Hi Everyone,
I have a few festool slot cutters and have so far only used them individually. I think it is possible to combine cutters to increase the size of the slot. Has anybody done this before? Specifically, I would like to mount a 4mm and a 3mm slot cutter to a single arbor to produce a 7mm slot to house a 6mm panel. Sjould I just mount the cutters and offset the carbide or do I need a spacer?

JF

@ferrij
I have never seen Festool branded slot cutters. Where did you get them?
I normally use Whiteside slot cutters and arbors. The one thing that you have to be careful about is the material you are cutting. Sheet goods and softer hardwoods are ok, but you need to be careful with harder wood or anything that might have knots in it. (Spruce, Pine, etc)
Cutting smoothly then hitting a hard knot can possibly slip the cutters. A single on the arbor is not that big of a deal, but two might bash the carbide into the steel backing of the other one.
This is potentially dangerous and may spoil the cut.
Not saying don't do it, just be aware of what's going on. If you can do this on a router-table with a fence, the bit is more surrounded, safer.

Thanks for the excellent responses. The wood I will be using is milled from  silver fir supposedly from the black forest. It is pretty clear but there are some difficult spots so thanks for the cautionary remarks. This will be done on a router table. The bits were purchased a long time ago when festo/festool sold a wider range of bits in the US, between 2001-2005 or so. Thanks guys. JF