proper taper. The depth of cut was regulated by the feed screw of the compound rest.

The tool was held in an ordinary boring bar, as shown at G. In the end of the boring bar I used the tool shown in Fig. 3. This tool is made of square tool steel and is held in the bar by a taper pin. One end of the tool is ground for a threading tool and the opposite end for a boring tool, the cutting face of one tool being upside down in relation to the other.

Now when the boring is finished all that is necessary is to loosen the setscrews holding the boring bar and rotate the bar half a turn, which brings the threading end of the tool into position. This effects a great saving of time over that which would be required to change tools. Mahone Bay, N. S.

ROBERT B. WESTOVER.

CUTTING RIGHT-HAND WORMWHEELS WITH A LEFT-HAND HOB.

Editor MACHINERY:

We had a number of wormwheels to hob, some right-hand and some left-hand, and not knowing any better at the time we made both a right and a left-hand hob for the cutting. The pitch was 8 (diametral), the pitch diameter of wheels 7 inches, and the consequent number of teeth 62. The pitch diameter of the worm was 2 inches, and the included angle 30 degrees.

The blanks were sized and stocked, and after several righthand worm wheels had been hobbed, much to the surprise of the boy at the milling machine a left-hand one was put in, the table swung around to the proper angle and we proceeded to hob a left-hand worm wheel with a right-hand hob. This may be common practice in some shops, but it was new here, and we now have a hob for sale. The purchaser can have his choice, right or left hand, and we will guarantee it to cut either pitch, one as well as the other.

I mail you a section of the rim of a right-hand worm wheel as hobbed by a left-hand hob. It was used as an experiment, to prove my theory, before trying it on a finished wheel. Had the width of face been correct the cut would have been smooth. The bright spots show the contact with the worm in action. J. C. WHITE.

Decatur, Ill.

[The segment of the worm wheel sent by Mr. White bears no evidence of having been cut by an unusual method, and no one could tell by the naked eye whether the teeth were hobbed with a right-hand or a left-hand worm. The bright spots referred to in the letter are uniformly distributed and

is illustrated in the accompanying sketches, where Fig. 2 shows a right-hand hob in mesh with a right-hand worm wheel. The axis of the hob is at right angles to the axis of the wormwheel, and if a section were taken on the line A B the teeth of the hob would appear like rack teeth and the teeth of the worm wheel like spur-gear teeth in mesh with a rack. This is shown in Fig. 1. When a worm and wormwheel are cut as they should be, the sectional view of their teeth, taken in a plane at right angles to the axis of the worm wheel, will appear like correctly formed rack and spur-gear teeth. But if this sectional view does not contain outlines of teeth that are conjugates of each other-in other words, that are properly formed-there has been some error made. Fig. 3 shows a right-hand hob cutting left hand teeth in a wormwheel and it will be evident that the sectional view would have to be taken on the line CD in order to show outlines of conjugate teeth. This is the position of the hob while it is doing the cutting, and a worm would have to occupy the same position as the hob to run perfectly with the wheel. When the lefthand worm that is to run with the wheel in Fig. 3 is placed in position, however, its axis will be parallel with the line EF, and it is evident that its teeth will not mesh correctly with the teeth of the worm wheel. The sketches, of course, are drawn in an exaggerated manner in order to better show the point it was desired to bring out.-EDITOR.]

A MILLING ATTACHMENT FOR THE DRILL PRESS.

Editor MACHINERY:

Everyone knows that a milling machine is almost indispensable in a machine shop, but it is sometimes impossible for a small shop to add so expensive a machine when first starting out. The writer was at one time connected with such a shop engaged in building small gasoline engines, for which

B

M

Industrial Press, N. F

B

Fig.2

Hobbing Right and Left-band Wormwheels.

F

Fig.3

show that the worm thread had a good contact with the teeth of the worm wheel. Practically considered, it appears to make no difference whether a wormwheel is cut with a right or left-hand hob, and with ordinary pitches and sizes of teeth it would be difficult to detect any error arising from the use of a hob of the wrong hand. Theoretically, however, the teeth will not be of the correct shape unless the cutting is done with a hob of the same pitch as the teeth of the wheel. This

Details of Drill Press Attachment.

a large number of cut gears were required. These, after being turned, were sent to an outside shop to be cut, and it occurred to me that a lathe or drill could be fitted up in the shop to do this work. The drill press attachment shown in the sketch was therefore constructed.

