Drill bits to drill main spar attach holes.

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Re: Drill bits to drill main spar attach holes.

Postby sonex892. » Sat Oct 07, 2017 11:43 pm

NWade wrote:All -

Resurrecting this thread for a quick question: When you use the long drill bit & steel tube bushing method and are drilling front-to-back, are you using a 90-degree adapter on your drill (due to the angled fwd fuselage sides)?

Thanks,

--Noel
Sonex #1339

Noel, I needed a right angle attachment for the front-to-back drilling. The tapered fuse got the way.

The back to front drilling was easy with bits chucked directly in an electric drill.
Steve
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Re: Drill bits to drill main spar attach holes.

Postby Bryan Cotton » Sun Oct 08, 2017 9:50 am

I think that for front to back, I put the bit in the bushing first. Then I chucked it up in the drill. I did not use an angle drill. It was tight.
Bryan Cotton
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Re: Drill bits to drill main spar attach holes.

Postby kevinh » Sun Oct 15, 2017 10:02 pm

Bryan Cotton wrote:I think that for front to back, I put the bit in the bushing first. Then I chucked it up in the drill. I did not use an angle drill. It was tight.


Hi Bryan,

So I'm finally (this week) rigging my wings to the fuse - thank you for the loan of the bushings! One question:

I understand using the bushing when drilling from the aft through the front 1/8" aluminum angle (or whatever it is). When then turning around and going the other direction, how did you updrill that front angle to 3/8"? I'm considering making a little aluminum block on my drill press with a 1/4" hole on the bottom 1/8"ish length and then 3/8" hole the rest of the way and then clamping that to the fuse to serve as a jig... Any other ideas welcomed ;-)

Then for the rear angle I can pop that one off and drill it to final size on my drill press.
Taildragger Waiex in progress, tail done, wings done, about to mate wings to fuse,
then cowl, canopy, paint (photos): flush rivets, turbo aerovee, acro ailerons
(I built my RV7A and happily flew it for about 500 hrs)
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Re: Drill bits to drill main spar attach holes.

Postby Bryan Cotton » Sun Oct 15, 2017 10:33 pm

Kevin,
Covered on page 78 of my thread:
viewtopic.php?f=39&t=578&start=770

You will need either the chrome or Firefox photobucket fix add on to see the pics. I'll send you an email too. I essentially used the idea you proposed, but went up to .3725" in several steps.
Bryan Cotton
Poplar Grove, IL C77
Waiex 191 N191YX reserved
Taildragger, Aerovee, acro ailerons
dual sticks with sport trainer controls
Prebuilt spars and machined angle kit
Working panel
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Re: Drill bits to drill main spar attach holes.

Postby kevinh » Sun Oct 15, 2017 10:40 pm

Bryan Cotton wrote:Kevin,
Covered on page 78 of my thread:
http://www.sonexbuilders.net/viewtopic. ... &start=770

You will need either the chrome or Firefox photobucket fix add on to see the pics. I'll send you an email too. I essentially used the idea you proposed, but went up to .3725" in several steps.


Thanks - OMG that chrome extension is awesome!
Taildragger Waiex in progress, tail done, wings done, about to mate wings to fuse,
then cowl, canopy, paint (photos): flush rivets, turbo aerovee, acro ailerons
(I built my RV7A and happily flew it for about 500 hrs)
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Re: Drill bits to drill main spar attach holes.

Postby sonex892. » Mon Oct 16, 2017 5:43 pm

kevinh wrote:
Bryan Cotton wrote:I think that for front to back, I put the bit in the bushing first. Then I chucked it up in the drill. I did not use an angle drill. It was tight.


Hi Bryan,

So I'm finally (this week) rigging my wings to the fuse - thank you for the loan of the bushings! One question:

I understand using the bushing when drilling from the aft through the front 1/8" aluminum angle (or whatever it is). When then turning around and going the other direction, how did you updrill that front angle to 3/8"? I'm considering making a little aluminum block on my drill press with a 1/4" hole on the bottom 1/8"ish length and then 3/8" hole the rest of the way and then clamping that to the fuse to serve as a jig... Any other ideas welcomed ;-)

Then for the rear angle I can pop that one off and drill it to final size on my drill press.


