Drill Bits

[markgrubb]

[ar15barrels]

My 118 degree HSS bits are Chicago Latrobe.
My 135 degree colbalt bits are Precision Twist Drill and Triumph.
My sharpener is a Darex M5 and I have the necessary parts to go all the way up to 1" diameter twist drills.

[markgrubb]

Thanks AR15. Much appreciated.

[kcstott]

mcmaster Carr is a good source for individual bits

[Fishfearme86]

I work on aircraft as well. Cobalt and carbide are the best bits you can find. Also have you ever used a drill bushing? It wont completely take the triangle out, but it helps! What we do especially for interference fit holes is ream to final size. Good luck!

[RustyIron]

My pedestal grinder is a Delta. I run a white stone on it and do all my drill bits freehand. Carbide tools are done on another grinder with a green stone. Once you understand the principles and geometry of a drill bit, you can sharpen anything.

If you're serious about your work, you MUST learn to sharpen freehand. Sharpening jigs that you can buy for less than four figures are gimmicky little tinker-toys. They will bring you nothing but sadness. They're tedious to use, and limiting in their utility.

It will be hard to learn without a sensei, but I'm sure you can find something on Youtube. A wonderful resource is "Handbook for Drillers" published by the Cleveland Twist Drill Company in the early part of the twentieth century. I just googled it and found the ninth edition online. I have the eleventh sitting here on my bookshelf. Read the book, learn, watch some videos.

Once you think you understand, practice your newfound knowledge on a 3/16 to 5/16 high-speed drill. That's an easy size to start with. Then drill some holes and see what happens.

No relief, and the drill won't cut. Too much, and the edge will chip. If you're cutting brass, too much relief will "feed" the bit into the work. Once you have all that down, then you can worry about cutting speed and feed rate. Drilling holes really IS a science.

[markgrubb]

[ar15barrels]

My pedestal grinder is a Delta. I run a white stone on it and do all my drill bits freehand.

If you're serious about your work, you MUST learn to sharpen freehand. Sharpening jigs that you can buy for less than four figures are gimmicky little tinker-toys.

I'm serious about my work, but I also see the value in repeatability that you get with a real sharpener.
I can sharpen a drill bit by hand when needed, but my $1000+ Darex (all steel, not plastic crap!) does is so much better and faster than I can do it by hand.
I use that sharpener almost daily because I am spoiled by how nice it is to use sharp drill bits.

[67Cuda]

Round holes come from boring, reaming and honing.

Honing will make an already round hole more precise for custom fits.

[hermosabeach]

sharpener

Stick with USA made tools like Triumph, Chicago Latraobe, L&I, Greenfield etc...
Different materials will require different geometry tools.
You will NOT find one drill bit that works well in all of those materials.

Get a GOOD drill bit sharpener and you will not need to buy very many more drill bits as you can re-sharpen good quality bits over and over until they are too short for your use.

What do you recommend for sharpening bits?

['ol shooter]

Who makes a “Good” bit sharpener?

Drill Doctor by Darex. I've had one for many years, as a mechanic I needed sharp bits for general use. They aren't terribly expensive.
I use HSS bits, they work and are easy to resharpen. I buy them from the local industrial supply as needed, no Chinese bits.

[kcstott]

I don't recommend the Drill Dr. Thing is a plastic pile of crap. If you can't afford a real darex or justify the cost. Learn how to sharpen off a snag grinder or just toss the drill in the trash and buy new. If you don't know what a snag grinder is just throw your bits in the trash and buy new

[71MUSTY]

I thought the 9mm was for drilling round holes.

[ar15barrels]

What do you recommend for sharpening bits?

Look for a used Darex M3 or M5.
They have not made them in probably 20 years, but they still pop up for $300 to $500.

Avoid any of the consumer grade (plastic) sharpeners like the Drill Doctor.
They are a joke compared to a real shop grade tool.

[Bigedski]

cobalt is the way to go