Centre punch that does not glide

Aug 24 2018

When using a centre punch in a wood like fir it is very common it slides of the brown line into the lighter brown part. The brown line is winter? wood and harder.

I want a centre punch that doesn’t do this but instead makes the hole exactly where I put it; want it.

One solution can be to have a tube, think drinking straw, but in metal, but sharpened in the business end. Pressing it against wood would make a round mark. Since it is a couple of millimeters in diameter there is a good chance it gets a grip so it doesn’t skid off any brown line. Marking with a centre punch is often done for drilling so marking a 4mm ring does not create any damage if one intends to drill with a +4mm drill; or an even wider mark if a screw head will cover.

Inside this tube is a sharpened rod. So when the tube has a good grip, just press the rod down, and now you have a centred mark.

If it is hard to centre the tube one could start with letting the rod protrude and put where wanted; but without the pressure that will make it skid; and then lower the tube so it grips, and finally press the rod.
Or one could have a template or jig, say a see-through piece of plastic with a hole exactly fitting the tube. Adjust the jig/template by eye, it should be easy with these small distances, insert the tube and press down the rod.
If the precision is not enough, have a see through inset with a cross hair. Adjust the jig/template with the exact crosshaired inset in place. Remove the inset. Place the tube. Press the rod.

I have seen semi automatic spring loaded centre punches but they all lack the sharpened tube.

Another solution, that won’t mark around the single mark we want is to have a see through plastic template with a, say 10mm hole in it. In this hole is placed an inset with a crosshair to align exactly. Then the inset is removed and the punch is inserted and pressed. This solution is very similar to the one above but relies on the template staying in place instead of the sharpened tube doing it.

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