bach33089

bach33089

Member
First post for me, but this is more of a warning than a request for information. Just got my QB fuselage in after completing the Empennage and started working on drilling the Main Landing Gear Attach Brackets and Wear Plates. I did not have a 7/16 drill bit in my box so I ran out and grabbed a Dewalt Titanium 7/16 Bit. The bit made it through 2 and a half plunges before it was entirely dull and unusable, leaving me with a half drilled Wear plate... Has anyone had similar luck with these drill bits, is there a better one out there. I have never purchased the Titanium ones as I always thought it was a marketing gimmick and maybe it was. Do I need to stock up on bits for drilling these steel pieces, if so which bits should I buy? Thanks in advance for the help (though this is my first post I have visited VAF daily for help and advice!)!
 
Welcome to VAF!!!!

Foster, welcome aboard the good ship VAF:D

Good to have you here, this is a great location for RV folks.

Sorry, no experience with the drill bit you mentioned.

Hopefully others will jump in with drill info.

Enjoy!!
 
This might be helpful. For what it is worth. Many hand held 1/2 drill motors spin way to fast. Slow speed with lots of pressure and plenty of lube usually prolongs the life of a good grill bit. Larry
 
drill bit

I have found that Nitro bits work very well. I agree, keep the speed slooooooow, and use lots of lube:D
 
Slow speed, high torque, & push hard

I've never tried titanium bits. I used an $8.00 cobalt bit in a big Bosch 1/2" electric drill set to a slow speed, and the combination drilled those holes lickety-split.

(That was after spending WAY too much time and effort with a smaller, faster, less-"torquey" drill motor and cheap bits.)

I was astonished at the difference. Here's the builder's log entry for reference and photos.

Welcome to the VAF family!
 
Heat kills them

I have used them and found as others have stated that a drill spinning too fast with not enough pressure on the bit will let it get hot. Once it gets hot it becomes toast. I have been able to drill a 5/8 inch thick steel trailer hitch with them and had no problems as long as they didn't get hot (usually by spinning). As others have said, slow, pressure and cooling lube.
Good luck,
Paul
 
I have not gotten to working on the Landing Gear yet, however, the general rule for working with large drill bits and thick pieces of metal is to use a drill press, have the bit turning at a low RPM with lots of torque, use a good bit of lubrication oil (the oil is much cheaper than the bit), and most of all very slow drilling. You are not in a race, so please take your time with it.
 
Thanks for the tips. I did have the bit in a drill press set to the slowest speed available which is around 300 RPMs. I used almost an entire bottle of Boelube to boot! I stuck the bit under a microscope the other day, it looks to me the the gold colored coating (supposed to be titanium I guess?) just separated revealing a very soft substrate metal that the coating was boded to. I remedied the issue with a good cobalt bit and was able to complete the rest if the plunges without issue and used much less Boelube! Thank you for the tips! I look forward to many more in the future!
 
My farm boy farm machinery experience has came to the same conclusion. Most drill bits labeled Titanium are only plated (coated) with titanium and once you break through this coating the bit is junk. The Cobalt bits are the very best for drilling through harden metal. They all wear out and a slower drill speed and lube goes a long ways as previously mentioned.
 
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