Currently Festool's Domino series of mortising machines are each designed to work with their own size range of tenons. With the Domino DF 500 being designed for 4mm to 10mm tenons in smaller stock, and the Domino XL DF 700 designed for 8mm to 14mm tenons in larger stock.
Our 3/8" cutters for the Domino XL DF 700 allow cutting mortises to work with tenons 3/8" in size, up to 70mm deep.
To make these cutters, we start with genuine Festool DF700 cutters and have them precision ground and sharpened to 5mm using an 8 axis CNC cutter grinding machine. We have found them to be rather durable and cut well, however, It's important to note that care should always be used not to plunge the cutter into the work surface too quickly or damage to the cutter and/or workpiece can occur.
These 3/8" cutters with their extended 70mm cutting depth are perfect for through tenons. However, for cutting 4mm/5mm/6mm/8mm/10mm standard depth mortises with the Domino XL DF700, a more economical and versatile solution is our RTS-500 Domino Cutter Adapter.
A note on our cutter pricing: because of the specialized nature of our reground cutters, the volume we produce and sell is relatively low, and so we have these produced by an outside vendor as it's not practical for us to maintain the equipment required to manufacture them. Recently our costs to manufacture these increased exponentially, so we had to increase our price accordingly. We'll continue to look for an alternative supplier and hopefully be able to lower the price on these in the future.