Thread: What's a good technique for making two boards each perfectly level for gluing togethe

A long metal straightedge and a sharp trying plane are the tools for the job. Straighten your edges to the metal straight edge with the trying plane ( the longer the plane the easier to get straight). The straight edge will rock on the high spots and you will be able to see daylight between metal and timber if there is a hollow. Once these anomalies are deleted your boards will be a good fit.

Don't try to sand them straight; power sanders always roll over the edges slightly and you will never get a flat surface.

Sounds like you need to learn how to joint using a handplane. The 18" Stanley you have is likely a number 6 foreplane; a bit short but it will do. Forget about the sander.

In a nutshell these are the steps to follow:

1. Get the blade sharp.
2. Set the depth of cut to the minimum you can get a full width shaving from; practice on some scrap first.
3. Support the planks along their length where possible; you don't want them to flex while planing.
4. As the edges are 25mm wide you can edge both planks at the same time; your plane blade is 60mm wide. Put them side by side with the face edges either both in the middle or both on the outside.
5. Run the plane along the edge until you are getting full width shavings; and check for square. If you are doing both together as per step 4 squareness is less critical.
6. Check with the straightedge. I use a quality aluminium spirit level, by rubbing the level along the wood the high spots get grey marks. Skim off those marks and the boards will match the edge of the level.
7. Place the boards together and look for gaps. A slight gap in the middle is fine; less than 0.5 is what you are aiming for. Gaps at the ends are NOT good...

This is something you need to practice, ideally with someone who knows how to set up and use handplanes. Maybe you could start a "please help me learn this skill" thread asking if there is someone local to you who can give you some hands-on instruction; you'll need to expand a little on "South Australia" as your location though!

Originally Posted by Chief Tiff

you'll need to expand a little on "South Australia" as your location though!

Might be South Africa...

Well thanks for that, guys. Very valuable help.

Main thing I take from that is the old Stanley hand plane is the tool for the job. Not the power planer, not the power sander.

O.K. That's going to take me back to my childhood. I've not done any such woodwork since then.

Better get to it...

Chief Tiff's tips are everything you need to know. Most are basics, but point 6 is a bonus. I've used a similar technique with chalk to mate two curved edges.

Matt Estlea has a YouTube video of edge jointing using hand tools:
How To Edge Joint Panels by Hand | The Cabinet Project #1 | Free Online Woodworking School - YouTube

Even if 'power' is your preference, your power sander & power plane still wouldn't be up to the job.

That's the domain of jointers... or in a pinch, a thicknesser with a jig. Good ones of which tend to be rather heavy and are more work-stations than hand tools.

You can push the boards together, clamp them to a saw horse and rip down the middle with a circular saw.

I use this method with my really large tables and get perfect results

If you have a Router you can use that.