amoolo 3/8" Cobalt Drill Bit(5Pcs), M35 HSS Metal Drill Bit Set for Hard Metal, Stainless Steel, Cast Iron

Bits work great and at a great price

So far, these seem to be well made, straight and sharp. They drill aluminum cleanly but I haven't used them on steel yet. So far, so good.

I found these drills to be outstanding in low carbon steel - easily out performing the brand purchased from my local “home improvement “ store. I am knowledgeable about cutting tool design - and given my high level of satisfaction I thought I should offer some details to support my 5 star review. 1 first use : the drills were stable in cut and made accurate sized holes and required minimum feed force 2. Close review: these drills have well manufactured tip grinds. I have found many drills have poor relief grinds ( behind cutting edge) or poor lip to lip run-out - both of which cause instability and poor chip morphology when in cut. Easily identified under magnification but can be simply observed with significant heat generated in cut to the workpiece. ( a properly made drill applied with correct feeds and speeds will impart more heat to the chips produced) The flutes are also polished. This allows the chips to easily flow out from behind the cutting edge. I highly recommend.

After researching drill bits that will cut hard steel, I found this set to be the only reasonably priced one on the internet, and ordered it accordingly. Very prompt service, nicely packaged (Prime), and just the sizes I needed. Have a small number of rivets to drill out of a steel frame, 8 to be exact. Using progressive drilling method (small pilot, gradually increase to full size), drills worked well, did the job. But failed after 5 rivets were drilled out; dulled, would no longer cut. Don't know what to do now. Order another set? I'll start shopping again, both internet and local industrial tool suppliers to see what I can find. No issues with the vendor, just the product.

Great drill bits at a good price! I have gotten a lot of "mileage" out of each bit before dulling. Very satisfied with this brand.

I tried 5 different Cobalt bits. Ordered from 3 different companies. They weren't sharp. Sent them back. Took a chance and ordered from a 4th company with good reviews for sharpness. A gain the bits were not sharp. Dent them back. Thought I would give it one more fifth try from this company. HURRAH !! Opened the package , took a bit out and tried it. IT DRILLED THE HOLE IN MILD STEEL ALMOST LIKE BUTTER. THEN DRILLED 2 MORE HOLES WITH THE SAME BIT. NO PROBLEMS DRILLED THEM EASILY. WOULD DEFINATELY RECOMEND THESE BITS. ARRIVED IN ONE DAY. VERY SATISFIED.

Shipped quickly and they work fine.

I haven't used them yet but they are as described. I plan to drill a hole in a bolt to extract it.

I bought these drill bits in 1/8 1/4 and 6.5mm for drilling out stainless steel rivets. They worked very well. Drill at slow speed for best results on SS. The 1/8 size, extra care is needed as they are small and break if to much pressure is used Never broke any of the larger sizes

This doesn't work as expected. Too high price

Excelente brocas para metal duro y diferentes tamaños para el uso de trabajo.

Très bonne mèches pour percer le stainless. Très bon prix pour la qualité.

Can't say much about these bits, I expected to blast through the pack as I had at least 400 holes to drill but I only needed just one bit.