ROSE-ENGINE. 



centre of the lathe, to adjuft it to the diameter of the work 

 which is turning. The foot has a ftrong cylindrical pin 

 fixed upright in the end of it, and this is fitted into a corre- 

 fponding focket S, formed out of a folid piece, with the 

 lower Aider K of the reft ; a clamp-fcrew in the fide fixes the 

 focket faft upon the pin, and there is a wheel s, cut with 

 notches, at the bottom of the focket, with a catch /, fixed 

 upon the foot R, to engage its teeth and hold it faft ; by 

 which means the Aiders, K, can be fixed, and held faft at any 

 required angle with the mandrel, for purpofes we (hall here- 

 after mention. 



The upper part of the flide-reft confifts of two hori- 

 zontal Aiders, K aftd^, placed in directions perpendicular to 

 each other ; to ene of thefe the tool is firmly attached,, and 

 by means of fcrews with handles, the Aiders and the tool 

 can be moved in any direction, to follow the tool to the 

 work ; K, in both figures, is a frame of metal, formed from 

 the fame piece as the focket S ; its upper furface is made 

 flat, and upon this a Aider, or flat plate, ee, is fitted, to move 

 with freedom and precifion. A fcrew is mounted in the open- 

 ing of the frame, and is tapped into a piece of metal, projeft- 

 ingfrom the lower fide of the Aider, fo that the fcrew, when 

 turned round by a handle d, fitted on its fquare end, advances, 

 or draws back the Aider, which is guided in a right line by 

 two pieces of brafs, fcrewcd to the under fide of it, to form 

 a dove-tailed groove, to which the edges of the frame K 

 are fitted very accurately : upon this Aider a frame, or two 

 rulers, are fcrewed, having a fecond fteel Aider g, fitted in the 

 dove -tailed groove formed between them, and provided with 

 a fcrew i, as the former, to move it. This upper Aider 

 carries a piece of metal, with a fquare hole through it, in the 

 direftion of its length, to receive the tool k, and a fcrew 

 at top to faften it in. The Aide-reft being mounted in the 

 manner of fig. 6, upon the bed of the lathe, the upper Aider, 

 g, is parallel with the mandrel, and the lower one perpen- 

 dicular thereto. For turning flat or face work, the tool 

 is put as there (hewn. Now, by turning the fcrew, i, of 

 the upper Aider, the tool advances to a contaft with the 

 work, which is mounted in a chuck, as in the figure ; then 

 by the other fcrew, d, it is moved acrofs the face of the 

 work, turning it as it proceeds to a perfectly flat furface. 

 For turning a cylinder, mounted between centers, the Aide- 

 reft is to be turned one quarter round upon the pin in the 

 focket S, fo that the upper Aider will be perpendicular to the 

 mandrel, and the lower one parallel thereto ; in this cafe, 

 the upper Aider muft be moved, to adjuft the tool to the dia- 

 meter of the intended work, and the lower Aider is moved by 

 its handle d, to carry the tool along the length of the cylinder, 

 and cut it as it goes. The whole reft can be fixed at any part 

 of the bed, and can be moved inftantly if required. The Aide- 

 reft will alfo turn cones by the following contrivance : the 

 plate, or dove-tailed groove fupporting the upper Aider, g, 

 may be turned round upon the plate ee, and taltencd at any 

 inclination by a fcrew paffmg through a circular groove in 

 the plate. By this means, the upper Aider is inclined, in 

 any required angle, to the mandrel, and will then turn a 

 cone, either hollow or folid. The flide-reft prefents the 

 tool fo firmly to the work, that it will not retreat in the 

 leaft when any protuberance comes by, but cuts it away, 

 if the drain is not fo great as to break the tool : but of this 

 there is no danger if it be properly managed, becaufe the 

 fcrews advance the tool fo flowly, that there is no need to 

 pufh it forwards fuddenly, as it is often unavoidable in turn- 

 ing by hand. The Aiders are often divided into inches and 

 lubdivifions, by which the work can be made cxaftly to any 

 dimenfions without trouble, or two things may be fitted 

 exactly together. The upper Aider, g , has a graduated arc to 



Vor.. XXX. 



