The two types of specialized shank found on most push drills are the
"Yankee" shank, patented in 1901 and the "old-style" or "cross" shank
found on many older and non-Yankee brand push drills.

The Yankee type push drill shank was derived from the similar Yankee
screwdriver shank patented in 1899. A similar shank appears in an 1896
announcement for the Forest City spiral-ratchet screwdriver, the
Yankee's predecessor. North Brothers purchased Forest City in 1897.=A0

Albert & Henry Goodell's Nov 17, 1891 push drill patent lists the
slotted 2-jaw chuck ["clip"] design with no reference to prior art or
existing products, but this type of chuck is found on push drills marked
Johnson & Tainter and other early push drills that likely pre-date 1891.
The 1869 Johnson & Tainter patent shows a different type of chuck and
shank system but I have never seen a J&T with anything other than the
cross-type shank/slotted 2-jaw chuck.


Millers Falls Co. manufactured many models of push drills, initially
only using the older style shanks, but according to Randy Roeder's
research published at oldtoolheaven.com, MF starting selling both types
after about 1904. Millers Falls described their products as "New-style"
and "Old-Style".

The old-style system holds the drill points with better concentricity
but is not as easy to use. Its often misused, in fact. Aside from the
wide variety of implements that are found retro"fit" into these chucks,
even the correct drill points are often as not inserted wrong.=A0

The old-style drill point shanks are symmetric about 180 degrees but not
90 degrees. Two of the ribs on the drill point shank have parallel
sides. These fit into straight, parallel-sided slots down the center of
each jaw. The other two of the ribs have tapered sides to match the tilt
of the jaws faces as the jaws are tightened onto the shank. The tapered
grip holds the drill point securely and prevents the drill point from
slipping out of the chuck.

So, of the four slot alignment positions that at first appear may fit,
two of them are wrong. Unfortunately, there is no feature to prevent
insertion into the chuck those two wrong ways.

The other minor problem with the slotted 2-jaw chuck is that the ends of
the chuck jaws on many push drills are machined to sharp corners but the
mating features on the drill point shanks are machined with a radius at
the end of the grooves. There is often interference. Later tools with
stamped jaws have less of this problem, and push drills with well-used
and worn jaws have sort of "fixed themselves" in this regard.

Anyway, the old-style can hold the drill point more precisely and
solidly but is much less quick and easy to use. The shift to Yankee type
shanks was a very practical one. I can change a Yankee bit one handed in
the dark but I always have to look twice at an old-style bit before I
insert it in a 2-jaw chuck.

Doc is correct that many of the smaller drill points are found broken.
Unless your push drill has an unusually light spring or is a Yankee
No.44 on the lightest setting, care and limiting the stroke to half-
length pushes are recommended to avoid breakage.

Tom Capellari


From: John Holladay <docholladay0820@g...> Precedence: list MIME-
Version: 1.0
Cc: oldtools@r... To: Thomas Conroy <booktoolcutter@y...om> References:
    <1336984659.3623.YahooMailClassic@w...o.com> In-Reply-To:
    <1336984659.3623.YahooMailClassic@w...yahoo.com> Date: Mon, 14 May
    2012 03:50:13 -0500 Message-ID: <CAB+91wiqG5AfkVoQvxYA-3O_5d-
    0ANEvokfGr5MtN1SWV8q3Tg@m...> Content-Type: text/plain; charset=ISO-8859-
    1 Subject: Re: [OldTools] Re: Stiff push drill advice Message: 12

Thomas,

You are correct. =A0I never understood why MF made these with a
different chuck, and therefore, bit shank. =A0There other tools all used
the same as the Stanley/North Bros. =A0I love my little MF automatic
still along with my many MF tools, but I wish bits were easier to come
by. =A0I have one size missing from mine, and it must have been very
common for it to break. =A0I've found and purchased several sets over
the years, and every time, the one that I am missing is the one that I
cannot find.

Doc On May 14, 2012 3:37 AM, "Thomas Conroy"
<booktoolcutter@y...> wrote:

> The bits Garrett Wade sells are for the Yankee-style push drills, with
> a shank rather similar to the shank of a Yankee screwdriver:
>
> http://www.garrettwade.com/garrettwade-push-drill/p/69P01.01/
>
> Garrett Wade's bits have the fluted cutting area classic for push
> drills, and I have some of these but I also have (courtesy of Kirk
> Eppler) some with this shank and a standard twist cutting area.
>
> The bits for Goodell-Pratt and Millers Falls push drills were somewhat
> different, with the same fluted cutting area but with a different
> shape shank, sort of four flutes I think, where the bit fits into the
> chuck or collet:
>
>
> http://www.worthpoint.com/worthopedia/push-drill-bits-fluted-millers-
> falls-goodell-pratt
>
> As far as I know nobody makes these any more, but they can still be
> found in the wild. I'll bet I've passed a lot by because I took one
> glance and assumed that they were machinists' mills. I just found out
> the difference between the different push drill bits this week, so now
> I have one more thing to keep an eye out for.
>
> Tom Conroy
>
>
> Tom Dugan wrote:
>
> For those like me who haven't found the bits they need for $2=2C and
> need a whole set=2C Garrett Wade sells a set of 8 for $24.95 that
> seems to do the job=2C although I haven't pushed them (ha!) too hard.
>
> http://www.garrettwade.com/product.asp?pn=69P01.01#more
>
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