Dull Screwdriver! Reprise

[Norman Barrett]

----- Original Message ----- 
From: "John Musselwhite" <john@musselwhite.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Tuesday, October 08, 2002 11:27 AM
Subject: Re: Dull Screwdriver! Reprise


One of the best shop classes I ever took at a PTG convention was Pris and 
> Joel Rappaport's class on sharpening tools that they presented in Toronto 
> in the 1980s. While they mostly dealt with chisels and scrapers, 
> screwdrivers were on the agenda too.
> 
> The tip of a flat blade screwdriver should be hollow ground on both sides 
> with the point ground flat so it fits right down in the bottom of the slot 
> and grips the sides. Hollow grinding lets the blade exert pressure in the 
> entire screw slot as opposed to flat grinding where the force is mostly on 
> the top of the slot. For an extreme example, check the slotted sockets on 
> one of those little multi-screwdrivers with all the short magnetic bits.
> 
I was sharpening a screwdriver in the manner you describe in a machine shop on day. When I got through, a machinist gave me an additional tip. Take a hammer and lightly tap the bottom edge of the screwdriver so as to form a slight burr, much like a scraper. With this burr formed correctly,  it is almost impossible to pull the screwdriver out of the slot of the screw when you have some torque on it.

Norm Barrett
Memphis Chapter