Keggers Posted August 9, 2010 Report Share Posted August 9, 2010 Hello Fellow Woodworkers, I need some advice on SAFELY flattening long boards. I'm talking about boards that are 7 to 8 feet long. Much too long for my jointer. I'm making my own chair rail molding and I have several hundred bf of rough cherry. None of the boards are perfectly flat and I'm sure there is some degree of cupping on each board. I'm thinking that if I just run them through my planer - alternating sides - I won't get sides parallel to each other. The finished thickness needs to be 1/2 inch. Any help will be greatly appreciated. If I can't find a good solution I'll just have to buy pre-made cherry molding. Thanks! Quote Link to comment Share on other sites More sharing options...
Sac Posted August 9, 2010 Report Share Posted August 9, 2010 Hello Fellow Woodworkers, I need some advice on SAFELY flattening long boards. I'm talking about boards that are 7 to 8 feet long. Much too long for my jointer. I'm making my own chair rail molding and I have several hundred bf of rough cherry. None of the boards are perfectly flat and I'm sure there is some degree of cupping on each board. I'm thinking that if I just run them through my planer - alternating sides - I won't get sides parallel to each other. The finished thickness needs to be 1/2 inch. Any help will be greatly appreciated. If I can't find a good solution I'll just have to buy pre-made cherry molding. Thanks! Have you tried to use some sort of infeed support? you might be able to make a MacGyver'd version of an accessory table extension.. Quote Link to comment Share on other sites More sharing options...
thewoodwhisperer Posted August 9, 2010 Report Share Posted August 9, 2010 If the boards are pretty flat to begin with, you can always try skip planing. Basically, try taking alternating light passes on each side with the planer. If there are major issues with the board like excessive cupping or twisting, this won't work. But I have used this technique many times on long boards that are already pretty flat. And don't forget, a little bow over a 7-8' span is really nothing to worry about as long as you have a consistent thickness. Quote Link to comment Share on other sites More sharing options...
Keggers Posted August 9, 2010 Author Report Share Posted August 9, 2010 If the boards are pretty flat to begin with, you can always try skip planing. Basically, try taking alternating light passes on each side with the planer. If there are major issues with the board like excessive cupping or twisting, this won't work. But I have used this technique many times on long boards that are already pretty flat. And don't forget, a little bow over a 7-8' span is really nothing to worry about as long as you have a consistent thickness. Skip planing was what I was going to try if I couldn't find a better method. Quote Link to comment Share on other sites More sharing options...
Ben H Posted August 9, 2010 Report Share Posted August 9, 2010 I've made a long sled out of two pieces of 3/4 MDF glued and screwed together for the planer. Lay the rough stock on the sled and wait for it......hot glue the board on the edge down to the sled. If you have a corner or section not laying flat, slide a door shim under it and glue it in. Let the glue set and send it through. I've had great success with this method. Once you get one side planed down, you can take it off the sled and run it through the planer without the sled. Just set up a few roller stands to help support the whole thing while running it, or get a helper. 1 Quote Link to comment Share on other sites More sharing options...
SawDuster Posted August 9, 2010 Report Share Posted August 9, 2010 Skip planing may work for you and I hope it does. I've not had much success with fairly narrow stock though. What did work fairly well was a long plywood sled for my planer. This link will show you the basics. Maybe you can adapt it to meet your needs. Quote Link to comment Share on other sites More sharing options...
Vic Posted August 9, 2010 Report Share Posted August 9, 2010 I agree with Ben H. Make a sled that will accommodate your longest board and do what he said. With that many board feet, the extra work will be worth it. Quote Link to comment Share on other sites More sharing options...
Rick LoDico Posted August 10, 2010 Report Share Posted August 10, 2010 For chair rail, it doesn't need to be flat. Just plane both sides even. The edges need to be parallel and it will nail on to the wall flat. Quote Link to comment Share on other sites More sharing options...
Vic Posted August 10, 2010 Report Share Posted August 10, 2010 For chair rail, it doesn't need to be flat. Just plane both sides even. The edges need to be parallel and it will nail on to the wall flat. lol..true Rick...always the voice of reason. I didn't think about what the wood was for. As long as the twist, bow or cupping isn't drastic, it will nail down flat. Quote Link to comment Share on other sites More sharing options...
Keggers Posted August 10, 2010 Author Report Share Posted August 10, 2010 Thank you for all the replys. They are very much appreciated! Quote Link to comment Share on other sites More sharing options...
Bombarde16 Posted August 11, 2010 Report Share Posted August 11, 2010 None of the boards are perfectly flat and I'm sure there is some degree of cupping on each board. Just to be sure, are they cupped or bowed...or both? Cup is across the face whereas bow runs the length of the board. I'm thinking that if I just run them through my planer - alternating sides - I won't get sides parallel to each other. Actually, that's precisely what you'll get. The planer will also take out any cup across the width of the board. The only problem to watch out for is that the feed rollers can squash a cupped board flat as it goes through. The board is artificially flat as it hits the knives, but then the cup springs back as it exits the machine. This phenomenon gets worse as the stock gets thinner. A few transverse passes with a scrub plane will give you a ballpark flat side prepped for the machine, The planer is not capable of taking out a bow along the length of the board. (Excepting a planer sled as other folks have mentioned.) But this isn't strictly necessary for your purposes. Millwork isn't furniture. Even if you owned a battleship scale jointer and trued these boards dead straight over the entire 96" of their length, you'll put them in and discover that the wall is wandering all over creation. Quote Link to comment Share on other sites More sharing options...
Charger Posted August 17, 2010 Report Share Posted August 17, 2010 Hey I have had very good results with the "Planer Sled" that I believe Fine Woodworking has made and show cased.I have attached the link to their site for it. It's easy to build and Believe me when I say this, "It Works Great".I have planed down rough White Oak and Pine to a very smooth ,cup free, twist free board, then removed the sled and finish planing the board. I hope that you build it and see for yourself. Good Luck. & "Keep Makin That Sawdust," Lance http://www.finewoodworking.com/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=5245 Just to be sure, are they cupped or bowed...or both? Cup is across the face whereas bow runs the length of the board. Actually, that's precisely what you'll get. The planer will also take out any cup across the width of the board. The only problem to watch out for is that the feed rollers can squash a cupped board flat as it goes through. The board is artificially flat as it hits the knives, but then the cup springs back as it exits the machine. This phenomenon gets worse as the stock gets thinner. A few transverse passes with a scrub plane will give you a ballpark flat side prepped for the machine, The planer is not capable of taking out a bow along the length of the board. (Excepting a planer sled as other folks have mentioned.) But this isn't strictly necessary for your purposes. Millwork isn't furniture. Even if you owned a battleship scale jointer and trued these boards dead straight over the entire 96" of their length, you'll put them in and discover that the wall is wandering all over creation. Quote Link to comment Share on other sites More sharing options...
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