INDUSTRIES

Planer Test #1
Material Thickness Consistency

The purpose of a planer is simple; it is used to provide smooth surfaces (on parallel faces) on pieces of wood. Most of us who own planers have needed to sharpen the knives at least once, and "dreaded" the experience of trying to reset them when they were reinstalled. After all, the little knife setting gauge that came with your planer can hardly be called the "crown jewel" of knife setting accessories, can it! In this section, we are going to give you some information about how to get the best possible results out of your planer, quickly and accurately.
  
The best place to start diagnosing planer problems is on the outfeed table of the planer itself. By making a close examination of the results the planer is producing, we will know whether the machine needs a little "TLC". If you have tearout, make sure the material was fed in the proper direction before you start removing the knives. (For more information on the proper machining of wood, see the page on "Material Preparation".)
 
Prepare for testing your planer by running a couple of pieces of wood through the machine. I would recommend that you use material around 3û4" thick. Rip a couple of pieces about 1 1û2" wide and around 18" long. If you have a jointer, straighten 1 face on each piece. Mark one piece "L" (left) and the other piece "R" (right). Place these marks on a side or end, so they aren’t removed when you run the pieces through the planer. Turn on the planer, and run the pieces through the planer (with the jointed faces down) at the extreme outer edges of the table. In theory, both pieces should be identical thickness. (If they aren’t, you’re doing a lot of unnecessary sanding on your projects!) Let’s see how close they really are.

The following procedure will allow you to test material thickness accurately.

1. Assemble the A-LINE-IT™ as shown in the photo above. When mounting the "Smart Bar", position it so that the tips of the spring plungers are away from the slot in the Mounting Bar. Mount the dial indicator on the flat area behind the slot.

2. Remove the "ball" tip from the dial indicator. (The first time you do this, you may need pliers. They’re pretty tight from the factory.) Install the wide, flat tip in the plastic case into the stem of the indicator "finger tight".

3. Clamp the Mounting Bar to a smooth, clean, flat surface as shown in the photo. Try to position the dial indicator as square to this surface as possible, and tighten the socket screw that holds the indicator in place.

4. Zero the dial indicator.

5. Lift the stem on the dial indicator, and position the "L" board under the indicator. I would recommend that you stay near the center of the piece, just in case you get "snipe" on the end of your boards. Lower the indicator tip onto the wood.

6. Zero the dial indicator, and note the position of the pointer on the revolution counter.

7. Lift the stem of the indicator, remove the "L" board, and position the "R" board in approximately the same position. The dial indicator will show you how much difference there is in the thickness of the two boards.

8. If the differences in the measurements is over .005", I would repeat the test one more time.

What is the dial indicator telling you?

If the dial indicator moved above zero on the "R" board, it is thicker than the "L" board by the reading shown.

If the dial indicator moved below zero on the "R" board, it is thinner than the "L" board by the reading shown.

I tried (while writing this information) to get specifications for tolerances for different machines from different manufacturers, with no success. Equipment companies are very reluctant to give out this information, as they feel they would only create more problems for themselves. I can sympathize with them, (as they’re probably right) but this doesn’t solve the problem of the average machine owner. If the boards are a different thickness, you will have a "built-in" sanding project, whether the pieces are used on a face frame or glued up to make shelves. I will do almost anything I can to avoid sanding, and if you feel the same way, you should take a look at "Planer Test 2".