Flattening

If you follow me on Instagram you’ll know that I’m building a Moravian workbench. I’m not writing about it here because it’s been so well covered by Will Myers in his step-by-step guide on wkfinetools.com and his video with Joshua Farnsworth.

I will be writing about the end vice I’m building which might be useful to those who haven’t yet fitted a vicious toothed planing stop and doe’s foot to their bench.

Checking for flat
Planes come with a built-in reference edge

 

Yesterday I was at Richard Arnold’s open day and listened to Oli Sparks talking about flattening the ways on his milling machine. He does this by hand marking the high spots using machinist’s dye and a very flat reference plate.

I have been struggling to find a way to measure the flatness of my workbench top end to end. Checking for wind and flatness side to side is easy.

 

Winding?

That’s straight enough for a six foot bench!

But other than squinting I have no way to check flat along the length of the bench. On the drive home yesterday inspiration struck. A piece of string, pulled taught will let me see hollow and humps. When I was fishing out a crayon to mark the spots shown by the string I found my chalk line. Even better. Pulled taught and dragged across the bench this showed up the humps very quickly.

 

 

IMG_2273

With the humps nicely coloured in I could flatten them out. I was a bit worried that I was making a rod for my own back. How flat does a workbench need to be? (That’s a rhetorical question – I’m happy with my own answer!) The chalk line quickly revealed that the ends were high. With a bit of planing I started to see the humps in the middle.

 

Planing
Plane until the blue has gone

I often find myself chasing my tail when flattening long wide pieces. I go too far on one section and then have to level the rest to it. With this method I did a lot less planing and a lot more checking (which is considerably less tiring!).

Once the big humps had disappeared and the chalk line was just colouring the whole bench blue I switched from the scrub to the jointer plane and made a couple more passes until the blue had disappeared. You’ve got to be sure that you’ve got the thickness to carry on planing once the humps have gone because that chalk gets everywhere and you’re going to need a final pass to get rid of it. On a 4 inch workbench top that’s not really a problem.

IMG_2294

Caveat: the blue gets stuck in the tearout. But this is workbench, not a piano.

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