Portable Hand Punch Tuneup

This type of tool can, within proper limits, exert up to 1.2 tons of force in mild steel, aluminum, brass and copper as well as plastics. Drilling holes in thin substances can be tricky, whereas punching may be a better option. The diametric range of the tool is from 3/32”[2mm] to 9/32”[7mm], a pretty decent spread for general purpose project needs as well as jewelry making. The classic Roper Whitney #5 Junior hand punch has imitators offering a more reasonably priced clone that, as may be expected, can use a little finessing before being put into service. With about an hour of time, a drill press, and an abrasive stone, workmanship of the assorted punches and dies can be improved in this one- time only effort.

It is desirable that the dies have a flat top, with no lead- in chamfer for best results. If chamfering is not removed, instead of a clean, burr- free hole, the material is extruded rather than cut, leaving a ragged crown on the bottom side. The easiest way to flatten it is to chuck it into a drill press set for the lowest speed, and lightly “peck” the surface of a lubricated oilstone to obtain fresh, flat material. Check progress frequently and stop when it is smooth across the top.

Leveraged force from the eccentric arm is applied to the top of the punches. The quality of their machining is poor as they are simple parted off the lathe, and thus can be very uneven at the top. Grinding them flat ensures maximum force is evenly distributed to their surface area, so use the same technique as with the dies to flatten them. Also check for dross, flash, or any other junk in the critical anvil area of the arm itself.

This lubrication scheme will probably only ever need to be done once every decade, but still, little things mean a lot.

The chart depicts the range of hole diameters the tool is expected to produce for a given material and thickness. Red text numbers are above the rated pressure range, but may be optional, depending. This extent should be achievable without any additional leverage amplifier like a section of pipe to increase the handle length, but then again, individual needs may dictate otherwise. Lubricating the material before punching metals may or may not make the effort easier, but is believed to prolong punch life.

While the above will initiate a marked improvement over using the punch set as is from the box, reality tells us that a $25 tool is only going to do so well no matter what other enhancements one tries to add, but if your need is simplicity and speed, not high accuracy, then this gadget is a good choice for the toolbox.