Serious drill bit purchase help!

[GunsOfNavarone]

Yeah, I went with the Norseman 115 pc Colbalt set. Maybe other will pick up that sale, seems like a killer deal!
Thanks!

 

[GunsOfNavarone]

So, here it is a month later... I used a 1/8" bit for a project for someone here, on aluminum. I used a 4mm on stainless for a job for work. Today I was drilling a size V (YES! The ones I never thought I'd use came in super handy!) 18mm deep through aluminum and about 1/2 through...CRACK...clunk, clunk, clunk.... I was pecking and clearing strings out the whole time- WD40 as lube. It actually snapped off the leading flutes! WTH?! All this research, not a super cheap set and ALUMINUM?? They are sending me a replacement, nice, but why did this happen?
I know aluminum gets gummy, but I really couldn't have been more careful. Flooding with coolant is great, but it's a drill bit set, not end mills. The Aluminum wasn't even warm. Help me out here guys...any ideas what I did that cause the fatal failure?

 

[jwmelvin]

I was drilling a piece of steel this weekend with my Norseman cobalt 135° (5/16” diameter) and chipped both cutting edges immediately upon entry. Wasn’t going fast (~80 SFM) but there was some mill scale on the bar. I figured it the mill scale was a bigger deal than I thought and resharpened the bit myself (losing the split point). I was disappointed in my fancy drill but though. Maybe I should call them; do I go through the company I bought them from?

 

[extropic]

So, here it is a month later... I used a 1/8" bit for a project for someone here, on aluminum. I used a 4mm on stainless for a job for work. Today I was drilling a size V (YES! The ones I never thought I'd use came in super handy!) 18mm deep through aluminum and about 1/2 through...CRACK...clunk, clunk, clunk.... I was pecking and clearing strings out the whole time- WD40 as lube. It actually snapped off the leading flutes! WTH?! All this research, not a super cheap set and ALUMINUM?? They are sending me a replacement, nice, but why did this happen?
I know aluminum gets gummy, but I really couldn't have been more careful. Flooding with coolant is great, but it's a drill bit set, not end mills. The Aluminum wasn't even warm. Help me out here guys...any ideas what I did that cause the fatal failure?

You say "about 1/2 through" so not a matter of binding at break through.
If your feed wasn't excessive, I suggest you write it off to a fluke.

 

[mikey]

I was drilling a piece of steel this weekend with my Norseman cobalt 135° (5/16” diameter) and chipped both cutting edges immediately upon entry. Wasn’t going fast (~80 SFM) but there was some mill scale on the bar. I figured it the mill scale was a bigger deal than I thought and resharpened the bit myself (losing the split point). I was disappointed in my fancy drill but though. Maybe I should call them; do I go through the company I bought them from?

Did you happen to spot drill first? If so, this should not have happened.

I would contact Norseman and ask to have the drill replaced. A cobalt drill in that size is not cheap.

 

[GunsOfNavarone]

I was drilling a piece of steel this weekend with my Norseman cobalt 135° (5/16” diameter) and chipped both cutting edges immediately upon entry. Wasn’t going fast (~80 SFM) but there was some mill scale on the bar. I figured it the mill scale was a bigger deal than I thought and resharpened the bit myself (losing the split point). I was disappointed in my fancy drill but though. Maybe I should call them; do I go through the company I bought them from?

Concerning.....
I purchased from Amazon...wrote them a note there and they are sending a new one. Probably who you bought them trough 1st, if no luck, go direct?

 

[GunsOfNavarone]

Did you happen to spot drill first? If so, this should not have happened.

I would contact Norseman and ask to have the drill replaced. A cobalt drill in that size is not cheap.

The 2nd time I did spot drill (and used a Dewalt bit!), but to be honest, brand new 135* split point and cobalt on aluminum...didn't think it was necessary. 9mm deep at that point...I was about 170 rpm. Yeah, these aren't kryptonite...Next time I'm gonna swaddle the bit first and sing it "Hush Little Baby".

 

[mikey]

Never had a drill bit 'splode on me before. Not sure what happened but I suspect you just had a defective bit.

 

[jwmelvin]

Did you happen to spot drill first? If so, this should not have happened.

I would contact Norseman and ask to have the drill replaced. A cobalt drill in that size is not cheap.

I did not spot drill because I didn’t care much about the location and the bit had a split point, which I understood to minimize walking.

I’ll reach out to my vendor.

Edit: I looked back and they are M7, not cobalt.

 

[mikey]

I did not spot drill because I didn’t care much about the location and the bit had a split point, which I understood to minimize walking.

I’ll reach out to my vendor.

Edit: I looked back and they are M7, not cobalt.

Still, that should not have happened.