Jointer Guidelines
Rough lumber is just that -- rough lumber. It often comes with dimensional distortions like twists and warps. A Jointer corrects these problems and produces lumber thats eady to be worked -- straight, flat and square.
Preparing rough lumber is a multi step pocess and the Jointer is the first tool, and step, in that process. It is used to first straighten a board by truing one face and one edge, followed by using a thickness planer to make the opposite board face parallel, then the final edge is cut parallel, to the one we jointed, with a table saw. Here is a image which shows the sequence.
The acutal cutting is done by a rapidly revolving cutter head equipped with two or more knives, which are arranged in a straight or sometimes spiral configuration. The size of a jointer is designated by the width, in inches, of the cutter head. The smallest size useful to most woodworkers is a 6-in. jointer. One disadvantage of a 6-in. machine is that it can't face joint (or flatten) stock any more than 6 in. wide. That means lumber that goes into wide surfaces, such as a tabletop, will have to be ripped down, jointed and then re-glued. The next size up is an 8-in. jointer. These machines typically have longer beds as well as wider knives so they can handle wider and longer material.
Here is a collection of tips and techniques for the jointer:
- Always wear hearing protection when operating a jointer, they make a lot of noise.
- Turn On the dust collector attached to this machine, jointers produce a lot of chips.
- Use a push stick, or push pads, as necessary, not your thumbs or hands.
- Feed the work so the knives will cut with the grain. Use only stock that is free of knots, splits, and checks.
- Trim the ends off stock that has been stored on end, dirt and sand can get embeded in a boards end and chip the knives
- Ensure that knives are balanced and correctly mounted.
- Adjust cut depth and fence before turning the machine on.
- Never edge joint material less than 1/2" thick, 1" wide or 12" long.
- Never face joint material less than 3/8" thick, 1"wide or 12"long.
- Allow cutter head to reach full speed before starting cut.
- Keep your undivided attention on the machine while using it.
- Never feed material with your thumb or fingers on the end of it, keep them on top of the material and use push pads.
- Always have the blade guard in place.
Squaring Rough Lumber
Preparing rough lumber is a multi step process and the Jointer is the first tool, and step, in that process.
It is used to first straighten a board by truing one face and one edge, followed by using a thickness planer to make
the opposite board face parallel, then the final edge is cut parallel, to the one we jointed, with a table saw. The image
on the left shows the proper sequence, click on it for a larger view.
Grain Direction
Visualize a feather cut by a jointer. It would be a mess, of course, but the point is that when you cut against
the grain, the wood reacts just like a feather. The grain is running right into the cutter head rotation. The woods
fibers are likely to catch and break apart ahead of the cut, producing tear-out. But when you run with the grain,
you get a smooth cut.
As with all tools, whether it is a jointer, a hand drill or your golf cart, it is best operated defensively. Know the tool, know its capabilities and know yours as well.
Safe edging!