TYPE STUDY
of the
Millers Falls No.2 Eggbeater Drill
Copyright 2004, 2008, 2010 by George Langford
Return to georgesbasement

Representative Millers Falls No.2 eggbeater drills
The Millers Falls Company developed the best single-speed, non-ratcheting, eggbeater drill there ever was ...

... until Marketing vanquished Engineering.
Group 1 - wrap-around frame These are the earliest types which appear in the oldest known Millers Falls catalogs. The earliest patent date I find on the chucks, for example, is August 14, 1877. Their wrap-around frames support the main gear wheel's shaft at both ends, but do not protect the brittle cast iron (or bronze) gear against deflections from the forces acting between the teeth of the mating gears.  The cast iron cranks occasionally bend but rarely break; however, they are weakly pinned to the main gear's shaft.  Watch for the flat face of the earliest main gears and the lining on the earliest main handles.  The Type M is further distinguished by the sixteen teeth of the pinion gear.  Later models in this series have seventeen teeth, a prime number, which improves the wear resistance of the teeth of the two gears because individual pairs of teeth rarely meet.  The evolution of the main handles of these types closely follow the evolution of the main handles of the early No.1, 3 & 5 eggbeater drills also made by Millers Falls.

The drill on the left is Type N, followed by Type M, Type L, and an untyped mongrel. 
Group 2 - LRRCW models Next, Millers Falls abruptly jumped to what I think is the best designed eggbeater drill ever. A modest little flanged roller was added, outboard of the main gear, which supports the thrust that tends to push the teeth out of engagement. Millers Falls called this the "adjustable friction roll to equalize bearings" and never showed it in any of their catalog images. No one ever copied it; Goodell-Pratt tried to emulate the roller with their little hardened steel wiper, but that's as close as anyone came to adopting this innovation. I call it the "Little Rail Road Car Wheel" (LRRCW) model. The drill arranged crosswise in the picture at left is my first LRRCW drill, which I rescued as a box of bits of rusty metal and splinters of wood, which I later pieced together and polished. It's my sweetest running eggbeater drill. The LRRCW and some well-hidden ball bearings make this drill sing; it takes less effort to operate than any other drill I use.

The Type F (Star logo) and Type E (triangular Since 1868 logo) are the commonest types found.
Type DC - both 2nd pinion and LRRCW
Back side of Type DC
About the time that the Millers Falls Company purchased the Goodell-Pratt Company and moved from Millers Falls to Greenfield, Massachusetts, someone tried out a method of adding a second pinion to support the side thrust between the main gear and the pinion gear.  This was presumably in response to market pressure from other manufacturers.  It is difficult to justify the change, as it almost certainly cost more to make and machine that second pinion than the roller, its cam-shaft and the adjusting screw of the LRRCW.  The second pinion of this model was installed on an extension of the threaded shaft of the main handle, and the frame had to be spot-faced and threaded to accept the extra parts.

I figured that this was a one-off prototype that some fortunate collector had stumbled upon or spirited away from an archival collection of the manufacturer.  Not so fast, buster.  Then I spotted another one in a different place.  Millers Falls actually sold their research & development models - perhaps to test the market.

Both examples of Type DC have the "Since 1868" triangular logo stamped on the crank.  The very next Type D was made in Greenfield.  One gets the impression that this was a last-gasp effort by a company being consumed ... not an improvement being developed by an energetic staff ... inspite of the fact that the record says that Goodell-Pratt was purchased by Millers Falls.
Two pinion types
Last (and least, to my way of thinking) are the double-pinion No.2's, which Millers Falls started to make some time after moving their plant to Greenfield, Massachusetts, from Millers Falls. The LRRCW was eventually ditched, and Millers Falls went to what had become the standard way of keeping the gears in mesh. Never mind that it takes a lot more work to turn a pair of meshing gears than to spin a roller (especially when neither method is supposed to be delivering any work through the process) and that the second pinion does nothing to take the side load off the main gear; that's just what the competition was doing. To make matters worse yet, all the auction action today is with the last two types in the picture at right, and the brighter and uglier the orange handles, the higher the price. Go figure.

