M12 Threaded arbor system These arbors and threaded bore cutters ( Trend refs . 33 / 10 & 33 / 20 ) are designed for flush recessing to produce capillary slots and weather seal grooves when making door and window frames . The cutter is used with a suitable diameter guide bush after the frame has been rebated .
Guide bearings
Guide bearings are used to set the depth of the cut and to guide the cutter against the edge of the workpiece . Changing a bearing for one of a different diameter will change the depth of cut , the smaller the bearing diameter the deeper the cut . When fitting bearings always check that shims or spacers are fitted correctly to provide clearance between the outer rim of the bearing and the adjacent cutter , allowing the bearing to turn freely . Remember that guide bearings cannot be re-lubricated . Avoid washing them in solvent or other solution that may dissolve the grease . Once the grease is removed , it cannot be replaced . Guide bearings should be checked frequently and replaced if indication of seizing or excessive play is apparent .
tips
Always assemble cutters with care , first checking that the arbor is free of burrs or scratches and the lock nut threads are clean and undamaged . Check that each cutter is facing the correct way , against the rotation of the router . To reduce the risk of flexing , always fit the cutters as close to the shank end of the arbor as possible and when stacking cutters always offset each cutter ( i . e . two cutters on arbor set at 90 ° to each other ) to reduce the impact force of the cut . Take care not to cross thread the locknut before tightening it firmly to prevent the arbor turning in the cutter bore . When fitting guide bearings always use spacers or shims to prevent the tips of small diameter cutter from touching either the bearing case or adjacent cutters .
Using slotting cutters
Rather than plunge cutting , slotting and grooving cutters are fed horizontally into the edge of the work . Not only does this produce a very precise depth and line of cut , but allows the router to be supported and balanced on the face of the work rather than the narrow edge . Slotting cutter assemblies can be guided by a side fence , running against the straight edge of the work , however the ability to fit a guide bearing in any position on the arbor , allows far more flexibility .
Generally when using slotting cutters , the cut is taken to its full depth in a single pass . However when using large assemblies of three or more wide cutters , the cut can be made in several passes , using either the side fence or alternative size bearings to limit the depth of cut for each pass . Smaller slotting cutters and cutter assemblies can be used in either hand-held or fixed table routers , but for both accuracy and safety , assemblies with four or more cutters are more suitable for table routing or other fixed head routing systems ( i . e . machining centres ). Cutter assemblies up to 50mm can be run at full router speed while larger diameter cutter speeds should not exceed those recommended by the manufacturer ( i . e . 86mm and 100mm run at maximum of 12000rpm ).
INProfile
17