160 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Mat, 



IRON LOCK GATES AT MONTROSE. 



" Description of a pair of Iron Gaits coiislriic/ed in 1843 for the 

 entrance to the Wet Dock at Montrose.'" By J.^Mts Leslie, M. Inst. 

 C.E. {Read at the Institution of Civil Enginun, Session 1844.) 



The frames of these gates are of cast iron, but bave the lower bar 

 and a false mitre of oak, so as to be more easilv fitted and made water- 

 tight, and they are entirely covered, on both sides, with wrought iron 

 boiler plate. They are in all their dimensions very nearly similar to 

 the gates of Earl Grey's Dock, at Dundee, which viere constructed in 

 1S34, also from the designs and under the direction of the author. 

 The entrance is 55 feet wide in the clear, and the centre of the beel- 

 post being 1 foot inwards from the face of the wall, the distance be- 

 tween the centres is consequently 57 feet. The gates are 22 ft. 6 in. 

 in height, they have a pointing (or sally) of 10 feet, and the ribs have 

 a curvature of 18 inches, on the hollow side. 



The lieel-posts, fig. 1, are of cast iron 1 foot 9 inches diameten 



Fig. 1.— Horizontal section of heel-post, 



and plan of the end of a bar. Vertical section of heel-post ana oar, 



forming a segment of a circle, somewhat larger than a semicircle, 

 which admits of their being accurately turned in a lathe; they are 

 li inch thick, at the thinnest part when finished ; but the straight 

 faces are Ij inch thick, and have snugs cast on them, fig. 4, for bear- 

 ing up the ends of the ribs, or horizontal bars, and holes for getting 

 in the hand, to screw up the bolts which fasten the ribs to the heel- 

 posts. 



The heel-posts have each a cast iron socket, fitted into the bottom, 

 working on an iron gudgeon 10 inches diameter, cast on a sole plate 

 4 feet 6 inches long by 1 foot 9 inches wide, and 2 inches thick, dove- 

 tailed, sunk and riveted into the stone, after being keyed up, so as to 

 press the heel-post hard into the quoin. 



After the hollow quoins, which are of Kingoodie stone, had been 

 tressed down and polished as nearly as possible to the circle, but be- 

 fore the gates had been framed togetlier, the heel-posts were set in 

 their places, and were kept turning round, backwards and forwards, 

 and hard keyed up, while sand and water were poured in at the top, 

 till the stone and the iron were made to touch throughout in the 

 height, so as to be perfectly water-tight. 



The mitre-posts fig. 3, are 18} inches 

 broad and li inch thick, with snugs 

 upon them for holding up the ends of 

 the bars, and two flanches li inch in 

 thickness for fastening the wooden 

 mitres. 



Holes were cast in the mitre-posts for 

 introducing an iron bar, to hold against 

 the rivets of the last row of covering 

 plates; but these holes were filled up, 

 after the riveting was completed, by 

 pins of iron, cast to fit them, and which 

 were fixed into their places by corrosion. 



There are eleven horizontal bars, figs. 4 and 5, to each leaf, distri- 



J 



ot-f-t-y 



Pig. 4.— Transverse section of a bar, and 

 elevation of heel- post 



FJg . 5.— Transverse section of the middle 

 of a bar. 



they are 2 inches thick, 16 inches broad at the ends, and 18 inches 

 wide at the middle, with two double flanches 9 inches broad and 2 

 inchrs thick on the hollow side, and 11 inch thick on the convex side, 

 excepting the lowest bar, which has only the upper flanch. 



The bars have cross ends 18 inches in height and 2 inches in thick- 

 ness, with four screwed bolts to each li inch diameter, through the 

 heel and mitre posts. 



The clap cill is cast in two pieces for each leaf, it is 8 inches deep 

 and 1 J inch tliick, with dovetailed snugs cast on it, tailing I) inches 

 into the stone; the joint between the iron cill and the stone, is closely 

 caulked in with iron cement, and the face of the cill is chipped and 

 filed, where necessary, to make it quite fair for the bottom bar to fit 

 upon; the height of the cill above the platform, is 15 inches. 



The bottom bar is of oak 12 inches thick, 17 inches broad at the 

 ends, and 19 inches broad at the middle ; it is bedded on felt to the 

 lowermost cast iron bar, and is fixed up to it by bolts H inch in dia- 

 meter screwed into the timber. 



