What Is a Parallelogram Jointer?

Parallelogram jointers are mid-sized power saws used for flattening the face or edge of lumber. Parallellogram jointers cost more than traditional jointers, but need less adjustment out of the box. While a traditional jointer may need periodic readjustment, the parallel bar design supporting the tables of a parallelogram jointer should not require adjusting.

This article will explain further what is a parallelogram jointer.

Parallelogram Jointer vs Traditional Jointer

Both parallelogram jointers and traditional jointers make quick work of flattening stock, and are an essential tool for your workshop if you plan on milling your own wood. The differences between a parallelogram jointer and a traditional jointer include the size, shape, and price of each machine, as well as the way the parts fit together.

Base Shape

A traditional jointer has a thomboid base that resembles the shape of a dove’s tail. They are sometimes called dovetail jointers or angled dovetail jointers. Used with a dovetail jig, they make help woodworkers make precise wood projects with speed.

The base of a parallelogram jointer is shaped like a parallelogram.

Base Size

The bases of parallelogram jointers tend to be longer and heavier than the bases on traditional jointers.

Cost

A parallelogram jointer costs 20-25% more than a traditional jointer.

Table Attachment

The major difference between the way a parallelogram jointer and a traditional jointer operate is how the tables move, relative to the base and the cutterhead.

First, some jointer basics:

• On either machine, two tables sandwich a rotating cutterhead. As stock passes from table to table over the the cuttinghead, thin slices of material are removed by the blade.

• The infeed jointer table is always adjustable, and some jointers have an adjustable outfeed table as well.

• For the stock to ride smoothly across the cutter head from one table to the other, and produce smooth, square edges, the jointer must be properly adjusted. The tables must be in parallel alignment with each other.

On a traditional jointer, the tables slide up and down a diagonal bar, moving closer to the cutting head as they are raised, and away from the cutterhead as they are lowered. The table sliding along the angled metal bar can cause wear and tear in both parts. Once this happens, it can be difficult to precisely adjust a traditional jointer.

In a parallelogram jointer, the adjustable parts of the jointer are moved using a cam or eccentric, which don’t wear out in the same way. You can precisely adjust the variables of your parallelogram jointer without throwing it out of alignment.

Parallelogram jointers are ready to use out of the box and should not need readjustment provided they are used within the manufacturer’s specified parameters.

A traditional jointer will need to be set up out of the box. Jointer adjustments are made via a set of gib screws. Shims can be used if necessary to compensate for twist. The gibs must be tightened or loosened in a specific sequence, and it can take quite a bit of trial and error to get things right.

Should I Buy a Parallelogram Jointer?

Most heavy-duty jointers intended for professional work are parallelogram jointers, so this decision will only come up when you’re contemplating a six or eight-inch wide jointer. Some things to consider:

• The lower cost of a traditional jointer makes them attractive, especially if you’re just getting started with milling lumber.

• A traditional jointer is a reasonable choice for a beginner or someone who will only use the machine occasionally. The problems with traditional jointers only show up after heavy use. Each time the table is adjusted, metal slides past metal, and over time this can change the way the parts fit together.

• If you’re making occasional minor adjustments to the table, it’s unlikely that you’ll wear it down enough for wear and tear to affect the performance of the machine. In that case, it’s probably not worth the extra expense.

• If you use your jointer all the time or make frequent, major adjustments to your cutting depth, the extra expense of a parallelogram jointer makes sense.

You also could consider a highly reviewed benchtop jointer.

Conclusion

Parallelogram jointers are a variation of traditional jointers and are used to flatten the faces and edges of stock. They are larger than traditional jointers and also cost more. However, they are much easier to set up and adjust, and should not need readjustment over the life of the machine.