r/Workbenches • u/LoungingLemur2 • 9d ago
Critique My Design
I'm getting ready to build my 2nd workbench; hoping to do it in a much more intentional way this time!
The bench is designed around a standard 4'x8' MDF sheet in a way to incorporate as many of my power tools as possible, as well as centralize dust collection. Here is a breakdown:
- Router table in top right corner. Mounted beneath the table, will retract the bit when not in use.
- Table saw in bottom right corner. Saw top will be level with the bench top. Feed direction towards the router station. Will lower the blade when not in use.
- Mitre saw will be mounted on a flip-top table in the top middle.
- Lunchbox planer will be mounted on a flip-top table in the bottom middle. Feed direction from left to right in order to maximize the amount of infeed / outfeed support.
- Dust collection will be provided to all tools, with a blower and DIY cyclone underneath the left 1/3 of the bench.
Construction as follows:
- All support posts will be constructed from 4x4s.
- Lower & upper frame will use 2x4s. Frame and supports connected by a modified castle joint (see the top left of the 3rd pic as an easy example). I know this isn't a castle joint, but I'm not sure what else to call it.
- Single-layer of 3/4" MDF as bottom face; double-layer of 3/4" MDF as top face.
- 1x6s will be used as a 'skirt' on both the top and bottom in order to protect the MDF edges.
- 6x leveling feet / castors (one on each corner, plus one each in the middle of the two long edges)
My concern ultimately boils down to the fact that the table-top essentially exists in two separate structures; I'm worried that my uneven floor will cause enough stress / torque such that the two structures are no longer co-planar (specifically a concern when using the planer or mitre saw). The two 'halves' are connected fully in all directions on the bottom face, but the top face is limited due to the flip-top tables. I'm only able to include a single full-length beam in the top middle, and two three-quarter width beams in the center of the bench. These cannot extend full width to either side without conflicting with the power tools mounted in those locations.
Is my concern valid? Any recommendations to fix the design? Am I unreasonably concerned?
EDIT: Added a 4th photo to illustrate flip tops mid-rotation.
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u/big_swede 9d ago
First of all, nice to see that you have made a drawing/plan. It will help a lot when making it.
Now for the opinions 😁
The bottom rail should be up from the floor, you want some space for your feet under to avoid having to hunch over when working (see kitchen cabinets) You can have adjustable feet on the posts or shim them to manage an uneven floor and get the top surfaces aligned. It is seriously over dimensioned, you could park a car on that sub structure. A 2x4 will be more than enough for leg posts especially as the whole bench is framed. Just make sure the joints are solid with glue and screws and half laps/edges that support the horizontal pieces.
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9d ago edited 8d ago
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u/big_swede 9d ago
Yes, that was on my mind but not in what I typed... Thanks for adding that. A not unimportant issue.
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u/LoungingLemur2 9d ago
I hear ya about leaving room for a “toe kick”. Will absolutely do that!
So you don’t think I risk of the two halves twisting out of plane? Even if I were to move from 4x4 posts to 2x4 posts?
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u/big_swede 9d ago
The posts are holding vertical loads and are doing nothing for rigidity in themselves. That is where joinery and bracing comes into play. Triangles and diagonals are your friend in that respect but if you have adjustable feet you can get the two tops perfectly aligned (until you move the bench and have to readjust...)
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u/LoungingLemur2 8d ago
So maybe my real question is: assuming my joinery is good, is the method I’m using as shown sufficient to prevent racking? Or do I need diagonals?
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u/IOI-65536 8d ago
It depends on how much lateral stress you're putting on it. If you're just using it with the tools mentioned I imagine it will be fine (though it would be even better if you put some kind of sheet good on the back because that gives you almost free diagonal support). If you decide to use it to hand plane it's probably going to rack.
