HYMNORQMetric Titanium Coated HSS Spiral Groove Step Drill Bit Set of 3pcs 4-12/4-20/4-32mm with 1/4" Hex Shank Packed in Reusable Case for Cutting Holes in Iron Plate Aluminum Plate, etc.

I randomly chose these since I wasn't going to shell out money for a known good brand for a small project. I used the largest of the the bits to create holes in a 55 gallon steel drum. Worked perfectly. I only needed 8 holes for the project, so I wasn't expecting much wear on the bit. Looking with a magnifying glass showed a near mint bit. I was impressed for the price and being unfamiliar with the brand. 11/10. Will look for this manufacturer for future project bits.

I'm a commercial glazier and drill holes into metal quite often. I don't use step bits often but when I do it's almost always into aluminum and most likely 1/4"-3/8" thick. I find this to size up holes for fasteners much faster than your typical proper way of upsizing metal holes with typical drill bits.This is definitely overkill as I do not need a cobalt m35 bit for aluminum but its holding up really well after over 200 holes. It's staying sharp. If you're consistently drilling holes non stop then I recommend you find yourself a way to keep this step bit or any bit cool if you're drilling aluminum. When it gets hot the shavings will stick onto the drilling edges.

Never knew how much I would use them till they arrived.

These step bits are ok for a housewife or an amateur working on tiny projects around the house. These are not for pros. Bought these and immediately dulled after second use. They are useless now!! Giving it one star because they are cute though!!!!!

Stem twisted inside the chuck of my brand new dewalt impact and snapped right off while I was using on light gauge angle iron. Insane $150 in the garbage.

I really needed these bits to get through ten holes in steel drums. I was hopeful since another reviewer said that's what he needed. I got three holes out of the two larger sizes, even using a lubricant. I will have to buy other bits just to finish the job.

Great tool, the steps make it easy to drill large holes.Used it to drill 7mm holes in alloy bike frame for 5mm nut rivets. Compact size along with a angle drill adapter helps get into tight bike frame spots.

Wow. These little guys look awesome. I've used one of them and as most unibits work they take a good amount of force to get them started but once this one git cutting it was like baatahh. They come in a great little case too. I didn't put any stars in the longevity option cause I just got them