Thursday 22 August 2013

How To Get The Most From Your Portable Planer

One of the most versatile machines you can put in a shop, is the portable planer. I have had a 12″ Delta for about 15 years, and it has become my best friend. The money that I have saved in trips to the mill alone, has been more than enough to buy a 24″ stationary planer. But I have a small workshop, and even on a permanent stand, this unit is light enough to store out of the way when not in use.

There are, however, a couple of drawbacks with the portables, but these are easy to overcome. One of the most common defects is the propensity to create “snipe”, which is the over-depth cut at the beginning and the end of the cut.

The machine consists of a revolving cutterhead and a pressure roller on each side of the cutter head, and snipe is caused when a long board exerts too much force against the pressure roller that feeds the stock through the machine. Until the board contacts the pressure roller on the outfeed side, the board acts as a lever with the fulcrum being the edge of the infeed table, thus causing the downward force of the outboard end of the board to lift the initial pressure roller, sending the board into the cutterhead at an angle.

The simplest way to overcome this is to lift the board as it enters the machine, and as it exits, because the same condition arises on the outfeed side.

Portable planers have a built in safety mechanism that prevents the cutter head from contacting the platen, or bed, of the machine. This limits the minimum thickness that the machine can produce from about 1/8 ” to 1/4 “, depending on the manufacturer. In order to plane stock thinner than this pre-set, I use an auxiliary bed to effectively raise the platen of the machine, which allows me to plane to the thinnest dimension that the wood itself will allow.

I made my table from 3/4 ” Melamine, which is MDF with a plastic coating on both sides, but plywood and plastic laminate would work as well. Put a stop on the underside of the auxilliary bed to keep it from feeding through the planer with the stock.

Some woods, when planed too thinly, will flutter from the air movement caused by the revolving cutterhead which can allow the cutterhead to literally eat the stock. The minimum thickness for a given species of wood can only be determined by trial and error. If your machine eats your stock, you've gone too far

The auxilliary bed will counteract snipe to a degree relative to the length of the bed,but I still lift the end of the board when entering and exiting the machine.

My particular machine will cut a maximum of 6″, so I have installed an aluminum angle fence, with a featherboard to hold stock square on edge against the fence, allowing me to use the planer as a jointer. When all the boards I'm using have been run against this fence, I turn them over and joint the opposite edge. This not only squares up both edges, but the boards all come to the same width.

As with all machinery, be sure to wear proper safety gear, such as safety glasses, ear protection, and gloves. Avoid loose clothing that can become entangled in moving parts. With a little TLC and sound operation, your planer should last for years.

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