Hi Kevin.
Once the wings are aligned my preference was to complete the whole process using the actual spar blocks for alignment to updrill both the forward and rear angles. I just went from 1/4" to 3/8" x 4 times. Here is an old post with a drawing of the process I used.
viewtopic.php?f=34&t=752&p=5543#p5543
Steve
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Re: Drill bits to drill main spar attach holes.

Postby kevinh » Mon Oct 16, 2017 10:36 pm

Thanks Steve - that's a good idea (and great drawing). I'll probably go that way. I'm ordering a suitable length 3/8" drill bit now and I'll test it on some scrap aluminum before using it on my (already nicely fitting 3/8" hole spars) and the virgin angles.

Also in measuring my shop I think I'll probably attach (my already drilled) gear and engine mount to make it easier to roll the plane in position (with one wing sticking out the door) rather than doing the plane on blocks. I'll be careful to check level at each step (because it will be on rubber wheels - at least on the front) because the logistics of moving plane around is much easier on wheels. Anyone think this is a horrible idea? ;-)

So exciting but nerve racking. That said, after rereading the description here and in the plans it seems less error prone than the method used for RVs (and I somehow got through that).
Taildragger Waiex in progress, tail done, wings done, about to mate wings to fuse,
then cowl, canopy, paint (photos): flush rivets, turbo aerovee, acro ailerons
(I built my RV7A and happily flew it for about 500 hrs)
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Re: Drill bits to drill main spar attach holes.

Postby NWade » Sun Oct 29, 2017 10:15 pm

All -

I finally got the main spars mostly drilled, but ran into a snag: I'm using the piloted bit from Fastenal that others have used, and I've found that its about 1/2" too short to drill from front-to-back through the entire stack of materials(!) I have the 1/4" hole drilled through all of the layers (using the steel bushing technique), but I still need to drill it up to 3/8".

How have you all solved that problem? I can think of two approaches; neither of which I love:

1 - Use a regular jobber-length 3/8" bit and hope that it doesn't cut the hole any bigger as I slide it through the existing hole.
2 - Keep the steel bushing in the hole but back it out by ~1/4". Then stick the piloted tip of the double-margin bit through the 1/4" hole and into the bushing on the far side (to keep it centered), then drill through the ~1/4" of material that needs to be opened up. There are two issues with this, though: [a] I'm worried about the front of the 3/8" bit getting chewed up by the steel bushing as it pushes through, and [b] the pilot is not a whole lot of material to keep the drill bit perpendicular to the hole.

Any thoughts or suggestions?

--Noel
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Re: Drill bits to drill main spar attach holes.

Postby wlarson861 » Sun Oct 29, 2017 11:23 pm

I had the same situation with the step bit being too short. I drilled as far as I could with the step bit and finished with a jobber length bit. The holes ran straight and had a slight interference fit. That was 400 hours ago and seem to be fine. In that time they have been removed once and reinstalled when I had to remove the wings. They showed no signs of wear.
Bill Larson
N861SX
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Re: Drill bits to drill main spar attach holes.

Postby lpaaruule » Mon Oct 30, 2017 7:46 am

I had already drilled my attach blocks to 3/8" with the fastenal bit before putting the wings in the plane, so I only had to drill through the vertical angles once the wings were in the plane.

I finished with a 6 inch long 1/4" and 3/8" Jobber bit. In my case the hole was so close to the side that I had to insert the bit then attach the drill to it (a real pain). This was because the sides slope in towards the front. I used the drill bushing for the 1/4" bit, and drilled normally. When using the 3/8" bit I used more pressure, and a slow RPM for less opportunity to enlarge the existing hole.

I have to lightly tap in the bolts, and my wings have no play.

I definitely wouldn't try drilling from the opposite side, even if a pilot hole is already there. I can't hold a drill perfectly perpendicular.
Paul LaRue
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Jabiru 3300
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