B O L 



•ailed hcd-bo'its. Befides thefe there are bolder, eye, breech- 

 ing, garnilli, joint, ilool-bed, and axle-tree bolts. See Car- 

 riage. 



Bolts, in Cmjpenlry, denote pieces of wood cleft with 

 wedges, in order to be fplit into laths. 



Bolts, or iron pins, in a Si!i[>, are of feveral forts, of 

 which the mod common have fniall round heads, and are 

 ufed to unite two or more pieces together. Some have 

 round flat heads, called fau.-er-heads, with a mortife in the 

 other end, or point, and are iifed to fallen moveable pieces 

 to thofe that are fixed ; others have an eye at one end, for 

 ladling or hooking blocks, &c. :md are driven in mad-heads, 

 yards, caps, &c. Some have a fquare part left at ^the back 

 of the eye, that they may not be driven on the eye, and en- 

 danger fplitting. Bolts are frequently diftinguidied accord- 

 ing to the places where they are ufed ; as, chain-bolts, bolts 

 for carruigcs, &c.; rinir-bo/ls, ferving for the bringing-to of the 

 planks, &c. ilrlve-bolts, ufed to drive out others ; fet-bolts, 

 employed for foi'cing the planks, and other works, and 

 bringing them clofe to one another ; rng-lolts, on each fide 

 full of jags or barbs, to keep them from flying out of their 

 holes ; clench-bolts, thofe which are clenched or fadened at 

 the ends where they come through ; fore-lock-bolts, made 

 like locks with an eye at each end, whereunto a fore-lock of 

 iron is driven to prevent Halting out ; furl, or fender-bolts, 

 made with long and thick heads, druck into the ontermod 

 bends or wales of a diip, to fave her iides fiom bruifes and 

 hurts. The following machine for drawing bolts in and out 

 of diips was invented by Cajnani Bolton of the Navy, and 

 obtained from the Society of Arts their prize of the gold 

 medal. A niodtl of it is prefervcd in the repofitory of 

 the fociety for the ufe of the public. The dcfcription 

 of it (See Tranfaftions of the Society, vol. xvi.) is as 

 follows : 



AAA AAA [Phile ofSh'ips) is the frame of the machine. 



B, a cylindrical tube, k:iving a female fcrcw in the infide. 



C, a wheel with teeth attached to the cylinder B. D, an 

 endlefs fcrew adapted to the wheel C. E, handle of the 

 vinch. F, the bolt drawing out. G G, blocks to fupport 

 the frame. H, a hollow piece of dctl, having on its out- 

 fide a male fcrew, whofe threads work within the female 

 fcrew in the cylinder B. To this piece of deel the bolt is 

 to be rivcttcd. I, a femicircular piece of deel, which is to 

 be introduced into the notches <i:i H, when a timilar notch 

 has been cut in the head of the copper bolt, which by this 

 means is prevented from turning in H, while drawing. K, 

 the bolt, as prepared to receive the machine. L, a Heel bar, 

 fomewhat fmaller than the bolt to be drawn, having at one 

 tnd a male fcrew. A, and at the other end another male 

 fcrew that fits into the female fcrew in B. M, a fedlion 

 of a male fcrcw, having a fqnarc hole larger than the 

 bolt. N, a bolt with a male fcrcw at one end ready to be 

 drawn in. 



The machine, of which a plate is annexed, confids of a 

 frame fupporting a cylindrical female fcrew tube. On this 

 tube is mounted a wheel with teeth adapted to an endlefs 

 fcrcw fitted to the frame, and woiked by a handle. 

 7'o (Iraiv the bolt out. 