What were the main engineering changes ? You might ask ...
Spindle of Type M drill
The Type M drill has a tapered socket in the spindle.  Earlier drills used a straight hole and set screw like a post drill.
Two-jaw, no-springs chuck patented August 14, 1877
This is the two-jaw springless chuck patented on August 14, 1877. The jaws each had a V groove in the middle, but the opening between the jaw guides only permitted 1/4 inch bit shanks to be gripped. The minimum bit size was about 1/16th inch, not a very wide range compared to later three-jaw chucks the same outside diameter. This jaw design was also prone to losing the jaws, distorting the chuck shell, or breaking jaws because they hang out too far in order to grip the smallest bits in the range.  It's better than that hollow-tapered spindle above, though.
Change in handle length
Type L2 on the left; the earlier Type L0 is on the right.

The bits that the shorter handle was meant to accommodate were all the same length, but the later twist drill bits were made in what became known as jobbers lengths, meaning that the larger diameter bits were also longer, because they could drill deeper holes.  The short, straight-flute bits had to be repeatedly withdrawn from the holes being drilled because they tended to clog with chips.
Little RailRoad Car Wheel

The three parts of the LRRCW assembly are the cam (at lower left in the lower right hand portion of the composite picture at left), the LRRCW (to the right of the cam), and a lowly round-headed No.6-32 clamping screw. The exploded parts are shown in the same orientations and relative positions as in the detail view above the picture of the individual parts, but the drill itself is shown rotated 90 degrees counterclockwise from the detail view.

The LRRCW should be adjusted so that it just barely allows the main gear wheel to rotate without binding anywhere in the rotation of the gears. That is done by loosening the clamping screw and then rotating the cam with a second screwdriver. A purist would tell you to orient the cam so that the frictional drag of normal rotation of the main gear will tend to loosen the fit of the LRRCW should the clamping screw lose its grip. Otherwise, just twist the cam back and forth while trying real hard not to push it in towards the rim of the main gear until everything is snug without binding. Then you can retighten the clamp screw.

The function of the LRRCW is to keep the main gear and single pinion gear in correct mesh along their corresponding pitch lines, thereby minimizing backlash and ensuring accurate, smoooooth rotation under load. The LRRCW assembly is extremely stiff, so it does not perceptibly deflect under load. The shaft upon which the flanged roller (the LRRCW) rotates is quite small in diameter, so there is little friction when the assembly operates, even under load.

