attaches your tail to your fuselage, you wouldn't even question re-doing those parts...you'd probably cringe and want them to be made of titanium.
Tim

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Thank you. This is actually a very helpful comment. Makes me feel good about the decision to buy the part from Steve Dineri. When I did my VS, I "fixed" something that turned out NOT to need any fixing. In the process, I ended up making the whole thing worse (before making it better), spending about 10 extra hours, and a lot of hassle and frustration. I wanted to be sure this needed to be redone before going through that kind of experience again. Knowing that the part is critical makes the decision obvious.

When cutting with the band saw, you could lay the other leg of the angle on the table. Then when you make your cut (non-perpendicular to the standing-up leg), you won't be at risk of this type of damage again.