Just drill bits . . .

[cheechi]

If your method works and does what you need it to do, stick with it

There are tool steels that are oil, air, and water quenched, it all depends on the type you have.

Sorry to be misleading. I was taught the technique but I don't do it personally. I'd rather buy a new one than change the chemistry or geometry on an existing one. I have no way to test the results anyway.

 

[Kevin54]

The reason you quench then in oil is so they cool slower. Water would cool rapidly and may make the end brittle.

 

[msgtsmithret]

Bought these last week for $140 They have 3-flats down to 5/32

I'm kinda liking those drill bits but can't say why. What is the purpose of the extra cutting face?

 

[Outlawmws]

The three flats are not cutting faces, that is so the chuck won't slip. You may sacrifice some concentricity though.

 

[67satellite]

Precision Twist Drill, Cleveland, Triumph, Hertel and Chicago Latrobe are all common industrial brands of good quality HSS drills. My personal collection is a mix of those and others. I buy the smaller sizes, 3/16" and under by the dozen. I never buy drills at a home or hardware store. Enco is a good source for the average guy, they have sales all the time.

Learning to sharpen drills is a worthwhile pursuit. Lubrication is a must. Feed and speed is what it's all about. Cobalt drills are great, especially in harder materials, but they tend to chip easily handheld or in a press with a lot of runout or the work not clamped securely.

Don't forget Dormer,I believe they're made in England.After 26 years running and setting up Acme-Gridley screw machines I can truthfully say I"ve got operators who can destroy the best of any of them.

 

[uart]

I wonder if your old school teacher's method of dipping it in oil was motor oil to harden it? Hot metal dipped in motor oil will increase the 'high carbon' of HCS metal and depending on the oil, temps, & metal may be enough to make HSS into a slightly 'high carbon' steel.

The reason you quench then in oil is so they cool slower. Water would cool rapidly and may make the end brittle.

+1 on what Kevin said.

There's no way that you'll get any significant carburizing by cooling in oil while grinding a drill bit. Ideally of course you shouldn't get the tip anywhere near cherry red anyway, stop and dip it well before that point.

The only reason to use oil is just in case you get too hot, you don't want to shock it with water and possibly make it brittle. So while you obviously shouldn't even get it that hot in the first place, if you do stuff up and get it glowing then the oil cooling is the most likely to preserve at least something close to the original temper.

 

[skruft]

Just my own experience:

As a hobbyist and general amateur, I just use any brand of quality USA twist drill and, when drilling metal, I always use whatever brand of cutting fluid or cutting oil is nearby. I learned to do this in metal shop class long ago. I keep bottles of it in different places to make this easy. I have no idea whether any one oil is better than any other. Special oil is needed for other things, like clocks, maybe not for drilling.

I see no difference among quality twist drills, except that there are ones with split points that are easier to use accurately without centerpunching the location.

Whenever possible I centerpunch and use the drill press. Besides precision, this seems to minimize wear and breakage. The spring loaded center punch is a good tool.

I tighten the chucks well, so that large sizes will not slip.

I still break some of the very small drill sizes when drilling by hand, so I keep many around, which I pick up cheaply when I see them. I could sharpen the other sizes when dull but I don't wear many out and I have so many extras that I often just toss them to save time.

 

[sasquatch12]

In Canada, a top of the line cutting tool manufactuerer for many years has been "Butterfield". Not sure but i think they also had a plant in the eastern US.
Two weeks ago just found a almost new/unused combo set with the drills and taps, all Butterfield for $10.00 .

 

[kenburkholz]

The thousands of of different types and ,styles, of drill bits can be confusing. Of the many types I have used I have found that H.S.S. is the best way to for general use. Lubrication is the key to longer lasting bits and more effortless drilling. If I have to drill hardened material I will go to cobalt, or even solid carbide bits, which can cost $25 to $50 dollars or more, and can shatter without warning . Ken.

 

[Jere]

I bought a $20 set of HF hss coated bits, aside from breaking them from using them wrong they have lasted a few years being used a few times a week. It is great they sell 1/8th multi packs tho, they get used for pilot holes and are easier to just throw in the scrap bin and grab a fresh one rather than try to re sharpen.