Woodworking Drill Bit Depth Stop Collars. It is recommended to use drill stop collars with a lubricant to prevent burning of the material surface. The collars work well on regular drill bits, but their outer diameter is often too small to work with a Forstner bit.
Woodworking Drill Bit Depth Stop Collars Non-marring set screws lock the collar at any point on the bit.
Also available in boxed sets with taper drill bits, stop collars and hex keys. Drill Limited ring, clamping device, positioner. Now clamp the jig to your workpiece to drill the hole. Split collars have several advantages over the standard grub screw type. Positively locks anywhere along the bit. They lock on solidly, they don't tilt, and there is no grub screw damage to the bit web. Size: Size Decimal Equivalent: Overall Lg.