86 ANNUAL OF SCIENTIFIC DISCOVERY. 



tools ordinarily employed. A circular planer, designed to supply the want 

 thus daily rendered apparent, has been patented by Mr. D. F. Mellen, of 

 Went worth, N. II., planing to any radius between one inch and twenty 

 feet by means which, avoiding technicalities as far as possible, may be 

 explained as follows : A rack is secured on the inner side of one of the 

 posts, and into this mesh the teeth of a gear-wheel, which latter is 

 mounted 011 a vertical axis on the carriage or " plate " of the planer. 

 On the same vertical axis is fixed a second gear-wheel, which may be of 

 either greater or less diameter than the first, and into this second wheel 

 mesh the teeth of a second rack. The latter is attached by an eye at the 

 extremity to a pin on the under side of a circular plate which lies in a 

 horizontal position a few inches above the face of the ordinary carriage. 

 On this circular plate, which is free to rotate or oscillate in a horizontal 

 plane, the article to be planed is secured in the usual manner, while the 

 gear-wheels, by locking on one side into a fixed rack, and on the other 

 into a rack which may be connected to the circular or face plate at any 

 point desired, compel the work to rotate or oscillate with every motion of 

 the carriage. The adjustment of the machine to planing in any curve 

 required is further facilitated by providing a set of wheels having a 

 variety of ratios each to the other, any of which may be mounted on the 

 vertical axis at pleasure. 



WOOD- SCREW ROT^feY MACHINE. 



Messrs. Wilson and Wiley, of Providence, Rhode Island, are the joint 

 inventors of a machine for making wood- screws, which equals in rapidity 

 of execution four of the best nachines now employed in that branch of 

 manufacture. The machine is termed the Wood- Screw Rotary Machine, all 

 the principal movements being of a continuous rotary character. Wood- 

 screws, termed screw-nails by some English authors, are usually completed 

 in three machines, one only of which is termed a " wood-screw machine." 

 The first takes wire from the coil and transforms it into " sere w- blank " by 

 motions closely analogous, if not identical, with those of the common 

 rivet- machine. Another machine saws a shallow score across the top of 

 the head, while the main machine, on which all the study and inventive 

 skill are necessarily bestowed, seizes the blank and cuts the proper thread 

 thereon. The thread of a wood-screw is all produced by removing the 

 metal between, there being none of the metal squeezed up as is done by 

 the ordinary dies of the machine shop, so as to make a screw of greater 

 total diameter than the original wire. The blanks being fed in by self- 

 acting mechanism, are successively caught by a pair of jaws in a revolving 

 chuck, held firmly by the head, and compelled to rotate steadily in one 

 direction, while a properly- shaped tool is repeatedly pressed against its 

 side and moved towards the point. Several reciprocating movements are 

 thus necessary, even with a sharp and keenly-adjusted tool, before the 

 thread is sunk to the required depth. Such, although usually concealed 

 with some care from the gaze of the uninitiated, is believed to be the method 



