LudoPam Cobalt Metric Drill Bit Set(1mm-13mm/25pcs), M35 Jobber Length Twist Drill Bits,Straight Shank for for Hardened Metal, Stainless Steel, Cast Iron and Wood Plastic with Indexed Storage Case

Good drill bits

I have to remove about a thousand screws from my deck. The screws are about 25 years old and are in pretty sad shape. Only about 30% of them were coming out with just a driver bit. The drive hole of the rest are stripped and are needing additional effort to extract them. While attempting this with this bit, some of the screws were driven further into the wood when the bit caught a bite in the head. That's not the direction I wanted them to go. I wound up buying a left handed bit. I believe the screws have a #2 square drive hole. An 1/8" bit tends to grab the sides of the drive hole. That usually causes the drill bit to break. Even if it's made of Cobalt. So, I'm using a 7/64 and I'm attempting to shave just a few microns of metal from the bottom of the drive hole. That's enough to give the drive bit more of the shoulders to grab onto but not enough to cause the screw head to pop off. The first 100 or so screws, that I tried extracting with this drill bit, went very well. I had to apply very little pressure to the drill to remove the thin layer of steal from the drive hole. Some time around screw 100, I started having to apply additional pressure. By inspection, I could see that that cutting edges had become dull. Having said that... it's hard to tell what caused them to become dull. There was a lot of grit and debris in the drive holes. Anyone who knows anything about cutting edges will tell you that sand and grit... while they seem soft at a macro level, they are boulders in the micro arena and nothing will dull an edge faster than a little sand and grit. In hindsight, I probably should have taken care and cleaned out the drive holes before attempting to drill them out. Considering everything, this drill bit held up very well although I will probably buy more left handed bits to finish the project.

We needed this to replace the wood on our trailer deck. We were amazed at how easily they cut through the metal by just dipping bit into cutting oil. We have used drills from THD before when doing the same type project. Even with cutting oil it was a tough job to get through the metal. We used a total of two bits…. Probably could have done the entire job with one… but we had plenty so why not change them! Will never by bits from a big box store again!!

Drilled hole in 1/2" stainless steel bolt for a cotter pin. Cut nicely if maintain slow speed, generating nice long spirals of waste material without overheating. However, bits are slightly larger than labeled size of 7/64". Should be .109" , micrometer puts these at .116" or .007" oversize. Probably metric. Noticed when put in drill bit case that they fit tighter, so checked.

Highly recommend, I was burning up HSS bits trying to drill through SS so I could tap it for 2-56 screws, and after wasting other drill bits I decided to try these. It stayed sharp and drilled through material that 10 other drill bits couldn’t. Extremely good value, the cobalt really works!!!

First of all, that is not as it looks in the picture! Was very disappointed as it was for a a present for a friend who has all their tools, black and red. Ease of use is poor very hard to open the box. Quality seems cheap. Drill accuracy is not good. Especially for the amount you pay. Expect these to be spot on.

So umm these are like decent? I bought a 10 pack of 5/64in expecting to kill one per hole in concrete. Since they weren't designed for it and a Titanium one didn't even make a full hole. Also I was using hammer mode. I only used 2 bits the first one managed 3.5 holes! Replacing the one I originally killed ive still got 7 left. I plan on buying these when I need replacements going forward. Highly recommended!

I needed to make a 23/64-inch hole in a sheet of stainless steel. The closest size that I could find was 3/8-inch which is 24/64-inch or 1/64-inch too large. These drill bits came in the 23/64-inch size that I needed and the price was most reasonable.