At 12:03 PM 6/28/2013, JRodgers wrote:
>used were the "Silver & Deming" brand name bits. Stayed sharp the
>longest. Pricey however.

John, take a close look at those bits for a maker's logo.  It's
highly unlikely that Dole, Silver & Felch, Dole & Silver, Dole,
Silver & Deming, Silver & Deming, Silver & Deming Manufacturing Co.,
or Silver Manufacturing Co. actually made your bits since the last of
those companies went out of business in 1954.  More likely they were
made by Cleveland Twist Drill or another high-quality mfr.

Silver & Deming is the name used by all manufacturers for twist-drill
bits with their shanks reduced to half an inch.  They were invented
but not patented by the Silver & Deming people, likely in the late
19th century.  By definition they're all larger than half an inch.

Yours,
David