A is the table of a drill press; B is the spindle carrying the arbor C, which may be fitted with any kind of a milling cutter. The lower end of arbor C runs in the adjustable bearing D. The bed E of the attachment is fitted with a carriage G, which is fed in or out by the screw and handwheel K. On this carriage is a table H, which slides at right angles with the movement of the carriage, and carries the

centers F and the dividing head M. The feed of this table is operated by the handle L. We thus had all of the feeds found on a milling machine-the carriage feed corresponding to the vertical, the table feed to the horizontal, and the drill press feed to the cross feed. These are, of course, all hand feeds, but they could be arranged for power with a little complication. If an accurate dividing head is provided exceedingly good results can be obtained with this attachment.

This fixture is also very handy for end milling, as a vise may be mounted on the table as shown at J; and last, but not least, it is a very handy attachment for all kinds of drilling. M.

THE CARE OF PATTERNS.

Editor MACHINERY:

Patterns that are in regular and constant use ought to be returned from the foundry at quite frequent intervals, and in addition to any other needed repairs, should receive two or three coats of varnish. For lack of such slight attentions, many patterns become wrecks long before their usefulness would otherwise have ceased.

There has been some discussion lately in some of the mechanical papers, as to what is the best method to use in varnishing patterns. The common practice, hereabouts, is to first give them a moderately thin coating of dead black shellac varnish, which, after it has got thoroughly hard and dry, is rubbed down with No. 0 or 00 sand paper; then holes are waxed or puttied up, small wax or putty fillets are run, and then a couple of coats of good luster black shellac varnish put on. In New York or in Philadelphia I think it is customary to use orange shellac instead of black; I doubt if there is any particular advantage in this, however.

For this work the patternmaker should be particular to keep his hands very clean while constructing the pattern, or the work would get so very soiled that it would look badly when finished. If the pattern was made of mahogany, I fear it would show many dark streaks, if made by some of us whose hands perspire much in warm weather.

At one time we had occasion to use some close-grained hardwood for some patterns, and we chose either straightgrained cherry or rock-maple, and found that it was impossible to make the black varnish stand much usage. It seemed to peel off, or wear off, very easily, so we had recourse to dry white lead mixed with the orange shellac, which gave a pink tint to the work. Probably, by the use of suitable pigments, almost any desired shade could have been produced. We found this to be the most wear-resisting of anything we have ever tried. The most serious objection to its use seems to be the "cuss words" emanating from those working who are unfortunate enough to have to make alterations on such patterns, for the compound forms a very hard, sheet-iron like coating, which plays havoc with edge tools.

Since any varnish we may use merely forms a thin skin, or coating, on the surface, I have often wondered why it would not be a good idea to first give the patterns a coating of linseed oil that would strike in deep, and thus tend to better preserve the wood from shrinking and swelling, and then to varnish them as is usual.

One thing I have noticed is that patterns returned from some foundries, where they have been cast from only a dozen times, are in much worse condition than similar patterns returned from other foundries where fifty or one hundred castIngs have been made. I well remember one notable instance of this kind. Thinking that, if I should "jump" on the foundryman, he would deny any wrong doing, I took a different method and gradually drew him out. I said to him: "I should think you would have turned the hose on those patterns, instead of leaving them covered with damp sand." "That is just what I did," he replied. "I gave them a thor ough washing." "Well, then," I said, "why didn't you stand them up against the steam pipes and dry them off quickly, instead of letting the water remain on them and soak into the wood," and he replied that he did, and that the pipes were nice and hot, and he gave them a thorough drying, letting them stand there over half an hour, "so they would get dry clear way through"-and I thought of all those glue joints!

In other instances it would seem as though the patterns, when being returned from the foundry, were laid in the bottom of the wagon, and the castings then piled on top, thus avoiding the danger of any of the patterns dropping off and getting lost, which, of course, would be deplorable. Incidentally the patterns got a few bruises, where the teamster did not drive very carefully over the cobblestone paving, but the castings arrived without serious damage, which appeared to be the main thing to consider. There would have been evidence of the possession of brains, had the driver wrapped those patterns up in an old blanket, and tucked them up forward under the seat, but then he probably "wasn't paid for furnishing brains," as the Irishman said when expostulated with one day for working out in the hot sun at the risk of injuring his brain. "Begob," he said, "do you suppose I would be doing this kind of work if I had any brains?"

