I was looking at a jointer on the Grizzly web site and they have jointers that have parallelogram adjustable tables. So what does this mean in the world of jointers and is it something I need? I don't see the word parallelogram used in the specs. of other jointers.

6" Parallelogram Jointer | Grizzly Industrial

Delta's DJ 15 and 20 jointers had parallelogram geometry. I can't remember if the smaller ones had it. The tables are on arms intend of dovetail keyways. As you raise the tables the parallelogram begins to approach the geometry of a square.

I have my doubts that whether you had a parallelogram system or dovetail ways it would make any difference. Really, you only move one of the tables such a tiny amount, likely less than 1/8" I think.

It might just be another selling point I suppose, although I don't see any practical advantage. Or disadvantage for that matter...except perhaps just one more thing to go wrong.

To understand Parallelogram, take a rectangular cardboard box and open the top and bottom flaps. Now lay the box on one of it's longer sides. Look into one of the open sides of the box as you move the present top of the box without moving the present bottom of the box.

The two present short sides of the box will change in angular relationship to the present top and bottom, but the top and bottom will remain parallel to each other. Only the space between them will change.

Put a mechanism that does this under your joiner tables with a way to adjust them and you have a joiner with parallelogram adjustment capability. I've had both types. With the
very slight adjustment range that most joiners need there isn't any user difference between them. It's just something to try to convince you that this is "newer and better" than the previous way to get you to upgrade. I'm still using my 30 year old old joiner with the dovetail type ways and have no plans to upgrade, at least not until this one can no longer be repaired. Then I'll buy whichever one I get the best deal on.

Charley

PR department hard at work???

Maybe cheaper to manufacture? Seems to me that there are fewer moving parts in the dovetail construction than the 4 hinge joints in the parallelogram system.

Herb

If there is any premium charged for the parallelogram, I'd likely use that difference to go up in table width. I have a 6 inch Powermatic, but wish I'd popped at least for the 8 inch model.

I would like to have an 8" also but I don't have 220 in my shop. Putting 220 in would cost a lot of money.

When I purchased a Radial Arm Saw years ago, I had to choose either 110v or 220v. the cost of wiring it myself was about 1/3 more for the cost of the breaker...and the real savings was 12ga wire instead of 6ga wire. It was a no brainer to dedicate 1 outlet (20amp) for the saw at 220v, it saved me a lot of money.

my early circa 1940's Boise Crane joiner has that table design...