Alex, if you take the male adaptor of the linac motor, what is the diamater of the motor shaft?

The link shown shows the motor shaft from the dewalt being 5mm. If the motor from the linac is also 5mm it might not be a big problem to change. if its smaller you will need to machine a bush, if its bigger- drill out the adaptor from the linac. then id suggest grub screwing the adaptor back onto the dewalt. (you might want to file a flat on the dewalt motor shaft for the grubscrew to sit on)