US922346A - Boring-bar. - Google Patents

Description

D. H. SHATTUCK.

BORING BAR.

APPLICATION FILED SEPT. 23, 1907.

360 Patented May 18, 19%.

Mhmasmem I Wag W 4/44 M .m;%m@ g u ,DAVID H. SHAlTUCK, OF WESTFORD, MASSACHUSETTS.

BQRING-BAR.

No. ceases.

Specification of Letters Patent.

Patented an is,

Application filed September 23, 1907. Serial N 0. 394,123.

T 0 (133 whom it mag concern:

Be it known that I, Dav n H. SHA-TTUOK, a citizen of the United States, residing at W estford, in the county of MiddleseX and Commonwealth of Massachusetts, have invented a certain new and useful Improvement in BoringdBars, of which the fol owing is a specification.

'lhis invention relates to boring bars or bars to which are secured cutters or cutting bits and adapted to be used in horizontal or vertical boring-mills or machines or in other usual ways.

The object of this invention is to rovide means for accurately and uickly a justing the cutters to bore holes of ill crent sizes and for rigidly holding the cutters without the use of set-screws or keys.

Hcretoforeit has been customary to use a single cutter in the bar by means of 'a key or set-screw. The driving'in of the key is. apt to spring the bar and to displace the cutter and where a set-screw is usedit is necessary to spot or to make a depression in the cutter to reteive the point of the screw, so that if the cutter is subsequently ground, it is difficult to get a new spot or hole to receive the set-screw without materially reducing the size of the hole to be bored, that is, a very slight reduction of the cutting diameter of the boring-bar cannot be made. Sometimes a double-header or cutter shaped to cutat both ends and extending through the bar to an equaldistance from the center of the bar on each side is held in are many times reground. I am also able to utilize ver short stock in the making of the cutters, t at is, pieces so short that they could not be utilized in cutter-bars heretofore. By the use of this cutter-bar without removing the cutters I can vary the cutting 1 diameter within a considerable range, that is,

l-can reduce the cutting diameter and subequently enlarge said cutting diameter while retaining the same cutters.

' With the very hard tool-steel now much tened side 0 to fit the washer D, which used and sometimes called self-hardening steel it is im )ossible to spot the cutters or drill the holes for the reception of the setscrew, such steel being affected only by grinding with emery or other abrasives. 'lhis invention makes the use of cutters oi the most refractory steel feasible.

' In the accompanying drawing, Figure is, a side elevation of a boring-bar provided with my improvement, the shank or bar proper being broken out to save space in the drawing and the lower end of the bar be" in central vertical section on the line l-l Fig. 2:; Fig; 2, a plan of the bottom of the cutter-bar,- Fig. 3, a side elevation of the part of the bar which in Fig. 1 is shown in section.

. The bar proper A is of the usual form, ere.

the usual horizontal chucking machines.

In the lower or o erative end of the bar a I is arranged a centra hole a, in which turns an adjusting screw-cone provided. with an it tefrmediate conical part 3), two extern: screw threaded portions 5 t and a cylindrical guiding sectionb which has a sliding fit in the hole a, the screw 5 engaging an iuternal screw-thread a in the hole a, and the screw 5 receivingthe nut F named below. The outer end I) i l thisscrew-cone is square or many-sided to be engaged by a wrench. i

'lhe bar pro or A is provided with a plurality of radia c lindrical holes a lying in the same radial plhne at equal angular intervals from each other.

In the holes a are arranged cutters C having cylindrical shanks, the outer or cutting parts c of which be of anysuitable shape and the inner ends 0 of whichare suitabl gr rounded or curved to allow the cone ll, witl'i which they are in contact, to move easily. The cutters are each provided with a l on said-flattened sides and is pressed against them by the nut E, which turns on the ternally threaded reduced lower end of shank or bar proper A, said nut it being represented as provided with a radial hole 6 to l. to

against the cone.

be engaged by a spanner or hand-s ike.

The amount of projection of the cutters rom the bar A is determined by the diameter of the cone B where the inner ends'of said cut ters are in contact with said cone. When the nut E is-loosened, turning the cone B farther into the handle A throws" the cutters outward, but when the cone is turned in the other direction, the cutters are pushed in When the cone .B is adjusted to the proper osition to secure the desired projection of t e cutters, said cone is ternal screw-thread and having radial cylindrical holes, shanks arranged in sa d holes and each provided with a flattened surface, and a nut arranged on said bar and adapted to enga e the flattened surfaces of said cutters to ho d the latter.

' 2. The combination of a bar having radial cylindrical holes, cutters having cylindrical shanks arranged in said holes and each pro-' vided with a flattened surface, said bar being provided with an annular groove concentric cutters having cylindrical withits axis and said groove intersecting.-

said radial holes, and a nut arranged on said bar and in said groove and ada ted to engage said flattened surfaces to hol said cutters.

In witness whereof, have'aflixed m signature in presence of two witnesses.

, DAVID H. snArrUoK. Witnesses ALBERT M. Moonn, GRACE CROWLEY.

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