Crank handles
The crank handles of the Type M, Type Pre-L, Type L and the Type K2 are shown arranged left-to-right at left. Each of the first three cranks has a boss cast in to hold the axle of the rotating crank handle, but the Type M's handle is held with a screw carefully tapped into the crank (but loosened for the camera) the Type Pre-L's crank is held with a pin apparently press fit into that boss but whose head is peened over a washer to retain the rotating handle, and the Type L's crank handle is held by a large-headed pin riveted at the inboard side of the boss, which was drilled clear through to receive the pin. The crank handle of the Type K2 was held like that of Type L, but the crank of the Type K's and all later No.2 drills are thin steel, and so their crank handles are not so securely attached as these early three drills' handles.
Thrust bearings
On the left is the worn thrust bearing of the Type L2.  On the right, it's the Type L0's thrust bearing, where someone has attempted to compensate for wear. The Type Pre-L had a little different arrangement for taking care of end thrustThe Type L uses a single, hardened steel ball to handle the thrust; perhaps this example of the Type L2 once did as well ...
Types K1 through K4 thrust bearing
The very first No.2 drill that used the LRRCW to control the running fit between the main gear and pinion gear had a very plain thrust bearing.  That bearing supported the force of pressing the bit against the workpiece being drilled.  The bearing was a simple cylinder whose position could be adjusted and held  in place with a small screw visible here between the spokes of the main gear.  That simple bearing was not easy to keep lubricated and had high friction compared to the efficient solution that appeared with the more heavily loaded Type K5 and later drills: a row of tiny steel balls between the upper end of the spindle and the inside of the spindle's bearing housing.
Frame design, early in the design of the LRRCW model
The first LRRCW model of the No.2 eggbeater drill did not just spring to life fully developed.  Only the LRRCW achieved that feat of inspiration, never imitated since in any hand drill that I've seen. The first frame, the Type K1's at right, was narrow and lacked any provision for a side handle.  The next model, the Type K2 at left, had a wider frame, presumably stronger.  I have never come across a broken frame in a No.2 drill.  These frames were made of malleable iron, a ductile, tough material in its time.  Later frames were made of pot metal; they didn't break, either.  Both of the drills shown here have the cylindrical, flat-ended plain thrust bearing that was barely adequate for the small bits these drills could hold in their two-jaw, springless, 1877-patent chucks.  The next model, Type K5, came with a side handle and an improved chuck, but the more important development was the addition of an invisible set of tiny ball bearings inside a redesigned spindle housing, behind the inboard end of the spindle.
Three-jaw no-springs chuck patented September 29, 1896
The Type K5's new, three-jaw, no-springs chuck is an improvement over the older two-jaw chuck, because the three jaws theoretically center the bit much more accurately than the two-jaw version did. The two-jaw chuck depended on a narrow Vee groove in the middle of each jaw to center the bit, and that was more effective for small drills than for larger ones. The patent date on this chuck is September 29, 1896. Similarly to the two-jaw version, each jaw is flat on the sides and is guided by grooves in the body of the chuck. There are no springs, so one has to wiggle the bit during insertion to move the jaws out of the way.
Flared cap on the main handle
The first LRRCW model of the No.2 drill retained the slender main-handle shape of the earliest No.2 types because the two-jaw, springless chuck could hold bit shanks no larger than 3/16ths inch diameter.  The associated drilling thrust did not tax a man's grip.  Later types such as the Type JI at right, carried chucks that accepted larger bits, 1/4 inch in the case of the Type JI, and so a nudge with the shoulder as well as a grip on the side handle were in order.  Hence, the mushroom shape of the end cap.  Type K1 is at left here.


Beefing up the frame for an insidious purpose ...
The later Type G at left has a heftier junction between the handle boss and the frame than does the Type H at right. Type G's ferrule is a replacement; the original overlapped the pinned joint of the handle's threaded rod.  The increase in heft of the Type G's frame at left was probably "sold" to management to handle the greater forces applied to the new chuck (below) but it also facilitated the changeover to the two-pinion model ...
Three-jaw, protected-springs chuck patented October 23, 1900
This is the protected-spring chuck design that was patented October 23, 1900.  The springs that keep the jaws pulled back and pushed out against the inner wall of the shell are behind the jaws, where no amount of poking with the drill bit can get at them.  Millers Falls used this design long after the patent ran its course of seventeen years.
Handle design
Continued handle development
Later versions of the main handle had progressively thicker waists, but the ferrules of these later handles were made from deep drawn brass, which ought to have been stress relieved but weren't, with the occurrence of season cracking (a military term of art) as the consequence.  The greater forces applied through the larger capacity chucks didn't help, either.

The comparisons at left are: first, Type J and Type I, and then Type I and Type H.
Frame design gets beefed up
Note that the Type D's frame (on top at left) now has a connection between the rear spindle bearing housing and the housing of the main gear's shaft, compared to the unconnected spindle bearing of the older Type E below. There was also a change in the shape of the side handle between these two drills, from the "doorhandle" shape of the Type E to the smaller knob, shaped much like the Type D's crank handle. Not only that, but the number of teeth in the main gear went down from 76 in the Type E's main gear to 73 in the Type D's gear; and the pinion lost some teeth as well, from 17 to 16.  These changes came before the move from Millers Falls MA, to Greenfield, MA.  Not only that, but the boss originally cast into the Type E's frame to hold the main gear has been replaced by an inserted steel shaft, whose threaded side-knob end can be seen at left.
Second pinion on a LRRCW frame
Parts of the second pinion
On the top at left one can barely see the C-clip that retains the second pinion on the main-handle stud extension of the Type DC transitional design.  Also, the steel insert can be seen protruding from the central boss of the frame.  This was a new feature of Type Post-E and later drills (at left).  It was necessary to spot-face the surface against which the second pinion bears, similarly to the machining done during the finishing of the frame for the main pinion.

