Terry Gordon of HNT Gordon & Co explains how he developed the square handle design on his spokeshaves.
I've been asked several times about why we use squarish handles on our spokeshaves so I thought I would explain the ergonomics of why we do it.
First I will tell you about buying a cheap plane in Thailand long before I was making planes. It was the typical Asian style, similar in looks to the smoother we make but it had a round handle as opposed to an oval shaped handle that these planes normaly had. When I took it home and tried planing a bit of wood with it, it just felt wrong in the hands. At the time I didn't know why but it certainly didn't get much use.
??Later on when I started making a smoothing plane and I tried to make an oval shaped handle to fit I soon realised there was a lot more work in making a nice oval shaped handle (that felt comfortable in the hands when using this type of plane) than buying a piece of round dowel and using it as a handle. Also, fitting a round dowel to the body had obvious time saving advantages.
So this was my first dilemma when I started making planes, should I go for the simple cheaper option that would make the cost of this plane less, so I could in theory sell more? Or should I go for the handle that felt right when using the plane and as a consequence giving the user better results. You know the answer to that. It took a lot of time to get the manufacture and fit of these handles right, but I'm glad I did it.
At this stage I still didn't analyse why the oval handle was so nice in the hands. Years ago I was fortunate enough to go to a talk presented by the late George Ingham where he explained the ergonomics of saw handles, eg how to accurately transfer the power from your arms via a correctly shaped handle attached to your tool to make it accurate and efficient.
He only gave one example and that was a tenon saw and was not about to explain this for any other tools, it was up to the listener to work that out for themselves. This was another valuable lesson for me as I was forced to sit down and work through these issues when designing tools, and George was correct in that the same/similar principles can be applied to all tools. ??So by applying these principles when I looked at the round verses oval handle on my smoothing plane I could clearly see that when you wrap your fingers around a small handle it forms an oval shape or more precisely a rectangle with rounded off corners. And that is why the round handle on that cheap smoothing plane felt uncomfortable, as it simply didn't fill the oval shaped space inside my fingers and hand.
If you look at the shape your hand forms when holding a tenon saw handle or a tote handle on a plane, the inside of your hand is an oval shape just like the shape of a good tenon saw handle or plane tote If you hold your wrist straight you will also see the oval shaped handle of these tools must lean quite a bit forward so that tool attached to the handle is in the correct position when using it at the bench. Photos 1 and 2 show this (hover over or click on them to see the numbers).
Back to the spokeshave. As photo 3 shows below, the handle is a rectangle shape and is tapered slightly back toward the user when the shave is pushed and this is to accomodate the the shape your hands make when they are holding a tool like a spokeshave.
Photos 4 and 5 show a hand with with the fingers forming the natural oval shape your fingers and hands make when wraped around something small like a spokeshave handle. Conversely if you were to grab a steel bar about 40mm in diameter, like say the monkey bars you swung on at school as a child, then your fingers and hands form a near perfect round shape that conform with the round bar shape which is comfortable and ergonomical when swinging on monkey bars. You may have also noticed when you were at school that the lower monkey bars for the little kids had a smaller diameter bar than the higher bars for the older kids and that was simply done to accomodate the size of the childrens hands. You can do this with your own hand to see the shapes it makes as you close and open your hands.??
A well made tote handle on a plane or a saw handle is perfectly shaped to accurately transfer power from your upper arm/body via a straight wrist into the palm of your hand straight to the cutting edge of a plane blade, or in the case of a saw, the centre of the sawblade. This is the correct configuration when using one hand/arm to do the work with the tool. In the case of a spokeshave, or the smoothing plane we make with a horizontal handle, these tools are designed to use both arms/hands to accurately transfer the power from the upper body and arms to the cutting edge.
When using a tool with both arms we stand directly behind the workpiece (where possible) and bring our hands close together to grasp the tool. This brings our lower arms into the tool at an angle which is where the transfer of power differs from the tote handle example. Now the golden rule when pushing or pulling any tool, for power and accuracy, is your wrist needs to be as straight as possible. The most direct power from your hand comes from the palm which is at the extension of your lower arm, and in the case of the tote handle this is where the power comes from, but where you are using two hands to move the tool this isn't achievable unless you break the golden rule of bending your wrist.
Photo 6 shows that when you hold a spokeshave handle so the handle is in the palm of your hands your wrists are clearly bent and locked in an inflexible operating mode which is highly undesireable when spokeshaving curved work. To keep a straight wrist when using both hands on a tool, the power transfer from your arms is via the various parts of your thumbs and and fingers. This transfer of power is not as perfect as the tote handle example but remember that the tote handle example is using one arm/hand to generate the force to make the tool cut, so when using two hands the force required by each hand is halved and your upper body is more in balance to create power
Photo 7 is the best and most comfortable way to hold a curved sole spokeshave to give you power and flexibility to accurately work curved shaped pieces of wood. Notice your thumbs (which do a lot of the pushing) are as low as possible to the cutting edge which minimises the roll effect.
?Another point to consider with tools used with two hands, where your fingers and thumbs do the transfer of power to the cutting edge, the position of your hands lends itself to easily pull the tool towards you with the same power and accuracy, just everything is in reverse. The same cannot be said about the tote handle design.??
Now getting back to the original question of why we use squarish handles on our spokeshaves. When your fingers are doing some of the holding for the transfer of power then the better the handle shape fits your hand, the more accurate the power transfer will be. Now lastly, but very importantly for the curved sole spoke shave, where the round sole has no support in the front of the blade, when you push or pull this tool the body of the shave will roll. To have success with a curved sole spokeshave you must be able to counter this role for the blade to remain engaged with the wood to continue the shaving. With the flat surfaces on the squarish handle you will feel the body of the shave starting to role and you will be able to easily resit that force by applying an opposing force with your hand. Conversely, if the handle was round the roll force would not be as obvious and to resist it is much more difficult because the round shape does not conform to the shape of your fingers/hand wrapped around the handle.??
This is a difficult subject to explain in writing and you may need to read it a few times, but in any case if you are not sure about this explanation I would be very happy to describe it in person with actual tools at a wood show, so don't be afraid to ask.
HNT Gordon & Co produces a range of handcrafted woodworking planes, for more information see hntgordon.com.au