I think Mike has hit the nail on the head here. Unlike a pen, a knife only works in one direction. The "pen" of a cutting plotter MUST swivel for it to work - and giving it some degree of caster to swivel itself loses accuracy really fast. I like the idea of a router in the pen part of a plotter - but it's a lot of mass for the pen carriage to move around! Philip. ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept for the presence of computer viruses. Power Technology Centre, Ratcliffe-on-Soar, Nottingham, NG11 0EE, UK Tel: +44 (0)115 936 2000 http://www.powertech.co.uk **********************************************************************