Determining Your Power Grip Size
Hands come in different sizes and shapes. When choosing a tool for the job picking a tool that fits your hand makes the work more efficient. A handle too large or too small will cause early fatigue because of over or under gripping. How do you decide what is the right size tool for you?
The first step is to determine the size of your hand. According to: Champney 1979: Muller Borer1981: NASA 1978; The 50th percentile hand length for male is 7.5”, female 7.2”. Grip diameter 1.9” male, 1.7” female
To measure your hand size measure the distance from your wrist crease to the tip of your middle finger with the palm open. (see image below) You will use this figure to determine your grip size. Hand 2
Take 20% of your hand size to determine your grip diameter. For example if your hand size is 7.5” multiply it by .20 for your grip size. (7.5”X.20=1.5”) so your grip diameter is 1.5”.
HandYou can check this number by making a circle with your index and thumb and measuring the distance across the circle. It should be close to the figure you calculated for your grip diameter.
Once you know your grip diameter you can calculate your grip size. Simply multiply your grip diameter by 3.14 (aka Pi) for your grip size. In the example above grip diameter 1.5”X3.14=4.7”grip size
Once you know your grip diameter and grip size you can select tools that fit your hand and will be more efficient to use. For a power grip like hammering NIOSH recommends tool handle diameters between 1.25” – 2”. Use your grip diameter and find the tool handle closest to your size. Handles can be built up with tape or foam padding to increase their diameter.
The Basics on Restoring Carburetor Performance
The Carter AFB carburetor was introduced in 1957, and the same basic design lives on to this day as the Edelbrock manufactured variant. For any mechanical device to remain in production for nearly 60 years is testimony to fine design work and functionality. It also means that countless examples of these carbs can be found—many in need of basic refurbishment. While a carburetor is not particularly difficult to rebuild, there are many performance enthusiasts who shy away at the thought of disassembling and rebuilding, often choosing to simply buy a replacement instead.
Rebuilding a carb is actually a fairly quick and easy process that requires little more than a few basic tools, a cleaner, and a carburetor kit. Before the advent of fuel injection in performance vehicles, rebuilding the carb was a routine procedure, performed in garages and backyards across the country. These days, few of us have a carbureted vehicle serving as daily transportation, but a vast majority of hot rods, race cars, and weekend toys still use carbs. As a simple mechanical device, a carb is reliable, relatively cheap, and long lasting. For the most part there is little to wear out, but dirt, debris, and deposits can take a toll, even rendering a carb inoperative. A carb kit will include the typical wear components, as well as new gaskets and seals. We had a 750-cfm #6212S carb off a jet boat application, along with a Walker 15271A kit. This is how they went together.
Our #6212 Carter AFB is a 750-cfm unit for a marine application. The carb has been on duty since the early '70s and will be good for decades to come with a simple rebuild.
The AFB design is ingeniously simple, being constructed from just two major castings—the main body and the air horn. Step one anytime an AFB is opened is to remove the metering rod assemblies.
To separate the carb, remove all of the external linkages, then the screws retaining the air horn. Sometimes the air horn gasket can be stuck. To break it loose, use penetrating oil and tap the periphery with a hammer. Avoid prying on the air horn.
There are very few parts in the air horn assembly. We find the needle and seats, floats, and fuel inlet—that's about it.
As can be seen here, the main body carries the majority of the AFB's parts, including the jets. Clockwise from lower left we have the choke dashpot, right primary booster, secondary boosters, velocity valve, left primary booster, accelerator pump pistons and spring, accelerator pump discharge nozzles and check needle, and the idle mixture screws.
