In The Shop: More Tool Design Considerations
Aug 18, 2011
Continuing from my previous blog about things I've learned about tool design:
-While there is no difference (other than price) in the performance or durability between "sand-finish" and polished hand wrenches made by the same manufacturer, there are differences in the "shape" of wrenches that can make a difference. Economy-grade wrenches are often thicker than premium-price wrenches. Thicker means heavier. Heavier isn't a big deal with small wrenches, but when you're working with wrenches larger than 15/16-inch or 24 mm, excess weight becomes clumsy. "Thick" wrenches can also cause problems when working in tight spaces without much clearance around nuts and bolt heads.
-Another issue that becomes apparent when using larger wrenches is the design of the handle. Premium-price wrenches are rounded or flattened on the thin edges of their handles. Economy-grade wrenches often have tapered, almost sharp, edges on their handles. The difference is especially noticeable when you're using big wrenches that require a lot of pressure to tighten or loosen fasteners---sharper edges quickly become uncomfortable when you put all your body weight into loosening or tightening.
-It's tempting to use chromed sockets for everything, rather than buy a separate set of "impact" sockets to use with air-powered or battery-powered impact wrenches. I've been there, done that, and paid the price. Chromed sockets are designed for use with hand wrenches. They are strong, but somewhat brittle and risk cracking, even shattering, when used on impact-type wrenches. Impact sockets--universally non-gloss black--are made of softer metal that can absorb the abuse of impact wrenches. If you use chromed sockets on an impact gun, you will eventually have to replace it because the square hole will get reamed out--if the socket doesn't first crack or split. Cracking and splitting becomes an issue because people universally guide sockets with their fingers while spinning them with an impact gun. Since chromed sockets are brittle, when they crack the edges of the cracks are razor sharp. More than a few folks have sliced their fingertips open while holding chromed sockets that cracked during use.
-Air- or battery-powered impact wrenches are wonderful. Their cousin, the air-powered ratchet wrench, was designed by the devil. Yes, there are times when they save the day and are worth every penny, but...most of the time they are the most knuckle-busting, wrist-wrenching tool ever inflicted on professional mechanics. No matter how hard you brace yourself, the torque of ratchet wrenches always seems to slam your hand, elbow, or wrist into the nearest (sharp) piece of metal. Fortunately (hallelujah and say amen!) tool manufacturers have recently introduced new air-powered ratchet wrenches that are "torque-free." The new design reduces kickback from torque and promises to finally make air-powered ratchet wrenches user-friendly.
No, I haven't got one yet, but it's on my short-list of tools to buy. Unfortunately, that list has two categories: "want" and "need." I don't "need" a new torque-free, air-powered ratchet wrench because my old knuckle-buster works fine, aside from the pain it inflicts. One of the hard facts of adult life is learning that "want" and "need" are entirely separate things.