The APT Model 137 Rock Drill is a versatile midsize Rock Drill used in general construction, utility work, and plant maintenance. It is designed for drilling through granite, hard faced rock, quarry drilling and for drilling secondary holes for blasting. It can also be used in conjunction with dowel hole drilling machines. This Model 137 is adaptable to wet drilling application by attaching the APT valve, wet tube and swivel assembly.


Part # Units 5223 5224 5225 5226 5227 5228
Type in Dry Wet Dry Wet Dry Wet
Hex Chuck Size in 7/8" x 3 - 1/4" 7/8" x 4 - 1/4" 1" x 4 - 1/4"
Bore Diameter in 2 - 3/8"
Stroke in 2 - 5/8"
Blows per Minute bpm 2300
CFM @ 90 psi in 85 - 90
Weight lbs 38
Length in 19 - 3/4"
Air Inlet NPT   1/2 MALE NPT


  • 4 Drilling Speeds
  • Replaceable piston stem bearing
  • Available in wet or dry models
  • Counter clockwise rotation
  • Rubber handle grips

Air Pressure

The recommended air requirement for the operation of APT tools is 90 psi (6.2 bar). Lower air pressure will decrease power, too high a pressure will increase unwanted stresses in the tool. For proper CFM ratings, please refer to the specification charts shown for each tool in this catalog.

Hose Size

APT recommends the use of at least 1⁄2” inside diameter or larger hoses to assure sufficient air flow to the tool. For portable compressor hose and longer lengths, 3⁄4 “ hose is recommended. Keep the overall length of the hose to a minimum to prevent pressure loss at the tool.

Connecting Hoses

Hoses should be rated for a minimum of 250 psi (17.2 bar). Before connecting the air hose to the tool, check the tool inlet connector to be sure it is clean and free of dirt or debris. Keeping dirt and debris from entering the tool will assure long and satisfactory operation.