US2667702A - Gauge for setting jointer knives and methods - Google Patents

Description

Feb. 2, 1954 s BEALE 2,667,702

GAUGE FOR SETTING JOINTER KNIVES AND METHODS Filed May 27, 1952 2 Sheets-Sheet l 22 F1 g. 7 I

2 f y 6 7 7 /0\ I l I fi Q 35 I I 5 7 4 5 5 6 INVENTOR.

. flay/4R0 5 5:45 ,920 72% r Feb. 2, 1954 H, s, BEALE 2,667,702

GAUGE FOR SETTING JOINTER KNIVES AND METHODS Filed May 27, 1952 2 Sheets-Sheet 2 INVENTOR. flow/Q0 5. 55415 Patented Feb. 2, 1954 UNITED STATES PATENT OFFICE GAUGE FOR SETTING JOINTER KNIVES AND METHODS Claims.

This invention relates to a device for setting the knives of a jointer relative to the cutter head in which said knives are secured.

The problem of properly setting the knives in a jointer is one which has not heretofore been satisfactorily solved. Many different methods have been proposed, but none to my knowledge has proven satisfactory.

When the knives in a jointer have been properly set the cutting edge of each knife is exactly parallel to the axis of the cutterhead and each of the three knives has the same cutting circle. The knives must be set properly after each sharpening and the difficulty attending the setting process has led many jointer users to send the entire cutter head to the manufacturers, along with the knives, for sharpening and resetting. This is not only an expensive procedure but may result in the loss of the jointer for long periods of time.

Other jointer users, fearful of not being able to set the knives properly, try to use the original knives of the jointer after the same have become dull and dented. This results in poor work and reduces the value of the machine, which value is directly proportional to its precision.

In the past, various methods of setting jointer knives have been proposed. One requires the use of a heavy magnet which is placed on the rear table of the jointer with the poles of the magnet overhanging said table and directly above the cutter head. An index mark is then scribed on the magnet and each knife is successively pulled up to the magnet and locked in place. The main disadvantage of this procedure lies in the difliculty of getting the magnet in the proper position relative to the knives, and even when properly positioned, inaccuracies result. Basically, such a method is unsound because the actual cutting circle of the knives is not measured but rather the radial distance of the knife edge from the axis of the cutter head. Inasmuch as the latter distance is relatively short, slight inaccuracies in measurement are greatly magnified when the device is in use, and this is especially so when it is considered that a difference of .001" in the radius of the cutting circle of two knives will result in poor work.

Other methods based on the same principle as the "magnet method have been attempted in the past but the same have not proven satisfactory.

The main object of the present invention is therefore the provision of a gauge for setting jointer knives which overcomes the disadvantages of prior art processes.

Another object of the invention is the provision of a novel method for setting jointer knives and by which method the greatest possible accuracy is achieved.

Still another object of the invention is the provision of a simple and inexpensive gauge which may be employed by relatively unskilled users and which gauge is fool-proof in operation.

Other objects and advantages will be apparent from the following specification and drawings.

Fig. 1 is a perspective view of the invention.

Fig. 2 is a side elevational view of the invention partly broken away and in section to show structure.

Fig. 3 is a fragmentary horizontal cross-sectional view of the setting gauge of Fig. 2 as taken along lines 33 of Fig. 2.

Fig. 4 is a semi-schematic transverse crosssectional view of the cutter head showing the gauge positioned on the rear table of the jointer and with one of the cutter knives engaging the gauge.

Fig. 5 is a semi-schematic view similar to 4 but showing one end of knife.

Fig. 6 is a semi-schematic view similar to Figs. 4 and 5 but showing the knife just before it is disengaged from the setting device.

Fig. 7 is a semi-schematic perspective view of a jointer showing the knife setting gauge in the position of Fig. 5.

