1-1/4"-7 Male to SDS MAX Core Drill Adapter for Core Bits. Heat-treated steel with high strength for longer durability.

I used the Core Drill Adapter 1-1/4"-7 Male to SDS PLUS adapter with a Bosch Bulldog and 4.5" core bit to bore some holes in 4" concrete slabs, and even though I was VERY careful to not let the bit seize in the hole or apply sideways/angled torque on the bit, the SDS-end of the adapter bent.This bit is just a bad idea for use with larger (2"+) core bits for concrete boring because the diameter of the SDS adapter is just too small to give it enough strength to handle the torque of a larger core bit in this application.

This has held up to the forces I have applied to it. Almost got a 5 star. The one feature it is missing is having flats machined onto it for a chuck. They don't have to be super huge, just enough that the chuck has a flat surface to grip onto when tightening. That would completely eliminate any slip that may occur from running a large hone/bit on the end of it.

It seems like it’s made out of quality material etc, but when you have a coring bit that is 4”+ diameter, you need a lot of sustained torque to turn it. That kind of torque is going to bend almost any type of thinner metal when the bit binds. Happened to me after about an hour, shaft twisted and now isn’t worth anything. Should’ve rented the coring rig up front and saved the $40 buying this adapter.

Drilled multiple 4" holes through 3" cast stone without a problem. My Dewalt runs at 850 RPM and kept the bit/hole wet. No twisting, no issues at all. The adapter may last longer than my diamond core bit.

The unit was paired up with a 6" diameter core drill bit and an SDS Plus drill, used lots of water and a vacuum (made up a jig to trap the water) - it worked extremely well to drill 14 holes in 5"+ thick solid concrete floor. Went slow and it worked perfectly. Glad to have purchased this adapter.

The core drill adapter and core drill worked great. Drilled through 6 inches of hard concrete in no time. Beats going to the rental yard anytimeand a heck of a lot cheaper.I would highly recommend.GMC

Worked perfectly matching up a 4 1/2” core bit to my Dewalt SDS Plus hammer/drill. No bending issues drilling thru concrete block.

Adapter fit my 6 inch, 40 deep hole saw with no issues. I have made only one hole with it sofar, but no issues yet.

Nice adapter, any longer and you might get a bit more torque flex.

Worked as needed with my dewalt sds and a 7/8 Milwaukee core bit

over Price