Adam Oke

Adam Oke

Well Known Member
After a hiatus on the tail due to work, I have returned with a relatively simple question.

I am about to drill my counterweights using E-713 as a guide. I plan on using a #40, then stepping up to a #12. I also plan on using some cutting lubricant. I just want to ensure that I will be relatively square when drilling. How did everyone ensure everything is square to meet edge distance on H-703 flange? Ideally, I would like to clamp the entire unite and use a drill press, but there doesn't seem to be a good way to do it.

Did everyone just freehand it horizontally on the table and hope for the best when it came to edge distance on the H-703 flange?
 
I clecoed the whole counterweight assembly together and then made sure everything was in its final position and started to drill the lead just enough to make an indentation. Then I pulled it apart and drilled with a drill press with #40 to be sure it went through straight. After that, I put it back in the assembly and drilled the #40 through ribs and they came out in the right spot. Then I just slowly enlarged the hole to 30 then 19 then 12 with the same process. Took about 15 minutes and it came out much better than when I free-handed it on the right elevator.
 
Thanks for the response.

I would think that going from #40 as the pilot hole and #12 as the final should be alright. I like your idea of removing it and using the drill press just on the lead. That will probably be the way I will do it, unless anyone else cares to chime in.
 
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Lube

Make sure you use lots of cutting lube, or you will break the bit. Removing the remains of a broken #12 is not easy. Don't ask how I know this. :D

If I had to do it again, I would use a 3/16" or 5/32" bit to drill a pilot hole. Less likely to break than a #40. Most importantly, go slow, keep the bit clean and be generous with cutting lube.
 
boelube

use a lot of lube, lead tends to grab the drill bit aggressively, and its melting point is very low, I used a lot of lube and retracted the bit often.

bird
 
Vice

Hey Adam,

I stuck it in the vice, made sure it was plumb and used the holes in the 713 as a guide. started with the 30, 21, then the 12. Lots of lube. I used my cordless drill for this, which also has a level on it.

By the way, heading down on Thursday to pick my wing kit. Stef Chambers is going as well as his fuse kit was shipped with my wing kit.

Can't wait to get back at it!

Have fun banging!
 
I drilled out the lead on the drill press. Then I assembled everything and used the holes I drilled as my guide to drill the holes in the aluminum. Everything lined up just fine.
 
I just got this job done this morning. This was a step that had me concerned too; I had heard some horror stories, so I took the time to do lots of research. Checked out this thread and others on the VAF site; did searches on drilling lead, cutting oil, drilling lubricant, etc. Mostly I followed the advice found here. I got some cutting oil and did a lot of careful prep work. I barely started the holes with the parts assembled, going up to the #12 size specified just enough to get through the counterbalance skin. Then I removed the counterweights and finished the holes on the drill press. I surrounded each weight with a ring of rolled-up paper towel to serve as an oil catcher, oiled the bit and drilled just long enough for the lead to snake up the flutes of the bit to the drill chuck. Then I'd stop, remove the lead spirals from the flutes and repeat the process. It took awhile, but I ended up wtih clean, straight holes that lined up properly with the rib flanges and no broken bits. It's actually a very easy job... just do the prep work and take your time, and it's no problem at all.
 
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