Jointer use for flattening boards

[Rick Johnston]

I don't have a jointer. If the board is cupped it can be run face dn prior to the planer. If the board is warped can that be face dn to flatten?
A 4 foot board will achieve a thicker net board than say an 8 ft one in theory?

[John TenEyck]

Yes and yes. I run a cupped board with the concave side down (so the edges are on the jointer table), and a board that's warped like a dolphin so that the leading and trailing ends are down. In the later case, take a little off one end, then flip it around and take an equal amount off the other, repeat until you can take a full pass. And, yes, you will maximize the thickness that can be gotten out of a warped board by cutting it close to it's final length before jointing it.

John

[Jason Beam]

Sort of, and no.
Planers don't make things flat - they make them parallel to a reference face. Jointers create reference faces where none exists - usually flat ones!

John's right from a JOINTER perspective. But I think you're asking about a PLANER taking the place of the jointer. You can sorta get rid of cup by taking very light passes as you describe - the problem is the planer will squeeze down on the board and flatten out that cup somewhat - when it comes out the other end, the pressure is released and you still have a cup. Taking light passes sorta helps with this - but you have to be patient. If you can shim the center of that cup so it won't be squeezed flat by the planer, you can get better results.

As for twist - no - with a planer, the game is banana-in, banana-out. Unless you fashion a means to hold that board true through the entire pass under the planer heads, it's just gonna twist and conform to the pressure of the feed rollers and you'll just end up with a thinner twisted board. A planer sled can do that - basically you create a flat board with a lip on the leading edge, put your twisted board on that and shim all the spots that don't touch the sled so the feed rollers don't press them flat. Then, again with the very very light passes, run it through the planer to skip the top till it's flat. Then you can flip it over and use that newly created reference face to make the other face parallel.

Clear as mud,, eh?

And yes - the shorter the board you're rough milling, the smaller the defects usually are and the more yield you'll get out of that piece.

[scott spencer]

Any board can be flattened on a planer with the help of a planer sled to act as a flat reference face that the jointer usually provides. Lots of ideas for planer sleds on Google.

Without that flat reference face, the results are much more random...

[Wade Lippman]

Probably not. The planer rollers will uncup the wood as you put it through, so you just have a thinner cupped board. And some wood is simply too cupped to flatten anyhow; unless you want a 1/4" board.

Rip the board in half. The halves will have less cup and not be flattened as much by the rollers.
Of course, we haven't seen your board.

[Matt Day]

I'm confused by the wording of the OP's post.

Are you asking if a planer can be used as a jointer? Then yes, with a planer sled. Personally I did not have much luck with it.

If you're saying a planer can "joint" a cupped board (without a sled), I'd disagree. The feed rollers apply too much pressure to remove bow.

[Robert Engel]

No, you can't get the cup out using a planer, even with a sled. The only think a sled can help with is warp or twist.
If you try to go that route you'll just end up with is a board about 1/4" and it will still be cupped (how do I know this?).

For your situation the best way to tackle the problem is with hand planes (scrub and jack).
Once you get it reasonably flat on one side you can use a planer.

[Terry Beadle]

I highly recommend you get a #5 or #6 wood plane. You can flatten any width board to a flatness that you can then put through a thickness planer ( if needed ).
They are not very expensive. You can get a good user plane for less than $65, more often down around $30 and then once it's paid for itself ( sell a project or two )
you can buy a Hock, LV, or LN replacement blade. Rob Cosman has a blade he recommends but he seems to be pushing Wood River planes ( and they are a bargain IMO ).

Or make your own plane using the Krenov method as it's easy to do and a great feeling using your own self made tool.

Also with a wood plane you have a ready weapon to take twist out fairly easily. Just takes a little practice.

Just a thought. Thickness planers are great but not the place to start with a twisted or cupped work piece IMO.

[Phil Thien]

No, you can't get the cup out using a planer, even with a sled. The only think a sled can help with is warp or twist.
If you try to go that route you'll just end up with is a board about 1/4" and it will still be cupped (how do I know this?).

For your situation the best way to tackle the problem is with hand planes (scrub and jack).
Once you get it reasonably flat on one side you can use a planer.

That sure is news to me, I've had no problem removing cup with a sled.

My sled page: http://www.jpthien.com/ps.htm

[Rick Johnston]

My comment was about using a jointer for the warped board - not a planer. Thanks

[glenn bradley]

I don't have a jointer. If the board is cupped it can be run face dn prior to the planer. If the board is warped can that be face dn to flatten?
A 4 foot board will achieve a thicker net board than say an 8 ft one in theory?

Like Scott, my first response to your first sentence is to make a planer sled. If you are asking if a board can be flattened on the jointer when warped the answer is yes. I keep a selection of small shims (bits of scrap from whatever) that I use to support the board for the first jointing pass is required. that is; if the board teeter-totters, I prop one end about half the difference and make the first pass. This splits the difference and removes less material to get me to a reference surface.

