Mastercraft Maximum Cobalt Drill Bit Set, 21-Pc
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Excellent bits - often go on sale, too
Bought these on a 60% off sale, and definitely never regretted it!! Best drill bits I've ever used. Leagues better than high speed steel, that's for sure!!
May 13, 2013
Makes drilling into steel much easier
If you're drilling into steel, cast iron etc, these cobalt bits are ideal. I find them much quicker and cleaner than titanium coated or black oxide bits. They also require less cutting fluid and having drilled around 35 holes in 3/16" steel, the bit still feels extremely sharp.
Work best in a drill press but if you have a steady arm, using in a regular drill would be fine.
February 9, 2012
Great Cobalt Bit Set
The Job
Ever tried drilling through a stainless steel? I had to do this while installing a new sink in the kitchen. Regular high speed drills will do the job, but you have to work the drill at very low speeds to keep from overheating the bit. This really slows down the job and I still broke several bits during the drilling. I barely got the job started and I had broken several bits. I ended up getting a package of cobalt bits at Canadian Tire. The set was expensive, but I didn't regret it.
The Theory
Cobalt bits have more cobalt than regular high speed bits (hence the name). They tend to more brittle than regular HSS bits, but they can work at higher speed than regular bits on stainless steel and other hard materials. In theory, the job should go quicker without cooling breaks.
The Real World
I was only an eighth of the way through the stainless steel by the time I had finished breaking my last HSS bit. I lost a great deal of time because I had to work at low speed and let the bit cool off. With the cobalt bit, I was able to finish the remaining 7/8ths of the job in less than 10 minutes.
Cobalt vs. Titanium
I mentioned cobalt bits to a friend, and he suggested I could have used cheaper titanium bits. A little research on Google confirmed Ti bits could have done the job. But titanium bits have a titanium COATING. If you try and sharpen them the Ti coating comes off. Cobalt bits are cobalt to the core...you can resharpen them over and over. Titanium bits are usually cheaper than cobalt. If you only use them occasionally, buying Ti bits makes sense. If you work a lot with metal and will resharpen the bits, then cobalt will save you money in the long run and save you effort in terms of drilling.
Summing Up
The MasterCraft cobalt bit set has a good selection of bits that meet my needs as an average homeowner. I haven't used them that I haven't had to resharpen them, so I can't say how well a drill doctor-type tool will work on it. Also, you can only get these in a set. If you need replacement bits, you can't buy them a la carte at Canadian Tire. Overall, this is a great set for a reasonable price, especially if you can get them on sale.
December 28, 2010
