Help with Extending a Plywood Bench

[John Serna]

Hey all,

I have a plywood bench that's attached to the wall with diagonal 2x4s and then the plywood top (looks to be ~ 3/4"). The previous homeowner put this in. It's fine. But the sides of the bench are too tall to attached an old, vintage bench grinder I want to put on it. The vise on the grinder won't open wide enough to clamp on the bench. So I think I need to build an extension.

I'm new to woodworking (since Covid). Since my garage is small and has other uses, I don't have much space. This is basically what I am trying to do:

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I'd like to attach this bad boy! He's at least 10lbs.

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What would be the best (strongest) way to make this attachment that is also going to be fairly aesthetic? Any/all options would be appreciated because given my skill level it would be nice to have a few choices.

Thank you!

[Wes Grass]

2x4 laying flat, and plywood on top? How much thinner does it need to be to mount the grinder?

Any chance there's a diagonal brace close to where you want the grinder? If so, maybe notch the 2x4 out underneath until it fits. A diagonal brace close by should keep it strong enough.

If it has to be plywood thickness (or the 2x4 becomes a splinter), cut a chunk of the 2x4 out completely, box it in on the sides and back, and add another diagonal brace tying into that.

[John Serna]

2x4 laying flat, and plywood on top? How much thinner does it need to be to mount the grinder?

Any chance there's a diagonal brace close to where you want the grinder? If so, maybe notch the 2x4 out underneath until it fits. A diagonal brace close by should keep it strong enough.

If it has to be plywood thickness (or the 2x4 becomes a splinter), cut a chunk of the 2x4 out completely, box it in on the sides and back, and add another diagonal brace tying into that.

I was thinking about cutting the 2x4, but I thought that might weaken the entire bench.

Maybe I should photo the bench. Here's a couple:

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Ideally I'd like to place it right around were that pencil is. It seems like if I make a plank extension like in the drawing, the plywood would be a weak link and probably crack under the weight of the grinder. And I wasn't sure what hardware to use (brackets?) if going that route. I was also thinking to notch out a few inches from the 2x4 and clamp it there, but wouldn't the entire bench become weak doing that?

Thanks!

[Gary Ragatz]

Before you drill any holes, and especially before you cut into any of the under-bench support structure, I'd play around a bit. Get a piece of stock that would work as your extension, and clamp it to the benchtop with c-clamps or f-clamps or whatever. This should help you figure out how stable the setup will be when you use the grinder, and you can also try out different locations for the grinder before you commit. If the grinder isn't an everyday-use item, you might even want to consider the clamping approach as a long-term solution.

I wouldn't think that a 10-pound grinder would tear up the plywood, as long as it's not hanging too far out in space. To be safe, you could always put another piece of solid stock under the plywood and use longer bolts to make a "sandwich" with the ply in the middle.

[John Serna]

Before you drill any holes, and especially before you cut into any of the under-bench support structure, I'd play around a bit. Get a piece of stock that would work as your extension, and clamp it to the benchtop with c-clamps or f-clamps or whatever. This should help you figure out how stable the setup will be when you use the grinder, and you can also try out different locations for the grinder before you commit. If the grinder isn't an everyday-use item, you might even want to consider the clamping approach as a long-term solution.

I wouldn't think that a 10-pound grinder would tear up the plywood, as long as it's not hanging too far out in space. To be safe, you could always put another piece of solid stock under the plywood and use longer bolts to make a "sandwich" with the ply in the middle.

Those are great ideas, thanks!

[John Serna]

What do you guys think about pulling the hardwood top off and replacing it with hardwood?

Would the diagonal beams support the heavier hardwood? What species and thickness do you think, if I do go that route?

Thanks!

[Tom Bender]

That's a pretty cool grinder but it is not common. There may be a reason for that. You might find it inconvenient to use. Gary's suggestion to try a temporary solution might be best.

Now about that bench, it may not be great for chisel work. You might want to begin planning a rebuild. I recently rebuilt my garage bench. Made it a few inches lower, a few shallower and flatter. Yours might benefit from a couple of legs to the floor. Two legs allow better storage than those several knee braces and more rigidity

[John Serna]

That's a pretty cool grinder but it is not common. There may be a reason for that. You might find it inconvenient to use. Gary's suggestion to try a temporary solution might be best.

Now about that bench, it may not be great for chisel work. You might want to begin planning a rebuild. I recently rebuilt my garage bench. Made it a few inches lower, a few shallower and flatter. Yours might benefit from a couple of legs to the floor. Two legs allow better storage than those several knee braces and more rigidity

Thanks for the input. I totally agree...been thinking about remaking it to fit my needs. The problem is wood is so expensive right now. So I was hoping to just remake the top.

Why would you say the grinder is inconvenient to use? I mounted it to a metal shelf I have to test it out, and it works great. Got it for a nice price of $20, too!

[Gary Ragatz]

Thanks for the input. I totally agree...been thinking about remaking it to fit my needs. The problem is wood is so expensive right now. So I was hoping to just remake the top.


John,

Don't know where you're located. The local Menards has a 25" x 96" x 1.5" birch butcherblock top for $219. They're running one of their frequent 11% off sales (but the savings comes in the form of a rebate on future purchases), so it's $195. Weighs 86 lb., so might well need some additional support.

[Tom Bender]

So you have tested it, good to go then.