Drill bit sets

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Joe Parish
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Drill bit sets

Post by Joe Parish »

I am in the market for a drill bit set. Thinking of getting a fractional, number and letter set all in one. Thinking Cobalt but open to other options, want to buy a sharpener also. Wondering if any of you had suggestions on a good set reasonable priced? Harbor freight has a Cobalt set but I have no idea of quality?
Joe
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prestwich
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Post by prestwich »

My 2 cents is that the consumer grade drills are completely useless. Go to an industrial supplier (wherever your local machine shops go to buy tools) and expect to pay $150-$200 for each set. So maybe $500 total for letter, number, and fractional. Those are high speed steel, not cobalt or carbide. You can sharpen high speed steel by hand with a decent grinding wheel and 60 seconds of instruction.

If that doesn't fit your budget, then buy the sizes you need when you need them, but buy *quality.* I'd rather have six good drills then 250 pieces of scrap pot metal.

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captain_john
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Post by captain_john »

I dunno... I didn't go through that many drill bits.

If I bought a complete set, most of them would go unused.

If I need to "step a hole up" I just use fractional stuff and end up on the number that is specified.

As for numbered bits, I just bought a bunch of the ones I needed and replaced them as they broke or wore out.

I still have the original #19, #12, #11 & #10 that I bought when I started the empennage!

MAYBE I went through ten #30's and twenty #40's???

Perhaps I am too gentle on my tools but they work just fine!

:) CJ
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bullojm1
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Post by bullojm1 »

Joe,

Like CJ, I didn't really go through that many drill bits. The standard #40, #30, #27, #19, and #12 got me through 99.9% of the build. I also bought some reamers and undersized bits for drilling the important holes (ex: rear spar). The only ones I wore out were the original #40 and #30's from my Avery kit, which have since been replaced.

I bought an el-cheapo numbered drill set from Harbor Freight (similar to http://www.harborfreight.com/60-piece-t ... 34627.html). They have worked great for when I have needed something in-between.
Mike Bullock
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BSwayze
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Post by BSwayze »

Same here! I never bothered to get a whole set of bits, preferring to spend the money on airplane parts. I still have my original larger bits that I've had since the very start, and I've been through maybe a half-dozen #30's and maybe 10 or 12 #40's. A few good bits will build a whole airplane.

I did get a nice set of reamers, in all the sizes we use. Use a reamer for match-drilling whenever possible with the pre-punched kit parts. You'll get cleaner holes, wear out fewer bits, and all-in-all it's just a nicer way to go. :)
Bruce Swayze
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Joe Parish
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Post by Joe Parish »

I had the impression I would need more of a variety. I will just buy what I need and go from there. I have picked a few reamers up already. Thanks for the feed back guys. Much appreciated.
Joe
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bruceh
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Post by bruceh »

A long time ago I bought a complete drill set at Costco. Can't remember what I paid but it was certainly less than $50. It has all of the letters, numbers and fractional sizes. I use odd sizes all of the time. I'll use a number smaller size for drilling out rivets and in prep for reaming a hole to the correct size for a bolt. The drill bits tend to not make perfectly circular holes like a reamer does. Tapping threads also requires some of the odd sizes that don't come with the standard tool kits.
Bruce Hill
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bullojm1
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Post by bullojm1 »

I attribute my long drill bit life to using BoeLube (Boeing Lubricant) to lubricate the bits, especially when drilling through thick material. On top of prolonging the life of the drill bits, it makes drilling easier and leads to better results.

Boelube comes in a number of varieties, and can be purchased from Aircraft Spruce. This is the one I used:
BOELUBE BL70200-13 SOLIDS LUBRICANT
Drilling - Tapping - Reaming - Abrasive Belts - Files - Deburring Tools -
Grinding Wheels - Chisels - Band, Circular and Hand Saw Blades.
Boelube Solids improve tool life by reducing heat build-up in belt, disc
or wheel grinding operations. Apply the push-up tube to the tool before
start up. Individual Boelube Blocks are ideal for grinding operations.
1.6oz Push Tube ........................... 09-01731 ..............................
$3.50
Mike Bullock
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leffler
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Post by leffler »

Add to the list with Bruce and Mike. I've only purchased a few extra replacement bits (pirmarily #30 and #40). Everthing else I needed came in my original kit from Avery.

I do find my el cheapo HF number set comes in handy when I need to drill the one or two odd size whole. Recently that set has been getting more use as alighnment pins for my magneto and engine.
Bob Leffler
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http://mykitlog.com/rleffler

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