Getting the Most from your Cutting Taps and Dies

By: Gord Thorogood

Wood cutting taps operates on the same principle as normal metal cutting taps, with the exception that the drill size can be made larger or smaller slightly to make the fit tighter or looser. You are not looking for a full thread but approximately a 3/4 thread for the best results.

Just as some metals are easier to tap than others, some woods will thread easily and some will be quite hard, and a bit of something like Dri-Cote will help quite a bit.

Wood cutting dies differ very much from normal metal cutting dies and actually are closer to the operation of cutting a thread in a lathe. The die has a single point that cuts only to the root of the thread and does not cut the crown of the thread.

The single point tool is set at the lead angle of the thread pitch and when the die starts cutting, the end of the thread enters a threaded aluminium sleeve that has the same function as the half nuts on the lathe. It feeds the material through the cutter at the proper rate and generates the thread.

All woods do not have the same qualities, some cut across the grain nicely but some splinter along the grain as soon as a tool touches, so be careful in selecting your material.

Size is very important also. True doweling must be under the nominal size by an amount that will allow it to enter a dowel hole easily. For example, a 1" dowel should be up to 1/32" less than one inch or it will not go into a 1" hole.

Remember, just because the material is round, it is not always dowelling. The block that the material goes through before it touches the knife, has a hole that is oversize and a dowel should pass through freely. If the material is at all tight it is definitely oversize and will probably destroy your die or at the very least break the knife. Again a little lubricant will aid the cutting of these threads.

When some care is taken to select the right size and type of material you can expect to good results from your unit.

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