The basic Sherline hold-down set consists of two strap clamps complete with bolts, "T" nuts, washers and a variety of lengths of socket head cap screws. Strap clamps provide the most versatile method of clamping work onto the milling machine. These clamps are adjustable so that they can accommodate different material thickness and they can be used to hold down parts of almost any configuration. At least one set of these clamps should be considered a necessity for every milling machine owner.
Holding parts firmly in place for milling is one of the most important challenges faced by machinists. A mill vise can hold flat or round parts, but rough or odd shaped parts like castings need to be clamped to the table. We now offer a set of step block hold-downs (P/N 3013) that are small versions of the type of hold-down clamp most often used in machine shops. The 3012 set described here is an earlier version that was developed to provide a simple and inexpensive way to adjust for height using a carriage bolt as an adjustable spacer. Should you need additional clamps, we highly recommend you add the 3013 step block set to your shop as your next purchase.
Not much is required in the way of instructions in order to use these clamps. The biggest problem you can create for yourself is overtightening the nut and damaging the T-slots on your mill table. You have to realize that you are stronger than your machine when you have both the lever (wrench) and the screw working to your advantage (or disadvantage).
Use the eight 3/16" I.D. washers to adjust the height of the clamping screw head. Use the two 1/4" I.D. washers to keep the head of the carriage bolt from marring the table surface.
When properly adjusted for height, the clamp should be parallel to the table or, if anything, the tip can be slightly low. If the tip is higher than the back, the clamp is only gripping at the very edge of the part, which is not desirable.
Joe Martin, President and Owner
Sherline Products Inc.
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