What is the difference between a parallelogram jointer and regular?

What exactly is the difference between a parallelogram jointer and a regular jointer and why is it more expensive? Is it worth the added expense? I'd appreciate some arguments for a parallelogram over the regular jointers.

+1

not sure of the difference myself

Rick...if you do a search you can find previous threads on this subject.

The typical jointer bed is attached to the body of the jointer via an angled dovetail. Thus as you move the beds down...the beds move farther away from the cutting head. As you raise the beds, the beds move closer to the cutting head.

Parallelogram beds are mounted on a parallelogram so as you move the beds down..the distance between the bed and the cutter head remains constant.

A wedge designed jointer has the cutterhead section shaped like a pyramid, with the tables attached via dovetail ways.

The tables move up or down by being forced along the side of the pyramid by screws.

A parallelogram jointer has the beds attached to the head via arms that pivot. The parallelogram shape is changed by screws to move the beds up or down.

The older wedge type jointers are just fine, as any 100 year old machine will atest to. Dovetailed ways last a long time, and are shimmed for jointer alignment.

A well made parallelogram would work well, as long as it has large bearing surfaces, with dissimilar metals with oil for lubrication. Otherwise if it has small bearing areas it will wear and become loose.

In another 80 years, we'll have good experience with the life of these machines.

As with all machines, quality means precision which means money, and a jointer is no exception, you'll get what you pay for with either design.
Regards, Rod.

Parallelogram jointers are probably cheaper to produce than dovetailed ways because of less machining, so why should they cost more??? A cynic might suppose that we are willing victims to a marketing ploy to sell higher margin tools. :rolleyes:

Rod has it right. Either sytle, done right, will last longer than you. The inverse is also true.

There are other systems out there too. Some of the Euro tools use different approaches.

Others have answered the part of your question as to the difference - with more authority than I can offer. Just let me say the I truly enjoy the Griz parallelogram jointer. It is so easy to adjust the depth of cut. Having had both, I much prefer the parallelogram. Others may differ.

As to durability, at 60, it is unlikely I would wear out either type:) Durability will be someone else's issue.

Rick, there is more opportunity for fine adjustment designed into the newer parallelogram-style jointers. If something goes out of whack, the eccentric cams can be turned to bring both tables in line. Plus, the new parallelogram machines are cheaper to produce! Less precision machining operations required! Perhaps we are paying for the repeatable adjustability built into the newer design???

With the older jointers with inclined dovetail ways, the precision must be *machined* into the cast iron. Any adjustment must be done to level the tables with shims, which is hit-or-miss. I have owned BOTH, and either type will give you good service if in alignment.

I had a Northfield with inclined ways and reliability and accuracy were never problems; I also -- duh! -- would have loved to have had an Oliver with parallelogram beds. Machines from good manufacturers can accomplish the same task in a variety of ways, with no one way necessarily the heads and shoulders best.

As for the infeed bed moving away from the cutterhead as depth of cut is increased on inclined bed jointers... well, maybe, sort of, but the cutterhead is round (as is the underside of the leading edge of the infeed table, to provide clearance), so as the table descends its path somewhat mirrors the shape of the cutterhead and really doesn't create a big yawning gap between the table and knives or anything like that.