CSP flush-trim router cutter

Review and photo: Neil Erasmus

Around the teaching circuit, I have noted a constant search for a router-table mounted flush-trim cutter that performs as well, or nearly as well, as a spindle moulder cutterblock. Many makers regard machines such as the spindle moulder with great apprehension, sometimes bordering on terror.

CSP Tooling recently developed their new 12.7mm shank, 30mm diameter bit which has 10 four-sided carbide insert blades arranged in a spiral pattern. Together, these add up to a cutting height of 55mm. While this arrangement doesn’t give a true shear cut, I wonder how much better that would be anyway. Bearings at each end means that shaping templates can be placed above or below the workpiece. At 30mm in diameter, these bearings are more robust than smaller versions.

I hoped to use this cutter in my router table with one of my spindle shaping jigs (jig down, workpiece above). This is a long, heavy cutter, so care has to be taken to ensure it runs true and without vibration. To this end, I cleaned the router collet and its housing, then tightened the shank as low as possible (within 1–2mm of bottoming out), and wound the variable speed control to its lowest, before turning on and re- adjusting it to a comfortable speed. Excess noise and vibration should be cause for alarm.

I was rather surprised this cutter ran at a happy 16,000rpm, indicating it is well-machined and balanced. This speed is still only around half of what a spindle can do, so the cutting quality is not likely to be as good. I was, however, pleasantly surprised.
This beautifully manufactured tool cuts through Tas blackwood with almost as much ease as a spindle cutter would. Obviously, feed rates must drop by comparison, but the cutter performed with little protest, even on endgrain.

Used properly with due care for safety, I regard this excellent cutter as a game changer for some. I would recommend this cutter be used only in a table router, and not by hand.

Available from www.csptooling.com

Neil Erasmus is a furniture designer maker based in Perth. See Instagram @neilerasmus