Sunday, 16 January 2011

Handles & Ergonomics

I love whittling and spoon carving but gripping the tool for long periods causes me to get a kind of pins-and-needles, hot/cold, numb feeling in my hands and fingers.  This is probably exacerbated by some bad accidents I had when I was an arborist so I have to accept that and try to work out what I can do to alleviate it.

When we look at edge tools we’re very often preoccupied with the quality of the steel and it’s edge-holding capabilities but the handle which forms our interface with the tool is usually overlooked.
Clothes and shoes come in a range of sizes so you can choose those that most nearly fit -or if you’re feeling plush you could have them handmade to fit perfectly.  But all the tools, artefacts, utensils, implements and vessels - all the things we pick up with a handle - come in a choice of one-size-fits-all.

I was perusing the latest tool catalogue from Rutlands recently and in the section of seriously gorgeous Japanese tools came across some carving knives.
They make the claim that “ Each blade is mounted in a solid hardwood handle that is shaped to fit perfectly in the hand.”  Whose hand? A child? A giant with hands like hams?  Someone suffering from arthritis?

I decided to have a look in Wiki and see what I could find out about Ergonomics.                  
“The term ergonomics is derived from the Greek words ergon [work] and nomos [natural laws] and first entered the modern lexicon when Wojciech JastrzÄ™bowski used the word in an article he wrote in 1857.  Later, in the 19th century, Frederick Winslow Taylor pioneered the "Scientific Management" method, which proposed a way to find the optimum method for carrying out a given task. Taylor found that he could, for example, triple the amount of coal that workers were shoveling by incrementally reducing the size and weight of coal shovels until the fastest shoveling rate was reached.”                                                     
This led to such things as Time & Motion Studies and probably ultimately to our dreaded Health & Safety Executive.  The information is interesting if a little wordy and technical - have a look at it here.

I’ve recently put handles on a couple of spoon carving knives made by Duncan Chandler alias FGYT and an old Marples adze which Jon Warricker kindly reforged into a curve and tempered for me.

I tried out Duncan’s knives in the Spoon Knife Passaround early last year and one of the things which impressed me about them was the shape and size of the handles.  I bought a couple of blades from him and he supplied a template of the handle shape.  It’s similar to the American Flexcut knife handles.
The manufacturers of these claim that “The comfortable curved ergonomic handle allows for long periods of carving without hand fatigue.”  I have one and it’s OK but a bit small so I made the handles for Duncan’s blades even slightly larger than the template and they’re ideal - for me.

Side and top view, Walnut & Ash
I modelled the adze handle on a Gransfors pattern but made it fatter and again it feels perfect for my hand.

I realise that other people will have to use them, and the knives, but hopefully I have enough different shapes and sizes for them to find one that feels right in their hand.

As an aside, whilst perusing the Japanese knives in the Rutlands catalogue, I came across this one which is shaped like a small Samurai sword.
It even has a little picture of a Samurai on the handle!
I’ve never seen them advertised before but my Dad gave me one about 5 years ago and couldn’t remember where he’d bought it.  I’ve kept it mainly for trimming paper and card.  The blade is made from three layers of steel, a hardened, blue paper steel core that forms the cutting edge which is flanked by a layer of softer, tougher steel on each side.  I’ve never sharpened it so no doubt about it’s edge holding capabilities but the brass handle is dreadful - absolutely, totally unErgonomic!


Mark said...

Superb post and again, i couldnt agree more, i spent a few hours the other day perfecting the grip on a helve i made out of Ash for a Kentish pattern hatchet, everybody who has picked it up so far doesnt like it, perfect for my hand though and as im the one using it, that's all that matters.

Gorges Smythe said...

You probably won't wear that last one out trimming paper and card, so maybe the handle will suffice. The adze handle appears to be made for an honest-to-goodness working man; good job!