I bought a Festool Domino XL recently. I've used it a few times and it's awesome. Of course, now that I have the XL for the large projects I have scheduled this winter, I'm thinking about how to use it for smaller projects.
I know I can buy this bit adapter: http://www.senecawoodworking.com/pro...-festool-df700
Which will, theoretically, allow me to use the original (smaller) festool tenons and bits: http://www.amazon.com/Festool-498899-Assorted-Cutters-Systainer/dp/B0073E5N8U
In other words, an additional $360 buys me the ability to cut original sized festool tenons. Not bad, considering an original festool domino is $900 + $285 in tenons and cutters.
However, after reading this page/chart: http://web.hypersurf.com/~charlie2/D...tiseWidth.html
It seems like the minimum width the original festool domino can make is 13mm + bit diameter. In the case of a 4mm bit, this would be a 17mm wide mortise.
How much shoulder width would I need to make a strong joint? Would I be able to cut a 17mm wide mortise in 21mm wide stock? Doesn't seem like a lot of shoulder material, but does it matter since the glue holds the tenon, not mechanical strength?
Finally, according to this page it looks like the Domino XL's smallest width setting is 13.5mm + bit diameter, so the smallest width it can make is 17.5mm wide mortises: http://www.manualslib.com/manual/511...00.html?page=8
That last bit of info seems like it wouldn't be a huge problem. You just wouldn't get snug reference tenons.