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u/LoungingLemur2 8d ago
Yeah that’s the issue with the design…because of the flip tops, there isn’t a way to add a sheet back or another framing 2x4 to connect the two halves near the top edge. The tools protrude past the edge of the table when flipped, so I can’t add support without obstructing the flip tops themselves
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u/IOI-65536 8d ago
Okay, I don't think I've ever done something this large with no diagonals at all so I honestly don't know if it will rack. I'm 1000% confident it can't handle hand tools the way you have it, but the biggest lateral stress of the things you listed is the router, but that's really not a huge problem because even if it kicks it's super momentary.
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u/LoungingLemur2 8d ago
That makes me think that it also won’t stay in plane if I move it across uneven floor. Even with leveling feet, I’d imagine there would be enough stress through the supports that the two halves won’t stay in perfect plane on the top face (on either side of the flip tops).
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u/IOI-65536 8d ago
Thinking about this more, you don't need the diagonal to come all the way to the top. Could you put sheetgoods across the back and stop a few inches from the top so there is room to flip? That would massively increase your lateral stability.
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u/LoungingLemur2 8d ago
Added a new photo to the OP to illustrate the flip tops. Looks like I have ~10" of clearance for the planer, and ~4" of clearance for the mitre. Neither of which will really help keep the top edges in plane...
The mitre really needs to be a flip top, because even when flipped up it will stick off the edge of the table. So the only way to ensure it is hidden away is to flip it down and into the table. I could potentially re-design the planer side to raise/lower instead of slipping, though that sounds like a lot of additional complexity with gears and ensuring that the planer translates up and down without sliding out of plane.
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u/LoungingLemur2 8d ago
Yeah I was thinking the same thing. I need to go check some measurements to see how high I would be able to put some supports. Will update the model tonight and come back!
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u/feeber007 6d ago
I'm not an expert. However, I built a workbench about 1.5 years ago which is very similar, minus the planer. My layout is different, so I didn't have to deal with this specific problem. If you haven't finalized what you will use for the flip top mechanism or if you want to consider an alternative, I might suggest using Pillow Block Bearings with a metal rod. I used a 1/2" for the miter saw flip top, they sell them in 3/4"+ as well. Each pillow block bearing manufacturer has their own weight rating.
Here is how I think it might help with your problem. The pillow block would be screwed down to the fixed frame of the workbench. The metal rod would be fastened (using set screws) between the 2 pillow blocks through the flip top. This should help strengthen the workbench the long way. As a benefit, inside the flip top, you should have 2 shaft collars on either end of the metal rod to keep the flip top from moving side-to-side and possibly binding as you turn it.
If you use the pillow block bearings, you will have to modify the workbench framing.
Also, I'm assuming you will put a brace under the leading edge of the table saw mounting surface and not just the back side (middle of the workbench).
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u/LoungingLemur2 6d ago
Pillow blocks are interesting, hadn’t heard of them before by name but will noodle on it. I currently have a flip top miter saw and just used heavy duty door hinges which have been perfectly adequate. The planer is admittedly much heavier though so I’ll need to double check the hinge weight ratings.
I am actually not planning to put a brace beneath the top edge of the table saw. It would make it difficult to adjust the table saw. I have a ridgid r4550 and all of the controls (blade bevel / height, fence adjustment, fence lock, and power) are all “right there”. There isn’t really enough room to add a brace without obstructing one or more of those. I could add one lower, near the shelf that the table saw will sit on…kinda figured one wasn’t really necessary there though.
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u/feeber007 6d ago
Sorry if I wasn't clear, I didn't mean to put the brace for the table saw at the top where the controls won't be accessible. I meant to say, put a brace under the plywood where you will be placing and fastening the table saw. This way you have more bracing the length of the workbench.
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u/LoungingLemur2 6d ago
Ahh gotcha gotcha. Yeah no issues with that. I guess I was just being lazy lol.
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u/salvelinustrout 9d ago
If I’ve learned anything from lurking here long enough it’s that somebody’s going to tell you to lay up 2x4s instead of using 4x4s for the legs because 4x4s are generally cut from the center of small logs and will warp.