If there is a universal shop tool, it is the bench vise. Whether a farm’s shop is a fully equipped shrine to Snap-on tools or a dirt-floored corner of a machine shed, there’s probably a vise bolted to some sort of workbench.
Vises come in a variety of sizes and designs. Any vise is better than no vise, but some vises are better suited for the abuse they must endure in a farm shop.
A blacksmith’s vise, aka leg vise, works well for farm use because it’s designed to hold an object while somebody hammers the daylights out of it. A leg extends from the base of the vise to transfer the impact to the floor. The jaws move horizontally on a sturdy slide bar but are actually hinged below the vise at about knee height.
Most leg vises on farms are hand-me-downs from grandpa’s shop. Many farmers don’t realize that these battered old vises are highly valued by collectors. A new leg vise with 6" jaws from Old World Anvils, suitable for day-in, day-out abuse on farms, retails for around $700.
The modern bench vise commonly found on farms today is technically called an engineer’s vise; a unit with 6" jaws retails for $200 to $500. Engineer’s vises are made of cast iron or forged steel and use some sort of Acme-threaded screw to move the outer jaw in and out on the slide bar.
Some slide bars are square, some are rectangular and some are round. When an object clamped in an engineer’s vise is struck, part of the impact is transferred through the slide bar to the slide channel in the vise’s body. The slide bars in high-quality engineer’s vises have a hardened steel surface to minimize damage.
Some vises have round slide bars that are completely enclosed. This adds to the price but helps keep debris from clogging the screw mechanism. Vises with square or rectangular slide bars have an adjusting screw beneath or within the hollowed-out bar to protect the screw from debris.
Ratings. Vises are rated according to their tensile strength. Size does not indicate strength when it comes to vises. A mammoth cast-iron vise could technically be weaker than a smaller forged-steel vise. Experts consider a vise rated at 30,000 lb. to 60,000 lb. of tensile strength to be suitable for the abuse that vises commonly suffer on farms.
The strength and stability of a vise is proportional to the way it’s mounted on a bench or stand. Quality vises have four mounting lugs on the base, compared with economy vises, which mount via three or two lugs.
When mounting a vise to a workbench, manufacturers recommend mounting it directly over one of the bench’s legs so impacts are transferred to the floor. When installing a vise on a wooden, nonmetallic or sheet-metal bench top, sandwich a metal plate between the base and the bench top. The thicker and larger the plate, the more stable the vise.
Vises should be mounted with the top of the jaws at elbow height. This offers a comfortable position for using a hammer to "remodel" objects. It also provides a better working angle when welding or torching objects.
Options. Bench vises come with few options, but those that are available can be valuable. Replaceable jaw pads or inserts allow users to keep the contact faces of jaws straight and square. A built-in mini-anvil—a small, flat-machined area on top of the body behind the rear jaw—provides up to a square foot of surface for flattening, straightening and other activities. Many vise-top anvils are merely a flattened square surface, but some provide a mini-horn similar to the metal-shaping horn found on full-size anvils.
- December 2012