When you need a clean 3-1/2-inch hole through soft brick or concrete block and do not want to set up a water feed, the MK Diamond MK Standard dry core bit (part 155944) is built for the job. It chucks into most hand-held drills, so HVAC installers, plumbers and general contractors can core a round, accurate opening on the wall instead of chipping out a rough one with a masonry bit and hammer.
Built for
- Coring dryer vents, bath and kitchen exhaust ducts, drain and vent lines and other large service penetrations in soft brick and concrete block.
- Remodel and retrofit work where running a wet coring rig and managing slurry is not practical.
- Punch-list and service calls where one portable drill and one bit have to get the hole done fast.
- Repeat penetrations on a job, where a laser-welded segment and slotted barrel help keep the bit cutting.
Why it works dry
MK builds this bit with laser-welded segments and bar-slot cooling. The slots let air move through the barrel to carry away heat and help clear dust, which is what makes dry coring in soft masonry practical. Segment height is 7.5mm, drilling depth is 9-1/4 inches on a 10-inch overall length, and the bit threads on with a standard 5/8-inch to 11 nut, the same connection used on common core drills and adapters.
Match the drill to the bit. MK lists a minimum of 10 amps for this size and a maximum speed of 5000 RPM, with a minimum of 700 RPM. Let the diamond do the cutting with steady, moderate pressure rather than forcing it, and pull the bit out periodically to let it breathe and clear dust.
Specifications
- MK Diamond part number: 155944
- Series: MK Standard dry masonry core bit
- Diameter: 3-1/2 inch (83mm)
- Overall length: 10 inches
- Drilling depth: 9-1/4 inches
- Segment height: 7.5mm
- Connection: 5/8-inch to 11 threaded nut
- Minimum drill amperage: 10 amps
- Maximum / minimum RPM: 5000 / 700
- Recommended material: soft brick and concrete block
Frequently asked questions
What materials is this bit made for?
MK lists the MK Standard dry core bit for soft brick and concrete block. It is not a general-purpose bit for hard or reinforced concrete.
Do I need water to use it?
No. This is a dry masonry core bit, designed with bar-slot cooling so it can cut without a water feed.
What thread does it use?
It uses a standard 5/8-inch to 11 threaded nut and attaches to most hand-held drills.
How deep can it drill?
The drilling depth is 9-1/4 inches on a 10-inch overall length.
What drill do I need?
MK specifies at least 10 amps for the 3-1/2-inch size and a maximum speed of 5000 RPM. Check your drill against those numbers before you start.
Discount Cleaning Products is an authorized MK Diamond dealer with US-based customer service, so you can confirm size and fit with a real person before you order.
