Jointing ?

[Jerry Thompson]

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?

[Chris Tsutsui]

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.

[Jerry Thompson]

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.

[Troy Turner]

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.

[Steve Baumgartner]

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?

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.

[glenn bradley]

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.

[Jerry Thompson]

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.

[Chris Tsutsui]

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.

[Richard Dragin]

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?

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.

[Zach Callum]

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.

[Richard Dragin]

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.
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.

[Will Blick]

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.

[Richard Dragin]

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.

[Chris Tsutsui]

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.

[jerry nazard]

... 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....

I agree with Richard. A sled with shims covers a multitude of sins....

-Jerry

[Will Blick]

Correct Chris....there is more than one way to skin a cat..... sometimes my jointer is down, sometimes I face flatten boards on a bandsaw, as a jointer with short beds could never get long boards flat as the reference surface is not long enough.

Unfortunately, some people insist on absolute statements, which include a bunch of assumptions which are never spelled out.

Just this weekend, I took a cutting board which was cupped.... put the cup up, ran through 20" HH planer several passes, you could see it lowering the cup to the point where the cutters were hitting every part of the board.....it was FLAT.... checked with a Strarrett straight edge, as good as jointer would have done (it was 17" wide, too wide for my 12" jointer). Next I put the flat side down in the planer and flattened the other side, worked like a charm....sure a sled might have been better, but due to the shape of cup, I used my common sense and my eyes, and knew this strategy would work, and, of course, it did.... I worked with the tools I had available for the job, and got a perfectly flat end product.

oh yeah, also checked it with some winding sticks.... as dead-on as my eyes could see...

[James White]

If you read the op's question carefully. Then the below is the correct answer. He stated both ends and edges where jointed flat with just a hollow in the center of the board. Enough reference surface to get the job done properly provided the board can resist the pressure of the feed rollers. At least that is how I understood the question. But in the end nothing is gained by doing what the op wants to do. Except if the knives in his jointer are on there last legs and he would rather use the planer to finish things up.

James


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.

[Zach Callum]

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.

We are not talking about a bow in the length of a board, but the cup or crown across the width. It doesn't matter if the board is 6' or 60'. And whether you agree or not doesn't matter because you can achieve a flat board as described in the op.

[Jerry Thompson]

Zach;
the cup is a small area in the center to the 8'' wide poplar 4/4 board. All areas around it have been flattened by the jointer.

[Phil Thien]

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.

The only thing I would add is that you may want to cut your boards to rough length (a little on the long side) before starting with jointing the face flat. That way you don't have to remove as much material to get the board flat.

[Jerry Thompson]

I lowered the infeed table qbout 1/16'' and it came off in good order. I then jointed one edge referencing the jointed face to the fence. I then ran the rough edge face uo through the 735. Then keeping the jointed edge against the table saw fence I ripped the raw edge and all was great. Untile this afternoon. The damn thing now has a slight rock to it when place flat on the table saw. I felt I had destressed it by ripping it and doing some light jointing on it. Well, who knows? It must be Fergusons Law,'' Murphy was an optimist!'' Thats wood working but I came away with more knowledge.
Thanks everyone

[Thomas Canfield]

The only thing I would add is that you may want to cut your boards to rough length (a little on the long side) before starting with jointing the face flat. That way you don't have to remove as much material to get the board flat.

Phil addition to Glenn's comment was correct that you should work with the smallest section possible. Cutting to rough lengths and even rough widths will help reduce the amount of cup/twist/bow or whatever that you are dealing with. I would add one additional caution - taking a lot off one side will release stresses that can cause the other side to warp or more again. You should check you original flat side as you plane to be sure that it is till flat, and possibly have to make a light cut to get it back to flat before going to final thickness. All rough cut material should be processed in group working thickest down to thinnest into the planer as height reduced, even if no cut is made on some passes.