Replies

1. 
   TomMGTC | Jan 13, 2003 05:50am | #1

   A jointers primary purpose is to flatten one face and one edge of a board removing any cup or twist and providing a reference face for the planing operation and a reference edge for the tablesaw.  The wider the jointer, the wider the board that can be flattened.

   Tom
1. 
   johnhardy | Jan 14, 2003 10:26pm | #2

   To amplify on Tom's (correct) response a little. You can't flatten a board in a planer because the board will be pushed flat and then planed. Any bow or cup is likely to be distorted by the pressure and the result won't be flat.

   What you ideally want to do is flatten one surface of the board and then you plane the other surface. This gives you two parallel surfaces so the board is now ready for use. You use the jointer to get one edge square and straight as well.

   John

1. 
   Elcoholic | Jan 14, 2003 11:49pm | #4

   If one uses a sled and supports the workpiece with wedges one can flatten the 1st (reference) face of a board.  This is a useful technique for boards that are too wide, long, or twisted to face joint.John O'Connell - JKO Handcrafted Woodworking

   Life is tough.  It's tougher if you're stupid - John Wayne

1. 
   johnhardy | Jan 14, 2003 11:56pm | #5

   Agreed. I actually use this technique with my Performax sander to abrasive plane wide boards. But philosophically, this is a very slow way to get boards "jointed" prior to planing. (I use the sander rather than the planer because my planer is a benchtop model and only 12 inches wide. The sander does a better ... albeit slower ... job.)

   John

1. 
   Elcoholic | Jan 15, 2003 02:28am | #6

   Yeah, it may be slower, but there's no tearout on wild grain to deal with.  I'd love to have a ShopPro25, I use a buddy's when it makes sense and it's awesome, slow but awesome none the less.  You have to raise the conveyor about 1/6 turn per pass with white oak.  The only thing I haven't seen it work with is oily/waxy exotics like purple heart, talk about burn.  I keep trying to get him to upgrade to the 37" so I can get his on the cheap, but so far it's no deal.  It's definately on my list, even if I have to pay full price for it.  John O'Connell - JKO Handcrafted Woodworking

   Life is tough.  It's tougher if you're stupid - John Wayne

2. 
   johnhardy | Jan 15, 2003 03:01am | #7

   We've sort of taken the thread on another direction, but I'm curious as to the power of that model. My 16-32 is way, way underpowered for planing wide boards, which is where this started. I have to go an eighth of a turn (1/128th of an inch) and sometimes have to make two passes without turning the crank. It's majorly slow doing that. But it does do great work.

   For my purposes, which typically doesn't go over 24 inches wide, I think a better choice would be the Grizzly double drum sander, which is 5 HP and a little over $1000. Have you thought of that one?

   John

3. 
   Elcoholic | Jan 15, 2003 05:42am | #8

   If you over feed it, it will either burn the wood & abrasive or slip on the feed belt and take a divit.  I will look at the Grizz before I buy.  I don't think any drum is up to aggressive abrasive sanding as the drum just can't dissipate the heat like a widebelt.  The 48" widebelt place I go to only takes 1/32" per pass anyway to preserve their $125 belts.John O'Connell - JKO Handcrafted Woodworking

   Life is tough.  It's tougher if you're stupid - John Wayne

4. 
   johnhardy | Jan 15, 2003 09:05pm | #9

   Good point about the heat. The Grizz is a double drum, so if you took 1/64th it'd probably work great. My Performax really has trouble at 1/128th. Guess this is why the wide belts are really the best choice, and are the most expensive. Sigh.

   John

2. 
   forestgirl | Jan 14, 2003 11:39pm | #3

   I'll put the earlier answers in another form just for fun:

   • Yes, the planer is used to "shave the surface of the board" but it shaves it to be parallel to the opposite face, so if the board is cupped or otherwise distorted, it'll stay that way (Sgian's "Bananna in, bananna out").  The jointer is used to face joint a board prior to planing, so that you have a flat reference face for your planer to work off of.
   • Yes, the jointer is used to "square up the edges of the board" but not simply for glue-up and assembly.  Again, you are producing a reference edge, this time for the table saw.  You are edge jointing to produce an edge that is 90-degrees to the face that is placed against the fence.  This is done so that when you go to the tablesaw to rip the board to the appropriate length, the edge that goes against the tablesaw fence is perfectly straight and 90-degrees to the face that rides on the table.
   • A jointer can also be used for rabbeting, bevelling and tapering.

   I could not believe the difference using a jointer made in the performance of my tablesaw.  Giving the saw a truly straight edge to work from showed in the finished product.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)