Taper from Jointer - Does it Matter?

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Forum topic by lumbermeister posted 324 days ago 1044 views 0 times favorited 18 replies Add to Favorites Watch
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95 posts in 582 days

324 days ago

Been practicing with a new jointer. I know that it is not fully calibrated, as my right angle square shows a gap near its base between infeed table and fence, but outfeed vs. fence is fine. Nevertheless, until I receive my precision straight edge, I am experimenting with jointing scrap.

Despite the above-mentioned calibration issue, the jointer gives me something awfully close to dead-flat, perpendicular face and edge surfaces. If I make enough passes, yes – the board will taper, but… Is this a problem? The jointer is supposed to give me a flat surface – even if the stock tapers, the planer should take care of that so long as my jointed surface is dead flat.

I read many forums where people mention their concerns about this tapering effect. While I know that I need to calibrate my machine for a number of reasons, I am not sure if tapering is one of them. Appreciate your feedback.

18 replies so far

View Charlie's profile


1001 posts in 888 days

#1 posted 324 days ago

Joint a face, joint an edge, then let planer and tablesaw do their job.

If you joint a face, and it’s flat and straight, when you run it through a planer, jointed side down, the planer will make the unjointed face parallel to the jointed one. Voila! No taper!

View firefighterontheside's profile


3320 posts in 459 days

#2 posted 324 days ago

Are you saying the more you run your board across the jointer that it becomes less flat, tapered? If so you definitely have a calibration issue that needs to be fixed or a technique error that needs to be fixed. If its just that the board is not constant thickness, that can be fixed at the planer or table saw after it has been jointed flat on one edge and side.

-- Bill M. I love my job as a firefighter, but nothing gives me the satisfaction of running my hand over a project that I have built and just finished sanding.

View ChuckV's profile


2378 posts in 2129 days

#3 posted 324 days ago

If you don’t have a lot of extra thickness, you need to be careful that the thinner end does not become too thin before the face has been completely flattened. I usually make a few passes over the jointer in the “wrong” direction unless the grain is rally nasty. This helps to reduce any possible taper. Make the last few passes in the “right” direction to avoid any tear-out when you are finished.

But, as Bill says above, lots of taper indicates something that needs to be fixed.

-- “That it will never come again / Is what makes life so sweet. ” ― Emily Dickinson

View Loren's profile (online now)


7260 posts in 2250 days

#4 posted 324 days ago

Tapering is often a technique issue. Using the jointer
effectively requires ongoing assessment of where to cut.

If a board is bowed, I don’t just run it over until it gets
flat. This will usually remove too much wood from the
ends by the time it is flat enough for the planer. Instead,
try jointing the ends individually.


View josephf's profile


52 posts in 698 days

#5 posted 324 days ago

this is not right .forget what it means but you need to change something . i thought it was the out feed table height but as previous post said could be how your running board through

View lumbermeister's profile


95 posts in 582 days

#6 posted 323 days ago

Thanks everyone for the responses. Yeah, I definitely need to calibrate – I have a straightedge from Lee Valley that should be here tomorrow. Until then, I will continue to practice my technique on scrap.

View kdc68's profile


1942 posts in 879 days

#7 posted 323 days ago

It may be redundant to practice technique to avoid tapering if your jointer is tapering because it is out of calibration…..Good luck and congrats to you on the new jointer purchase…

Here’s possibly a couple helpful videos via The Wood Whisperer….

-- Measure "at least" twice and cut once

View AlaskaGuy's profile


566 posts in 911 days

#8 posted 323 days ago

If your jointer is making the stock flat and straight I would worry to much as long as the out-feed table is set correctly.

-- Alaskan's for Global warming!

View kdc68's profile


1942 posts in 879 days

#9 posted 323 days ago

In no time you will be jointing like this

Photo from Ferrazzutti Furniture via Facebook

-- Measure "at least" twice and cut once

View Sandra's profile


4151 posts in 677 days

#10 posted 323 days ago

Yep, it matters. I don’t own a precision straight edge, but I can tell you that any deviation from flat, straight and of equal thickness becomes amplified exponentially the more pieces involved.

-- No, I don't want to buy the pink hammer.

View PurpLev's profile


8476 posts in 2251 days

#11 posted 323 days ago

I’m not sure where all these comments saying that it is not right are coming from ?!?

A jointer WILL taper depending on your technique to more or less- that is normal jointer behavior. as Loren suggested above, there are ways to minimize the taper, and the loss of material/thickness, but by definition a jointer will produce 1 flat surface + 1 perpendicular surface to it – nothing more (no parallel aka no-taper part)

A jointer will not produce a parallel face – that’s what a thickness-planer is for and why a thickness planer performance is impossible to reproduce with any other power tool.

so yes- this is normal behavior and has nothing to do with your jointer calibration.

jointer calibration will either give you or not give you the following:
1. flat surface/plane/face
2. perpendicular face to adjacent face (with the use of the fence)

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View yrob's profile


340 posts in 2255 days

#12 posted 323 days ago

it does not matter. a jointer is not supposed to make parallel edges, just
make it flat. First off flatten a face. then use that face against the fence and flatten and square one edge.
All you need to do is to make enough passes to get flat. Check
this by putting chalk on the edge or the face you are flattening. if you can take it off in one pass you are there. next, you simply take it to the tablesaw and produce a parralel edge by ripping with the jointed edge against the fence and jointed face on the table. Finally make the other face // and bring to final thickness by running jointed face down in your planer.

-- Yves

View mantwi's profile


299 posts in 498 days

#13 posted 323 days ago

The comments recommending you flatten the face then joint one edge square to it and finishing the board at the tablesaw and planer are right as rain. Regarding the gap at the bottom of the fence you should remove the fence and check it for flatness across it’s height. Sometimes the edges get beveled back a bit when they surface grind them. If this is the reason You can live with it if the fence is cupped or twisted you can’t and should return it for a replacement. A little hollow at the edge won’t effect the end product but a cup will make it impossible to joint square edges on any board that’s narrower than the fence is high.

View lumbermeister's profile


95 posts in 582 days

#14 posted 323 days ago


”In no time you will be jointing like this”

“Photo from Ferrazzutti Furniture via Facebook”

Hmm – Hard to tell from the photo… Is that a 4” or a 6” jointer he is using :)

View Sandra's profile


4151 posts in 677 days

#15 posted 323 days ago

Okay gents, I humbly stand corrected.

My thinking is that if you joint an edge and face, then plane the board the two faces will indeed be parallel, but then the width of the board is not the same at the ‘tapered’ end.

Or something like that.

Anyway – I defer to the more experienced.

-- No, I don't want to buy the pink hammer.

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