cobalt

[joblo]

hi all
where can i find the best cobalt drill bet ?

 

[DocsMachine]

Why do you need cobalt? All it does, assuming they even added enough to matter into the steel, is improve it's high-temperature strength. As in, near-red-hot.

If you're not turning your drills *far* too fast, and/or not drilling exotic alloys like Inconel or AR400, you don't need cobalt drills.

Besides the fact that "cobalt" drills that you get in box stores usually only have a small percentage of cobalt- it's extremely expensive- when you need upwards of 8% to actually provide the high-heat benefit.

Doc.

 

[MBeaty]

I would also second the opinion that unless cobalt is a necessity for your application, HSS would be a much more versatile bit. Another problem with cobalt drills is that cobalt is more brittle than normal HSS drill bits. In order to compensate for this, the web of the bit has to be thicker, thus leaving less relief to evacuate chips. This can be problem in some materials and actually lead to slower drilling than a HSS bit.

If you could list some intended uses for the bits, we could probably point you in the right direction.