The head of the bolt mud be cut otf, and a hole made in 

 the timber big enough to receive the male ftrew H, which 

 is put over the bolt : a flit is then to be made, either by a 

 faw or cold chidel, in the head of the bolt, to receive the 

 key I, and which corrcfponds to the flit in H ; the bolt 

 head is then to be rivetted as firmly as poflible upon H: the 

 cylindrical tube, B, is then to be fcrewed on, turning the 

 whole machine round till it can be done no longer, when 

 the endlefs fcrew is to be ufed. If the machine is of a pro- 



B O L 



per ftrength, and the rivetting well done, the power is fuck 

 as to extraft the bolt or break it, but generally it will be 

 drawn out uninjured. 



To draw bolts intojl.nps. 



It will be necedary to have a'bar, L, which is recommended 

 to be made of deel, long enough to pafs from the infide to 

 the outfide of the diip, and fomewhat fmaller than the cop- 

 per bolt intended to be drawn in. This may be called a 

 conduftor. On one end fliould be a male fcrew, a ; the 

 bolt to be drawn in diould be tapped at one end to receive 

 the male fcrew, a, on the condudor, and at the other end 

 fliould be another male fcrew that fits into the female fcrew 

 in B ; after which the operation is the fame as drawing a 

 bolt out, and the machine fliould be applied accordingly. 

 When the bolt arrives at its dedined place, it may be lecured 

 on the infide by a nut, which is as good a way of fadening 

 as clinching, and much more expeditious. 



This machine, though only of the height of eighteen 

 inches, will draw bolts in or out of any length; tor, after 

 the bolt has rifen to the top of the tube, it will only be ne- 

 cedary to fcrew the machine back, and follow up the work 

 with blocks of timber, as reprefented in the drawing. 



Ni:lc. If the upper part of the hcle in H be made fquare, 

 larger than the round hole as fliewn at M, and the head of 

 the bolt rivetted into it, it will do away the iiectfiity of tlie 

 key, I, render the inachine Itfs complicated, and fave much 

 time and trouble. 



Bolts of an Anchor, are cylindrical iron pins for faden- 

 ing the tw^o parts of the dock together. 



Bolts for -whirls, in Rope-making, are large iron pins 

 with round heads, driven in the board over the crank-wheel 

 for the whirls to run on. 



Bolt is alfo ufed for a meafure or certain quantity of can- 

 vas, amounting to twenty-eight ells. 



Bolt of filk or dud' denotes a long narrow piece, of in- 

 definite meafure. 



Bolt, peafe, in Efftx, denotes the peafe-draw, when the 

 grain is threflied out of it. 



Bolt, thunder. See Th UNDER-io//. 



BoLT-ro/ii", in Sea Language, is a rope fewed to the edges 

 of a fail, to prevent it from rending by the force of the 

 wind, or any other caufe. 



A bolt rope fliould be made of fine yarn fpun from the 

 bed hemp, and fewcd neatly on with good twine. To avoid 

 dretching, the rope mud be kept well twided while fewing 

 on, and care taken that neither too much nor too little 

 flack is taken in : that part of the rope at the leech of the 

 fail is to be crofs ditched at every foot in length, at every 

 feam, and in the middle of every cloth at the foot, with 

 three crofs ditches : four crofs ditches diould be taken at all 

 the beginnings and fadenings off ; the firll ditch given twice, 

 and the lad three times. Small fails have two crofs ditches 

 at every feam, and three at every fadening off. 



BOLTED y/oiic, that which has palTed through the 

 bolter. 



BOLTEL, in Building, any prominence or jutting out, 

 as of a piece of timber, end of a beam, or the like, advancing 

 beyond the naked of the wall. 



BOLTERS, or BouLi ers, a kind of fieves for meal, 

 having the buttons made of woollen, hair, or even wire. 

 The word feems derived from the German, icutal, a Jievc ; 

 whence alfo bentelcn, to bolt. The bakers ufe bolters, 

 which are worked by the hand ; millers have a large fort, 

 WTOught by the motion of the mill. 



BOLT-HEAD, a veflil ufed by the chemids, the fame 

 as matrafs ; which fee. 



Bolt- he AD, in Geography, a promontory of England, on 



the 



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