Wobbly Workbench

[JMWorkbench]

Hi All,

I have recently made my first workbench, and much to my dismay it has a wobble that I suspect is what is referred to as ‘racking’.
This has happened despite my (what I thought was) meticulous measurements and squaring.

The wobble happens when I put lateral movement on the front left or back right of the bench only. The strange thing is there is no racking when I put lateral movement on the front right or back left of the bench. I suspect this may be caused by my framing around the bench pulling or twisting the frame somehow.

Any suggestions on how to narrow down where this issue is coming from would be greatly appreciated.
I have already measured the bench all the way around and it is level within 1mm, the legs are also the same height and using a spirit level the bubble lies dead centre across the table both parallel and perpendicular.

Appreciate the help,
J.

[auscab]

Can you show us a few pictures please.

Basic tables do this sort of thing . Easier to lift a leg from one side compared to the other . Its the same sort of thing .
The longer a piece the easier it is to notice .

Workbenches need bracing and weight to be good workbenches . You can either add bracing as direct braces like 45 degree struts . Or its better to use the space to build in useful components that also act as bracing . Divisions for drawers or shelves done the right way that have a use and brace and add weight .

Rob .

[JMWorkbench]

465546465547465548

Here are the pictures. The front and back are basically identical.
Excuse the shoddy workmanship on my first project!

J.

[poundy]

are your legs themselves glued and screwed, or just butted up against one another? Were the faces prepped at all? It doesn't look like they were prepped in any way (because of the visible line caused by the rounded edges left on the timber) meaning there's potentially a poor face-to-face joint, even with glue.

In your first and third photos where you can see the screws into the front face of the legs. You basically have one lag screw into each piece of timber. That means you have the potential for rotation. As a first attempt to shore it up I'd add second screws into each of those places, so you end up with 4x screws in a "square" configuration.

[BobL]

The differential racking is probably due to the different degree of "tightness" of the screws which are a poor choice for a bench frame.
As pounds says, well prepped joint faces are essential, however assuming you do not want to remake the bench here are a few ideas.

- replace the screws used in the frame with bolts and tighten these really firmly. Then as the wood compresses/drys with age you can at least further tighten up the bolts
- cover the back of the bench with a sheet of 12 mm ply and longish screws into the frame.
- add large triangular pieces of wood at the inside corners - however these may get in the way of drawers etc.

[Treecycle]

When I made my first bench I did pretty much what you have done and screwed the components together and ended up with the same problem you are having. Even though you have quite a bit of timber in there making it look really strong, as poundy has said the components will rotate on each other where the screws have been put through.
What I needed to do with mine was put 45 deg bracing in where the trouble is occurring, ie. front to back and side to side up under the bench top. It is amazing how much that will reduce movement.
When you look at benches that are constructed well, all the joints will be fitted together rather than screwed through. By making proper fitted joinery the joints are self supporting and captive, and will create enormous strength.
You have constructed a very heavy bench there and with a few refinements it will serve you well.

[tonzeyd]

I think we've all been there and done the same thing at one point or another, whether out of necessity or speed. Unfortunately over time the racking will only get worse especially if its a mobile bench. as others have mentioned the best thing you can do at this point is brace all the corners and use bolts rather than screws.

Also you may find that your floor isn't dead flat so any discrepancy in your floor will stress a joint/screws and overtime if you move it to a different location will move at the stressed location.

[auscab]

465546465547465548

Here are the pictures. The front and back are basically identical.
Excuse the shoddy workmanship on my first project!

J.


Good on you for having a go . looks good and a bit of tinkering will help . Id suggest taking off the front rails first and setting them in to a chiseled out housing that's a tight glued fit . Maybe chisel and rout flat at its bottom of each . You could cut them a little shorter for a better fit . Then do the back and sides. Just back in 15 or 20mm will do . After that add a fitted ply panel 15 to 18mm sheet glued and nailed over both ends .
One of the best ways to appreciate good design is to put up with bad for a while .

Rob

[JMWorkbench]

Thank you all very much for the tips.

[Chief Tiff]

As well as doubling up on the screws you could add extra pieces to the legs to trap the rails. If you can put TIGHTLY fitting additional pieces into the legs so that the legs and rails are all flush you will replicate the effect of lap joints. This will essentially achieve what Auscab is recommending but without the chisel and routing work if you can’t take off the rails for some reason.

[GraemeCook]

Hi JM and welcome to the Forum

We've all had bigger problems than yours with early (and recent?) work. Its solvable. An early hardwood bench of mine also wobbled. It took me ages to realise that the floor was not flat!

You have received some good advice, well summarised by Rob (Auscab).

As Poundy suggested, I'd do the laminations on the legs first; if the two pieces of each leg are not well glued together, then the component pieces of each leg will actually rack. If its too hard to dismantle to glue the legs, then you could put several screws into each leg just to hold the laminations together - screws should be as long as possible and course thread to grip on the soft pine.


It will all work out.


Good Luck

Graeme

[JMWorkbench]

Thanks again all. I will be giving some of these tips a go this weekend and will hopefully resolve the racking!

Cheers,
J.

[Damienol]

You just need some bracing from left to right. I can see
A couple of ways you could configure it without impacting your overall design.

Good luck and welcome

[JMWorkbench]

I think I have fixed it. I tried the easy option with extra screws in a square formation which didn't work unfortunately.
Then I fixed a sheet of plywood to the back, which helped but there was still some flexing. Then I added a diagonal 45 degree brace to the affected side which helped some more.
Finally, I added some more structural plywood to the bottom side ends of the legs while pushing down on the affected leg which seemed to make it rock solid.

It doesn't look extraordinarily pretty, but I'm not fussed.

Thanks again all for the suggestions, if it starts to rack over time I will employ some more suggestions.

Cheers,
J