On arriving at Durham, he met Bland's dragoons on their march from the North to York; they loaded his waggons again for Northallerton, and would willingly have engaged them to York; but this he was obliged to decline, having promised to bring twenty-three wool-packs to Knaresborough. He was just six days in performing this journey; and cleared, with eight horses and the one he rode, as much as £20.

Some horses belonging to the Queen's Bays, stationed at Durham, were to be sold, and Metcalf, hearing of the sale, set off from Knaresborough only the day before, and arrived there in time. Amongst the horses to be sold was a grey one, belonging to one of the drums. The man who had the charge of him not having been sufficiently careful in trimming him, had burnt him severely, which caused a swelling. Had his careless conduct been known to his superiors he would have been punished for it; upon that account the matter was hushed up. Metcalf, however, having been apprised of the circumstances from a farrier whom he had got to know, determined to purchase him, judging that the horse would be sold cheap. He was not mistaken. He bought him for very little, and realised a good profit out of him shortly afterwards.

In the year 1754 Metcalf commenced a new business. He set up a stage-coach between York and Knaresborough, and conducted it himself, twice a week in the summer season, and once in the winter; and this business, together with the occasional conveyance of army baggage, employed him until his first contract for making roads, which suiting him better, he disposed of his draught and interest in the road.

An Act of Parliament having been obtained to make a turnpike from Harrogate to Boroughbridge, a person of the name of Ostler, of Farnham, two miles from Knaresborough, was appointed surveyor. Metcalf being in company with him, agreed to make about three miles of it, between Minskip and Ferrensby. The materials were to be procured from one gravel-pit for the whole length. He therefore provided deal boards and erected a temporary house at the pit, took twelve horses to the place, fixed racks and mangers, and hired a house for his men at Minskip, distant about three-quarters of a mile. He often walked from Knaresborough in the morning, with four or five stone-weight of meat on his shoulders, and joined his men by six o'clock. By his attention and diligence he completed the work much sooner than was expected, to the entire satisfaction of the surveyor and trustees.

During his leisure hours he studied measurement in a way of his own, and when certain of the girth and length of any piece of timber, he was able to reduce its true contents to feet and inches, and would bring the dimensions of any building into yards and feet.

About the time that this road was finished the building of a bridge was advertised to be contracted for at Boroughbridge, and a number of gentlemen met there for that purpose at the Crown Inn. Metcalf, amongst others, went also. The masons varied considerably in their estimates. Ostler, the surveyor of the roads, was appointed to survey the bridge, and Metcalf told him that he wished to undertake it, though he had never done anything of the kind before.

On this the surveyor acquainted the gentlemen with what Metcalf proposed; when he was sent for and asked what he knew about a bridge. He told them that he could readily describe it, if they would take the trouble of writing down his plan, which was as follows:—"The span of the arch 18 feet, being a semicircle, makes 27; the arch-stones must be a foot deep, which, if multiplied by 27, will be 486; and the basis will be 72 feet more. For the arch, it will require good backing; for which purpose there are proper stones in the old Roman wall at Aldborough, which may be brought, if you please to give directions to that effect." The gentlemen were surprised at his readiness, and agreed with him for building the bridge. The persons who had given in their estimates were much offended; and as the stone was to be procured from Renten, a sale quarry belonging to one of the masons who was there, he was unwilling to sell any to Metcalf; upon which he went to Farnham, and found good stones which the lime-burners had left (being too strong for their purpose), got them dressed at the place for a trifle, conveyed them to Boroughbridge, and having men to take them off the carts, set them, and completed the arch in one day.

Soon after, there was a mile and a half of turnpike road to be made between Knaresborough Bridge and Harrogate, for which Metcalf also agreed. Going one day over a place covered with grass, he told his men that he thought it different from the ground adjoining, and would have them try for stone or gravel, which they immediately did, and found an old causeway, supposed to have been made in the time of the Romans, which afforded many materials for the new road. Between the forest lane-head and Knaresborough Bridge there was a bog in a low piece of ground. The surveyor thought it impossible to make a road over it, but Metcalf assured him he could accomplish it. The other then told him that if so he should be paid as if he had carried the road round the bog. Jack set about it, cast the road up, and covered it with whin and ling, and made it as good as any part he had undertaken. He received for his contract about £400. He afterwards contracted for making five miles of road between Harrogate and Harewood Bridge, and received for it £1200. For a mile and a half through part of Chapeltown to Leeds, and for lengthening the arch of Sheepscar Bridge, he received £400.

The following are some of his other contracts:—Four miles of the road between Skipton and Colne, and two miles on the Burnley Road. Two miles of the road through Broughton to Marton, and two miles more through Addingham and over part of Romalds Moor, for all which he received £1350. Four miles between Mill Bridge and Halifax, and five miles between Wakefield and Chickingley Beck, near Dewsbury; and received for the same £1200. Three miles and a half between Hag Bridge and Pontefract, and one mile and a half on the Doncaster Road, from Crafton, through Foldby. For the road from Wakefield to Pontefract, Doncaster, and Halifax, he received £6400. From Blackmoor foot to Marsden, and from thence to Standish foot; also from Lupset Gate through Horbury; and also three miles from Standish to Thurton Clough; from Sir John Kaye's seat to Huddersfield; and thence to Longroyd Bridge toll-bar, in the course of which were several bridges, the whole distance about twenty-one miles, for which he received £4500.