Sawing, Chucking, Boring Machine
It is always pleasing to have the honor of announcing a new Richardson-Graff machine. It is easy to describe the highly developed, beautifully accurate, and enormously productive machines which come from the Sheboygan Falls shops. We have never yet seen a mechanism from the hand of Jairus S. Richardson which did not function with all the smoothness of a hot knife going through butter. This type L. B. (Little Brother), is no exception to the rule.
This new machine, unlike other R-G tools, is designed for working one end of chair and similar stock at a time. The stock is trimmed to a precise angle, and at the same operation bored or chucked. A paramount feature of the machine is the speed with which setups are made. Simple, easily read scales in connection with the accurately cut screws of ¼" pitch cover all adjustments and make setups almost instantaneous as well as extremely accurate. All the scales are calibrated from a zero or neutral reading. Thus, for example, to bore or chuck in the center of a 13" -16" chair stretcher , it is only necessary to set a vertical scale to 13/32 and a horizontal scale to the same setting. The stock will be precisely centered on the tools with no cutting and trying and no wastage.
The adjustable gauge which positions the stock for the cut carries a scale which gives precise length of stock cut. When the stock is to be chucked, a scale on the swinging arm gives an accurate reading of the length of tenon. It is thus entirely possible to make a predetermined setup chart for any given piece, make the setup in accord therewith, and go ahead with assurance that the operations will be accurately accomplished. Setups are made in one minute or less, and thus the field of the machine is enormously broadened—small lots which would not warrant a double end setup are run efficiently on the Little Brother.
The table proper is pivoted at a point which extends directly through the center line of the chucking head on a horizontal plane and directly through the front edge of the saw when set at zero. The table carries a radius "T" slot, the center of which is exact neutral point of the pivot pin on which the table is adjusted to arrive at vertical angles. Stock is clamped by a hydraulic unit actuated by a cam-driven master unit. The table is adjusted to a maximum of 45 degrees throughout its entire radius of 360 degrees. The design throughout makes possible simple and rapid setups. The trim saw is mounted on a ball bearing arbor carried on a swinging arm. Normally, the saw is at rest below the table. Arbor is driven by belt, which belt serves also to carry away the end trimmings and deposit them in a box. Just below and in front of the saw is a guard plate which completely covers the saw except when cutting.
The stroke of the chuck is taken from an arm in which a "T" slot has been milled to an accurate radius, thus any change in the stroke of the chuck or boring head is not reflected on the forward travel. The chuck or bit will always reach a forward position which is identical regardless of the length of back travel. The same is also true of the saw stroke.
Geared head boring units may be mounted on the end of motor housing, which is machined to receive such heads, to bore either vertical, horizontal, or at an angle. The entire clamping mechanism may be removed in a few seconds, and a flat table substituted. Thus a thoroughly competent horizontal multiple borer is arrived at. This change involves only the removal of one nut and the disconnecting of the saw, and is accomplished in less than 45 seconds. The feed mechanism is completely housed within the base and involves a heavy duty worm and gear which drives the cam shaft, mounted in two extra large roller bearings. The cams are very accurately machined to shape and are timed closely so that the feeding time is minimized, and the actual cutting time allowed the tools is extended. This results in much cleaner work. When boring only is required, a slight adjustment of one cam lever gives 50% more loading time. The entire mechanism is safe-guarded by the use of spring loaded draglinks which automatically open in case of stalling or starting the feed with tools dead.
Feed control is vested in a pedal which actuates a large plate type clutch. This clutch requires but 3/32" plate movement between driving and braking position. Thus a pedal movement of only 1½" under six pounds pressure serves to instantly stop the feed motion at any point in the cycle. Pedal pressure being released , the feed mechanism resumes its continuous cycle. A small pedal locks the control pedal in stop position when required. A variable speed pulley provides stepless feed rates ranging from 13 to 30 pieces per minute, thus the operator is enabled to instantly reconcile the feed rate with his ability to feed the particular job in hand. It is quite apparent that Jairus S. Richardson would far rather develop a smooth-working, beautifully accurate, and enormously productive mechanism than be president—and who can blame him? Certainly he has developed a machine in the Little Brother which rates a place in hundreds of chair and other shops.