Reply To: Workbench question – how to flatten rounded corners after lamination?
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Start accross the grain, because this requires less force. The round corners will protect the edges for a while, so you can go all the way of the width. You can use a wall to rest your table against, then clamp the wood at the front edge. You have all glue lines as depth markers, so keep watching, how they get smaller. Once you are about one or two mm away (3/16) from the final thickness, start planing with the grain and get rid of the tearout as far as possible. Be patient around knots, better use a shallow setting and spend more time. And do sharpen whenever you are in doubt, if the blade is still sharp. By the way, this will take time and it will be exhausting, but you don’t need to finish it in one go. Only make sure, you are working the complete surface in one go, because this will ensure, that you remove about the same amount everywhere. And do check often. Or, better check even more. I think, I needed roughly two hours per face, pure planing time, no rests, sharpening or taking breath included.
Measuring equipment:
Eyes make quite good measuring equipment. You can check an edge for straightness by scanning it from corner to corner. By scanning the short edge on the other side of the board against one of the near corners, you can even tell, if a board is twisted. Unfortunately, this requires not only good vision but also experience, and even an experienced eye can be fooled by ondulating grain.
Instead of winding sticks, you can use metal rulers (with support, so they can stand on the side) or spirit levels. If you have one spirit level, you can check the position of the bubble while in one place. It should be at the exact same position in any other place. Not very accurate, but better than nothing.
For a long straight edge, you can use a square aluminium “tube”, the wider, the better. There are special boards to check the flatness of concrete floors, which cost about as little as these tubes, while the manufacturer hopefully paid even more attention to have it straight. I was quite happy, when I discovered Paul’s video about making straight edges. But eventually, I figured, that I would need a straight edge to check them for straightness…
Alternatively, you can use a fishing line or any thin string with a fairly smooth surface. You have to stand the slab on the side, because the line won’t ever be straight vertically. But under tension, it will be perfectly straight horizontally. This is, how brick masons measure their walls for straightness.
Ok, I hope, this helps a bit. Anyway, don’t give up. I found, that building my work-bench is one of the best projects to learn planing and measuring. In the end, nothing needs to be absolutely perfect and you can even out mistakes even after years. During assembly, only one side of the bench-tops needs to be flat, so I decided to flatten the harder side first, expecting the other side to look better when done.
Dieter
- This reply was modified 7 years, 6 months ago by Hugo Notti.