In detail, the invention is adapted to be used in connection with a conventional jointer having a front table I, a rear table 2 and a cutterhead 3 between said front and rear tables (Fig. 7). Cutterhead 3 is a generally elongated cylindrical member and is provided with three axially extending knives 4 secured at circumferentially spaced points around said cutterhead and projecting generally radially outwardly therefrom. The knives 4 are about equal in length to the length of the cutterhead 3. In operation, it will be understood that the rear table 2 is secured in a position with the plane of the upper surface of said table tangent to the cutting circle of the knives 4 and with the front table spaced below the rear table a distance equal to the desired depth of cut to be made. When a piece of wood is fed from the front table to the rear table with the lower surface of the wood sliding on the front table the rapidly rotating knives 4 cut away all of the wood below the plane of the rear table.

The term cutting circle as used herein may be defined as the locus of the cutting edges of the knives 4 during rotation of the cutterhead 3.

Fig. the gauge raised by the cured to chipper bar 6 at spaced points along the length of the latter with their shanksprojecting from the side of chipper bar 5. opposite the side which engages the knife 4. By tightening the heads of bolts i against theadjacent side of slot the knife 4 is firmly secured in; saidisloti disposed on the rear table with the line 2| on scale IS coinciding with the line 26 scribed on rear table 2; the cutterhead 3 is then slowly rotated by hand in the normal direction indicated by the arrow in Fig. 4 until the edge of knife 5 engages the bottom wall I! of gauge I9. In this connection it should be noted that the gauge body is preferably made of aluminum or other soft material so. that the knife edge 28 will not slip thereon. It will also be understood that the knife 4 being recently sharpened will be iinbedded very slightly in the bottom wall II thus overcoming any tendency'for the knife to slip on the gauge.

"Upon continued rotation of cutterhead 3 from theposition of Fig. 4 the knife edge 28 will raise the front end of the gauge and drag the rear end along;rear table 2 until the knife edge 28 passes The present invention comprises an elongated. generally rectangular hollow body generally d'esignated I9 (Figs. 1, 2) and having a base or bottom wall I I, a top wall I2 and front an'drear end walls I3, Is respectively."

The body If! is relatively thin in comparison with its length so that the body engages only a very shortsection of the length of the knifeto be set. The height of body as: between the t'cp and bottom walls i2, I1 is preferably between two and three times its width so as to make the body very rigid and at the same time heavy enough to be positively engaged by the knives of the j'ointer in a manner to be described. 5 7

Between the endwalls I33, I4 are a pair of longitudinally spaced transverse ribs I 5 Iii respectively, which extend between top and bottom wals I2, II. Between ribs I5, It, bottom wall II is removed so as to provide a downwardly opening recess 9. Bottom wall I I is slotted asat-I'i, I3 to receive the opposite ends of a transparentsca-le I9 of glass or plastic. This scale 19- may be rigidly secured to bottom II by any desired method such as cementing. Reinforcing-webs 28 may be formed integral with the wal-lsof body H1 and the ribs i5, It as desired (Figs. 1, 2, 3).

below the plane of the rear table at which time the'knife edge 28 will be disengaged from the bottom wall I i and the gauge Iii will come to rest in aposition closer to the front table-"I from its Adjacent the end of scale 19 that is nearer endwall l3 the same is scribed with a transversejline ZI (Fig. 3). At a point spaced a predetermined distance along scale I9 from line 2i is another line 24 for a purpose to be described. The distance between lines 2| and 24' represents theidistance between the two points at which-the cutting circle of a properly set knife intersects the plane of the rear table when the latter is substantially tangent with the rear table. This will be more fully described in the following description of the operation of the gauge.

In operation, the first step in setting'the knives is to adjust the height of the rear table until the tially tangent to the upper surface of' the cutter head (Fig. 4). This may be readily accomplished by disposing the gauge on the rear table with the front endwall I3 overhanging the cutter head so that the cutter head just clears the bottom ;I I of the gauge. The rear table is then secured in place and is not moved until the knife setting operation is completed.

With the gauge Ill in about the position of Fig. 4 a line 26 is scribed on the rear table 2' parallel with the axis of cutterhead 2 and coincident with line 2! on scale I9 (Fig. 7) This linelt may be scribed with a sharp. pointed instrument and should be very fine so as not to impair therear table. However, if desired the line may beternporary in which case a hard pencil maybe used. Referring againto Fig. 4, the gauge; {this then.

