I used this tool again to remove more HMS Victory CNC cut parts from their sprues. I noticed that the blade guide pulley could be improved on, it had too much axial movement (too narrow for it's slot) & the blade groove was too wide - a 0.4 mm wide blade in a 1 mm groove - no doubt, this causes it not to follow cut marks as noted from other users. I machined a new one from brass, cutting a 'V' groove to guide the blade, & making it wider. Now the tool is much better to use. I've now got some coarser blades.
Stuart
Stuart