why does my workbench rack?

[Tom Hassad]

I built a version of the essential workbench by Lon Scheinling and I noticed after building it that it racks (if I put lateral force on the workbench top the top can move side to side). I do have to use some force but I can see it may be a problem if I were to do any handplaning.

I was wondering what causes the racking - if this is unavoidable. I used douglas fir and I did shrink the dimensions of the legs from 3 inches to 2.25 but I also shrank the tabletop to just two inches thick. I am thinking it could be how the legs are attached. It is one lag screw through the trestle top of each base into the workbench.

Was it the design, the materials, the smaller dimensions or is this something that will happen to any workbench?

I did put small feet on the legs to raise up the base from the floor (2 inch square) blocks on each end of each foot. Can the reduced surface area contribute to racking?

[Callan Campbell]

It will help with peoples diagnoses of your workbench. It sounds like you have figured it out with your changing of sizes and the addition of the smaller feet. If the base isn't strong enough and you don't have enough in the way of a stretcher either down low near the floor or at the top of the trestle bases, this could also be an issue.

[Chris Friesen]

I built a version of the essential workbench by Lon Scheinling and I noticed after building it that it racks (if I put lateral force on the workbench top the top can move side to side).

I was wondering what causes the racking - if this is unavoidable.


Get someone to push on it while you watch from a ways back. Look carefully at the leg/stretcher joint and see if it's moving at all, then look if the legs are bending, then look at the trestle/top joint. You should be able to see what's going on.

[glenn bradley]

The stretchers in that design are a bit shy in height for my taste. Since you mention reducing their already small dimensions I have to ask you to think about; How much shoulder did you leave above and below the mortise to take the racking stress? If the shoulder size is adequate, are your wedged tenons good and tight? I agree that some pics will help. It is probably recoverable.

[Gary Curtis]

Before I built my bench out of maple/euro beech I owned a small Sjoberg bench from Sweden. It was a toy. And it was obvious that the flexing, shaking, instability started with the dimensions of the feeble legs.

On top of that, joinery technique is critical, as Glenn says. Ample shoulders on any tenons. My bench plans were a mix of printed Lee Valley, Garrett Wade and Christopher Schwartz blueprints. But I increased dimensions on the legs to a true 4x4.

If you are going to plane by hand, you need mass/mass/mass.

Gary Curtis

[John Coloccia]

One simple thing to check: are the feet making good contact? If not, it will rack much easier. If it's in your garage like many of use, you will find that your floor is probably not very flat and you'll have to shim to get solid contact. It may even look like solid contact because the weight will bend things enough so everything touches, but it's actually torqued and will easily move...even a nice, heavy bench.

Anyhow, that's a quick thing to check before tearing into the design.

[AJ Quinter]

If I had to guess, I would bet that your issue is the connection of your trestle bases to the bench top if you only used one lag bolt on each end. I would check there first. You may consider using multiple bolts (some with slotted holes perpendicular to the bench top to avoid wood movement problems). If the top of the stretcher that supports the bench is wide enough, I would stagger the additional bolts so there are bolts closer to each edge of the stretcher.

[Jim Heffner]

Well, I don't know for sure how the floor is in your shop...but it sounds as
if the floor is not completely level at the spot where the workbench is sitting.

Take a good quality level (4ft size) and check several areas close to the workbench and see how close to level the floor really is...might be surprised!
I have a carpenter's bench that was made to be carried to and from a jobsite
as needed, one place in my shop the bench won't sit completely flat, I move it around just a few inches from it was sitting and bingo! it is sitting flat!
So give that a try and see if that cures the problem.

[Tom Hassad]

There are some good ideas here. I will need to post pics.

One thing I should point out is that although I am not sure on how much shoulder was left on my tenons - I think it was maybe half an inch, but I did not use wedged tenons. Since I used douglas fir I figured that trying to use a wedge would just send a crack through the wood. Also, for the stretchers I ended up using carriage bolts on the ends with a barrel nut to allow for tightening - I was even able to stand on my stretchers and they felt pretty tight - I was not able to drive the bolt all the way because the wood was so tight. I do need to get a visual on what is happening and I'll try to post a pic in the next few days. Thanks, Tom.

[Jeff Bratt]

One thing I should point out is that although I am not sure on how much shoulder was left on my tenons - I think it was maybe half an inch, but I did not use wedged tenons. Since I used douglas fir I figured that trying to use a wedge would just send a crack through the wood. Also, for the stretchers I ended up using carriage bolts on the ends with a barrel nut to allow for tightening

So you instead of a beefy, solid wedged mortise and tenon joint between the stretchers and legs, you have what, exactly? A stub tenon held together with a bolt and barrel connector - a knock-down style joint? Is it glued? That could be the explanation for pretty much any amount of racking...

[Tom Hassad]

I decided to take a closer look so I could report back and provide more information. I decided to try to tighten the bolts a little more. Two of the bolts I could not tighten but the other 6 bolts still had room to make several turns. I was surprised. I guess the wood shrank. I would not call the tenons stub tenons because they are seated almost 3/4 in to the thickness of the legs.

After tightening I tried to rack it and it was noticeably firmer - it took a good amount of tugging to get any movement. I am pretty happy with the results. I should have considered the obvious but I did not think I had to retighten the bolts given how much I tightened them when I put this together.

I think if I had to do this over again I would use two lag bolts on each leg instead of one in the center to connect to the top and I would definitely beef up the legs. I'll try to get a pic posted soon. Thanks - Tom.

[Jeff Bratt]

I think if I had to do this over again I would use two lag bolts on each leg instead of one in the center to connect to the top and I would definitely beef up the legs. I'll try to get a pic posted soon.

Well, it all makes sense. The bolted together joints will never be as sturdy as glued and wedged through tenons. And a "bolt and barrel" knock-down connector is better than lag bolts. Even two lag bolts per joint would be significantly worse - lag bolts into end grain are very weak - and they cannot be re-tightened. I don't think changing the size of the legs from 3" to 2.25" is that big a deal... but changing the leg-to-stretcher joints makes a huge difference.