Saturday, March 24, 2018

Re-flattening the Benchtop

I built my current workbench the last two months of 2015 and it has been great.  But I've known for a while that the top is not as flat as when I first completed it.  I've recently completed a few projects and cleared off the benchtop and now is the time to re-flatten it.
Before re-flattening
I use a Record vise on the front and a Jet vise on the right end.  When I installed the Record vise, I probably didn't leave enough room between the top of the vise and the benchtop.
Less than 1/8" from top of vise to top of bench
The end vise has more space - about 3/16"
I was concerned about having the metal parts of the front vise this close to the benchtop (don't want to hurt my planes), but I didn't end up taking much off the benchtop to flatten it, so I'll probably be able to flatten it a couple more times before I need to lower the vise.

I started by penciling lines on the top to help gauge progress.
Penciled lines across top
I'm fortunate to have a LN #8 that I found at a garage sale a few years ago (for a great price, too).  It's almost 24" long and perfect for flattening a large benchtop.
The Lie-Nielsen #8
It's obvious that my benchtop has shrunk a bit over the last two years.  The removable center board was once a tight fit and now it has about 3/32" space.
Large gap around removable center board
This caused issues when planing the top, so I wedged it in place from top and bottom to keep it from moving.

I started planing straight across the benchtop to get a feel for where the high spots were and quickly found some.  After leveling that out a bit I used diagonal strokes first from right to left, then from left to right.
Diagonal planing
It's important to stop and gauge your progress.  The picture below shows areas not yet touched by the plane.
A low area at front section of bench where I do a lot of pounding;
not sure why the rear section was low there
After a few diagonal passes I used the edge of the #8 to find high spots.  I marked high spots every few inches across the length of the benchtop.
Checking for high spots
Used a smoother to remove the high spots
After a few repetitions of the last two pictures, I was fairly happy.  I checked for twist with makeshift winding sticks since my usual sticks are far too short to use on a benchtop.
Using a 24" straightedge and a 48" level as winding sticks
There was minimal twist - not enough for me to worry about
Then I used the #8 to make a few light passes with the grain of the top and followed up with a quick scraping.
Last was a little scraping to remove any planing marks and fuzzy bits
Now it's flatter than it was and looks much better, too.
Vise chops re-installed and the bench is looking good!
I use the flatness of the benchtop to check for twist on project pieces.  It's good to be able to rely on that before using the winding sticks.

I've got a question for anyone who has read this far.  Like all garages should, my garage slopes down towards the garage door.  So while my benchtop is parallel to the floor, it's not level to the ground.  I could fix this by lifting the left end a little.  Is it important to you that your workbench be level to the ground?

8 comments:

  1. My opinion is that It helps with odd shaped pieces if the top is level as read with a level. It gives you another reference. But if the floor varies a lot, it might be uncomfortable to work at different heights.

    Your bench should settle down soon so future tune-ups aren’t so bad.

    I just flattened my 41 year old bench for the fifth time. 1 yr ( kinda drastic crown developed ), 6th yr, and about every 10-12 years since. All I needed this time was a number 80 scraper. The originallly 4” top varies about 3/16” in thickness. I don’t notice.

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    1. I recall making a chair once when it would have been nice to have the benchtop level with the ground. I'd probably have to lift the left end about 1/2" to make the top parallel with the ground. The top is about 36" high now and I like it there. I'll probably keep it the way it is now, but it's something to think about for the future.

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  2. If you use a lot of round tools, marbles, golf balls or liquids in shallow pans it may be worth leveling. More important, you must get rocking out but level is up to you.

    If the bench is out of level in the short direction it may have an effect on your ability to plane square. Out of level in either direction could affect your ability to drill square (but not as bad as progressive lenses).

    If it's easy, you can do it now or do it later. See if you notice and if it bothers you.

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    1. You make a good point about drilling, Steve. There have been times when drilling/boring a hole horizontally that I wished the benchtop was parallel to the ground. My bench is pretty close to level from front to back, but it's way out from left to right. I'll probably keep it as is for now. I can always make some platforms for the left side feet for the times when I need it to be level. Gotta think about that ...

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  3. Go to the borg and buy some 3/4" aluminum angle iron and make winding sticks with it. I have a set 36" long that I used on my bench flattening. I got this idea from Chris S.

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    1. Thanks Ralph. I've heard that one before, but still have never used the angle iron. I've got my regular winding sticks that are about 18"-20" long and they handle everything I've done other than the workbench. Don't think I can justify the space to store the angle "iron" if I'll only use them on the workbench.

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  4. Looks shiny and new now!

    I thunked on the "vise-level-with-the-top" problem when I made my bench. I have that big 24" long white oak chop, and I didn't want to have to go at that again. I set it a skinny 1/4" low. Probably more than I need, but I'll never have to worry about it again.

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    1. Hey Derek. Well, so much for shiny and new - that lasted a few days. I'm now rehabbing an old #7C that is/was horribly dirty and a bit rusty - a very dirty job.

      I think 1/4" below the benchtop is about right for the metal vise tops. I won't make the mistake again (if I ever build another workbench). I use plywood chops and they get flush with the benchtop. It's easy enough to plane them down with the benchtop when needed.

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