Friday, September 28, 2012

V3.39 - What is a Planer to do?

OK, I jumped the gun a little bit last week. I said we would start talking about lunchbox planers...and we will, just not quite yet. The reason is that we should really have a discussion about what a planer will, and will not do. What’s it designed for? Does it straighten out crooked boards? Will it flatten out twisted boards? …or not?

As I mentioned last week, Europeans call a planer, a thicknesser and I said that ‘thicknesser’ is a more appropriate description of what it does, than the word ‘planer’ is. Here is what I mean. The wood planer (remember, aka - thicknesser) is designed to make the stock that is passed through it, the same dimensions in both the left/right directions and the front/back directions. In other words, after being passed thru the planer, the piece of stock should be the same thickness in all areas.

A planer is NOT designed to flatten warped stock, or straighten curved stock, or remove a twist in the stock. Those are the jobs of other shop machines. A planer simply makes the stock the same thickness. I have seen people try to flatten bowed stock by running it thru their planer. The stock comes out the same thickness, but the bow is still in it. What happens is that the planer forces the stock down, removes some of it and then, as it leaves the planer, the wood springs right back to its previously bowed shape. Here is the secret: Surface joint your stock first. If you will create a flat bottom surface which will slide on the planer’s table (aka, bed), then the planer (thicknesser) can do what it was designed to do and make the stock the same dimension in all directions.

Now, that is what a planer is meant to do. So, let’s start our discussion about the lunchbox planers. For the sake of discussion, let’s say that you bought one of these little beasts- and there are several good ones to choose from- and you’ve been using it, and it has been working just fine…but all of a sudden, it refuses to plane the wood. You can’t even shove the wood in and get it to work. It used to be that it practically pulled the wood out of your hand as you fed it…now, it ain’t happening. How frustrating.

Let’s hold up for this week and we’ll get you out of this predicament next time.
Send your questions or comments to: and we’ll see what we can do to help you.

No comments: