Make a True Flat Board

[Dennis Lopeman]

So I was talking to a buddy of mine, and we started discussing how to get a board truely sqaure... and so the differences between Planers and Jointers was the topic... and I'm sure there's varying "true-ness-es" - let's just say, generally true, good enough for nice woodworking projects...

He said that the only way was with a jointer. Well - we have a 6" that I'm "housing" for him until he sets up his garage... and so you could only face and edge a 6" board...

I argued that you could do it just fine with a planer... for the flat part and then a jointer for the edges...

He said if you plane a "cock-eyed" board, what you will get out is a slightly thinner "cock-eyed" board.

I have a ShopSmith planer... so thats all the experience I have on those... But I sent a couple boards that were quite a mess - and they came out purty darn flat.

So he says for me to get "on that forum" and ask those guys...

Well - Anyone care to join the argu... uhhhm... errr... Discussion!??!

[Neal Clayton]

it's true that a planer will only make a twisted board thinner and twisted. the rollers will press it flat as it goes through, but it pops right back up like it was on the other side.

however some people have made makeshift sleds that support a twisted board against the rollers to accomplish facing a board on a planer.

[edward alexander]

dennis-hope you didn't make a wager-i'll leave it to someone else to explain-with a 6" jointer you can only face a 6" board you can try to face up to 12" by turning it around and taking a pass from the other end and the other half-that's never worked for me-i have a 16" jointer and never plane a board to thickness without first facing it on the jointer anyway your buddies right.

alex

[Calvin Crutchfield]

however some people have made makeshift sleds that support a twisted board against the rollers to accomplish facing a board on a planer.

I'd be interested in hearing / seeing more about this...

[scott spencer]

A planer can flatten the top of a board that's cupped fairly well, and it'll take off some of the bigger "hills" on an uneven board, but it's true that a planer won't produce a reference flat face without the help of a planer sled unless one side is already flat....it tends to just mimick the opposite side while removing thickness.

I follow the same steps for flattening that Norm and David Marks use...flatten a face on the jointer, square the adjacent edge placing the reference face against the fence, then plane the opposite face flat on the planer. I usually rip the final edge to width then crosscut to length.

[glenn bradley]

I joint one face, use face as a reference and joint one edge, plane to thickness, rip to width and crosscut to length. Planers make faces parallel, jointers make faces flat. With only a 6" jointer, one of these may help on larger stock. It got me by for quite awhile till I got a larger jointer.

[Jack Briggs]

Joint a face then adjacent edge. Plane opposite face then rip the second edge on the table saw.

Theoretically, a 2-sided planer (one with cutter heads atop and below) could give coplanar faces with the same pass, but it's doubtful that they would be necessarily flat. At least they'd be parallel.

[Randy Klein]

He said that the only way was with a jointer.

Well, that's simply not true. You can also use a jack or a fore. Although a jointer is a good choice.

[Rob Luter]

A planer can flatten the top of a board that's cupped fairly well, and it'll take off some of the bigger "hills" on an uneven board, but it's true that a planer won't produce a reference flat face without the help of a planer sled unless one side is already flat....it tends to just mimick the opposite side while removing thickness.

I second that, although I've been able to get some pretty decent results on some major cupping and minor warps by cutting the boards to length and width first then using multiple extra light cuts where the feed rollers barely engage. On cups I orient the board "cup down". Once I get some decent reference surface established, I flip the board over and do the same to the other side. After some back and forth and many passes it will usually come out pretty flat. When the boards are really bad I'll resort to my neander planes and winding sticks to get things started, then move to power.

One day I'll have a jointer. Until then I'll need to keep improvising.

[Greg Robbins]

I use a planer sled all the time to flatten one side of a wide board. I use either MDF or Ply wood for the sled. Most of my sleds are about 12 inches wide and are of varying lengths. I attach a thin stop block on the end with screws to keep the piece from sliding around. You lay the board to be flattened on the sled and shim the spots that don't touch the sled. I have a lot of wedges that I use. Sometimes I use double sided tape on the wedges to keep them from moving. I also use playing cards as shims or small pieces of veneer. Anything that will support the spots that aren't flat against the sled. After I have the shims in place I screw another stop block at the head of the piece. Now is nice and secure. I usually put some pencil marks across the piece so I can see my progress. Now just run it through your planer taking light cuts until one side is flat. Once it's flat, you just flip it over and plane the other side and now you have two flat services that are parallel. Been doing it this way for years. A little extra work but I'm sure not going to rip a nice wide board so it will fit my jointer.

[Dennis Lopeman]

Thanks Guys!!!

It was a friendly discussion - no wager!

I'm actually quite interested in this infromation anyway, because I have started milling my own wood. I have a Logosol. I'll have to take a picture of my current setup - its pretty crazy!

Keep coming with the ideas.

I can certainly see how if a board is very wacked out, that the planer would do no good. Those type a boards I would either discard, re-warp (the wet grass in the sun idea - which I have since used successfully on 2 boards) or I would cut the piece into smaller lengths to get several smaller boards that could be flattened...

[Frank Drew]

I'm with Greg in being very reluctant to rip a wide board, but a jointer can effectively face joint a board just slightly less that twice the cutter head width by revolving the board around end for end after every cut. I've used this method to get a reference surface before thickness planing lots of times and to good effect, on a variety of sizes of jointers. And it's rather quicker than using a planer sled (although there's nothing wrong with that method if it works for you).

[Note: This face-jointing method will probably leave a somewhat uneven surface, with a slight ridge, or step-up, in the center of the board, but this isn't a problem -- even though not perfectly smooth, it is "flat" for the purposes of providing a reference surface for the planer. Obviously, the bottom uneven face needs to be planed once the top is flat.]

[Matt Ocel]

With a planer its "banana in, thinner banana out".

[Jim Becker]

Your friend is correct...a planer will not flatten a board and his reasoning is sound...outside of using some special jigs designed to keep a "not flat" board from deflecting under the planer rollers, you will basically get a thinner version of the board that went in, including any bows and/or twists.

A jointer is the correct tool to flatten the face of a board before thicknessing. That includes both powered and hand-plane jointing. If your jointer isn't wide enough for the board(s) you need to flatten, you'll need to use other methods. That could include using the planer, but again, with a special jig to insure your board is processed without deflection.

[Calvin Crutchfield]

I use a planer sled all the time to flatten one side of a wide board. I use either MDF or Ply wood for the sled. Most of my sleds are about 12 inches wide and are of varying lengths. I attach a thin stop block on the end with screws to keep the piece from sliding around. You lay the board to be flattened on the sled and shim the spots that don't touch the sled. I have a lot of wedges that I use. Sometimes I use double sided tape on the wedges to keep them from moving. I also use playing cards as shims or small pieces of veneer. Anything that will support the spots that aren't flat against the sled. After I have the shims in place I screw another stop block at the head of the piece. Now is nice and secure. I usually put some pencil marks across the piece so I can see my progress. Now just run it through your planer taking light cuts until one side is flat. Once it's flat, you just flip it over and plane the other side and now you have two flat services that are parallel. Been doing it this way for years. A little extra work but I'm sure not going to rip a nice wide board so it will fit my jointer.

Wow. Very interesting. That lends more weight to me getting that 20" planer with helical heads since a 20" planer=20" jointer. Not discounting my 8" jointer of course, this just seems like a good methods for wider boards.