Flattening a bench top

[Peter Hawser]

Hi Everyone. Long time "lurker" as they say and first post.

Can anyone offer a good tutorial on flattening a bench top? Like almost everything there are many opinions and it's easy to get a little lost. Right now my bench has a sort of 1 3/4" thick maple butcher block top (from these guys (http://www.mapleblock.com/)) with some dishing and twisting perhaps. I'd like to get in some practice now before I build a real bench. I started with my LV LA jointer going across the bench until all was evenly being removed. Then I proceeded to taking 45 degree swipes, alternating direction with each pass. It seems like I am getting there, but what has been the hardest thing for me to do is to identify any particular high/low spots or twists. It's getting better, biut not there yet. I fear I need much better straight edges and my Lee Valley winding sticks seem to short to really help identify any twist (I know, I should make my own). My "arsenal" of planes includes a LV scrub, LV LA jack, jointer and smoother, LN #4.

Overall this is a lot of fun and with the heat, this is outstanding exercise!

[Archie England]

check out the introductory video offered by Shannon at The Renaissance Woodworker. He demonstrates the principles and tools for flattening any wood surface. Definitely worth the look @ renaissancewoodworker.com

[Luke Townsley]

The most useful straightedge is the bottom of your plane, particularly with a jointer. If you are having trouble, take thinner shavings and you can feel when you are going over a high spot and when the shaving gets thinner as you go over a low spot. I think the most tricky is getting out the twist.

It is a longer distance and is more involved, so it is harder to feel with your plane. It is also much easier to get a hollow flat than a hill. If you have a high spot, you can take it down a bit lower than flat and then a pass or two or ten will bring it back to flat. If your bench is high in the middle, it is possible to whittle your bench down to nothing and never get it flat! The plane can simply ride over a hill preserving the profile. That can't happen with a low spot.

[Peter Hawser]

Thanks Luke and Archie

Can't find that particular video on the site, but it seems worth browsing through.

Luke, I think I know what you mean. You aren't suggesting so much as sighting down my jointer as using it. However, given the former, I can't use the edge of my jointer as a straight edge since Veritas has a weird sort of bump out (Cossman does this all the time on his rough and ready video). I think I have a few more diagonal passes to go. Right now each end of the bench seems flat but the middle has something going on. Luckily my top was dished and no high spots in the middle - quite the opposite.

[Curt Putnam]

Pick one end of the bench and set the winding sticks over it. Each will identify high and low spots under them. In combination they show twist. Flatten that one end. Move towards the other end slowly, using your newly created flat end as a reference. Piece of cake .....

[john brenton]

Not sure how long your bench is, but there comes a point where a 24" jointer/try plane doesn't really do what you need it to do. With mine at about 8 feet, I used my eye, the longest straight edge I have, and winding sticks to get it close to finish. I used string and feelers to see what was doing after I had it at "good enough". It's alot of surface to be messing with, but even so you can hog off quite a bit of wood before you know it once you get in the groove, so you have to watch what you're doing. You can be making a perfectly flat top...but end up with a trapezoidal butcher's block. It's a bear when you go to attach the legs. Don't ask me how I know that.

[Randy Bonella]

Pick one end of the bench and set the winding sticks over it. Each will identify high and low spots under them. In combination they show twist. Flatten that one end. Move towards the other end slowly, using your newly created flat end as a reference. Piece of cake .....

+1 on this method. That is what I did and it works great! Went very fast.
Randy...

[Jim Koepke]

Peter,

Welcome to the Creek. Your profile doesn't indicate your location, where do you call home?

Getting a bench flat is a good goal, but it doesn't have to be prefect.

My bench has a few spots where it has been hit by a saw or chisel. Then there is that spot where for one time my plane was set down on its sole rather than its side.

It taught me that maybe the idea of laying a plane on its side wasn't so much to protect the blade as it was to protect the bench top.

jtk

[Peter Hawser]

Thanks everyone. What clued me into this is I built a cabinet that stands perfectly on my Kreg klamp table (flattest think I own), but wobbles on my bench! This must have happened in the past year, because it used to be flat. I'm going down tonight and will try out some fo the suggestions here. I need to stop planing and really assess what is going on. I need longer winding sticks - anything.

Oh, I'm outside of Philadelphia.

[Luke Townsley]

Good point. Benches do go out of flat with use and weather changes and as the wood settles in to its new shape and environment. When you first flatten a bench, if you are really going for perfection, it isn't a bad idea to get it close to flat and then wait a week or a month to finish flattening it. If you got it fairly close initially, you may forget about perfection if its close enough for the kind of work you are doing.