W. A. SYLVESTER.

CASES FOR KEEPING BOLTS, WASHERS, ETC. Editor MACHINERY:

It is well known that much time is lost in a machine shop owing to the fact that bolts, washers, clamps, etc., are usually left where last used, and, in consequence, when again desired considerable time is spent in hunting them up. To avoid this if one or two cases, similar to those shown in Fig. 1, are provided they will be found of great service.

In the case shown the uprights and shelves are of 1-inch lumber, the back of inch. On the front of each shelf is a strip of wood projecting about 4 inch which keeps the bolts,

etc., from falling off. On the sides of the case are fastened a number of rods, shown in Fig. 2, for holding washers. On the front of each shelf and below each rod is tacked a card bearing the size of the bolt or washer that is to be kept on that shelf or rod. If a sheet of mica or of transparent celluloid is tacked over each card it will prevent it from being soiled or defaced. A strip of wood along the top of the rack bears the inscription: "Keep Clamps, Bolts and Washers here when not in use.-Superintendent."

These cases are much appreciated by the workmen, who follow the directions without any trouble. H. R. ASH. Chicago, Ill.

REGARDING CHUCK WRENCHES. Editor MACHINERY:

In the notes on the Skinner Chuck Company's shop mention is made of the one advantage possessed by lathe chucks hav ing projecting screws over chucks having flush screws. That is, the single-end wrench used on projecting screws affords a greater leverage for the same weight and length of handle, and is handier to use than the double end wrench necessarily

employed on the ordinary flush-screw chuck. The double-end wrench is awkward and unhandy to use, especially when a piece larger than the chuck is being gripped. On the other hand we all appreciate the danger of lathe chucks having projecting screws and many can testify to it from personal experience in which they have lost generous patches of skin or have received more serious injury by coming in contact with the screw heads of a rapidly revolving chuck.

What I wish to suggest is that the flush-screw chuck be made so that it will have the advantage of the projectingscrew type, without its dangers. A single-end wrench could be used just as well on flush screws as on projecting screws provided the counterbore around the squared ends was made large enough to take in the end of the wrench, a feature of contruction that so far as I can see would be entirely unobjectionable. I have seen a single-end chuck wrench rigged up for a flush-screw chuck by cutting the wrench in two and drilling a new hole for the handle close to the end having the squared hole. The handle was then put in so that it projected on one side of the wrench only, thus making a poor sort of single-end wrench, but one that was better adapted to rapid chucking than the ordinary form of double-end wrench. By all means let us have flush screw chucks adapted to the use of singleend wrenches. F. EMERSON.

Newark, N. J.

RECENTERING AN ARBOR.

Editor MACHINERY:

I was recently required to fit a tool-steel center into one end of a large special arbor, the original center of which had never been properly casehardened and had given out in a short time. The arbor is used on very fine work, and my instructions were to make it run perfectly true. As I succeeded in doing a first-class job, the method I used may be of interest to some one.

I first placed the arbor in the lathe, with one end on the live center, running the body of the arbor in the steady rest. A piece of thin, hard sheet brass long enough to encircle the arbor was used as a protection from the jaws of the steady rest, one end being bent to keep it from turning with the work. Hold-back bolts were used to keep the arbor against the live center. A tapered hole was then bored in the end of the arbor 11⁄2 inch deep and slightly recessed at the back, care being taken to have a round, smooth hole.

New Center for Arbor.

Industrial Press, N. Y.

The steady rest was then removed, and a piece of toolsteel 6 inches long was placed on the centers of the lathe. the ends faced off, and one end turned back for about an inch. The steady rest was then called into requisition again, running one end on live center and the end which was turned, in the steady rest, using hold-back bolts as before.

The center was then cut into the end with a centering tool to the required size and polished very smooth, after which the steady rest was taken off and the piece placed on the centers of the lathe, and one end turned to fit the tapered hole in the end of arbor, allowing .005 to grind off after being tempered.

The piece was then partly cut off as shown in the sketch, and after being hardened and ground to size on centers was easily broken off and driven in the end of the arbor. The arbor when placed on centers ran dead true and was pronounced very satisfactory. R. B. CASEY. Schenectady, N. Y.

