Tapered reaming bits from Crowder Supply enlarge pilot holes to a finished diameter of 2-1/4, 2-1/2, 3 or 3-1/2 in., each ground with a 6 degree taper that seats in a bit shell rather than threading onto the rod directly. That shell mounting lets one string of extension rods swap between drilling and reaming duty in mining, quarrying and construction work.

Reaming keeps the enlarged hole on the pilots centerline instead of collaring a fresh, larger hole from scratch, and Crowder Supply stocks the 2-1/4 through 3-1/2 reamer bit sizes at the same 6 degree taper angle. For one-pass reaming on a threaded connection, the threaded reaming button bit covers 2-1/2 to 8 in. faces, and the rock drill bit buyers guide sorts out which rock drill bits belong at each stage of the hole.

• Finished reaming diameters: 2-1/4, 2-1/2, 3 and 3-1/2 in.
• 6 degree taper on every diameter seats in a standard bit shell, sold separately
• Reams existing pilot holes to final diameter in rock drilling applications
• Shell mounting lets one drill string alternate between drilling and reaming
• Stocked by Crowder Supply in Denver in all four diameters

Tapered Reaming Bit FAQ

Do I need a bit shell to run these bits?
Yes. Every diameter is ground with the same 6 degree taper that seats in a standard bit shell, sold separately the bit does not thread onto the rod directly.

What diameters can I ream to?
Four finished diameters: 2-1/4, 2-1/2, 3 and 3-1/2 in., each enlarging an existing pilot hole on its original centerline.

Tapered reaming bit or threaded reaming button bit?
Shell-mounted tapered bits let one rod string swap between drilling and reaming; a threaded reaming button bit runs one-pass reaming on a threaded connection and covers larger faces. Our article on choosing drill steel and rock drill bits sorts out the system question.