A Simple Hand Milling Machine
By THOMAS REED
Fig. 1. General View of the Hand Milling Machine Which Every
Experimental Machinist Will Want to Build. Not Only Is It An
Extremely Serviceable Device, But It Gives the Fundamental Ideas of
the Larger Milling Machines. This Device, Altho Quite Simple, Is
Capable of a Surprisingly Large Variety of Work.
Fig. 2. A Side View of the Hand Milling Machine With a File Being
Used in the Guides. The Machine Is Held in a Bench Vise.
Figures 5 to 13 Illustrate the Great Variety of Work Which Can Be
Turned Out on the Hand-Milling Machine Here Illustrated and
Described. This Is, However, Only a Partial Number of the Different
Shaped Parts Which Can Be Made With the Aid of This Hand- Miller,
and With a Little Ingenuity on the Part of the Building Machinist,
Many Other Useful and Intricate Parts Can Be Conceived and
HONEST, I'm sorry about that "Arabian alarm-clock," Bugs. I know
you were just beginning to feel, whenever you saw my name attached
to an article, that you were assured of a sober, dependable
exposition of demonstrated fact; and that fake bing-clock must have
jolted your confidence worse than it did the "Sheik's" slumbers.
Well, to commence the long, up-hill fight to regain my reputation
as a purveyor of "Frozen Truth" exclusively, I'll present you with
a little hand milling machine, designed so you can make it
yourselves, for the production of milled objects, such as those in
Figs. 5 to 13.
The germ of this idea was a machine which our crowd made years ago,
following one said to be used by the old Swiss hand watchmakers.
That tool, however, employed a revolving cutter, and, you had to
make a separate cutter for each piece of work.
The present, greatly simplified machine makes use of files of
various shapes, hack-saws, drills, etc., requiring only a special
guide for each class of tool.
Referring to Figs. 1 and 2, the frame, A, A, A, would, in a
be a casting: but I have designed it from 3 pieces of heavy flat
wrought-iron, bent into shape and held together by the screws B, B.
These screws would probably not be sufficient except for the fact
that in operation the machine is held firmly in the vise, C, which
gives all the stability required.
The soul of the machine is the index plate, D. This is a disc of
thin metal, perforated with rings of small holes ; the number of
holes being different in each ring, but dividing the circle into
equal spaces, 60, 11. or whatever the case may be.
The index-plate is fastened immovably to the shaft E, by the nut F;
(see Fig. 2) and as the plate and shaft turn, they carry with them
the work G, held on by the nut H. Long pieces of work can be
steadied by the back-center S.
While the work is being operated on, say while the ratchet tooth J
is being filed out, the index-plate is held in a fixt position by
the spring lever K ; a peg, L, on the end of which, enters one of
the holes in the plate. The lever, with its peg, is placed in line
with any of the circles of holes by loosening the wing-nut M, on
the bolt of which the lever K is pivoted.
The ratchet-tooth J being finished, it is desired to rotate the
work into position for the next tooth. Say you are cutting a 30
tooth wheel, and your outer index circle contains 60 holes. By
pulling on the small handle N, the spring lever K bends, and the
peg L is withdrawn from the hole.
Be careful now, and don't lose your place. Rotate the index-plate
in the direction of the arrow, count off two holes, and let the peg
slip back into the second hole. Now your work is held for the next
cut just 1/30 of a revolution ahead and so on around your
ratchet-wheel, which, if you count correctly, is sure to "come out
The holes in the index plate should be spaced off and drilled as
accurately as possible, but errors tend to eliminate themselves,
from the fact that the diameter of the index-plate is so much
greater than that of the work. If you drill the plate anything like
near enough to satisfy you, you will be surprised at the apparently
perfect regularity of the work.
It is best to make the index plate from 1/16 inch-stock, but thin
sheet iron will do. If we must (which is my delight) draw on our
household resources, I should think the bottom of a tomato-can,
carefully un-soldered by rotating over a gas-flame, would make an
excellent plate. And don't forget the invaluable pic tin.
The guides, Q, Q, which hold the file P, should of course, be made
out of steel, and hardened. The pivots R, R, are eccentric with the
shaft E, so that the file may approach the work at different
Fig. 3 shows a hack-saw guide. The disc turns eccentrically at T,
forming a variable bottom-stop for the saw.
Fig. 4 shows two forms of punch-guide, where pegs are desired to be
set at regular intervals, as in making rotary spark-gaps.
After marking the work, the punch U can be withdrawn from the
sleeve W, and the hole drilled with a hand-drill. This peg-setting
is illustrated in Figs. 9 and 13.
Of the various forms shown in Figs. 5 to 13, Fig. 5 is done by a
drill and hacksaw; Fig. 6 by two hack-saw blades in the same
handle; Fig. 7 by a knife-file. Fig. 8 by a flat file. Fig. 10 by a
half-round. Fig. 11 by very small flat file, and Fig. 12 by a round
file. Among the many-shaped files, and one or more hack-saw blades,
you ought to come pretty near producing any figure that even the
wild requirements of a "Bug" may find essential to his happiness!
Oh, as the numbers of the holes in the index-plate ; a ring of 60
holes gives you the following equal divisions : 2, 3, 4, 5, 6, 10,
12, 15, 20 and 30. Another ring of 56 holes would give you 7, 8,
14, and 28. This covers most of the desirable low numbers, and
shows how easily you can figure for yourselves any other factors
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