In the end, this particular drill was quite unsuccessful because the main handle wobbles along with the pinion.  The original LRRCW mechanism was so good for adjusting the meshing of those gears ! It isn't possible to make the stud a tight fit in the hole tapped into the frame and still assemble the pinion onto the main-handle stud.
Pot metal replaces malleable iron one for one
The cast iron frame used from Type M near the beginning through Type B (at left, top) near the end of development was finally replaced in Type A (at left, bottom) with a diecast frame of a zinc-aluminum alloy known as Zamak [thanks to Russell Davis for correcting me about the makeup of Zamak - GL].  Many manufacturers had trouble (unbeknownst to them) with the purity of the molten metal, with the result that the castings fell apart many years later by a corrosion-cracking mechanism.  Although this was probably the alloy used by Millers Falls, to their everlasting credit, none of these diecast frames has fallen into pieces.  I haven't found any broken frames made either from malleable iron or this pot metal.
Military vs. retail versions of the Sogard gears
This is the final stage of development.  The retail version of the Sogard (the purchaser of the Millers Falls drill operation) drill at right was made to a much tighter budget than was the military version at left.  The military version has nicely cut, evenly spaced teeth.  The retail version's teeth are notchy and unevenly spaced.  Either version costs far more to make than an electric drill with greater complexity and more heavily loaded gears.  Other industries have followed a similar path.

About the new table below
Rather than assign Type Numbers right at the beginning of this study, I'm identifying the drills that I've found to be distinguishable from each other with letters, starting with the Type A, the last in the series. I'd use thumbnails here, except that you'd not be able to tell one drill from another at that level of detail. Instead, you can simply click on one of the numbers in the "Groups" column below, and your browser will take you to the details.  If this newly inverted table is confusing or too new to comprehend, the former table is retained at the bottom of this page.  Click on the Group Number in the left-most column to see an individual drill.
Group
Types
Frame
Crank
Handle
Main
Handle
End
Cap
Ferrule,
Main Handle
Side
Handle
Spindle
Nose
Thrust
Brng.
No.'s of Teeth
Driver
Pinion
Chuck Patent Date
Markings
1a
N
Wrap-around,
non-ferrous
Long HW
one-P
Long, solid
HardWood
None
Long tube None
 ?
Cone
69 flat
19
?
None
None
1b
M
Wrap-around,
Malleable iron
Short RW
screwed
Short, solid
RoseWood
None
Long tube None Hollow Cone
78 flat
16
None
None
None
1c
L0
Wrap-around Malleable iron
Short RW
pin &
washer

Short RW lined,
hollow
Round,
lignum vitae
Long tube None Threaded
Cone
78 flat
17
2-jaw
NS
August
14, 1877
Millers Falls
on chuck
1d
L'
Wrap-around Malleable iron
Short RW
pin &
washer
Short RW
hollow
Round,
RW
Long tube None Threaded Cone
78 flat
17
2-jaw
NS
August
14, 1877
Millers Falls
on chuck
1e
L
Wrap-around Malleable,
thicker members

