Furry edges when cutting mortises with router
Hi. I'm using a router, in a router table, running a 6mm square bit to cut some shallow mortises. The problem I'm getting is that the edges of the mortise are furry - in other words little whiskers of grain remain affixed, rather then getting a clean cut across the grain. These whiskers are surprisingly time-consuming and damaging to remove by hand.
I'm using an older Makita single speed (22000 rpm) router. If speed is the problem, I could modify the router table to take a variable speed router, but its a lot of work so I'd like to be sure it is the most likely problem first.
I"ve tried two 6mm bits, both midling quality but both new. I'm doubting that the quality of the bits is an issue as both are new, so even if poor quality they should cut cleanly for a short while (shouldnt they ??).
Other info - timber is cedar, blackwood and some other unid timber. Mortise is 1.5mm deep.
Any advice.
cheers and thanks
Arron