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Harold Hall

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Unfortunately, it is not easy to remove the jig for inspecting the result, as one could with the "Reliance" so it is necessary to remove the drill from the jig. First, check that the cutting edge is straight to prove that you have sharpened the drill with the correct angle. If that is satisfactory, then check the chisel angle with the gauge. It is likely that when first using the jig that you will find that an adjustment to the projection will be needed. Remember, more if the chisel angle is too great and less if too small. Repeat the process until a satisfactory result is achieved, at which time you can check the clearance angle against a similar size new drill just to be doubly sure as you may consider a little more clearance is required even if the chisel angle appears OK. With that done, make a note of the drill's diameter and the projection used, for future reference.

 

My advice would be to arm your self with a few drills of varying sizes and set about sharpening these making a note of the projection used as above. Keep the results for future reference and as the values are not crucial you can use these to interpolate for drill sizes between, adding to your records as more sizes of drills are sharpened.

 

180° Rotation

Users of the "Reliance"  did for many years achieve this  just visually so reasonable results can clearly be achieved using the method. However, I believe greater accurately is  worth aiming for, especially as it is necessary to remove the drill for inspection with the jig being used. In this case, I feel the simple attachment shown in Photographs 10 & 11 to control rotation to be all but essential and therefore worth making. The photographs should make the method of using it clear and whilst in theory it will work with any drill the length of the vee in which the drill rests is of a length that will prevent it working much below a 5mm diameter drill. Incidentally, the jig is stated as working with drills from 3 to 18mm diameter.

 

One point about its use that I will mention is that the two arms should be parallel when secured onto the drill. Again, precision is not called for, visually should be sufficiently accurate, perhaps measure with a rule for larger drills.

 

More information

For greater detail on sharpening standard drills, frequently known as jobber drills, and also dimensions for the 180 degree setting assembly, see my book Tool and Cutter Sharpening in the Workshop Practice Series. The book also covers such subjects as drills specifically for drilling brass and aluminium. Point thinning is also covered which reduces the length of the chisel, especially beneficial when using larger drill sizes on smaller machines.

Drill grinding jig, 180 degree drill rotation device.
Drill grinding jig, 180 degree drill rotation device.
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10

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11

Metalworking

Workshop Processes