Short, ?
Short RW
hollow
Round,
lignum vitae
Long tube None Threaded Ball ?
78 arch
17
2-jaw
NS
August
14, 1877
Millers Falls
on chuck
1f
L2
Wrap-around Malleable,
thicker members
Short RW
one-P
shaft
Long, slim,
hollow RW
Round,
RW
Long tube None Threaded Cone
78 arch 17
2-jaw
NS
August
14, 1877
Millers Falls
on chuck
1g
L3
Wrap-around Malleable,
thicker members
Short RW
one-P
shaft
Long, slim,
hollow RW
Round,
RW
Long tubeNoneThreadedCone
78 arch 17
2-jaw
NS
August
14, 1877
Millers Falls
on chuck
2a
K1
Narrow ladder,
LRRCW, Malleable
?
Long, slim,
hollow RW
Round, RW
Short tube
None
Threaded Flat
78 arch 17
2-jaw
NS
August
14, 1877
Millers Falls
on chuck
2b
K2
Ladder
& LRRCW, Malleable
Short RW
one-P
shaft
Long, slim,
hollow RW
Round, RW Short tube None
Threaded Flat
78 arch 17
2-jaw
NS
August
14, 1877
Millers Falls
on chuck
2c
K3
Ladder
& LRRCW, Malleable
Short RW
one-P
shaft
Long, slim,
hollow RW
Round, RW Short tube Egg ?
Threaded Flat
78 arch 17
3-jaw
PS
Never
patented
Millers Falls
on chuck
2d
K4
Ladder
& LRRCW, Malleable
Short RW
one-P
shaft
Long, slim,
hollow RW
Round, RW Short tube Egg ?
Threaded Flat
78 arch 17
3-jaw
NS
Pat. App'd.
For
Millers Falls
on chuck
2e
K5
Ladder
& LRRCW, Malleable
Short RW
one-P
shaft
Long, slim,
hollow RW
Flared, RW Short tube Egg RW
Threaded Balls
78 arch 17
3-jaw
NS
September
29, 1896
Millers Falls
on chuck
2f
J
Ladder
& LRRCW, Malleable
Short RW
one-P
shaft
Long, slim,
hollow RW
Flared, RWShort tubeEgg RW
ThreadedBalls
78 arch 17
3-jaw
NS
September
29, 1896
Millers Falls
on chuck
2g
I
Ladder
& LRRCW, Malleable
Short RW
one-P
shaft
Long, slim,
hollow RW
Flared, RW Short,
larger tube
Egg RW
Threaded Balls
76 arch 17
3-jaw
NS
September
29, 1896
Millers Falls
on chuck
2h
H
Ladder
& LRRCW, Malleable
Short RW
one-P
shaft
Long, stout,
hollow RW
Flared, RW Drawn,
stepped
Mushroom,
hardwood
Threaded Balls
76 arch 17
3-jaw
NS
September
29, 1896
Millers Falls
on chuck
2i
G
Ladder, LRRCW
& heavy boss, Malleable
Short RW
one-P
shaft
Long, stout,
hollow RW
Flared, RW Drawn,
stepped ?
Mushroom,
hardwood
Threaded Balls
76 arch 17
3-jaw
PS
October
23, 1900
Millers Falls
on chuck
2j
F
Ladder, LRRCW
& heavy boss, Malleable
Long RW
one-P
shaft
Long, stout,
hollow RW
Flared, RW Drawn,
stepped
Mushroom,
hardwood
Threaded Balls
76 arch 17
3-jaw
PS
None Star logo
Millers Falls on crank
2k
E
Ladder, LRRCW
& heavy boss, Malleable
Long CB
one-P
shaft
Long, stout,
hollow CB
Flared, RW Drawn,
stepped
Mushroom,
hardwood
Threaded Balls
76 arch 17
3-jaw
PS
None
Star logo
Millers Falls on crank
2l
E'
Ladder, LRRCW
& heavy boss, Malleable
Long CB
one-P
shaft
Long, stout,
hollow CB
Flared,
CocoBolo
Drawn,
stepped
Mushroom,
hardwood
Threaded Balls
76 arch 17
3-jaw
PS
None "Since 1868"
Millers Falls on crank
2m
D
Ladder, LRRCW,
Malleable, beefed up
Long CB
one-P
shaft
Long, stout,
hollow CB
Flared, CBDrawn,
stepped
Chef's Cap,
cocobolo
ThreadedBalls
73 arch 16
3-jaw
PS
NoneMF No.2,
Greenfield
on crank

3a
DC
Ladder, LRRCW, 2ndpinion, Malleable, beefed up
Long RW
one-P
shaft
Long, stout,
hollow RW
Flared, RWDrawn,
stepped
Mushroom ?
ThreadedBalls
73 arch 16
3-jaw
PS
None"Since 1868"
Millers Falls on crank