' starting position of Fig. 4. The gauge'is shown in the latter position in Fig. 6. The distance moved by the gauge It is then measured by reference to lines ZI-Et. If line 24 (Fig. 3) is spaced from line 2| a distance equal tothe length of chord- C (Fig. i) which subtends the arc of cutting circle A above theplane of reartable Z it will be apparent that line 24 will coincide with line 2% (Fig. 6) after the knife has moved the gauge If! as above described.

By making the spacing between lines 2|, 26 equal? to the chord C of a properly set knifeit will be apparent that any deviation between the position of line 24 and line 25 (Fig. 7) will be directly proportional to the amount which the knife must be moved to place it in its proper position. However, it should be understood that the distances measured on table 2 are large in proportion to the radial adjustment of the knives, thus making for greater accuracy. V

If; after the above operation, line 2'4 on scale "it coincides with 26 (Fig. 7) the knife 4 is in a correctly set position. If line 2% does not'coincide with line 25 the knife should be moved inwardly or outwardly of the cutterhead depending upon whether the distance travelled by gauge It is too long or too short with reference to line 25. The above operation is therefore repeated until gauge I 0 moves the distance between lines iii and 2d.

The above described operation is preferably carried out with the gauge iii positioned on one end of the knife Li and is then repeated at the opposite end of the knife. In this manner the knife edge is set exactly parallel to the axis of the cutterhead.

Each of the knives A. may be set in the manner above described, the operation being identical in each case.

As pointed out above, it is important. that the knife edge 28 does not slip with respect'to the gauge If) during the setting operation. For this reason the Weight of the gauge Iii should be sufficientto insure a good engagement between the knife edge and the bottom wall I I. The tendency of the knife to slip with respect to the gauge I0. is greatest just before the knife is disengaged. from the bottom wall and it is at this point that the resistance of the gauge to being dragged over rear table 2 is maximum. For this reason, it is preferable to reduce the resistance of gauge II] by providing. a roller 36 at the trailing endof the same (Figs. 1, 2).

Roller 30 is relatively small .in diameter and the juncture between rearwall I4 and bottom wall i l is provided with a relatively narrow slot 3| to receive the roller so that the same is substantially tangent with the rear wall is and bottom wall ll (Fig. 2). A pin 32 may be driven through H a suitable aperture in body it) to provide a bearing for the roller 36. In addition, the juncturebetween rear wall is and bottom wall Ii should be rounded off at 33 to insure engagement of roller 30 with table 2.

By the above structure slippage between the knives and the body is completely obviated and the distance moved by the gauge is exactly equal in all cases to the length of chord C (Fig. 4). The gauge I is stable at all times being adequately supported at its forward end by the knife edge.

From Fig. 7 it will be apparent that the transparent scale l9 may be viewed by an operator from above thus facilitating the setting process.

To adapt the gauge for use with jointers having different sizes of cutterheads lines 22, 23 may be scribed in addition to line 24 above described. Thus line 24 will be employed for the largest size of cutter head lines 22, for smaller sizes.

From the foregOing it will be apparent that line 2| constitutes a fiducial line for measuring the length of chord C (Fig. 4) and lines 22, 23, 24 represent indicia for different sizes of cutting circles.

The spacing between fiducial line 2| and indicia 22, 23, 24 is predetermined from the cutting circle of a knife set with the heel 29 of the bevelled portion of the cutting edge adjoining the periphery of the cutterhead (Fig. 4) In this manner adequate support is provided for the knife and at the same time the chipper bar 6 is correctly spaced for ejecting the chips cut by the knives.

The above described method may be followed with the gauge placed on the front table but it is preferable to employ the rear table and rotate the cutterhead in the normal direction.

The above detailed description should not be taken as restrictive of the invention but merely as the preferred form thereof, it being obvious that various minor changes may be made without departing from the invention as defined by the following claims.

