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Advice: drilling the main gear titanium leg

PostPosted: Mon Jan 16, 2017 4:11 pm
by 1labelloj
I am ready to drill the main gear titanium leg. I am looking for some advice before I start.
1. I know the size is 1/4 inch. What is the best type bit to use?
2. What is the best speed for drilling?
3. What is the recommended cutting oil or cooling oil to use?

Jake LaBello
Waiex #0217
labelloj@comcast.net

Re: Advice: drilling the main gear titanium leg

PostPosted: Mon Jan 16, 2017 5:25 pm
by NWade
Jake -

Do you know about the Sonex videos on EAA "Hints for Homebuilders"? There are a bunch of them (most are linked from the Sonex main website).

Here's the one on drilling the titanium legs:
http://www.eaavideo.org/video.aspx?v=29739778001

Hope it helps! I'm going to be doing this myself in just a few weeks... :-)

--Noel
Sonex #1339

Re: Advice: drilling the main gear titanium leg

PostPosted: Mon Jan 16, 2017 5:40 pm
by rizzz
I remember stressing about this as well, then when the time came it was a bit of an anti-climax.
I can't remember how I went about it, just that I was a bit surprised at how much easier it was than I thought it would be.

Drilling the stainless steel firewall however, what a traumatizing experience that was.
I still wake up screaming in the middle of the night :D .

Re: Advice: drilling the main gear titanium leg

PostPosted: Mon Jan 16, 2017 6:40 pm
by jowens
Consider listening to the sonexflight.com episode 9 that discusses landing gear.

Re: Advice: drilling the main gear titanium leg

PostPosted: Mon Jan 16, 2017 6:58 pm
by Bryan Cotton
I have some documentation on page 39 of my thread.
viewtopic.php?f=39&t=578&start=380

Don't use your motor mount or tailoring mount as a drill guide. I marked the hole location then brought the gear leg to the drill press on a V block. The I transferred the hole to the back of the mount.

I had bought a fancy bit but it died right away. I had HSS bits handy and they worked fine. Slow speed, lots of oil, lots of pressure, and have faith.

Re: Advice: drilling the main gear titanium leg

PostPosted: Tue Jan 17, 2017 1:36 am
by wlarson861
You should definitely use Cobalt bits to drill both Titanium and stainless steel. Not knowing this I attempted to drill the gear leg with a standard bit that snapped off half way through the cut. Luckily I got the broken bit end out of the hole. I read about cobalt bits and that was how I finished that hole and made the others. Cobalt bits can be found at most hardware stores, I think I bought mine from Menard's. For the #30 and #40 I think I had to order them. I tried using regular bits in the fire wall, I think I got 2 or 3 holes drilled before needing to sharpen the bit. If I remember right I used 3 or 4 bits just to do the filler box. The cobalt cut fast and clean.