4a
C
Ladder, 2nd pinion,
M, beefed up
Long CB
one-P
shaft
Long, stout,
hollow CB
Flared, CB
Drawn,
stepped
Mushroom,
hardwood
Threaded Balls
73 arch 16
3-jaw
PS
None MF No.2,
Greenfield
on crank
4b
B
Ladder, 2nd pinion,
Malleable, beefed up
Chef's Cap, CB
Long, stout,
hollow CB
Flared, CB Drawn,
stepped
Chef's Cap,
cocobolo
Threaded
Balls
73 arch 16
3-jaw
PS
None MF No.2,
Greenfield
on crank
4c
A
Ladder & 2nd
pinion, pot metal
Chef's Cap, CB Long, stout,
hollow CB
Flared, CB Drawn,
stepped
Chef's Cap,
cocobolo
Threaded Balls
73 arch 16
3-jaw
VS
None Millers Falls
on crank
5a
SoJo - R
Ladder & 2nd
pinion, pot metal
Chef's Cap, HW
Long, stout,
hollow HW
Flared, HW
Drawn,
stepped
Chef's Cap,
hardwood
Threaded Balls ?
73 arch 16
3-jaw
VS
None 2-01: SoJo,
Sogard, or
Brookstone
on crank
5b
SoJo - M
Ladder & 2nd
pinion, pot metal
Chef's Cap, HW
Long, stout,
hollow HW
Flared, HW
Drawn,
stepped
Chef's Cap,
hardwood
Threaded Balls ?
73 arch 16
3-jaw
VS
None Sogard
USA
on crank

About the original table below
Rather than assign Type Numbers right at the beginning of this study, I'm identifying the drills that I've found to be distinguishable from each other with letters, starting with the Type A, the last in the series. I'd use thumbnails here, except that you'd not be able to tell one drill from another at that level of detail. Instead, you can simply click on one of the letters in the series below, and your browser will take you to the details. Below the single letters are some more rows, some of them with doubled-up letters. These are comparisons that will enable you better to visualize what changes were made. Each row is identified with a specific aspect of the drill or type of transition, such as a change in type of chuck, the shape of the frame, or of the handle, and so on.  The original table was generously HTML-ified by Jeff Youngstrom of the OldTools list; he introduced me to the concept of "col-span" so well that I have since made the current additions all on my own.
Mug Shots: N M L0
L' L L2
L3
K1 K2 K3 K4 K5 J I H H' G F E E' DC D C B A
Spindle Nose & Chuck: N M
L' L L2

K1 K2 K3 K4 K5


H' G F E
DC D C
A
Main Gear & Shaft: N
L0
L' L L2
Gear held onto integral frame boss by screw Shaft added
Thrust Bearing: N
M
L0
L'
L
L2

K1 thru K4 Ball bearings under end of spindle inside upper bearing
Crank Logo: <----------------------------------------------------No crank logo  F
E'-DC D

A
Spoke Design: <--------------------------------------------More to come--------------------------------------->
Main Handle: UM
M
L0       -       L2 K1 and later------> J-I-->  <--I-H <--Same, except for wood & finish-->
Side Handle: <------No side handle------->
K4-J------> DC K4-J------> A
Crank Handle: L0-L2         and           M-L'-L-K2 and later H-F E-D C-B A
Crank Attachment: <-----------------------------More to come-------------------------->
Frame Design: N-M L0
M-L L2
K1-K2------> H-G------>
E-D----> D-C B-A
No. of Gear Teeth: 69 78 78
78 78 78

78 78 78 78 78 78 76 76 76 76 76 76 76 73 73 73 73 73
No. of Pinion Teeth: 19 16 17
17 17 17

17 17 17 17 17 17 17 17 17 17 17 17 17 16 16 16 16 16
Double Pinion Gears? N N N
N N N
N N N N N N N N N N N N N N Y Y Y Y Y
LRRCW? N N N
N N N
N Y Y Y Y Y Y Y Y Y Y Y Y Y Y N N N N