CUTTING KEYWAYS AT RIGHT ANGLES. Editor MACHINERY:

Having recently to cut two keyways at right angles in a shaft and cam, I used the method shown in the sketches which may be of use to some other planerman having a similar job to do.

Fig. 1 shows the method for cutting the keyways in the shaft. The single arm spider a was held fast on the shaft by the setscrew, and the adjusting screws bb were set so that the distances cc should be equal to the distances of the center of the shaft from angle plate d and from the planer platen respectively. Having cut one keyway in the position shown the shaft and fixture were turned, as shown by the dotted lines, and the second keyway was cut, necessarily at right angles to the first.

A hint for the settlement of strikes and other labor troubles, arising from a disagreement or misunderstanding between employers and employees, is to be found in the means adopted for the settlement of the great steel fight of 1900, when Messrs. Carnegie and Frick were at odds. Word reached New York that the papers for the famous suit were to be drawn and that a conference was called at Atlantic City. Lawyer James B. Dill was summoned, and the simple plan used by him for the settlement is thus described in the World's Work: In the words of an attendant at that memorable meeting: "Dill took in the situation at a glance. Going straight to Mr. Carnegie, Dill asked him to write out his views and note what he wanted. He did so. Mr. Frick did the same thing. Taking both memoranda, Mr. Dill locked himself in his room and did some hard thinking. Brushing aside non-essentials, he busied himself with what was vital. Then he got both gentlemen to agree to let him settle the dispute, and within a few days he showed each how the company could be recognized on lines satisfactory to all. It meant several millions more for both Mr. Carnegie and Mr. Frick; so Mr. Dill's suggestion was accepted as the solution of a very difficult problem. Had the fight continued and the whole matter been rehearsed in the courts no one knows how serious the consequences might have been."

The Aluminum World says that Dr. Goldschmidt's thermit powder for alumino-thermic welding of iron, etc., is furnished by a Paris firm in lots of 50 kilos (110 pounds) at 2.75 francs (55 cents) per kilo (25 cents per pound). The ignition powder costs 10 francs per kilo (90 cents per pound).

THE IMPROVED ACME BOLT CUTTERS AND NUT TAPPERS.

The Acme Machinery Co., Cleveland, Ohio, the well-known manufacturers of bolt cutters and nut tappers, have for some time past been making and experimenting with various designs of automatic bolt threaders and nut tappers, with the idea of perfecting the same and placing upon the market, but not until the present have they reached the state of perfection desired to make the machines perfectly automatic and reliable. Many difficulties were necessarily met in the designs of such automatic machinery, but these have finally been overcome in a way to make them very reliable and even self-protective,

arranged so as to reverse and back out of the nuts quickly after tapping, and, furthermore, their driving connections are so arranged as to immediately reverse and back the tap down the instant a nut without a hole or any other obstruction is met, thus preventing the breakage of taps.

Fig. 1 is a side elevation in section of the nut tapper showing the course of the nuts and the tapping mechanism. The hopper, or nut receptacle, H, which is divided into six parts by partitions, receives the blank nuts and, by means of the stationary plate at its bottom with a hole in one side of it, discharges a portion of them at intervals onto a revolving or centrifugal plate beneath. This centrifugal plate works

for they throw themselves out of gear if defective or improperly sized pieces are presented to be machined, and, furthermore, great rapidity of work has also been incorporated in the design. The bolt threaders have a capacity of threading 8,000 %-inch bolts in ten hours, while the nut tappers will tap 16,000 %-inch nuts in ten hours, and the attendance required is so small that one man can easily attend to ten of the machines of either kind.

The engraving, Fig. 2, presents an exterior view of the improved nut tapper as now made. It consists in general of a nut hopper and feeding mechanism which feeds the blank nuts down into nut holders in readiness for the taps, which then come up from below and tap them out. The taps are

the nuts to its outer edge where they find entrance to the inclined nut chutes, R that lead them down to the taps. At the bottoms of these chutes is the mechanism M for rejecting the threaded nut from the nut holder and putting in its place another blank for the next operation, and the mechanism is fitted with a relief spring attachment for the purpose of throwing any particular chute out of gear if a ragged nut or piece of scrap gets in the way in it, so that there is no danger of breakage.

There are four nut runways leading to four nut holders N, and the tapping is accomplished by four vertical tapping spindles S which are arranged to run upwards into the nuts, guided by lead screws A running in pairs of split nuts T at