Flattening Board

[whippedUP]

Hello all,
I am flattening some scaffold boards up to make a unit.
I have a Makita thicknesser and have a sled/jig made.
Was just wondering what way the wood should pass through, wedge end 1st or level end?
please have a look at photos, all help and advice greatly appreciated.
Have a great weekend.
thanks
Matt

 

[pe2dave]

Cup up? Letter n rather than u.
Last photo implies longitudinal twist as well? How flat do you want it?

 

[whippedUP]

Got the cup up thanks, yea the boards are quite bowed, cupped.
I was just going to pass them through and see how flat/thin they come out. Bit of a test.

 

[sploo]

If the board sits reasonably stably on a flat surface with the cupping resulting in the centre to be higher (like in the second picture you've posted) then you can get away with taking several light passes on a thicknesser to plane the upper surface flat, then flip it over and thickness. Too much roller pressure and you'll bend the board; leaving you with a banana (albeit one that's consistent thickness).

If you have wedges (like your last image) then I'd probably insert the wedged end first; as it's better to take a few light passes than just remove the high spot; vs feeding in the thin end first and getting a nasty surprise as the thicker/higher spot overloads the machine. Definitely fix the wedges though (e.g. hot glue).

If there really is as much twist in the board as indicated by your final image then do be aware there won't be much thickness left once you've planed the top side flat and thicknessed the other side.

 

[sploo]

Got the cup up thanks, yea the boards are quite bowed, cupped.
I was just going to pass them through and see how flat/thin they come out. Bit of a test.

Do be aware that gritty/mucky boards can be quite aggressive on planer knives. Prepping with a wire brush or coarse grit sander can help.

 

[MikeK]

If I was forced to use that board, I would rip it into several strips to remove the split areas and run them individually through the thicknesser to the same dimension. Assuming you can joint the new edges, I would glue the strips together with alternating ring patterns.

 

[whippedUP]

Thank you guys, really appreciate all the advice.
I will get to work on this Monday and post results.
thanks again.

 

[Inspector]

If I were putting it on a sled I would wedge both ends to split the difference of the amount you take off.
Do consider Mike's advice about ripping the heartwood out.

Pete

 

[thetyreman]

If I was forced to use that board, I would rip it into several strips to remove the split areas and run them individually through the thicknesser to the same dimension. Assuming you can joint the new edges, I would glue the strips together with alternating ring patterns.

+1

if you remove the centre pith wood you will be left with a quartersawn board that should be stable, and it will remove the worst of the shakes/cracks.

 

[julianf]

Make sure they are properly dry before you start.

If one side is wetter than the other, from being stacked together, that will create a bow. If you flatten it before it's normalised, it will then bow again as it dries.

 

[Stevekane]

Im assuming your not trying to make “chippendale” quality furniture with scaffold boards, in which case I have been quite surprised what I can get away with/overcome useing crappy old wood. My “saw bench” is a home made affair and yet its quite possible to split down boards like yours, cup up and holding them as flat as possible, then pass the uphill bit through again holding it flat and you have sliced out a neat wedge, and Ive then just glued them back together, its not perfect and you can get a “pillowed” effect but it looks okay when sanded up. Twist Ive found will usually be pulled out by whatever its fixed to. Ive just finished a big 7ft table, 3ft across that I clamped ferociously as I glued it together to try and pull it as flat as possible, but when it came to it it was still curved up in the middle across the ends where I wanted to fit breadboard ends, this was 45mm thick softwood, but some clamps pulling down a peice of 4x2 sitting across a noggin in the middle pulled it flat enough for me to line up with some hefty oak loose tennons and its all been sitting for the past week or so and nothings happened yet,,,I keep expecting a loud crack but Im hopeing that being over engineered it will all just settle into its new position. Its not fine carpentry, and if I knew what I was doing I could probably do a much better job, but I enjoy what Im doing and surprisingly the end results are usually just fine.