The false mitres fig. 3, are also of oak, fitted closely into the cast 

 iron posts, and fastened by bolts 1 inch in diameter, riveted through 

 the flanches, and they are tongued down into the bottom bars. 



Both sides of the gates are lined with boiler plates, arranged so as 

 to break joint; the plates of the lower tier, averaging about 6 feet in 

 height, are i inch in thickness, and all above them are -j^^ inch thick ; 

 they overlap each other about 2s inches, and are fastened by rivets J 

 inch diameter foi the lower plates, and i inch diameter for the upper 

 plates, all riveted while hot, and made to fill up the holes completely. 

 The gates are perfectly tight f.n both sides, and were proved by hav- 

 ing water filled into the inside. 



The anchors are of cast iron 3^ inches square, dovetailed, sunk info 

 the top hollow quoin, and run in with lead. 



The wrought iron collars of the heel-posts are 4 inches by 2 inches, 

 keyed through the anchors. 



The roller segments, or railways, are 10 inches broad by li inch 

 and 4 inches thick, sunk and bolted down to the stone and bedded on 

 felt and white lead ; the upper surface is chipped and filed where 

 necessary, to make it fair and straight. 



The cast iron rollers are conical, IS inches diameter and 5 inches 

 thick, with steeled axles turned. The roller boxes are of cast iron li 

 inch thick, moulded so as to suit the bevel of the gates, and are fat- 

 tened by .screw bolts, through the flanches of the horizontal bars ; there 

 are cast iron covers, to confine the roller blocks, which slide up and 

 down within the boxes, by the action of the top screws. The roller 

 bars are of wrought iron 3 inches diameter, keyed into the blocks at 

 the bottom ; each is steadied by three plummer blocks, and each bar 

 has a coupling near the top, with a square threaded screw and a brass 

 nut at the top, working in a strong cast iron bracket, which bears the 

 whole weight of the outer end of the gate, and is fastened by screw 

 bolts, through the flanches of the horizontal bars. 



There is one sluice, measuring 3 feet by 2 feet, in each leaf of the 

 gates. The sluice frames have faces 7 inches broad and li inch thick, 

 and cheeks J inch in thickness, going quite through the thickness of 

 the gate, with a flanch on the two side cheeks, for riveting the boiler 

 plate to. 



The sluice valves are li inch thick, with flanches on the back, and 

 both the frames and valves have raised margins planed and grooved 

 so as to clap quite close. There is no brass about the sluices, but the 

 backs are covered vrith zinc plates, and all the screwed bolts have 

 zinc nuts, screwed over the iron nuts, so as by the galvanic action to 

 prevent the iron from rusting.* 



The sluice rods are 2 inches in diameter ; they have a square 

 threaded screw, and a brass nut at the top, worked by a wheel and 

 pinion under the gangway, and bevilled |gear with a crank handle 

 nearly level with the hand-rail. 



There is a gangway 3 feet 6 inches wide, supported on six cast iron 

 brackets, for each leaf of the gates ; there are fixed cast iron balusters 

 and a wrought iron hand-rail, on the convex side of the gates, and 

 wrought iron moveable stancheons with a chain along the other side, 

 which is more liable to injury from vessels. 



There is a small water-tight hanging valve in each leaf, a little 

 above low water, for running oft' any leakage water from the interior 

 of the gates, down to that level ; and there is also a pump, with a 

 brass chamber and boxes 2i inches diameter in each heel-post, with 

 a lead pipe down to the bottom, for pumping them dry; it is worked 

 by a rocking shaft, fixed to the cast iron covers of the heel-posts. 



To let the leakage water down to the pump, there is a hole 1 inch 

 diameter in each horizontal bar except the lowest. 



vicvBuou ui Deei-post 



t>Ute(} M 39 to be clsier KSetber towards the boltom, than at the top ; | 



* Rlr. Leslie has since examined the iron work of the Dundee Dock Gates, which waa 

 similarly protected, and he lound that after three years' use llie iioc had apparently lost 



Its power of galvanic action, at corrosion of the Irpn nuts \ai g(in)miii9?J,-»Septeal>{r, 

 isa. Sec. ]n|t,C.£, 



