Drill bit quality

I'm not certain that the price difference matches the qualitiy difference. I think I bridged the gap years ago with something between the cheapest from China and the top of the line. Having the 115pc index _is_ definately nice. However, 90% (swag) are rarely used for my work. I find that from habbit for pilot/step drilling I use 1/8", 1/4", ... fractional sizes often, and the tap & body drills for 4-40 through 1/4-20 the most frequently, the latter usually 6-32, 8-32, and 10-32. So I wrote down those sizes and built up an inventory. Some at retail (ouch) many at auction (IRL) and many off of ebay. For the larger sizes having used bits resharpened can be very much worthwhile.

You can pick up quality drills from many sources. Flea markets, auctions, large lots on ebay. Most will need to be sharpened. Off hand grinding on a bench grinder is a skill that only takes a little practice with attention to detail. It is well worth learning. Find a large drill to practice on, even if you will never use it. Larger is easier to get down the basics. If you can't find the angle info, I can scan and email it to you. It is in almost every machinist type book. If you need specific drills right away, I'd suggest buying them one at a time for the job at hand. A full index is nice to have around, but most are never used. I try to use the odd sizes whenever I can to even out the wear on the set.

Wait a minute.... 'having used bits resharpened'? You don't sharpen your own drill bits? Granted sharpening wee little ones is a prick, but...

The shanks on the larger bits in the set I bought a few weeks ago for $80 are stamped "USA" as is the Huot case they came in. Nice set of bits and I've been very happy with them.

One of the best descriptions on how to do it was teenut's post on the subject. Do a google search for "Bionic Darex" IIRC.

Or a package of ten or twelve for the smaller sizes which are likely to be frequently used, like the common tap and body drill sizes.

There are times when you want something like the parabolic flute drills for a project -- *those* you buy in the sizes you need, and usually in a minimum package (10 or 12, depending on size.)

I'm happier to have a full 115-bit index, plus several smaller indexes, including a 1-60 index of Cobalt screw machine drills with split points. Also two metric indexes -- 10-6.0 mm and 5.9-1.0mm just to cover other needs.

They are also useful for making a slightly oversized tap hole if you don't need as much of a percentage of full threads in the harder materials. Also when you need to make tap holes for thread-forming taps, which are *not* the standard size holes for metal-cutting taps.

Enjoy, DoN.

Well, that's interesting. There was a crazy series of buyouts involved, as I got involved with Hertel when they bought out our previous client, Adamas Carbide in New Jersey. Then we had to go to Fuerth, Germany, to service the client. Then Hertel moved some offices to the US and I lost touch with them. And then, Kennametal bought out Hertel.

It makes you wonder what's in a name these days...Iscar (Israel) bought out the tooling division of Ingersoll (Rockford, IL), and now the Chinese are in the process of buying out the rest. I wonder if the Chinese/American milling machine company will be running American/Israeli cutting tools, all named "Ingersoll"?

But, what the heck. The new, 2004 Chevy Equinox SUV will have an all-Chinese engine, shipped complete from Shanghai to Canada for installation. So an American/German/American/American drill bit is no big deal, I guess.

Ed Huntress

Are we talking about core drills or something? Why do I feel so alien to this conversation? Sharpening drill bits is easy. Tip-thinning is easy. Using a center drill or spot drill is mandatory if you want the hole within a few thou *regardless* of the type of grind.

More cheap import bits have split tips than non, in my experience.

Another nice thing about sharpening your own, you can custom grind a bit to drill oversize to get a hole you don't have a drill for.

Quite true... *providing* there is no pilot hole. Well, I suppose it's possible to get a drill so messed up that it will drill oversize even with a pilot hole... but it would take some doing. 8-)