US2350055A

US2350055A - Scratch bit

Info

Publication number: US2350055A
Application number: US434422A
Authority: US
Inventors: Sr John F Mcquillan
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-03-12
Filing date: 1942-03-12
Publication date: 1944-05-30
Anticipated expiration: 1961-05-30

Description

May 30, 1944 J. F. MCQUILLAN, SR 2,350,055

Patented May 30, 1944 UNITED STATES vPA'TEIWF OFFlCi SCRATCH Brr John F. McQuillan, Sr., East Orange, N. J.

Application March 12, 1942, Serial No. 434,422

2 Claims.

This invention relates to an improved scratch bit or blade for use with heighth gauges, planer gauges, and gauge blocks.

The scratch bits now in use with the above mentioned types of instruments are provided with a single beveled top surface which intersects with the bottom surface to form the scratching edge. As a result, the groove formed by the scratching edge in a piece of work has a substantially flat lower side and an inclined upper side. This results in a definite tendency of the scratch bit to rise or climb While in operation from .001 inch to .002 inch above the desired height. As the scratch bit is used with measuring instruments intended for extreme accuracy this variation is very undesirable.

It is, therefore, a primary aim of the present invention to provide a scratch bit having a beveled scratching edge to produce a substantially V-shaped groove in the work and to thus produce a bit which will have no tendency toward climbing or. rising.

Still a further aim of the invention is to provide `a scratch bit having a flat bottom surface which is adapted to rest in a suitable support and which is adapted to be disposed at the level at which the scratch is to be made, and having a beveledscratching edge which is disposed inthe same plane as said bottom surface.

Still a further aim of the invention is to provide a beveled cutting edge disposed in the same plane as the bottom surface of the scratch bit.

`Still another aim of the invention is to provide a scratch bit wherein the beveled surfaces forming the scratching edge are each disposed at .the same angle to the bottom surface of the bit.

Other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, which illustrate preferred embodiments thereof, and wherein:

Figure 1 is a side elevational view showing one form of the scratch bit attached to a conventional planer gauge,

Figure 2 is a top plan view of the same,

Figure 3 is a side elevational view showing the same form of the scratch bit applied to a gauge block,

Figure 4 is a vertical sectional View taken substantially along the plane of the line 4-4 of Figure 3,

Figure 5 is a longitudinal, substantially central vertical sectional view of the scratch bit shown in Figures 1 to 4,

Figure 6 is a fragmentary side elevational view showing a slightly modified form of the scratch bit applied to a height gauge,

Figure is a fragmentary top plan View of the same, and Figure 8 is a perspective view of the scratch bit shown in Figures 6 and 7.

Referring more particularly to the drawings, wherein like reference characters designate like or corresponding parts throughout the different views, and referring particularly to Figures 1 and 2, for the purpose of illustrating one application of the invention, a supporting surface which is flat is indicated at i9. II designates a piece of work such as a forging, casting or steel shape, on a side of which the scratch is to be made and which has one edge resting on the supporting surface I0. I2 designates generally a conventional planer gauge of common construction and as this instrument forms no part of the invention a detailed description thereof Ais considered unnecessary.

The scratcher bit, designated generally I3, and comprising the invention constitutes an elongated bar of hardened steel or the like which is provided with a flat bottom surface I4 and a substantially flat top surface I5 which surfaces are disposed parallel. The bit I3 is provided with a beveled upper surface I6 at one end thereof which is inclined toward andk merges with one end of the top surface I5. The bit I3,

beneath the surface? I6, is provided with an' elongated, depending portion or projection I1,

forming an integral part thereof, and which depends below the bottom surface I4. The projection I'I at its outer end is provided with an upwardly and outwardly inclined surface I8 which intersects the surface I6 to form the scratching edge I9 of the bit I3. The scratching edge I9 is disposed in the same plane as the bottom surface I4 and the beveled surfaces IB and I8 are each disposed at an angle of 30 degrees to the bottom surface I4 so that the included angle of the scratching edge I9 is 60 degrees. The scratching bit I3 is provided with a perpendicular opening or bore 20 which extends therethrough.