[David Keller NC]

Peter - There are several videos of the bench flattening process on the web. Here's one by Al Navas:

http://sandal-woodsblog.com/2008/05/20/episode-11-flattening-the-workbench/

There are couple of things that Al does in this video, while not wrong, do mean more work than was necessary (Al points out that he's not a hand-tool person):

1) Starting at one end instead of working just the center that had developed a severe crown. Both methods will get you a flat bench, but not working just the high spots means taking off more wood (which is more work). If you do this carefully, you can use a much smaller plane to work the high spots, which is also a lot less work than using a jointer to do the whole procedure.

2) Working one end of the bench until it's flat, instead of working out the high spots and then traversing the entire bench with very slightly overlapping strokes. This last method results in the fewest number of passes to get the desired result.

3) Not waxing his plane. Those that use hand planes to surface most stock will tell you this - I would guess that it easily halves the amount of force you have to put into the stroke to take the same size shaving. Typically, you want to re-wax the sole about every 5 strokes or so (so it pays to develop a very quick "scribble" technique with a solid wax block going down the plane sole - stopping every 5 strokes to apply paste wax would be a huge waste of time).

4) Using a steel straightedge to check for flatness. This isn't "wrong" by any means, and it may be that he used it because he has one. But you don't need it - any reasonably straight-grained board with the edge freshly jointed will be more than sufficient to check for flatness (and it's much lighter than a steel machinist's straightedge).

[Peter Hawser]

Thanks David, Your advice is very helpful. I'm glad I decided to do this. I have some twist and off little high spots and am starting to get the hang of this. I have taken off A LOT of wood (maybe 1/16th to 1/8th off the whole top) and it took me a while to figure out how to be more efficient. However, better to learn here on this cheap bench top vs the one I hope to build in the next year.

[David Keller NC]

Peter - This operation is one reason to go for a relatively thick solid lumber top instead of a thinner top with a skirt, as flattening will have to take place throughout the bench's life. Perhaps not every season, but probably every year or two unless your shop has a very highly controlled humidity atmosphere. A 4" thick benchtop of solid wood will likely last your working lifetime, but one of the commercial types with a 2" thick benchtop surrounded by 4"-6" skirts may not - after a few flattenings, these designs may get thin enough to flex under planing pressure, which isn't good.

[Peter Hawser]

Peter - This operation is one reason to go for a relatively thick solid lumber top instead of a thinner top with a skirt, as flattening will have to take place throughout the bench's life. Perhaps not every season, but probably every year or two unless your shop has a very highly controlled humidity atmosphere. A 4" thick benchtop of solid wood will likely last your working lifetime, but one of the commercial types with a 2" thick benchtop surrounded by 4"-6" skirts may not - after a few flattenings, these designs may get thin enough to flex under planing pressure, which isn't good.

Absolutely David! A roubo-esque bench is in my future this year. I have ALL the books and I have started my wood search.

[Chris Fournier]

Simply put, don't rush to flat.

Start by taking off high spots. Concentrate on identifying the high spots and slowly remove them to approximate the areas surrounding them.

You can't fill in low spots.

The trickiest part of flattening your bench will be reconciling the diagonally opposed high spots created by twist. The solution to this is work micro but think macro.

Use a pencil to identify your benchtop topography as you flatten it. Update these pencil musings as you go.

Think of the process as iterative and sooner or later you'll be done - until the next big seasonal tune up!

[Wilbur Pan]

Here's how I flattened the top of my Roubo bench when I was first building it.

http://www.sawmillcreek.org/showthread.php?102141-New-Year-new-workbench-mucho-pics!&p=1396889#post1396889

If you want quick and dirty winding sticks, go to the local borg and get some 1" aluminum angle iron. It's cheap and straight enough for winding stick purposes. You can cut it to whatever length you want. Spray paint one of the pieces a dark color to provide contrast.

You don't need machinist precision for this task. The "straightedge" that I'm using to flatten my benchtop is a 48" metal rule from the borg.

[John Coloccia]

Personally, I would get it close enough that it won't wobble or flex when you lean on it, and then bring it down to the local mill and have them put it on their belt sander. IMHO, flattening a workbench with puny little hand planes is a poor use of my time....but that's just my opinion.

[Peter Hawser]

But John, you look like a pretty healthy fellow and some of us could use the exercise!

Wilbur, that is a fantastic thread and post. Thanks. I was up looking for clear 4x4's today and no luck.