Unlike firearms, swords were not standardized until 1786. Even then, standardization only came in terms of the blade dimensions, entire standardization only fully appeared with the 1796 pattern. Prior to 1786, the infantry officer’s symbol of authority was the spontoon. A staff-like item, rather impractical for fighting but useful for directing troops. Though officers did also carry a sword, it was often a style of their choice and privately purchased. For many the style chosen was of the small-sword or hunting sword variety or a style known as a short sabre which can be found under the Slot Hilt category.
As war evolved in Europe and abroad, the spontoon was gradually laid aside in favour of the sword. “The [official] order abolishing it and substituting the sword in its place was issued by the Adjutant-General on 3rd April, 1786:
‘His Majesty having been pleas’d to order, that the Esponton shall be laid aside, & that, in lieu thereof the Battalion Officers are, for the future, to make use of Swords, it is His Majesty’s Pleasure, that the Officers of Infantry Corps, shall be provided with a strong, substantial, Uniform-Sword, the Blade of which is to be straight, & made to cut & thrust;- To be one Inch at least broad at the Shoulder, & 32 Inches in Length: – The Hilt, if not Steel, is to be either Gilt or Silver, according to the Colour of the Buttons on the Uniforms – & the Sword Knot, to be Crimson & Gold in the stripes, as required by the present Regulation [the 1768 Warrant].’’
– Brian Robson, Swords of the British Army – The Regulation Patterns 1788 – 1914, Revised Edition, pages 142-143.
The blade style is known as a spadroon type. Though there are examples of diamond-shaped blades as well – there is one example of the diamond type in the 1796 pattern examples. I have seen just one example with a curved blade – which I believe may have been noted as having been a private purchase.
As noted earlier, it was primarily the blade dimensions which were specified and left the field open for hilt design, aside from colouring. There were three typical hilt patterns with minor variations. The first example is composed of a “D” guard with five balls moulded into the guard, often called the five ball hilt (an example below, but lacking the balls). The second (which I have yet to acquire an example) is the slot hilt. The third is the rigid shell guard (examples below).
There is some debate among authors as to how or when these hilt styles evolved and some are thought to have already been in use by the time of the American War of Independence between 1775 and 1783.
For more in-depth information on the 1786 pattern see Brian Robson’s Swords of the British Army or Harvey Wither’s book British Military Swords 1786 – 1912.