Sand Blast File Sharpening
The sand blast process of cutting raised figures on glass,
marble, and other hard, brittle materials has been used for
several years, but its use for sharpening files is a recent
The large engraving on this page will give a general idea of its
operation. To the steam pipe (as near the boiler as convenient)
is attached a finch pipe with elbow; to this is attached a piece
of pipe of suitable length, inclined about 16 degrees from a
horizontal line, with valve, into which a brass steam jet is
Next, the iron nozzle is wrapped with paper to fit the cylinder,
the steam cylinder slipped on to steam jet to shoulder, with
sand tube perpendicular, and the set screws fastened. The gun is
then ready for use.
The operator then suspends a hopper, or funnel, of suitable
size, to contain the sharpening material, as near directly over
the gun as convenient, and connects with the gun by a rubber
tube. When done using he removes the tube and plugs the hopper.
A box is made about four feet long, one foot wide, and eight
inches deep, open at end next to the gun, also underneath the
outer end, for the escape of steam and for carrying sand to the
reservoir. This is inclined same as the gun, and set so that the
end of the nozzle shall be flush with end of box, and opposite
the middle of the aperture. The reservoir is placed under the
end of this box from which the hopper is replenished as needed.
For a sharpening material moulder's parting sand is used. Flint
sand or emery will wear longer, but any gritty substance may be
used. The sand and water is kept in the hopper as thick as it
The file is first dipped in hot soda water and brushed with a
card; should any metal remain in the grooves it is pecked out,
as the blast does not remove it. The file is held so the blast
strikes it at an angle of 16 degrees. It is passed under the
blast from point to tang, giving it also a lateral motion so as
to grind it evenly. The action of the blast is very rapid.
Two or more files can be placed side by side in cutting by the
blast. Both old and new files are now being sharpened by the
sand blast. The effect on new files is to remove the burr or
curl from the teeth, thus changing every tooth into a sharp and
regular chisel-shaped form.
This prevents the teeth breaking off and adds largely to the
working value of the file. The burr is shown in Fig. A. In Fig.
B the teeth are exhibited as left by sand blasting.
Many advantages are claimed for sharpening files by this
process. The temper of the steel is not drawn; they cut faster
and with less labor; leave the work very smooth; are superior
for wood-work, as they cut like a plane, and do not tear the
wood away; can be sharpened at small expense; secure the highest
H. S. Manning & Co., Ill, - Liberty St., New York, have the agency
for sharpening files by the sand blast.
American Machinist, October 18,
1879, (New York: American Machinist Publishing Co.)