Topline USA M42 Cobalt #29 Drill Bits 6-Pk

I used this bit for drilling 300 holes in 1/8" aluminum plate, using a drill press and Tap Magic aluminum fluid. The first bit lasted for first 200 holes, and the second finished the job just fine. I think this is very reasonable performance for these bits.

They work great for what I do with them, but I'm not drilling through really hard stuff. Usually, M42 drills will have some sort of designation like "m42" or ''co" stamped in the drill to indicate they are cobalt. These only have "HS" indicating high speed steel. Who knows if they are cobalt. I suggest if you are drilling through hardened material go with m42 through a trusted supplier like mcmaster carr.

Reasonably priced bit for drilling and then tapping some bolts into car door hinges. Made multiple holes and the bits stayed sharp and didn’t shatter. Look to be good quality bits so I’m recommending them.

Save your money, not true cobalt

Good product

I expected to need several of these to drill the 16 holes in 3/8" thick hot rolled steel since there are frequent hard spots in the metal and my original bit from my drill index shattered part way through the first hole. When I used these bits I probably could have managed to drill all of the holes with just one bit, but replaced it with a second after the tenth hole since the first bit was beginning to dull from the hard spots in the metal. The second bit finished the job with ease. From this experience, they seem like very high quality bits.

Fast shipping, great product just as described!

The service could not have been better. Just a small order for personal gunsmithing use in a home shop and these guys came through like champs. They send them to me quickly and worked perfectly for my sight mounting project. This size seems to a little hard to find so I was glad I found them in a 6 pack. They were priced right also. Now I have spares in the toolbox. THANKS, CML SUPPLY, and TOPLINE USA!.