The jointer looks today much as it has for more than 70 years, with only minor mechanical changes and improvements to the motors, controls, table movement systems and the visual scales used to locate and align the guide systems. Most of the features common to a jointing machine are now universal among the several manufacturers. The machine is still one of the mainstays in any cabinet shop, especially those doing a wide range of short-run products and those using only S2S stock materials.
The working parts of the jointer are:
- The cutting tool, which operates at a fixed location, turning between 3,600 and 8,000 rpm, with two to four knives, revolving against the feed direction.
- The outfeed table, which is movable vertically, to be mated exactly with the location of the cutting tool's highest cutting circle arc.
- The infeed table, which is also movable vertically. The height of the infeed table below the elevation of the tool's cutting circle arc dictates the cutting depth, or amount of material removed in each pass.
- The vertical guide fence, which is movable to tilt toward or away from the machine table, for cutting bevels or chamfers. Most are also adjustable/moveable across the table width.
The most common misconception about jointers is that their primary, and perhaps only, function is for edge surfacing or jointing. This is probably the most common function for the machine, but it is surely not limited to that process. Some other uses for a jointer include:
- Facing or surface planing can be accomplished on a jointer to correct a cupped, twisted or warped board. Though not an easy or single-step process, nearly any lumber piece can be shaped into a flat usable form with a jointer.
- Edge surfacing is the most prevalent and common use of a jointer, especially when using S2S lumber stock. Work pieces are easily edge squared and surfaced while being guided against the fence.
- End-jointing, though not a common machine process, can be accomplished on the jointer. Consideration and care must be exerted and only small amounts of material should be removed in each pass.
- Chamfering and beveling are also easily accomplished on a jointer with the use of the guide fence tilted either inward or outward to trap or rest the workpiece stock on while being machined. Care has to be given to the wood species, growth direction and grain character.
- Short tapers, long tapers and stop tapers can all be machined on a jointer with the use of correct procedures that may involve fixtures and stop blocks. Care has to be given to the length of the infeed and outfeed tables, the condition of the workpiece materials and growth direction, especially if the taper is longer than either table. If it is, the stock will have to be fed from both directions.
- Cutting both tenons and rabbets is also possible on a jointer, assuming the machine is provided with a rabetting ledge. In both of these instances the cutter guard has to be removed, adding another element for the machine operator to contend with to preserve his safety and the accuracy of the machining process.
Here are some operating conditions and procedures:
The cutting knives on a jointer need to be kept sharpened. Because of the nature of the machining process and because stock is hand fed, the material to be removed must be cleanly cut without having to push too hard into the operation. Dull tools are generally dangerous, but more so in a jointer. While a jointer does not make a deep cut, it can be as wide as the cutter width itself, requiring considerable horsepower.
When you are first using a jointer, the setup procedures can seem complex, lengthy and involved. With time and experience though, the sequence of needed adjustments will become more accurate, easier and faster to accomplish. The location of the infeed and outfeed tables is the most critical element of the setup procedures, as well as securing the locking mechanisms.
The infeed table location determines the amount of material removed in each pass. The outfeed table must be exactly at the same location of the highest elevation of the tool's cutting circle arc. Otherwise the workpiece will be at the worst, tapered, at the least, sniped.
The condition, grain orientation and species of wood involved has to be carefully considered. A jointer will only highlight and refine what is already present. The machining process is a shallow planing operation that will easily true and surface whichever of the six surfaces are addressed. A workpiece can be completely squared using a jointer.
In summary, a jointer is like other woodworking machines in the sense that with repeated use you will find more and more involved tasks for it to accomplish. Additionally, there are easily constructed fixtures and holding devices that will make all of your operations safer, faster and more accurate. There are a number of unique stock pushing and handling devices made expressly for use with a jointer. It is possible to cut complex tapered parts, with the use of stop blocks and a reasonable means for holding the parts.
In very large manufacturing facilities the jointer may have been relegated to the corner of the plant where we keep our collection of buggy whips. That said, in the same large plant surely there is a very functional and busy jointer in the model shop.
The jointer is not only functional; its use teaches us a lot about machining wood.
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