- Joined
- Jan 6, 2003
- Messages
- 1,139
After using a Cuda Maxx Stiletto blade for a while, I started to get interested in the technical aspects of the biomechanics of knife use as well as the shape of blades. I dediced to start reading up on biomechanics first. Anyone who has knowledge in this area, feel free to jump in.
One of the first things I found were some occupational safety and health guidelines for tool design. These were interesting because they actually gave specific numbers to things like handle diameters, and because they suggest specific features that aren't present in traditional knife designs (compressible handles).
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Diameter
Handles should be cylindrical or oval in cross section, with a diameter of between 30 mm (1.18") and 45 mm (1.77"). For precision work the recommended diameter for handles is between 5 mm (.2") and 12 mm (.5"). For a greater torque large screwdrivers should have a handle diameter up to 50-60 mm (~2").
Length
A handle that is too short can cause unnecessary compression in the middle of the palm. It should extend across the entire breadth of the palm. Tool handles longer than 100 mm (preferably 115-120 mm or ~4.5") will reduce the negative effects of any compression exerted. Rounded handles will minimize palm compression on the palm still further. Keep in mind that the use of gloves requires longer tool handles.
Separation between handles
Crushing, gripping or cutting tools such as pliers or tongs are equipped with two handles. The recommended distance separating handle is between 50 mm and 65 mm (~2"). Such a range will fit both male and female users. Tools with larger or smaller spans will reduce one's maximum grip strength and may contribute to the onset of carpal tunnel syndrome.
Materials and texture of handles
To ensure a good grip on a handle, sufficient friction must exist between the hand and the handle. This is particularly important where a considerable force must be applied with a sweaty hand. Hand tools should be made of non-slip, non-conductive and compressible materials. For example, textured rubber handles provide a good grip, reduce the effort needed to use the tool effectively, and prevent the tool from slipping out of the hand. Glossy coatings and highly polished handles should be avoided. The electrical and heat insulation properties of the handles are important for power hand tools. Handles made of plastics or compound rubber are recommended. Sharp edges and contours can be covered with cushioned tape to minimize lacerations.
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Next I found a PDF that gave an overview of Hand Tools: Principles of Design and Selection. Some things I learned from this were:
- 70° natural wrist angle for gripping
- value of pistol grip versus inline grip
- contact stress and how to avoid it
- finger grooves usually not a good idea
- impact on grip of glove use
- the two sample designs for the hammer and poultry knife
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Along the way, I found out that there have been 2,483 patents issued from 1976 with the word knife in their title at the
United States Patent Office Online Database.
These included patents to
Michael Walker
Allen Elishewitz
Mick Strider
Warren Osborne
and many others.
==================================================
To be continued
One of the first things I found were some occupational safety and health guidelines for tool design. These were interesting because they actually gave specific numbers to things like handle diameters, and because they suggest specific features that aren't present in traditional knife designs (compressible handles).
==================================================
Diameter
Handles should be cylindrical or oval in cross section, with a diameter of between 30 mm (1.18") and 45 mm (1.77"). For precision work the recommended diameter for handles is between 5 mm (.2") and 12 mm (.5"). For a greater torque large screwdrivers should have a handle diameter up to 50-60 mm (~2").
Length
A handle that is too short can cause unnecessary compression in the middle of the palm. It should extend across the entire breadth of the palm. Tool handles longer than 100 mm (preferably 115-120 mm or ~4.5") will reduce the negative effects of any compression exerted. Rounded handles will minimize palm compression on the palm still further. Keep in mind that the use of gloves requires longer tool handles.
Separation between handles
Crushing, gripping or cutting tools such as pliers or tongs are equipped with two handles. The recommended distance separating handle is between 50 mm and 65 mm (~2"). Such a range will fit both male and female users. Tools with larger or smaller spans will reduce one's maximum grip strength and may contribute to the onset of carpal tunnel syndrome.
Materials and texture of handles
To ensure a good grip on a handle, sufficient friction must exist between the hand and the handle. This is particularly important where a considerable force must be applied with a sweaty hand. Hand tools should be made of non-slip, non-conductive and compressible materials. For example, textured rubber handles provide a good grip, reduce the effort needed to use the tool effectively, and prevent the tool from slipping out of the hand. Glossy coatings and highly polished handles should be avoided. The electrical and heat insulation properties of the handles are important for power hand tools. Handles made of plastics or compound rubber are recommended. Sharp edges and contours can be covered with cushioned tape to minimize lacerations.
==================================================
Next I found a PDF that gave an overview of Hand Tools: Principles of Design and Selection. Some things I learned from this were:
- 70° natural wrist angle for gripping
- value of pistol grip versus inline grip
- contact stress and how to avoid it
- finger grooves usually not a good idea
- impact on grip of glove use
- the two sample designs for the hammer and poultry knife
==================================================
Along the way, I found out that there have been 2,483 patents issued from 1976 with the word knife in their title at the
United States Patent Office Online Database.
These included patents to
Michael Walker
Allen Elishewitz
Mick Strider
Warren Osborne
and many others.
==================================================
To be continued
Eeeevil stats.... :barf: 