ZELCAN Hole Saw Kit, 4pc Drill Hole Cutter Set with 30 50 65mm Hole Drill Bits for SDS Plus Hammer Drills, Circle Drill Bits Hole Saw Set for Concrete Brick Cement Stone Wall Drilling Home Improvement

I am IMPRESSED! I had to drill through 12 inch cinderblock from 75+ years ago and was extremely tough. The cinder block back then wasn't like the stuff you find today that is easy to drill through in comparison. This stuff was thick walled, had large chunks of actual rock aggregate, and was a tough challenge.The 65mm bit went through it with ease with a Bosch drill. I didn't need to use the hammer setting it did such a good job. Super clean hole right through the block on both sides.I did a separate drilling job on a poured foundation and used an $85 wet/dry diamond bit and that was much harder to do. My guess is this bit would have done the job better than that bit.TIP: Many people talk about losing the pilot bit set screw. I wrapped a little bit of plumbers tape around it and it did not fall out at all and was still just as tight when I installed it, and removed easily after the job was done.The downside? The bit gets stuck onto the shaft. I didn't have an o-ring so I wrapped some plumbers tape around the shaft hoping it would allow me to remove the bit after drilling slightly easier, but it has proved to not help and I still haven't gotten the bit off the shaft. I tried in a bench vice and pipe wrench quickly, but the shaft is perfectly round so it just spun. I'll get back to trying again.At this point, I'm stuck with the shaft and 65mm bit, and have no way to get it off the shaft and can't use the other 2 bits. If I find the time and get the bit off the shaft I'll come back and update this review and share how I got it off.

I bought this set to bore a couple holes thru my brick& concrete wall on my house. I had to run a gas line and a water line for my BBQ and my irrigation hose bib. The hole saw worked perfectly. a COUPLE THINGS TO NOTE ABOUT THE PRODUCT>>>>> (1) I was impressed with the packaging. the drills were individually packaged in their respective plastic holders. The kit comes with three masonry hole saws, mandrill, pilot bit (I'm not sure way another reviewer said there was none?) and an Allen wrench to set the pilot bit in the mandrill. There is a flat keyway that the set screw needs to set in the keep the pilot bit tight. (I'm also not sure where the other reviewers said the pilot bit loosened up?) (2) Prior to boring my holes, I put a little bit of white grease on the threaded end of the mandrill and then tightened the hole saw bit to the mandrill. I had no problem removing the hole saw after I was done. I only need to use my channel locks to get the hole saw off the mandrill. (3) IMPORTANT!!!! This drill set is not for use with a standard 3 jaw drill chuck. It is intended for use with a SDS rotary hammer set up. If you attempt to use any of these bits with a standard three jaw chuck, it will wobble and the drill will not stay centered. Buy or rent a smaller rotary hammer to use with these bits.

These are surprisingly good for the price. I live in Mexico and concrete is king here. Pushing them with a Bosch Bulldog hammer drill they are efficient. I did lose a tooth from one after hitting rebar (repeatedly for a while, should have stopped) which they are not made for although they do eat solid concrete cleanly. The set screws don't stay in long so the pilot bit eventually falls out but once the hole is started and the cutter registers in the hole you dont need the pilot. After a job the mandrel can be a bit hard to remove from the cutter as the threads have been hammered on. When I wear them out I will buy more (and avoid rebar). Wear ear and eye protection and rest occasionally to avoid overheating your drill. I rig a vacuum hose next to the cut to minimize dust and clean-up.

I used this to core a hole through a brick wall to install a mini-split air conditioner. The cutter went through Sheetrock, OSB and brick with ease. I did have to clear the brick trash from the hole saw, but that's to be expected, as the bricks are wider than the saw depth. Several reviews stated that the set screw came loose during use. Mine did not come loose while I was using it, but the pilot bit did fall out while I was putting it away. Please follow the suggestions to use some thread locker on that. Also, please note that the pilot bit has a flat spot machined into it for the set screw to press against. If you aren't putting the set screw against that flat spot I'd assume you are going to have problems.Highly recommended and would buy again.

Overall I been very happy with the kit. It is a great value compared to the big box store’s options. I found the items to be well made and work as intended. Some helpful watch outs / suggestions: Add some never-seize paste on the shaft threads, as removing the hole saws can be tough after long drilling. Another, is to add lock-tight to the set-screw as it tends to loosen or fall out. In a pinch, I wrapped electrical tape around the shaft covering the set-screw and then put a slice in the tape at the screw. This way I didn’t lose the screw and I can re-tighten it through the slit. Finally I would like to thank ZELCAN for their great customer service with an issue I had with one of the hole-saws. They were very quick to respond and resolve it. More importantly they stand behind their products! Finally, I am so impressed with this kit that I bought one for my son to have for his jobs.

It drilled a great 30mm hole, but not without Threadlocker.The drill bit set screw came loose immediately, a total of three times. Rummaging around found some Red Threadlocker (Blue probably would have worked as well). Liberally applied to the set screw and we were ready...sorta.Unfortunately, Threadlocker takes 24hrs to setup. However, you can bake it in the oven at 200F for an hour and get the same result.One hour later, a few minutes of drilling, a perfect 30mm hole.The downside is, you have to heat the assembly to 500F to breakdown the Threadlocker and remove the set screw.Still giving it 5 stars, even with the extra prep work.