Slot Cutter Arbor Setup: Stacking Cutters for Custom Grooves

Quick answer

To set up a slot cutter arbor, mount the arbor in your router, stack the desired cutter(s) and shims, then secure with the nut. Adjust depth by changing the bearing, and always test cuts in scrap.

Step-by-step arbor setup and stacking

1. Mount the arbor in the router: Insert the 1/4″ shank of the Whiteside A200B arbor into the router collet, ensuring at least 3/4″ of the shank is engaged. Tighten the collet nut firmly with the router unplugged. Check that the arbor spins freely by hand before applying power.
2. Select and stack cutters: Slide the desired cutter(s) onto the arbor, followed by any shims needed to achieve the total groove width. Ensure the cutters' rotation arrows (if marked) face the correct direction—typically clockwise when viewed from the top. Stack cutters with the same bore size (5/16″) and do not exceed the arbor's maximum stack height.
3. Install the bearing and secure the stack: Place the chosen bearing (B5 for 1/2″ depth, B20 for 9/16″, B25 for 3/8″) on the arbor, then thread on the retaining nut and tighten it snugly. Do not overtighten, as this can distort the bearing. Verify the stack is tight and the bearing spins freely without wobble.
4. Set the router speed: Adjust the router speed to match the cutter's recommended RPM. For the Whiteside 6715A, set the router to approximately 13,000 RPM. Never exceed the maximum RPM marked on the cutter or arbor. If your router lacks variable speed, use a speed control or choose a cutter rated for your router's fixed speed.
5. Test the setup in scrap material: Make a test cut in the same material and thickness as your workpiece. Measure the groove width and depth, and adjust the stack or bearing as needed. Check for smoothness and burn marks. A test cut reveals if the stack is tight, the depth is correct, and the feed direction is safe.
6. Cut the actual groove: With the router bit clear of the workpiece, start the router and let it reach full speed. Feed the router from left to right (for a hand-held router) or use a router table with the workpiece fed against the rotation. Maintain a steady pace to avoid burning. Always feed against the cutter's rotation and use push blocks for safety.

Product facts

• Slot Cutter Arbor x 1/4″ Shank – Whiteside A200B: Slotting Cutter Arbor 1/4′′ shank is designed for use with the 6700 series Slotting Cutters; includes B5 bearing for 1/2′′ depth of cut. This arbor is the foundation for stacking 6700-series cutters, and the included bearing sets a baseline depth that you can adjust with optional bearings.

  

• .312″ 5/16″ Slot Cutter – Whiteside 6715A: Cutter makes a small slot; requires arbor (sold separately); carbide tipped 3 wing; fractional kerf 5/16′′; recommended RPM 13,000. This 5/16″ kerf cutter is ideal for small grooves and can be combined with others to build custom widths, but you must pair it with a compatible arbor like the A200B.

  

• 5/32″ Biscuit Slot Cutter Router Bit – Whiteside 1908: Biscuit slot cutter router bit produces clean, consistent grooves for drawer bottoms, cabinet backs, and spline joinery; depth adjustable by changing bearing size. Use this bit when you need a dedicated biscuit slot without stacking, or as a reference for the groove quality you can achieve with a properly set up arbor and cutter stack.