BOSCH CO21 21-Piece Assorted Set with Included Case Cobalt Metal Drill Bit with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, Light-Gauge Metal, Aluminum

Worked well for what I need you to do. Bites well

Great for hard metals, excellent product.

Good value for the money. I use these bits to drill mild steel and aluminum and haven’t noticed any major wear on them so far.

Got to replace some I broke in a kit of bits I have.

I haven't had a chance to really use these yet. I have a set of older bits I am trying to use up before breaking into these new bits. I have used it a couple times and I wasn't as impressed with the drill speed given other reviews and videos on them. I think they did just fine and better than most but not by a large or even meaningful difference. I haven't used it on a lot of material types, so it may be better suited for something I haven't tried yet.

excellent. very pleased.

Works great

I've only tested it a few times on some thick steel angle iron, and once on stainless, but it showed no sign of dulling. It drilled through it like butter, after my cheap harbor freight drill bit just sat on the surface making a hot divot instead of a hole. I used cutting fluid (WD-40 or water works if you don't have your tapping fluid around), and I always recommend cutting fluid as well as stopping to cool before there's any smoke or smell of hot metal/fluids. Getting a drill bit too hot is the best way to ruin it, besides using it as a pry tool. I drilled right through a stainless steel hose clamp, which my cheap titanium coated bits won't even make a dent in. The price is great, and the bit definitely cuts into hardened steel like a champ. I'll be using these for drilling easy out holes and whatever else I need. I haven't checked the dimensional accuracy, but it has no visible bend or wobble. I will say it walks around instead of starting where I want it to, unless I use a center punch. That is not a problem for me, because I normally do use a spring loaded center punch, but I have noticed some bits walk more than others. I would say this one walks a bit more than the cheap, soft ones, but once it starts biting it goes right through your steel. I'll be ordering some of these in the common sizes I drill for tapping holes (for me, that's 5/16", 1/4", 3/8", 4mm, 6mm, 8mm). I'm not sure this brand offers metric sizes, but I'm going to look. Disclaimer: I'm not a machinist, and no expert on drilling. I'm just a hobbyist that does a lot of customized repairs around the house, RV, Jeep, and motorcycle.

Watch the price going up and down . Tuesday was £39, Wednesday £29! Ive just used them and they are the tits. All the others I've tried were useless. Used with cutting oil to keep the heat down. I melted my other drill bit!

great

Excellent

The 5/64, 7/64 and 9/64 inch sizes are basic smaller drill bits. They are ones you are most likely to break in a bit set. So you will likely have to go shopping for replacements for broken bits in these sizes. I recommend the reasonably priced Dewalt DWA1205 and DWA1207 for the first two sizes and the Bosch CO2136 for the 9/64 inch. All are available from Amazon.

Produto excelente. Muita qualidade e durabilidade. Recomendo.