Jointers Buying Guide

Although you could say that lumber grows on trees, what you can't say is that it grows on trees in nice, straight lines. Even after a tree is cut into straight-edged boards by a lumber mill, the natural stresses as it dries cause a certain amount of twisting and curving. This causes problems when you are trying to fit piece of wood together into panels or furniture.

The solution to this problem is the jointer. A jointer is a machine designed to produce as straight and flat an edge as possible. The name comes from the term jointing, which is when pieces of wood are glued together to produce a wider board. If you look at the straight lines on a wood floor, or an older piece of furniture, you can see how important it is to have straight edges in order to fit boards together tightly, with no gapping.

A jointer looks a bit like a squat metal T, with two long arms that extend out from a central base. The arms are actually called tables, the in-feed table and the out-feed table. Between the two tables is a wide cutter head, set with three long thin cutting knives. A flat blade guard sits over the cutter head.

When operating the machine, the board is pushed from the in-feed table to the out-feed table and over the spinning cutter head, pushing aside the blade guard as it moves. Each time it passes over the cutter head, a bit of wood is shaved off the board, creating a uniformly flat edge. A metal fence running parallel to the tables and perpendicular to the board helps ensure that 90° angles are created (especially if all four sides of the board pass over the jointer).

When you are looking for a jointer, you are probably going to search first by bed width. The most popular sizes for home woodworkers are 6 inches or 8 inches. But there are also 4", 12", and 16" jointers available. They are less common, either because of limited use (in the 4" jointer) or because of their prohibitive expense (the 12" and 16" jointers cost several thousand dollars each).

Closed-Stand Jointers Most of the jointers manufactured, whether 6", 8", 12", or 16", have a closed stand design. An enclosed base helps keep dust out of the motor and helps keep down the noise and vibration. It adds weight and stability to the machine.

Open Stand Jointers The advantage to an open stand jointer is that it is less expensive than the closed cabinet machines. It will also be easier to move if you can't dedicate a spot of the machine in your workshop. But it is going to be a bit noisier than a cabinet-base jointer.

Benchtop Jointers Benchtop jointers are smaller versions of the table jointers. They are fine for working on smaller projects and great if have limited space in your workshop. But you may need something stronger if you want to work with large boards, as their maximum cutting width is about 6".

Jointer/Planers

There are a few companies that manufacturer a jointer/planer combination machine. Planing a board is cutting it to a specific thickness, while also creating a flat surface. There are two kinds of jointer/planer combinations. The over/under combination uses a single cutter head and a single table. To switch from one function to the other requires adjusting the machine.

The side-by-side combination puts the jointing table next to the planer. Each has separate cutter heads, but share a single motor. The main advantages to a combination jointer/planer machine is the savings in dollars and space. A single jointer/planer will cost less and take up less room than two separate machines.

Cutting Capacity

The cutting capacity on a jointer determines how wide a board you can cut and how deeply you can cut into the board. The depth capacity is especially important if you want to use the jointer to create rabbets, the small l-shaped cuts made along one side of a board. The cutting bed width will range from 4" to 16". The wider the bed, the more expensive the machine. For example, an 8" jointer will run about twice as much as a 6" jointer. Depth capacity will run from 1/2" to 3/4".

Horsepower

It seems obvious to say, but the more horsepower in your machine, the stronger it will be, the faster the blades will rotate, and the smoother it will cut.

Flatness

The point of jointing is to create as perfectly flat a surface or edge as possible. For that, you need a jointer with perfectly flat beds. In this case "perfect" means no more than .003" variation in the width of the bed and no more than .006" in the length.

It's hard to determine that variation until you've actually purchased and measured your particular jointer. You should test your jointer by laying a straightedge across the length of your out-feed table, flat against the fence. Then try to push a feeler gauge underneath the straightedge. If you can't, then the table is perfectly flat. Check the width variation by laying the straightedge diagonally across the bed.

Perfectly flat means no more than .003" variation in the width of the bed and no more than .006" in the length. Most manufacturers will not sell a table that doesn't meet those specifications. So, if your table is off, contact the manufacturer for a replacement or help in shimming the table so that it's as flat as possible.

Bed Length

The longer the beds, the better an edge you're going to get on your wood, because you'll have more support for the board as it travels over the cutters. The general rule is that you can joint a board that is twice as long as the length of each bed.

Some jointers, but not all, can be lengthened with special extensions.

Fence

The fence on a jointer (unlike a table saw), is permanently mounted onto the table. Check the fence assembly to see if you are comfortable with the way it moves. Some jointers have an adjust lever that can get stuck on the back of the assembly. A rack-and-pinion fence can be more easily adjusted. Most fences will adjust from 45° to 135° with positive stops at 45° and 90°.

Cutting Knives

There are two methods adjusting the cutting knives on a jointer. The first is through jackscrews. The second uses springs. Of the two, the spring system seems to be a bit easier to use.

Table Adjustment

Some jointers are adjusted with levers. Some manufacturers prefer to use knobs or wheels. Both have their advantages. Some people find the levers easier to use, while others like the precision of knob adjustments. Those who prefer wheel adjustments find that front-mounted wheels are easier than those located on the sides of their jointers.

You may need to make adjustments to the depth of cut (how deeply the knives cut into the wood on a single pass). If so, a jointer with a parallelogram table is a good investment, as it keeps the gap between the table and the cutting knives constant, even as the tables are adjusted up and down. This helps prevent splintering.

Connectors Most jointers have dust collection ports that connect to your vaccum to help alleviate dust particles. If yours doesn't, you can get connectors that attach to your jointer for that purpose.

Push Blocks Push blocks help guide the board through the jointer, allowing you to use your weight to keep the wood aligned correctly. More importantly, they keep your hands well away from the cutting blades.

Moveable Bases If you don't have room to dedicate an open space for your jointer, you can mount it on a rolling base. That way, when you are finished with your project, you can move the machine out of the way.

Cutter Knives Sooner or later, you are going to need to replace the knives on your cutter head. Make sure to get the correct size, as they vary according to the cutting width of the jointer.

Knife Jig A knife jig makes it easier to set the cutting knives to the correct, uniform setting.

There's a very simple pricing rule with jointers. The wider the cutting capacity, the more expensive the machine. A 4" jointer, suitable only for very small projects, will cost between $100-$200.

A 6" bench jointer, limited in its effectiveness for long boards, will cost between $150-$300. Open stand jointers with a 6" width capacity will sell for about $400-$600. Closed stand jointers, which are generally run quiet and with less vibration, sell for anything from $400-$800.

Jointers with 8" capacities start at $1,000. Those with 12" capacities are nearly $4,000. Finally, a 16" wide jointer will cost almost $6,000.

Delta Machinery
Craftsman
Jet
Powermatic
TD Industrial Inc.