these are horrible. The bit that they include s3u is a no.3 square undersized bit. It is not the proper bit. The box states that it recommended to change one bit per box. LOL yea ok. The bit last about three strips of screws and its shot. Because the bit is so small the screws wobble and go in at funny angles and almost never countersink before stripping the heads.
Try using the S3 bit that isn't undersized. Night and day difference. I was going to throw this kit in the trash until I tried the different bit. The tool has a WAY higher reliability rate of properly driven screws with this S3 bit. NOT the S3U bit.
Quik Drive CB3BLG114S 1-1/4" #10 Tile Underlayment Screws
- #10 x 1-1/4" flared head with nibs
- Use for HARDIBACKER backerboard
- For use with Quick Drive PROLDH or PROCGB tools only
- 1,500 screws per box
- Uses #3 bit
- Bugle head / QuikGuard coating
- Attaches fiber cement board to wood
- #3 Undersized square drive - BIT3SU
- Coarse threads
- Nibs under the head for easier countersinking
- Type 17 point
- .375" Ribbed wafer head
- C-3 coating, (a mechanical galvanization,) provides a protective zinc and tin coating over base metal to delay rusting straight collation
- 23 screws per strip
- These 1-1/4", #10 Tile Underlayment Screws from QuikDrive (CB3BLG114S) are for attaching fiber-cement board to-wood
- They have a .375" ribbed wafer head and require a #3 undersized square drive. They have C-3 coating, a mechanical galvanization which provides a protective zinc and tin coating over base metal to delay rusting.
- The coating is applied by mechanically tumbling zinc and tin powder with the base metal and non-metallic impact beads. (Results in less than .1% surface red rust at 1000 hours of ASTM B117 salt spray test.)
- These screws come in a straight collation and meet the requirements of ANSI 108.