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Best drill bits?

kcameron

Well Known Member
I'm considering buying one of those 115 piece drill bit sets with fractional, number, and letter sizes. I'm looking for bits that will hold up well even when drilling steel. I've got a "Drill Doctor" sharpener on order. Basically, I'm tired of not having the right size on hand and having to run to the hardware store when a bit goes dull. Using the sharpener, it seems like I want bits which have strong/hardened steel through and through rather than a surface coating.

I see that Harbor Freight sells two kinds:
Titanium nitride coated M2 (whatever that means) steel : $39.99
Cobalt : 79.99 (on sale regularly $99.99)

They're both made by Drill Master.

I'm not against spending more money for quality tools so I'm leaning towards the cobalt. However I'm not sure about Harbor Freight's offering. Does anyone out there have an idea about the quality of these bits? Perhaps there's a better place to get drill bits?

Thanks for any guidance.
 
drill bits

Kevin,

I have been using the cobalt drill bits from Avery Tools and have been very satisfied. You will need to order multiple #30 and #40 bits and also consider multiple 6 in and some 12 inch bits as well. I did order the #1-60 and fractional sets, in cobalt, from averys and use them all the time. I wouldn't waste my money on high speed steel.

Jim
 
I have used all of the above. Here's my two cents worth:
I bought the $39 set and have had them for a long time and have broken a bunch of them. But, they are fine for aluminum drilling and will last for that. However, they are not as good for steel & SS, such as drilling through the firewall and the canopy frame, roll over bar, etc. Using Boelube is a must for all drilling in any hard surface or you will ruin them almost immediately.
Get the cobalt drills for any drilling into steel. Identify the common sizes and get some extras...41, 40, 36 (for tapping #6 threads), 31, 30, 27 (For tapping #8 threads), 12 and any other sizes you think you will use often. The Cobalt drills are harder and more brittle, so take care not to put much side pressure when using them. They break just as easily as the high speed steel bits.
If you live in a city or larger town you should be able to find a local tool supplier that handles cobalt bits and you should be able to get them quicker and probably cheaper than ordering through Avery, etc. They'll also have taps, reamers, etc., etc.
The drill doctor works fine but not for the smaller bits. Sharpening a #40 is questionable and I have found it does not work well for this size drill, especially in the jobber length. The short length makes the drill doctor set up problematic.
Good luck.
 
Make sure they are 135 degree split point drills, these definetely willl not "walk" like ordinary drills. These are the aviation standard for folks who build or repair aircraft for a living. -- Les
 
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