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R4™ Multi Purpose Screw
R4™ Multi Purpose Screw
-- patented --
Some sizes available in PHEINOX™ Stainless Steel
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GRK’s R4™ self-countersinking screw has a new under head with saw-blade like cutting teeth and six self-contained cutting pockets. Together these features act like a circular saw blade, transporting the "drill dust" away from the edge of the screw hole while cutting a perfectly clean hole into even the most brittle materials without cracking any surface treatment.
This design further enhances the R4™’s versatility by allowing the fastener to be installed without countersinking into even the hardest woods. The screw head closes the hole off with precision, leaving no damaged fibers around the head.
R4™ screws which are 2" and longer have a four threaded CEE thread that enlarges the screw hole for the non-threaded portion of the fastener. This technological advancement allows the wood to settle easily and increases the screw’s drawing strength, reducing the friction on the screw shank and lowering the driving torque.
The R4™ is a multi-purpose screw that can be used in all woodworking and plastic applications. Because the head has a 90 degree angle at the underside, the screw fits perfectly into the pre-countersunk holes of hardware fittings such as hinges or locks. Stocking of different screws is no longer necessary because the R4™ is a very versatile screw.
Multi-use
Wood
Particle Board
Plastic
Sheet Metal
Cement Fiber Board
Composite Decking
Wood Decking
Melamine
1.New cutting teeth
under the screw head act like a saw blade to cut a perfectly clean hole into even the most brittle materials
without cracking any surface treatment.
2.The 6 self countersinking cutting pockets act like a circular saw blade.
3.The top of the screw head closes the hole exactly leaving no damaged fibers around the wider area of the head.
4.The self countersinking cutting pockets transport the "drill dust" away from the edge of the screw hole. They also widen the countersunk hole only around the head shape.
The head has a 90 degree angle at the underside which allows it to fit perfectly into the pre-countersunk holes of hardware fittings such as hinges or locks.
R4™ Multi Purpose Screw Test Data
| R4™ Shear Test Results | ||||||
| Diameter | Avg. Ultimate Load (lbf) | Wood Failure Rate | ||||
| #4 | 139 | 50% | ||||
| #6 | 301 | 70% | ||||
| #8 | 361 | 30% | ||||
| #9 | 452 | 65% | ||||
| #10 | 687 | 75% | ||||
| #12 | 720 | 75% | ||||
- Test ASTM D 1761 Lateral Resistance/Slip, Wood to Wood connection.
- Testing stopped when screw displaced 1/8" or upon wood failure. Wood failed in majority of tests prior to screw failure. Test conducted in wood with specific gravity 0.42.
- Please note, the above stated values are ultimate loads. For construction design purposes an applicable safety margin should be applied. An architect or engineer should be consulted for this.
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