In Figures 1 and 2 the scratch bit I3 is shown with its flat under surface I4 resting on the at top surface of the movable block 2| of the planer gauge I2. A bolt 22 extends downwardly through the opening 20 and is in threaded engagement with the recess 23 in the block 2| for securing the bit I3 to the top surface of the block 2I in a, conventional manner. The elevation of the bit I3 can be adjusted to one-thousandth of an inch by adjustably positioning the block 2| relatively to the inclined channel surface 24 of the base portion of the planer gauge I2, in a conventional manner. It will thus be readily apparent that when the block 2| is set at the correct elevation 'the edge I9 will be in the same plane as the top surface of the block 2| and the under side I4 of the bit I3 so that by relative movement of the bit I3 and the piece of Work II a scratch 25 will be made in the side of the Work II which scratch will be parallel to the bottom edge of the Work II. Scratch 25 will be V-shaped in cross section, and as previously explained, the shape of the cutting edge I9 will prevent the bit from rising or climbing While the scratch is being made so that the scratch at all points will be in` the same horizontal plane.

In Figures 3 and 4 the same scratch bit I3 is shown applied to and employed with a conventional gauge block. This use of the scratch bit I3 has the work I I shown supported by the member 26 which is secured to the surface III by a clamp 2l. The gauge block, designated generally 28, and which is of conventional construction, includes a base 2S having threaded openings, not shown. Base 29 rests on and is adapted to be slid relatively to the surface III and has its top surface disposed at the same height as the top surface of the portion 30 Which supports the bottom end of the piece of work II. Individual gauge blocks 3| of the desired sizes rest one upon the other upon the base 29 and the bottom surface I4 of the bit I3 rests on the upper side of the upper gauge block 3I for supporting the bit I3 at any desired elevation to .0001 of an inch. Another block 32 rests on the base 29 and extends to substantially the level of the upper surface I5. A hold-down bar 33 extends across the surface I and the top surface of the block 32 and has a slot therein through which extends a bolt 34, the lower edge of which is in threaded engagement with one of the threaded openings of the base-28 for drawing the hold-down bar 33 tight against the upper surface of the bit I3l for holding the bit secure1yin place. It will thus be seen that the gauge block 38 can be slid over the surface I to'cause the scratching edge I9 to make a horizontal scratch in the Work II at the exact level of the under side I4 of the bit.

A conventional height gauge 35 is shown in Figure 6 having a supporting arm 36 provided with a clamp 37. The supporting arm 36 is adjustable by means 38 relatively to the upright supporting standard 39 Which is provided with scale markings 4U for adjusting the supporting arm 36 to fractions of one-thousandth of an inch. With the heighth gauge 35 a slightly modified plane surface form of bit, designated I 3', is employed instead of the bit I3. Bit I3 differs from the bit I3 only in that it is narrower and not provided with an opening or bore 20. The bit I3 is positioned in the sleeve portion 4I of the clamp 31 and with its bottom surface I4 resting on the top, at surface of the supporting arm 36. A set screw 42 of the clamp 37 is tightened against the top surface I5 of the scratch bit I 3' to hold the bottom surface I4 securely against the top surface of the arm 3S. zWhen thus positioned, it will be readily apparent that the scratching edge of the bit I3 will be in the same horizontal plane as the upper surface of the supporting arm 36. The work II is shown resting on the surface I II and against a backing member 43 and it Will be readily apparent that by moving the height gauge 35, by sliding its base over the surface I0, that the scratching edge I9 will make a scratch in the exposed side of the Work II all parts of which scratch will be in a horizontal plane and at the level of the upper side of the supporting arm 35, which is the level at which the height gauge 35 is set.

Various other modifications and changes in the embodiments of the bits, constituting the invention, are contemplatedand may obviously be resoi ted to, provided they fall within the spirit and scope of the invention as hereinafter dened by the appended claims, as only preferred embodiments thereof have been disclosed.

I claim as my invention:

l. A scratch bit for use with height gauges, planer gauges, and gauge blocks, said bitvhaving a flat bottom surface, said bit having a beveled upper plane surface at one end thereof, a depending projeetion on the bit disposed at said end thereof and extending downwardly from the bottom surface, said projection having a beveled at its cuter end, and said beveled surfaces intersecting to form a scratching edge, said scratching edge being disposed in the same plane as the bottom surface of the bit.

2. A scratch bit for use with height. gauges,

i planer gauges, and gauge blocks, said bit having a flat bottom surface, said bit having a beveled upper plane surface at one end thereof, a depending projection on the bit disposed at said end thereof and extending downwardly from the bottom surface, such projection having a beveled plane surface at its outer end, and said beveled surfaces each being disposed at the same angle tothe bottom surface and intersecting to form a scratching edge in the same plane as the bottom surface of the bit.. v JOHN F. MCQUILLAN, SR.