Empennage Shortcut ream instead of match drill?

I've finally after years taken the plunge and started on the Emp kit.

After taking a couple of builders courses and talking to a few tool vendors at Oshkosh I want to run by a potential shortcut on at least the Emp kit that was suggested to me to see what people think.

Instead of assembling everything with clecos, match drilling to final size, disassembling, deburring holes, reassembling what about simply reaming the holes to final size, deburring by running a scotchbrite over the holes (reamer is cleaner), and then assembling? Sure you have to ream twice the holes but it is much quicker than assembling twice.

I hear a lot about match drilling to ensure proper alignment of parts, but in my so far limited experience the parts are very accurate and this process seems to get the same result.

Any thoughts? Hopefully this isn't the primer wars part II This was suggested to me by someone with some experience, but want to see if there are negatives from others who have already been down this road.

Thanks.

Seeking "short cuts" during the very first part of building an airplane is not a healthy philosophy.
Most of the entire airplane will be assembled and reassembled several times for proper fit and/or alignment.
If this discourages you, then prepare yourself!

Mel, thanks.

Perhaps short cut was a poor choice of words, how about streamlining?

Seriously though is there something technically wrong with the approach?

Your procedure does not ensure proper alignment. Yes, these parts a very accurate, but all may not be. Follow the plans and you will have fewer disappointments.

Oblong holes?

I hear what Mel is saying, but in my way of thinking the math doesn't support the argument. As received, the holes are only a few thousandths smaller than the final hole size. There is no opportunity to move a hole in a pre-punched part without creating oblong holes. After completing much of my metal work I can't help wonder why I match drilled most of the holes on the airplane. A slow build fuse and some other parts are going to require an initial assembly as you will need to create many holes in the longerons.

I say enlarge those holes and rivet away. I do agree with Mel's point about not setting your standards low, I'm just not convinced this method of construction reduces the overall standard.

Jeff,
I definitely understand your intent. I built my RV8 fuselage according to plans, and then wondered why I needed to go through everything twice. I used a piloted reamer on virtually every hole on the airplane and it leaves very little of any burr. I used the same technique on my RV14 wings and used the scotchbrite pads to smooth things over. Be advised that when you do this, you'll be removing most if not all of the alcladimg on the flanges and skin rivet line, so you'll probably want to at least prime these areas. I don't think there is any increased value in clecoeing everything together in undersized holes to line things up before drilling/reaming. I plumb-bobbed, and measured everything firewall to tail before match-reaming on my RV8, and it was in perfect alignment before and after. I could have saved myself some time by just reaming, dimpling, and then start clecoeing & riveting and probably not sacrifice accuracy. That being said, it still only took two months to get from the crate to well past QB stage on the fuselage.

There is such an incredible amount of repetition, and once you get into a routine, it doesn't take all that long, and you get very good at what you are doing. Having built a couple of these and done parts of others, I have to say that the journey is half the fun. Don't take ten years, but don't be in such a hurry. You may learn a few things you didn't think you would.

Have fun!!

Hmmmm.......

I think I need to change my comments on this subject. After my post, I spent the evening preparing skins without match drilling. I learned a few things.

While I stand by my statement that we are not removing enough material to really move any holes, I think this technique is a bad idea for other reasons. When we assemble for the match drilling it gives us a chance to see 3 dimensionally what prep work needs to be completed on the skins and the substructure. Some of it gets dimples, some countersunk, some this direction and some from the other direction. Many of these parts get a significant variety of prep work. I spent most of the evening referring back to the prints to try and keep all this straight in my head. It is easier when the structure has been assembled as the reason we are doing specific prep in specific locations becomes more apparent.

Additionally, when enlarging the holes while the parts are not in assembly it effectively doubles the number of holes which need enlarged. I thought the technique outlined by the OP would save time. I think it cost me time. I didn't think it was possible for me to go any slower but I guess I was wrong

A lesson I keep learning over and over and over is that it is nearly always better to stick to the plans.

Tools, tools, tools

Hey Jeff,

I can't really comment on that method of building because I didn't try it. Personally I would just go strictly to plans, but I am a big fan of using reamers when possible. The holes seem much better with less burring. a side benifit is that it's a lot harder to drill a hole through my finger.

The goal here sounds like saving time. If I had a time machine, I would go back to my tail building days and recommend that I get an extra drill, (cordless, corded, or ideally air powered), and an extra countersink cage. If money were no object, I would also invest in a 2nd rivet gun, maybe a used one off Ebay.

It seems that a lot of time could be saved if I weren't forever retooling for different sized holes or flush vs. round headed rivets. I'm forever changing counter sink cutters which means that I have to always play with the adjustments to get the ideal depth set for them. You will pretty much be using the #40 and #30 cutters most of the time. It's worth the effort to get a piece of angle aluminum from the hardware store so that you can make a guage of how deep the countersinks need to be set for each operation. For example, if you need a countersink for just a rivet, or for a 0.020" piece that's dimpled, a 0.032" piece that's dimpled etc., then mark them with a sharpie or label maker so that depth setting is easier in the future. I would still try the cutter on scrap first, but it gets me in the ballpark quickly.

If you've talked to anyone with a pneumatic cleco tool, I doubt if you'll find anyone who regrets owning one. It saves huge amounts of time installing and removing the clecos. It also cuts down on the chances of getting.. carpel tunnel syndrome. Just watch your finger tips with this tool!

http://www.cleavelandtool.com/Pistol-Grip-Pneumatic-Cleco-Tool/productinfo/CLN12/#.UjyygMu9KSM

There are probably tons of ways to save time and increase production. I always learn lots by visiting others projects to pick up tips and tricks. Perhaps others can chime in with their thoughts on what saves them the most time.

Happy Building

Steve W.

Thanks Everyone

Thanks for all the advice everyone. As mentioned my intent was certainly to save time, not take shortcuts in the sense of less safety.

I am already seeing the benefit of getting another countersink cage, and I agree that pneumatic Cleco removal tool would be a plus.

After now reaming all the holes using the plans method I do see for the skins absolutely the benefit of assembling and drilling in place.

JDBoston said:

Thanks for all the advice everyone. As mentioned my intent was certainly to save time, not take shortcuts in the sense of less safety.

I am already seeing the benefit of getting another countersink cage, and I agree that pneumatic Cleco removal tool would be a plus.

After now reaming all the holes using the plans method I do see for the skins absolutely the benefit of assembling and drilling in place.

Click to expand...

When you are in "High cleco count mode" and using the cleco removal tool having a woodworkers or BBQ apron will help.

Clecos go straight into one of the apron pouches....