C.N.C. Workholding

A spoilboard is a sacrificial flat surface attached to the CNC router bed that accepts T-nuts and clamp hardware without damaging the machine table. Proper workholding on the spoilboard ensures the workpiece cannot shift, rotate, or lift during machining, which is essential for dimensional accuracy and operator safety.

A cam clamp uses an eccentric cam to apply clamping force with a single rotation of a handle, allowing very fast workpiece loading and unloading. A step clamp uses a bolt and a stepped block to generate clamping force, which is more secure for heavy cutting but slower to operate. Cam clamps are popular for production CNC work where cycle time matters.

CNC router bits follow programmed toolpaths that pass very close to the workpiece perimeter. A tall clamp body positioned in or near that path will be struck by the router bit, damaging the tool, the clamp, the workpiece, and potentially the machine. Low-profile clamps stay below the cutting plane so the bit can pass without contact.

Yes. Bench dogs inserted into spoilboard dog holes provide positive lateral registration against the workpiece edge, preventing sideways movement during cutting. They work best when combined with clamps that apply downward holding force, giving full three-axis restraint to the workpiece.

Standard T-track profiles for CNC spoilboards typically accept 1/4-20 or M6 hardware. The 149-piece hardware kit and similar kits include fasteners in the most common sizes. Verify your spoilboard's T-track profile before purchasing hardware to ensure compatibility.

Vacuum workholding is excellent for flat, non-porous sheet goods and provides a clutter-free spoilboard surface. However, it requires a vacuum pump and a properly sealed spoilboard, and it is less effective for porous or small workpieces. Mechanical clamps and dogs are more versatile for varied stock sizes and materials.

Mill the spoilboard flat (skim cut) with the CNC router to ensure it is coplanar with the machine's X-Y plane. Install T-tracks or drill a grid of dog holes at consistent spacing. Then install T-nuts for clamp hardware. Resurface the spoilboard periodically as clamp impressions and toolpath scars accumulate.

The hardware kits, bench dogs, and cam clamps work with any CNC router that has a T-track or dog-hole spoilboard. They are not machine-specific and can be used with ShopBot, Avid, Laguna, Axiom, and other popular CNC brands as long as your spoilboard is set up to accept the appropriate hardware.

Visit the Infinity Tools blog for CNC setup articles and technique guides that cover spoilboard preparation, workholding strategies, and bit selection for common CNC operations.

Our team is happy to help you choose the right workholding solution. Contact us with details about your CNC router model and the types of materials and workpieces you run, and we'll point you toward the best option.