What is the Difference Between a Penknife and a Pocket Knife?

In today’s blog, Peter Smithurst, Curator Emeritus of Historical Firearms at the Royal Armouries explains the difference between a penknife and a pocket knife.

I was asked recently about terminology in cutlery, especially pen and pocket knives.

Firstly, when is a penknife a pocket knife?

Traditionally a penknife was used of course for cutting a quill pen. Its blade was fairly small and had a razor-edge. To enable it to hold an edge, the blade was also very hard which also made it very brittle and easily chipped or simply broken – they are often found damaged because people used them for other things like sharpening pencils and finished up taking a chunk out of the blade. A pocket knife was much tougher – its blade is not so brittle so it can be used for other things like whittling bits of wood or taking insulation off electric cable or cleaning out pipe bowls and the thousand other things knives are useful for doing. The versatile nature of the general purpose knife, though doubtful that it had a folding blade, is mentioned in Chaucer’s ‘Reeve’s Tale’ – “a Sheffield thwytel bear he in his hose – the thwytel being the crude knife”.

Back to pocket knives – or are they penknives? Another little pearl of wisdom; traditionally (in the cutlery trade at least) if a knife has 2 blades and they are pivoted at opposite ends, it is a penknife; if they are pivoted at the same end it is a pocket knife! Usually both types have a small ‘pen blade’ but it is never used as such these days, unless you write with a quill! If there are more than 2 blades then it is a pocket knife, or a specialist knife such as a ‘coachman’s’, or a ‘sportsman’s’ – but never a penknife.

The fun doesn’t end there. There is some interesting terminology to compound and confound. Best shown in a diagram I drew many years ago:

Diagram of the anatomy of a pocket knife drawn by Peter Smithurst. © Peter Smithurst.

The ‘choil’ is a small nick at the junction of the blade with the shoulder of the ‘tang’. Its purpose seems to have been lost in the fogs of antiquity! The ‘kick’ is a small projection on the tang, usually of the pocket blade, so when it snaps shut, the edge does not strike the spring and become damaged. Pen blades do not usually come anywhere near making contact with the spring so rarely have a ‘kick’. What isn’t shown is the ‘French nail’ which is a long straight ‘nail nick’ as opposed to the crescent shaped one shown above. A swage in this context is a bevelled back edge of a blade. The ‘pin’ is a rivet used to hold the ‘covering’ on, which can be almost anything from gold to horn or wood. In fixed blade knives, the scales are usually the coverings – again a variety of materials were used.

Just to give you an idea of how good the pen and pocket knife craftsmen were, blades were hand-forged and were then hand-ground on a revolving sandstone (later emery) wheel about 2 feet diameter and around 4 inches wide with its edge running in water (to keep the dust down and to stop the blades from ‘burning’. They were then polished using a leather faced edge of a revolving wooden wheel dressed with crocus powder (rouge) to give them a depth of polish never seen today. It is very different from buffing. And it was all done with amazing accuracy.

This is a packet of pen knife blades I bought along with a hoard of other stuff from a cutlery company that was closing down in the mid 1980’s. I could not stand by and see it all go in a skip. This packet had not been opened since the blades were put in there around 1900.

A packet of penknife blades, purchased by Peter Smithurst. © Peter Smithurst.

They were carbon steel, crocus polished, not stainless, and still retained their lustre after being protected from Sheffield’s foul atmosphere (where even sparrows coughed) for decades by nothing more than a bit of oil and brown paper. What may appear as rust is old congealed oil!