Biscuit Jointing with a router?

you can buy 4mm grooving cutters for a 1/4" collett with a bottom bearing. all you need to do is make sure the size of bearing to cutter diameter will give you sufficient depth for your biscuits.

 

I do.
I have an old B & D router with the groove cutter in it set at 20mm. 3 or 4 slots in each worktop. works a treat.
Mr K.

 

It's no good for intermediate shelves though.