beginner question - why not just a thickness planer

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Forum topic by JoeRPhilly posted 09-30-2012 02:51 AM 3295 views 0 times favorited 8 replies Add to Favorites Watch
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172 posts in 2149 days

09-30-2012 02:51 AM

I just got a good amount of rough maple, some looks to be nicely spalted. Can’t wait to start planing it and see what it’s like.

My question, I think you’re supposed to take rough lumber to the jointer, make one straight edge, then clean one face, then to the thickness planer. Why can’t you just put it through a thickness planer? or can you?

I have a 5” jointer that I picked up used, have never used it and it needs blades and possibly some adjusting. I’m thinking about investing in a thickness planer, I may have come into a good source for rough lumber. I may even be getting a bunch of rough pine for free tomorrow. I’m thinking about getting the dewalt, any suggestions are welcome, thanks!

8 replies so far

View A10GAC's profile


191 posts in 3075 days

#1 posted 09-30-2012 03:00 AM

A thickness planer will make the top & bottom faces parallel to each other but will not guarantee that either will be at a right angle to the adjacent side.

Gizmodyne has a short video that shows the basics better than I can explain in text here. Click for Video

-- Men have become the tools of their tools. - Henry David Thoreau

View rance's profile


4258 posts in 3157 days

#2 posted 09-30-2012 03:09 AM

  • Search online for ‘Squaring Lumber’ to understand the tools needed.
  • Yes, you can skip the Jointer if your board is not twisted, cupped, bowed, or crooked.
  • The DeWalt “4-poster”(DW735) is a good machine. Consider a helix head for it when it is time to replace the knives.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View Garzzo's profile


5 posts in 2069 days

#3 posted 09-30-2012 03:09 AM

I have a Dewalt 735 and really like it. It’s a good deal of planer for the money.

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4128 posts in 2187 days

#4 posted 09-30-2012 03:16 AM

i have a dewalt 734 planer and it was well worth the investment,and the price was reasonable also.

-- Marty.Athens,AL

View derosa's profile


1577 posts in 2833 days

#5 posted 09-30-2012 03:30 AM

If you have small boards that are cupped the planer can remove that and a planer sled can also solve making boards straight and flat, even better, a sled can let you do a 12-13” wide board depending on your planer safer then a jointer will. But, a jointer will do narrower boards faster and easier then a planer with a sled will. If you already have the jointer get it running, I resort to the sled for all of my stock because I can’t get a jointer up the stairs to my shop safely.

-- --Rev. Russ in NY-- A posse ad esse

View shampeon's profile


1775 posts in 2180 days

#6 posted 09-30-2012 05:12 AM

Think about a board that is cupped into an arch. Running it through a planer will temporarily flatten the wide sides so that both sides are equal thickness, while it’s going through the planer. But the board is still arched, and basically unusable.

You need a way of making a reference face that is perfectly flat. That is typically by using a jointer, although a jointer plane works great if you know what you’re doing. As can a planer sled with shims. But you have to make a reference face that’s flat to square up all the rest of the faces.

-- ian | "You can't stop what's coming. It ain't all waiting on you. That's vanity."

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Craftsman on the lake

2790 posts in 3435 days

#7 posted 09-30-2012 10:47 AM

If the board isn’t flat on the bottom by using a jointer then the planer will just cut off the hump or thin the ends. Either way you’ll have a board with varying thickness.

If you don’t joint the edge first then the saw guide will follow the curve of the board and give you a curved cut on the opposite side.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

View knotscott's profile


8012 posts in 3372 days

#8 posted 09-30-2012 11:16 AM

A jointer flattens a face and squares an adjacent edge to a true 90°….it’s step one and everything else references off that flat face and squared edge.

A planer doesn’t really flatten….it creates consistent thickness. It needs a flat reference face in order to make both sides parallel with each other (usually the bottom side of the board) ....otherwise the deviations in the bottom face get translated to the top side and the board simply comes out a smoother thinner version of what went in….not truly flat or straight. Twisted in, twisted out….

A planer would require the use of planer sled to act as a flat reference in order to produce flat wood with two sides that are flat and parallel to each other. Then you’d need to do another step to get a reference edge at 90° to the face….often a router or TS if you choose the planer only route.

Here’s a Planer sled:

Here are some examples of non-flat, non-square lumber….very common. (a board that “looks” straight isn’t always a good reference point for a project, because it’s often not really straight/flat). A planer by itself would simply duplicate the devations you see in these boards, but they’d come out thinner and smoother to touch.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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