Gary, Don, Claudio & Galoots,

Interesting, don't you think, that P.L. Robertson came up with his screw 
pattern after badly cutting his hand while demonstrating Yankee spring 
loaded slot screwdrivers.  In over 100 years of use here in Canada I doubt 
that the Robertson drivers have shed much blood, while more than a few folk, 
I'm sure, have had a run in with the tip of a slot driver or been cut by a 
burr raised on a slot screw head.

Robertson screws required one less step to manufacture as no slot had to be 
cut after the head was formed, the head shaping and tapering square socket 
were stamped on the same machine stroke.  The result being Robertson screws 
cost less to manufacture. However P.L. was able to sell them for more than a 
slot screw by demonstrating that the Robertson screw when set on the tip of 
his screwdriver would stay in place, even if you pointed the driver holding 
the screw to the ground.   Robertson was a good salesman.

Just fanning the flame,

Marv Paisner
Kootenay Lake, BC





-----Original Message----- 
From: gary may via OldTools
Sent: Tuesday, February 19, 2019 10:11 PM
To: Claudio DeLorenzi ; Don Schwartz
Cc: oldtools@s...
Subject: Re: [OldTools] Screw Head

Don Schwartz---
   Oh yes, in my 'opinion'-- :) and you know more that most how humble it 
is!
    Some may disagree and they may be right.  But it's not shit vs shinola. 
Square drives do the job and do it just fine. Same as slots do. So IMHO,  if 
you like riding donkeys as well as you do riding thoroughbreds, maybe get a 
donut pillow and take the train.
                          with humbleness--yr pl gam.


    On Monday, February 18, 2019, 11:15:42 PM PST, Don Schwartz 
 wrote:

On 2019-02-18 10:04 p.m., gary may wrote:
> a slotted screw is a perfectly fine fastener

in your opinion?

Don

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