GrovTec US Mach inche Screw 7/8 inch Bulk Nickel 0. If you're making your own gun sling and need a little more security the look of stock elevator machine screws might be for you. They have almost the same look and function of stock elevator machine screws. Don't worry about using the wrong machine screw. All screws are clearly marked on the packaging. Specifications for GrovTec US Machine Screw: Manufacturer: GrovTec US Color: Nickel Length: 7/8 in Additional Features: Bulk Package Contents: GrovTec US Machine Screw GrovTec US 062387: Mach inche Screw 7/8 inch Bulk Nickel