Jointer table coplanarity tolerance

[Christopher Wellington]

Coplaner gets misused a lot when discussing jointers

Thank you Mark. You're correct about the geometry, and this is a bit of a pet peeve of mine.

Honestly, the word "coplanar" doesn't have much use in woodworking at all. I'm more likely to use the word "flush" in situations where actual coplanarity is desired.

Certainly in milling we deal with flatness, parallelism, and perpendicularity, not coplanarity. A board with the two faces coplanar would have zero thickness!

[Erik Loza]

Here is the thing: You can take any modern jointer designed for the hobby woodworker, adjust it as perfectly as possible, then wait until the sun creeps into the shop and hits the machine or get (as we do here in TX) 40-degree temp swings in a single day, and those measurements will totally change. My suggestion for any new machine: Square the fence up to 90 degrees and then joint a few boards. See what you get. THEN, start playing with the machine if needed. Just my 2-cents.

Erik

[Andrew Hughes]

I use the term coplaner to describe a jointer that has tables in alinement. I think it gets the point across without getting all scientific. Woodworking has lots descriptions that are not necessarily true but gets the point across.
We call cypress cedar sometimes juniper cedar. Sometimes we call cherry black cherry. We all know black cherry is a fizzy drink.
My jointer has tables coplaner and very flat. I have one spot that has a small 2 thou dip it’s a 60 years old Oliver. It think it’s the finest jointer ever made. Probably not true but you get the point.

[Warren Lake]

you also have to take into account if a machine is new or used as used may have wear. If i check lead in edges on the infeed and out edge on the outfeed both with will be worn on a 60 year old machine yet going in some amount maybe 10 inches of less it will not be down that much. Its happened from boards not being put on flat or tipping at the ned of the outfeed and is sort of the same as a shaper that has had a power feed mostly one area. This is very easy to see on a machine with factory broach marks even before you measure it.

[Jim Becker]

I stand corrected on the correct use of the word coplaner ...but also kinda agree with Andrew.

[Christopher Wellington]

I use the term coplaner to describe a jointer that has tables in alinement. I think it gets the point across without getting all scientific.

Not to belabor the point, but why not just use the term "parallel"? That gets the point across arguably even better than "coplanar", and it's technically correct to boot.

[Andrew Hughes]

Not to belabor the point, but why not just use the term "parallel"? That gets the point across arguably even better than "coplanar", and it's technically correct to boot.

I guess we can try. For some reason I’d don’t think it will catch on. How about coparallel ?

[Bill Dufour]

Coparallel is a needless complication. To be parallel you have to have two lines or two planes already. Otherwise they are just straight or flat.
Bill D.

[Andrew Hughes]

Coparallel is a needless complication. To be parallel you have to have two lines or two planes already. Otherwise they are just straight or flat.
Bill D.

I agree it’s too complicated coplaner it is! Drinks for everyone

[Mark Hennebury]

I think that Andrew is just having too much fun.
People can continue to use incorrect terms and add to confusion, or just use the correct terms to help clarify.

Its not complicated, drinks all round.


jointer tables 1.jpg

I agree it’s too complicated coplaner it is! Drinks for everyone

[Jim Eisenstein]

Lots of interesting, and some funny, comments. Thanks all!