If I run an 8''boared through my jointer until both sides and the ends are flat and a cup remains in the middle can I then run it through the thickness planerand have it come out OK?
[OP]
Contributor
If I run an 8''boared through my jointer until both sides and the ends are flat and a cup remains in the middle can I then run it through the thickness planerand have it come out OK?
Member
I think that the cup would remain there after planing but you would probably have a uniform thickness.
The jointer makes one side flat, then the opposite side should be cut by the planer which makes both sides parallel. I don't think I would ever run both sides of a board on a jointer because you might not end up with parallel faces.
[OP]
Contributor
Chris;
I am not going to run the piece over the jointer on both sides. I would run the lumber through the planer with the side jointed, as described above, down.
Member
I think you'd be better off running the cupped face down across the jointer until it's gone, then run the other side through the planer. Depending on the amount of cupping, you may lose quite a bit of wood. Sometimes it's better, if the project allows, to rip the board down to reduce the amount you have to take off. Then you could always glue it back up. Again though, depends on the project.
Member
Depends somewhat on your planer and on the kind of wood. If the wood is stiff and thick enough and if your planer has relatively soft infeed and outfeed rollers (e.g. many lunchbox types) and you take very light passes, you can take the convex side down until it is flat and then turn it over and plane the concave side until it is also flat and parallel. However, this will not result in any thicker a board than if you take the concave side down to fully flat on the jointer and then plane the other side, so it is usually not worth doing.Originally Posted by Jerry Thompson
Quick discussion on process;
- Joint one face flat
- Place flat face against fence and joint one edge
- Place flat face on planer bed and plane opposite face parallel
- Place jointed edge against tablesaw fence and rip to width
- Crosscut to length
If you joint one face and cannot get it dead flat, address that first. Everything else will fail if this first step fails. As stated, jointers make things flat, planers use "that flat surface" to make the opposite side parallel. If the reference side for your planer is bowed, you will get an even thickness board that is bowed.
Last edited by glenn bradley; 05-09-2012 at 7:37 PM.
"A hen is only an egg's way of making another egg".
– Samuel Butler
[OP]
Contributor
Glen;
Your schedule for milling lumber is what always do. I just thougt I might be able to save some time and still be OK. Thanks for the reply.
Member
Glen nailed down my procedure though I would add
1. I feed the wood into the jointer or planer in a direction that results in the least amount of tearout. The cutter cuts in the same direction as the flow of the grain.
2. If a wood has a bow, I perfer to have the crown facing up when I joint so that the board is supported on both ends as it passes over the jointer. Then when I plane that board I'll measure the thickness in the middle, and subtract a small amount for the first pass. Or as somebody suggested, place that board so the middle (high point) is under the cutterhead of the planer, then slowly raise/lower planer so that it grabs the wood.
I use a digital caliper to measure the thickness of the boards. Properly setup machines get rid of a lot of headaches.
Member
Is the cup just in the un-jointed side of the board and the jointed side is flat? If that is the case than the answer is yes. If the jointed face has the cup than the answer is no.
Member
Jerry, I get what you are asking, and yes, you can run those boards through your thickness planer with the crown up, and it will be ok.
Member
I disagree. A crowned board through a planer will still be crowned. It may work on a 2' board that is thick enough to not deflect under the pressure of the rollers but it is not going to fix a 6' piece of 4/4.
Contributor
if the crown faces up, the planar can make the top flat with enough passes..... it doesn't solve the cupping on the other side.... if you are not too picky, you can flip the board around now that you have a flat side on the bottom...but this is not recommended way method of dimensioning lumber. But sometimes you make due with what you have to work with.
I agree with previous poster.... jointer is best used with a board that is close to flat... if not, find another way to get the board flat, face cut on bandsaw, or if an edge, track saw with long rail to produce a near flat edge, then a few swipes over jointer is all that is required. The jointer beds length vs. the board length also comes into play...with short beds and long boards - another strong reason to get the boards close to flat on the two sides (one face, one edge) b4 jointing.
Member
For anyone following along....take Glenn Bradley's advice and ignore the other posts in this thread because it is full of misinformation. If you only have a planer and need to flatten a board it can be done with a sled and shims. Running a bowed board through a planer will not straighten it. If you think it does I bet you have some sloppy joinery and don't know why.
Member
There's just some confusion amongst the terms used in this thread.
If one side of a board is flat and the opposite side is rounded, then you pass that board with the flat side down through a planer and you should end up with a flat and parallel board.
If an entire board is cupped or warped, then you can adjust the thickness of that board through a planer and your resulting product will have the same cupping or warping, only the thickness will be reduced.
Member
I agree with Richard. A sled with shims covers a multitude of sins....
-Jerry
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