Planed all round timber - Is it usually perfectly square?

[tomown]

Newb DIY woodworker here. I'm about to embark on my first few projects. I want to use solid timber for the most part, including surface tops (shelf + tabletop). I've loaded up on tutorials and for the most part they use either sawn or raw timber, and then mill/plane using machines. I don't have these machines, so my options are limited to buying planed all round timber. Is this designed to be good enough to start joining straight away without any extra planing, ie is it totally square? I'm thinking wickes planed all round redwood for tops, PAR whitewood for shelves. Will I be able to biscuit join these and get a smooth finish for tops etc?

If anyone wants to know anything about building computers or CAD modelling then I know loads, I have a degree in 3D Digital Animation so ask away if you think I can help. No doubt I'll be back here asking questions as I progress through my projects. Cheers.

 

[foxhole]

Although it's usually square it may well be warped or twisted, so it pays to check each purchase carefully to reduce wastage.
If you post you projects here you may get tips and tricks to save time and effort and also get alternative methods.

 

[JohnD]

no, it will generally go trapezoid as its water content changes up or down. This is because of the way it is sawn from the log.

 

[foxhole]

no, it will generally go trapezoid as its water content changes up or down. This is because of the way it is sawn from the log.

Planed kiln dried timber?

 

[AronSearle]

no, it will generally go trapezoid as its water content changes up or down. This is because of the way it is sawn from the log.

Planed kiln dried timber?

And what does kiln dried mean?

Could be kiln dried to 20-25% or 10%, kiln dried means very little.

 

[JohnD]

I can't find a diagram for plain sawing, but it gives the most usable timber per log, with the least skill or effort. The timber resulting suffers most from warping, cupping, and going trapezoid. Because of the way the grain of the wood runs, it is always going to change shape as moisture content varies per season or when drying out.

For some fine work, you may be able to order quarter-sawn timber, which is more stable but more expensive
http://en.wikipedia.org/wiki/Quarter_sawing

 

[tomown]

I've heard it's worth checking each piece from the tutorials I've looked at so far, mainly for knots and imperfections. I've read a bit more about the timber I'm planning on using and it says in the detailed description "planed square edges" 80+ years old and kiln dried so if it was badly off then I could get a refund under the trades description act I guess.

As these will be my first projects, they don't need to be fine quality, just functional, decent looking and lasting. I'm starting with a solid desk, no drawers. Mortis & tenon the frame, using a cad model for measurements. The solid worktop will use lengths of timber, joined using biscuits, glue and clamps, then sanded/finished. The other is a large simple shelf where I might try out some lap joints for the frame, just so I can practice with the joint. The shelf needs a solid frame as I will be attaching a lowered clothes rail to the supports (for a sloped attic room where regular wardrobes are not ideal) I'll look into the more fine and advanced timber once I've got some stripes with some simple projects. Cheers guys.

 

[foxhole]

no, it will generally go trapezoid as its water content changes up or down. This is because of the way it is sawn from the log.

Planed kiln dried timber?

And what does kiln dried mean?

Could be kiln dried to 20-25% or 10%, kiln dried means very little.

It means the timber is more uniform as it's drying method is controlled, it's unusual to achieve better than 18% under most conditions. Far superior to most methods of drying. We are talking planed timber not sawn.

 

[Dave54]

If it's decent, old timber as it sounds from your description, which has been resawn and machine planed, then for furniture you really need to at least "clean it up" with a hand plane (not an electric planer) to get rid of the cutter marks from the machine planing. Also I have rarely found bought in planed timber to be really square. You will need to check for squareness with a try square as you clean it up.
If you don't at least clean the parts up, then you will end up with cutter marks visible when you apply a finish. Not all of them will be easy to get rid of with a finished piece. The alternative is to get a power fed drum sander to do the cleaning up. They are expensive.

 

[tomown]

If it's decent, old timber as it sounds from your description, which has been resawn and machine planed, then for furniture you really need to at least "clean it up" with a hand plane (not an electric planer) to get rid of the cutter marks from the machine planing. Also I have rarely found bought in planed timber to be really square. You will need to check for squareness with a try square as you clean it up.
If you don't at least clean the parts up, then you will end up with cutter marks visible when you apply a finish. Not all of them will be easy to get rid of with a finished piece. The alternative is to get a power fed drum sander to do the cleaning up. They are expensive.

Noted, I'll check with a square and hand plane if neccesary, thanks.

 

[AronSearle]

no, it will generally go trapezoid as its water content changes up or down. This is because of the way it is sawn from the log.

Planed kiln dried timber?

And what does kiln dried mean?

Could be kiln dried to 20-25% or 10%, kiln dried means very little.

It means the timber is more uniform as it's drying method is controlled, it's unusual to achieve better than 18% under most conditions. Far superior to most methods of drying. We are talking planed timber not sawn.

Not sure what you are saying?

Kiln dried means dried in a kiln. Some timber (including planed) is only kilned to "shipping dry", 20-25%, to stop mould. Some is dried to 10-14%, some to 8-10% depending what it is.

planed all round timber could be any of these moisture contents without checking, and yes, some diamonding can happen on higher moisture contents, as well as change in cross sectional thickness.

Probably very little, but enough to sometimes matter if you are laminating it together and don't have the tools to re-thickness/plane it, which is what it sounds like the OP may be doing.

This isn't so much of an issue if you buy from a decent merchant, but sometimes it catches people out.