[Robert Engel]

I highly recommend you get a #5 or #6 wood plane. You can flatten any width board to a flatness that you can then put through a thickness planer ( if needed ).
They are not very expensive. You can get a good user plane for less than $65, more often down around $30 and then once it's paid for itself ( sell a project or two )
you can buy a Hock, LV, or LN replacement blade. Rob Cosman has a blade he recommends but he seems to be pushing Wood River planes ( and they are a bargain IMO ).

Or make your own plane using the Krenov method as it's easy to do and a great feeling using your own self made tool.

Also with a wood plane you have a ready weapon to take twist out fairly easily. Just takes a little practice.

Just a thought. Thickness planers are great but not the place to start with a twisted or cupped work piece IMO.
Great advice.

My only suggestion is pretty hard to get a user plane for $65, at least Ebay has collector prices.

I think for the money you can't go wrong with a WR 5 or .
You can make a scrub plane out of anything, even a Harbor Freight plane.

[Matt Day]

My comment was about using a jointer for the warped board - not a planer. Thanks

Yes a jointer will make a warped board flat.

Yes, a 4' board will achieve a thicker final thickness than an 8' board, theoretically, because the 8' board gives you more possibility for warp/bow/twist. I generally cut boards close to final length before milling so I have more thickness to work with.

[Kent A Bathurst]

My comment was about using a jointer for the warped board - not a planer. Thanks

Yep.

As J10 said [using different words]: "Horns Down".

And - for a lot of cupping on longer boards, I will make a few passes just at one end, flip the board end-for-end, and make a few passes there too. Kinda getting rid of the pointy-part of the horns quickly. Particularly important if the board is long enough that one end leaves the table before the second end is thru the cutterhead.

On your "4-foot" question......dead-nuts on spot. As a general rule I pre-cut the rough sticks into oversized parts - so I am not jointing or planing any more than necessary. I also do this to get the best grain orientation possible, and to sidestep the worst of the cup/bow/twist. The sawmill's board edge is often not the best guide for getting the most out of the grain - may want to lay it out catty-wampus, rough it out on the BS.

[Allan Speers]

No, you can't get the cup out using a planer, even with a sled. The only think a sled can help with is warp or twist.
If you try to go that route you'll just end up with is a board about 1/4" and it will still be cupped (how do I know this?).z

Simply not true, Robert.

I've gotten by without a jointer for years, by using a planer sled, and never didn't get perfect results.

However, getting rid of cups properly and without waste is not all that easy. It requires a really GOOD sled, (mine has threaded inserts, so I can turn nylon screws up in the middle) and lots of time.

LOTS of time !

- but it definitely can be done. (How do I know this? )

[Myk Rian]

That sure is news to me, I've had no problem removing cup with a sled.
I've done it many times with a sled.

[Jim Becker]

Just to clarify....the purpose of the sled when using a planer to face joint (flatten) a board, regardless of whether it's a bow or twist, is to securely hold the workpiece such that the planer will not "bend" the board as it passes through the rollers. Shims are used to stabilize the board to that effect so that material is removed from the "high spots" on each pass until you get a flat surface. You can then remove the board from the sled and work the other side with the planer.

One thing...if you have to remove a lot of material from one side to flatten it, be sure to consider balancing what's removed from the opposite side to help alleviate moister related warp afterward. This is a judgement call, but it's a "best practice" when milling lumber to remove similar amounts from each side while flattening and thicknessing.

[Cody Colston]

I don't have a jointer. If the board is cupped it can be run face dn prior to the planer. If the board is warped can that be face dn to flatten?
A 4 foot board will achieve a thicker net board than say an 8 ft one in theory?

Yes, yes and it depends.

I rough-cut all my stock to 1" over length before jointing and planing. On a warped board, the shorter the length, the less stock that will need to be removed to flatten a face and then thickness. On a cupped board, it doesn't make much difference if the length is straight.

For the record, using a planer to flatten a cupped face will work with thick boards. On a 4/4 or thinner cupped board, the planer will flatten the cup and then it springs back when the pressure is relieved. On 8/4 or thicker stock, especially hard, hardwoods like Oak, there will be little to no flattening of the cup from the planer if light cuts are taken.

I mill and dry 99% of the lumber I use so if I have a board that is cupped or warped much, I usually discard it and select straighter, flatter rough stock. Life is too short to deal with crooked boards unless it is unavoidable.

[Al Launier]

As several have already noted a cupped or twisted board can be "flattened" on a thickness planer. BUT, one really should use a planer sled. For cupped boards on a sled, shims would be needed to keep the board from being pressed down by the rollers. This is a planer sled I made a while back which allows 3/8"-1/2" of adjustment for the individual supports. The sand paper on each support prevents slippage of the board, as does the stopper board at the end of the sled. Shims used on the sand paper to secure a cupped board will not slide while providing adequate support. http://www.sawmillcreek.org/showthread.php?224652-Planer-Sled