I claim:

1. A gauge for setting the knives in the cutterhead of a jointer comprising an elongated body having a straight longitudinally extending base adapted to lie flat on a table of said jointer with one end of said base projecting over the cutterhead, a fiducial point on said base spaced from said one end for registration of said point with a predetermined fixed point on said table, indicia on said base spaced from said fiducial point a distance equal to the chord length of the arc travelled by the edge of a correctly set knife between two points on the plane of said table when the latter is substantially coplanar with the upper surface of said cutterhead, said body being provided with a downwardly opening recess and a longitudinally extending transparent scale positioned across the open side of said recess coplanar with said base, said fiducial point and said indicia being scribed on said scale whereby the same are viewable from a point above said body through said recess.

2. A gauge for setting the knives in the cutterhead of a jointer comprising an elongated body having a straight longitudinally extending base adapted to lie flat on a table of said jointer with one end of said base projecting over the cutter-. head, a fiducial point on said base spaced from said one end for registration of said point with a predetermined fixed point on said table, indicia on said base spaced from said fiducial point a distance equal to the chord length of the arc travelled by the edge of a correctly set knife between two points on the plane of said table when the latter is substantially coplanar with the upper surface of said cutterhead, a roller at the other end of said body adapted to engage said table for supporting said body at said other end for movement over said table when said body is tilted upwardly at said one end.

3. The-method of setting a knife of a jointer to a predetermined cutting circle comprising the steps of positioning a table of said jointer with its working surface substantially tangent with the upper surface of the cutterhead to which said knife is secured, disposing a scale on said table with one end projecting over said cutterhead and with said knife in a position below said scale, rotating said cutterhead slowly with said knife moving toward said scale whereby the cutting edge of said knife will engage said scale and move the same along said table until said edge is disengaged from said scale, measuring the distance moved by said scale on said table and comparing said distance with the predetermined distance said scale is moved by a knife set on said predetermined circle, moving said knife inwardly or outwardly of said cutterhead depending on whether said measured distance is under or over said predetermined distance and returning said knife and scale to said first mentioned positions and repeating said steps until said measured distance equals said pre ete mined distance.

4. A gauge for setting the knives in the cutterhead of a jointer comprising: an elongated rigid body having a straight longitudinally extending base adapted to lie fiat on a table of a ,iointer for supporting said body in a stable position, a fiducial point on the surface of said base and spaced from one end thereof for registration of said point with a predetermined fixed point on said table, indicia on the surface of said base spaced from said fiducial point a distance equal to the chord length of the arc travelled by the edge of a correctly set knife between two points on the plane of said table when the latter is substantially coplanar with the upper surface of said cutterhead, the width of said base in a direction transversely of its length being relatively narrow in comparison with its length to engage a short section only of said knife, and the height of said body in a direction at right angles to said base being substantially greater than its width to provide an inertial weight adapted to engage said knife, the portion of said body adjacent said point and said indicia being transparent to permit viewing said point and indicia from a point elevated from said base when the latter is flat on such table.

5. A gauge for setting the knives in the cutterhead of a jointer comprising: an elongated rigid body having a straight longitudinally extending base adapted to lie flat on a table of a jointer for supporting said body in a stable position, a fiducial point on the surface of said base and Spaced from one end thereof for registration of said point with a predetermined fixed point on said table, indicia on the surface of said base spaced from said fiducial point a distance equal to the chord length of the arc travelled by the edge of a correctly set knife between two points 'on the plane of said table when the latteris substantially coplanar 'With the upper'surface of said 'c'iitterhead, the Width of 'said base in'a direction transversely of its length being relatively narrow in comparisonwith its length to engage ashort section only of said knife, and the height of said body in a direction at right angles to said base being substantially greater than its width to provide an inertial weight adapted to engage said 'knife, the portion of said body "adjacent said point and said indiciabeing transparent to per- 'mit viewing said point and indicia from 'a point elevated from said base whenthe latter is flat on such table, said base being formed of relatively soft material adapted to be cut by the edge of' said knife.

HOWARD 'S.

References Cited in the -fl1e of this patent UNITED STATES PATENTS OTHER REFERENCES Publication: 1923 Catalog of Central Scientific Co., Chicago, 111., page 47, No. 11882. (cop in Library.)

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