(hew the angle of inclination which it makes with the lower 

 one, when fet for turning cones, fo that a hollow cone 

 being bored out in a chuck, a folid plug may at once be 

 turned to fit it, without trial, the reft making it certainly 

 of the true angle. 



The lathe is put in motion either by the hand, or by the 

 foot of the fturner. The latter, when the work is to be 

 turned or reduced to the circular figure, as in any common 

 lathe ; and the former, when the work, after being turned, 

 is to be ornamented, an operation which, from its delicacy, 

 requires a very regular motion. 



When the machine is turned by the foot, it is done by the 

 prefture upon the treadle E, which ac\s upon the crank C, 

 on the axis of the foot-wheel, or fly-wheel, D. The motion is 

 communicated from the treadle by a crank-hook, or con- 

 necting rod, a, faftened to the crank of the wheel, by a collar 

 embracing and turning round at the upper end. When the 

 foot pulhes down the treadle, it gives the wheel a rotative 

 motion ; and when the crank has been drawn to the loweft 

 point, the momentum which the wheel has thus acquired, 

 draws up the treadle, and thus, by the alternate preflure of 

 the foot, and the momentum of the wheel, the motion is 

 regularly continued. The wheel is made of caft iron, and 

 fixed on the extreme end of the axis ; it has two rims of 

 different fizes, and the furface of each is made conical, and 

 cut with three annular grooves, which are receffed, with an 

 angle at the bottom, fo as not to have a flat bottom. This 

 form is advantageous, on account of the band having more 

 power to turn the wheel F. Thefe different grooves are 

 made, in order to give different degrees of velocity to the 

 lathe, or to increafe the power. The axle of the wheel is 

 made of wrought-iron, except the pivots or centers, and it 

 is bent in the middle to form the crank C : the pivots at the 

 ends are made of hard fteel, welded to the iron parts of the 

 axle. The band which cannefts the fly and mandrel is made 

 of catgut, of fuch thicknefs as the nature of the work may 

 require, and is either fpliced at the joining of the two ends, 

 or they are faftened together by a fteel hook and eye. The 

 band may be either tightened, by (hifting it to other grooves 

 in the great wheel, or in the pulley F, of the mandrel ; or 

 otherwife by a Aiding-piece in the leg B, which is regulated 

 by a fcrew x. 



The motion for the hand is given by a fmall handle O t _fig. 6; 

 this is fixed upon the end of a fpindle, which at the other 

 end carries a fmall wheel N, communicating by a band with 

 the great wheel D. The fpindle is lupported in a frame, 

 which is attached to the lathe-frame, by a centre or joint, on 

 which it can be raifed up, and fixed by a toothed feftor, to 

 tighten the band when it ia required. 



The pulley F has three or four grooves, of different fizes, 

 to receive the band, and by this means the mandrel may be 

 turned with different degrees of velocity, and made to ac- 

 commodate itfelf to the length of the band. The wheel 

 N is made in the lame manner. 



When a piece of work is to be made in the rofe engine, 

 it is firft turned true to the fize and figure, and then 

 poliflied, before it is ornamented : therefore the machine is 

 lirft fet to turn circular. For this purpofe, the piece n,_fig. 7, 

 is withdrawn, fo as to be beyond the reach of the rofette, and 

 a head at 2, Jig. 6, being turned, it fhoots a double bolt, 

 which locks the frame G H faft in its perpendicular pofltion ; 

 that i;, when the point of the back centre-fcrew L will be 

 exactly in the line of the mandrel, the frame being thus ren- 

 dered immoveable, the machine will turn the lame as any 

 common lathe. If the work is of conlidcrablc length, it 

 mull be fupported at the end by the back centre L, at 

 leaft whilft it is turned circular, previous to being ornamented. 

 4 D The 



