Replies

1. 
   RW | Apr 28, 2008 07:06am | #1

   The terminology simply reflects how the adjustment mechanism works. A wedge bed raises and lowers on dovetailed ways and the beds are basically cantilevered off the sides of the main framework. In that style of jointer, which is a style that has been around, you might say "tried and true" theres some advantages. One is cost. It is cheaper to machine than a parallelogram style.

   Another is adjustment, to a degree. You can shim they pretty easily if they get out of alignment, but your shimming is limited to basically one plane.

   A parallelogram has more parts, costs more to make, can stay true or go out of true just as easily, but has 4 points of adjustment, albeit more difficult to do so.

   So on one hand, cheaper to build and easier to fix with limitations, on the other, more expensive but potential for more accurate if you have the wherewithall to know how to maintain it.

   I can only think of a couple out there, though I'm sure thats not it. Grizzly and PM make them. Give me a couple months and I'll have a new 8" Powermatic. I'll give you a better review then. Though I think someone did post a neat writeup on it here within the last month. Think it was in a thread asking about helical heads. Might search and see if you find it.

   Real trucks dont have sparkplugs

1. 
   hostrock | Apr 28, 2008 07:09pm | #2

   Thank-you for the info. I am looking to get one soon. I will look forward to see what you say about your new PM "

   Thanks Bob Harris

2. 
   RickL | Apr 28, 2008 07:22pm | #3

   "A parallelogram has more parts, costs more to make, can stay true or go out of true just as easily, but has 4 points of adjustment, albeit more difficult to do so."

   Actually they are quite easy to adjust. Simple eccentric cams.

   I been repairing and tuning them for 25 years.

   They are a lot more difficult to remove a table compared to a dovetailed ways machine. On a  dovetailed jointer the tables are ground in place after assembley. On a parallelogram jointer they can be ground then assembled. Pretty much all the European machines are parallelgram beds. The DJ series from Delta was one of the first American companies to copy the Euro jointers.

   The best system is the Inclined ways  type found on old Olivers, Crescent and a few others. The simplest to adjust and replace tables on.

2. 
   bones | Apr 28, 2008 09:11pm | #4

   Hey I went though the same decision process back in november when I went jointer shopping.  I also looked at that subject and carbide cutters.  As to the dovetail .vs. parallelogram its all about adjustability.  As others mentioned you have two points of adjustment .vs. four points.  If you never have to adjust then no problem.  If you need to adjust the dovetail design, you will need shims.  If you need to adjust the Parallel design you have the four points.  Another feature I liked with the parallel design was that the infeed and out feed stay the same distance away from the head and with the dovetail design the gap would be increased as it moved away.  In the end I went with the Parallel design and 12" in width. Unfortunately the spiral head put it over my budget, but I plan on upgrading to the cutter head latter.  There was no price break for taking the leap to cutter head now or doing it later, except my labor to change the parts out.  Anyway that's my two cents worth.  Take care and enjoy the new toy whatever you decide on. 

   Government's view of the economy could be summed up in a few short phrases:
   If it moves, tax it. If it keeps moving, regulate it.
   And if it stops moving, subsidize it.
   
1. 
   hostrock | Apr 28, 2008 11:47pm | #5

   Thanks for the info. I am leaning toward the parallelogram jointer. I have read about using a 12" jointer. Do I need ont that wide? I figured that 8" would be big enough.

   Thanks again Bob Harris

1. 
   bones | Apr 29, 2008 05:49am | #7

   Need a 12" is relative. I used a 6" for years but it had numerous disadvantages.  Of which, I would put at the top other than the obvious is the lenght of the tables.  The more mass you have the better off.  I absolutely love the 12". I can pass long board over in a single pass instead of cutting into smaller pieces like I did with the 6".  That 6" frustrated me to the point of using hand planes. Sometimes I would cut a long board down to work it to only find I had cut it in the middle of some great grain patterns(you can't always tell what you have till you take her down).  I priced the griz 8" and for a small amound more the 10" with spiral cutterhead.  The 12 was close with the 4 blade hss blades.  When I called to talk to them the 8" was on back order so the decision was easy. I love the 12 and would not trade it.  Did I have to have 12, nope but you will never complain that you have too big a jointer.  Good luck on the decision and I'll leave you with one thought, get the biggest you can afford. you won't regret it, but an 8" will do just fine. Government's view of the economy could be summed up in a few short phrases: If it moves, tax it. If it keeps moving, regulate it. And if it stops moving, subsidize it.

1. 
   hostrock | Apr 29, 2008 06:20am | #8

   Well a 12" jointer is something to think about. I have been told the longer the bed is the better also more weight is better. Do they make a 24"? Just kidding!!!

   thanks   Bob Harris

1. 
   troys | Apr 29, 2008 08:45am | #10

   Be careful what you ask:) Oliver made a 24" jointer I think it weighed about 5000 pounds. The bed was something like 100" long. Anyway good luck with your hunt for a new jointer.Troy

2. 
   JohnWW | Apr 29, 2008 03:39pm | #12

   I'll second the point that others have already made, the clearance between the edges of the tables and the cutter head is irrelevant to the function of the jointer, and in fact the clearance on the parallelogram machines doesn't stay constant either it just varies less than on a dovetailed ways machine.John White

1. 
   hostrock | Apr 30, 2008 06:08am | #14

   I will you the same thing. What is the better machine?

1. 
   gb93433 | Apr 30, 2008 08:08am | #15

   I have an Oliver 166 jointer and it has a large diameter cutterhead. It seems that the larger the diameter of the cutterhead the better. That machine wil cut smoother than my 8" and 6" jointers. The Oliver is direct drive and the others are belt driven machines.

2. 
   JohnWW | Apr 30, 2008 04:05pm | #16

   A parallelogram machine has a very slight theoretical advantage in that it can correct for one type of table warpage, the twisting of a table. But warpage is a fairly rare occurrence in any jointer and the most common type of warpage is cupping of the tables, which can't be corrected on either style of jointer. The care that a company takes in casting and machining the parts, which is unfortunately hard to judge, is far more critical than the style of table adjustment.John White

3. 
   flairwoodworks | Apr 29, 2008 04:29am | #6

   Bob,

   Parallelogram beds move in an arc so that the distance from the cutterhead to the edge of the table remains the same, whereas the table on a regular jointer moves in a straight line.  Not too big of a deal, me thinks.  I like the easy lever adjustments typical of a parallelogram as well as the simple eccentric cam adjustments.

   Chris @ www.flairwoodwork.spaces.live.com

    - Success is not the key to happines.  Happiness is the key to success.  If you love what you are doing, you will be successful. - Albert Schweitzer

1. 
   hostrock | Apr 29, 2008 06:27am | #9

   Then the parallelogram works like a zero clearence insert on a tablesaw. That is good. Thank-you !!

   Bob Harris

1. 
   RickL | Apr 29, 2008 02:22pm | #11

   The curved arc of the table lowering on a parallelogram jointer isn't really like a zci. It's not signifigant enough to base a decision. I have both types of jointers and there is no measurable difference. At a 1/16" cut there is no difference between the two.

   A point that few people know is the chip breaker on a jointer is the curved gullet on the gib. If you compare the gib on a planer it's flat and the chip breaker is in front of the head.

   There are such things as 36" jointers. A powered jointer is called a facer and it has a feeder of hundereds of steel spring loaded fingers that move the wood over the tables. A friend who  does high end flooring has such a machine and it's at least 30" wide.

1. 
   hostrock | Apr 30, 2008 06:06am | #13

   OK then what is the best of the two?

   Thanks Bob Harris