IMPROVED COMBINED APPARATUS FOR SAWING MITRES AND BEVELS, OBTAINING LEVELS, AND DETERMINING ANGLES
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at
the Office of the Commissioners of Patents, with his Petition, on
the 24th March 1873.-A communication from abroad by James
Henry Carpenter, of Paterson, in the County of Passaic, and State of
New Jersey, United States of America.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVED COMBINED APPARATUS FOR SAWING MITRES AND
BEVELS, OBTAINING LEVELS, AND DETERMINING ANGLES," to be as follows:-
The object of this Invention is to furnish an adjustable guide for
sawing mitres and bevels of any desired angle, and for obtaining levels
and determining angles. It consists in an adjustable platform bar and
adjustable table and saw guide, and in combination therewith a spirit
level, sight guides, and transit, the construction and arrangement being
as herein-after described.

page_text: The apparatus is mounted on a tripod or stand. A semicircular table
or plate is rigidly fixed to the top of a column or pillar of this stand,
which table supports the saw guide, the base of which at one end is
connected with the centre of the column or pillar by a pivot, the other
end extending over the edge of the table and provided with a hanging lip
and fastening screw therein. The sawing table or platform bar is pivoted
to a plate attached to the side of the column or pillar, and has a platform
at each end, a portion of it extending above the platforms, thus forming
angles in which the lumber to be sawed is laid. The platform bar turns
on its pivot to any desired angle, and there is a semicircle attached to its
under edge, a set screw in a bracket projecting from the pillar or column
serving to fasten the semicircle in any desired position. The semicircle
as well as the table which supports the saw guide is marked off into
degrees and fractions thereof, so that the saw guide and platform bar
may be fixed at any required angle. When the bar is horizontal
the saw guide is readily set, so that a true mitre or angle of 45°
may be sawed, but if a bevel or compound mitre is required the bar is
inclined.
For making joints in ship building, roofs, or bridge building, or for
other purposes, bevels of various angles have to be made. By properly
adjusting the sawing table or platform bar and the saw guide any required
bevel, either simple or compound, may be cut. The saw guide consists
of two uprights between which slides a back guide which as the saw cuts
through the piece of lumber descends and keeps the saw steady. The
piece of lumber or timber to be sawed is held in position on the bar by
means of adjustable clamp bars which slide through holes beneath the
table and are fastened when adjusted to the lumber by means of screw
nuts or by set screws as may be desired.
To form an instrument for leveling and striking angles in the
operation of building, laying out foundations, improving grounds, and
other purposes, I attach a spirit level and sight guides to the adjustable
platform bar. By means of the spirit level the bar is readily brought to
an exact level and is fastened in that position by the set screw as before
described, then by sighting through the guides the level line is obtained.
A transit provided with sight guides is placed on the adjustable table
in place of the saw guide before described, said transit being made to

page_text: traverse the top of the table by means of a central pivot, and is fastened
in any desired position by means of a set screw. By means of this
transit a line of any required angle with the line of the bar may be
obtained, the whole forming a light and compact apparatus for sawing
mitres or bevels, or striking levels or angles.