Sharp­en­ing drill bits with the Eclipse 39

The Shed - - Sharpening -

Pic­tured is the drill-sharp­en­ing jig I use. It is the Eclipse 39, a Bri­tish-made de­vice whose in­ven­tor won Bri­tish In­ven­tion of the Year com­pe­ti­tion in 1970. The abra­sive ma­te­rial is sand­pa­per taped to a flat sur­face. I use the plate glass top from a dam­aged set of bath­room scales.

The drill bit is ac­cu­rately po­si­tioned in the jig and pushed over the sheet of abra­sive. After a few pas­sages across the sur­face the drill bit is repo­si­tioned and the other facet of the drill’s cut­ting sur­face is sharp­ened. The process is re­peated un­til two good cut­ting edges are pro­duced.

It is rather a long and de­mand­ing pro­ce­dure, but has the ad­van­tage that a com­pletely in­ex­pe­ri­enced am­a­teur can trans­form a blunt drill bit into a use­ful item. I have seen seasoned me­tal­work­ers sharpen drills free­hand on a bench grinder in just a few sec­onds and pro­duce qual­ity re­sults. That is ob­vi­ously a bet­ter way, es­pe­cially for large bits, but re­quires skill which I sus­pect was hard won; there be­ing plenty which can go wrong.

Sharp­en­ing a drill bit with the Eclipse 39 jig

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