Harold Hall

Workshop Projects


Cutter Holder (1)

These will be required for every shank diameter that you need to work with. Place the 25mm square steel in the four jaw and centralise it , face the end, centre drill and drill to the required diameter. If you wish to bore the hole rather than drill it you can do this but do test it will all the cutters you have, else if you happen to make it to fit the smallest one (shanks are made with a tolerance)  you will find the others do not fit. Photograph6 shows the complete set of parts which also includes the Nut (8) that has not been mentioned.


Using the rest

Place the cutter into the holder with its cutting edges horizontal and vertical, visually will be sufficiently accurate.  Next  loosely secure the body to the table using the most suitable hole in it for the length of cutter to be sharpened. Then, with the cutter holder held against the body and stop, position the end of the cutter such that the right hand edge of the wheel is just clear of the lower vertical cutting edge, whilst at the same time setting the body parallel with one of the guide lines on the table, Photograph 7. With that done, secure the body using the single screw.


Now, wind the stop back sufficient to ensure that the cutter will not touch the wheel when plunged and, with the grinder now running, very gradually advance the cutter using the stop until it just contacts the wheel.  Remove and advance it two more marks on the dial and plunge all four cutting edges and inspect. If it is still not fully sharp advance another two marks and repeat. Continue repeating the process until the edge is fully sharp.  Incidentally, do not turn the knob holding it with the fingers but use an Allen key in the head of the screw.


Eventually, the cutter having been sharpened a number of times, the width of the primary clearance will become too great, say over 3mm, and the secondary clearance will have to be ground to bring it back to about 0.5mm. These values do though tend to be size dependant being about right for a 12mm end mill but increased a little for large cutters and visa versa. The process of sharpening the secondary clearance is identical to that detailed above but with the rest suitably angled, see Photograph 8, compare this with photograph 1.



End Mill Sharpening Fixture
End Mill Sharpening Fixture