Drill bits?

[lance]

What drill bits do you guy's prefer for drilling the holes for the bolt in c-notch?
Brand
Dewalt/Kobalt/Hitachi/Skil/Irwin?
Kind?
cobalt/titanium/gold oxide/high speed an so fourth?
Was thinking 1/4 for pilot hole then 1/2 to finish.

Thanks for any help/ info.

 

[SCOTTYINWV]

We use these cryo treated Kimble Midwest bits for anything serious or heavy duty. I've never done a c notch, but we have used them on frames, hitches, plate steel etc. no issues with needing sharpened or breaking after a few years of abuse.
https://kimballmidwest.com/Catalog/CatalogIndex.aspx?p=6.324.433.548.4208
They ain't cheap though. I always keep pb blaster or something to keep them cool.

 

[great white]

Cobalt.

Real ones, not the cheap coated things.

/end thread

 

[michael hurd]

You aren't drilling anything exotic, nor will you wear out the bit doing that job. A regular high speed steel bit will do quite fine for what you are drilling.

Now, as reference, I have drilled quite a few holes, and at work there are times where I have to drill 2 1/2" plate in a turret drill press. Drilling the hole to size requires drilling 1/64" undersized, then using a reamer. Imagine watching a reamer turn at 36RPM... it's like watching paint dry.

If you ever have to drill out something that's hard like a set screw, if you can use a torch on the item, get it glowing red hot and allow it to cool, it drills much easier that way. We have to drill out hardened lock pins often, what we use is cement bits that have been sharpened. With a proper edge on it, they will gnaw through hardened stuff like butter.

 

[JollyGreen]

You can use high speed steel bits, but if you want to get a nice set of bits I wouldn't get anything but cobalt. They'll hold an edge better than HSS before you've got to sharpen them. Low speed and pressure is you're friend along with some lubricant.

 

[lance]

Cobalt.

Real ones, not the cheap coated things.

/end thread

Are these good ones?

http://www.lowes.com/pd_71204-70-DW...=?Ntt=1%2F4+drill+bit&page=1&facetInfo=DEWALT

http://www.lowes.com/pd_71208-70-DW...=?Ntt=1%2F2+drill+bit&page=1&facetInfo=DEWALT