Four facet drill grinding.

Thanks Brian, Article has been half written fo ages perhaps I should finish it!

The advice with an old kit for the Worden advised making a collet for each size of drill.

I followed, without realising, Giles Parke's method, of making an ER20 collet holder in a piece of 1" square steel, (The size used in the fixtures for the Worden. )

his allows drills of up to 13 mm to be held.

The drill is clamped in the ER20 collet, so that one cutting edge is vertical.

My holder is marked to identify the faces, so that rotating the holder through 180 degrees is obvious, if a an already ground face has to be revisited.

The Table is set square to the grinding wheel.

Fitted into one of the "standard" drill grinding fixtures (Inclining the drill at 31 degrees ) the complete assembly is swung through 30 degrees to produce the secondary clearance.

Once this is done, the fixture is reset to 10 degrees to produce the primary clearance.

The end result should be the primary reliefs being of equal width where they meet at the chisel edge in the centre.

Howard

I've just completed a joint cooperation with John Moran to produce a hybrid 3D print / metal version of his four facet sharpener. The hybrid construction concept works very well making the whole thing much easier to produce.

You can download a ZIP file with Fusion files, STEP files and PDF drawings from my blog.

Coincidentally, Howard's detailed article on this subject will be in MEW 320!

I passed the proof half an hour ago!

Neil

Maybe Brian ,I am trying to write another article at the moment and finding it quite hard work as pen and paper are not my forte. If this one goes OK I will give it a go.Hope you are well.