AutoLock™ drivers hold onto the head of a screw mechanically using ball bearings which lock under the head of the screw. We currently make drivers for standard Hex-Washer-Head screws (Drive Hex + Flange). This means they are compatible with all standard self drilling tek-screws, typical pole-barn roofing/siding screws and more. Please reference the table below for specific dimensions:

Driver	Max Diameter Screw Flange	Common Screw	Largest Tool Diameter
1/4" Hex Std	3/8"	#8 tek, steel roofing screws	7/8"
5/16" Hex Std	7/16"	#10 and #12 tek screws	1"
3/8" Hex Std	17/32"	#14 (1/4") tek screws	1-1/8"

 

Floating Neo-Bonded Washers

These will not interfere with tool operation as long as there is a 1/4" or greater gap between the washer and bottom of the screw head. Since AutoLock™ drivers lock around the screw head, that gap is required for the ball bearings to lock onto the forged head of the screw.  

There are manufacturers that make screws with larger heads, and we see this most commonly for self-drilling roofing/siding screws with a rubber o-ring type screw. 

Stainless Steel

One of the beautiful things about the Autolock Driver is holds screws mechanically, so the material the screw is made out of does not matter. This is especially important when driving 300 series stainless screws for high corrosion applications. If you've ever worked with these screws, you're probably very familiar with two things: these screws are very pricey and a magnet doesn't hold them whatsoever. This is a great application for the Autolock Drivers! 

*A quick note: 400 series stainless steel screws are somewhat magnetic. They can be hardened and are far less expensive than 300 series stainless screws but offer lower corrosion protection. 

A note on screw holding variations

Due to manufacturing variations among screw producers, there will be a varying amount of wiggle with screws when held in the driver. Applying force directly in-line with the screw will generally align the screw to the tool. Care should be taken to not apply force so as to cause or maintain misalignment between the screw and the AutoLock™ driver.