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Niels J. Larsen
02-13-2009, 2:02 PM
I've been tinkering with the design shown in the image.

It's a low table/bench which will be used as a printer table.

Everything is 40mm thick Wengé. The table top is 500mm deep and 1200mm wide.

The legs are 500mm deep and 500mm high.

Each leg is attached to the top with two 20mm thick stainless steel rods epoxied into the wood (20mm depth in the top and whatever is necessary in the legs). An alternative would be to drill through the top, and let the rods sit flush with the top face of the table top.

As I hope the drawing shows, the legs are attached 50mm from the side of the table top, to avoid breaking of the grain in the top.

I really like the design - I'd like it better if the legs were mounted flush with the sides of the top, but I doubt it'll hold.

I also have my doubts about the design shown, as I fear the stainless rods will break the table top, due to racking. On the other hand, this table will only be used for two printers, so it will probably not see that much weight and movement.

An alternative is to mount the legs to the top with domino-reinforced miters - which was actually my first choice - but I like this better.

So, to sum up my questions:

1) Will the table top break with the design with the legs 50mm from the sides, and "only" 20mm of the rods in the table top?

2) Will the table top break with the legs flush with the sides and "only" 20mm of the rods in the table top?

3) Will the table top break with the legs in any position and the rods all the way through the top face of the table top?

4) Is this just a plain wrong design and the *only* way to do this without any stringers/stretchers is with reinforced miters? :D

Any and all comments are VERY welcome!

Thomas Bank
02-13-2009, 3:38 PM
I made a stand similar to that for easy disassembly when I was in college. Add a small stringer across the top of the legs at the back. You're not going to see it and it will significantly strengthen it. As is, with the pins, any side load is going to collapse it quite easily.

Niels J. Larsen
02-13-2009, 3:50 PM
I made a stand similar to that for easy disassembly when I was in college. Add a small stringer across the top of the legs at the back. You're not going to see it and it will significantly strengthen it. As is, with the pins, any side load is going to collapse it quite easily.

How small? :-)

Thomas Bank
02-13-2009, 3:55 PM
Had to look up metric conversions quickly... :)

I'd say it was about the same thickness you are working with - say about 40mm x 80 to 100mm.

It still wasn't a table that you wanted to set anything significantly heavy upon or lean against or it would have still pushed over fairly easily. But it was against the computer table on one side and within a couple feet of the wall on the other side, so it wasn't going to see too much abuse.

Niels J. Larsen
02-13-2009, 4:13 PM
So something like this: ?

The extra stainless steel rod in the stringer will probably help a lot.

Rod Sheridan
02-13-2009, 4:22 PM
Hi Neils, the stretcher will help for certain, however if you're only placing a couple of printers on it, where would the racking come from?

It's 40mm wenge, it's going to be so heavy that nobody will be picking it up and moving it.

If you're really worried about racking, join the sides to the top with wedged through mortise/tenons and forget about the pins, or use finger or dove tail joints.

Regards, Rod.

Prashun Patel
02-13-2009, 4:30 PM
If this is going to be against a wall, is there any chance of making a solid back? It could be out if 1/4" ply rabbeted into the back to hide the edges. That will add a LOT of dimensional stability.

You can also just use more rods, spaced closer together. Extend them deeper into the leg if you wish.

Alternatively, you could just use wooden dowels - through and flush with the top or concealed.

John Schreiber
02-13-2009, 4:31 PM
I wish I had more expertise to share, but I've got some ideas at least. Without any triangles or flat surfaces to prevent it, a table like that will fold up unless heavily reinforced.

Running the steel dowels from the top of the top down four or more inches into the bottom would add strength, but I'm not sure if it would be sufficient. You would probably want to make the dowels about 13 mm (1/3 the 40 mm thickness), and for the exposed part between the surfaces, you might have a tube which would slide over the dowel. That gives you a little bit of a tenon shoulder effect. I still don't think it would be strong enough though.

You could have a machine shop make up a plate with steel dowels welded to it which you would inset into the bottom of the top and attach with screws (allowing for wood movement), then connect the dowels to the inside of the leg using another plate. Allowing for wood movement in the cross grain/steel connections is critical, but it could be done without too much difficulty. I think that would be strong enough.

If the table is not going to be visible from the back, you could add a thin (8 mm) sheet along the back near the top, but it would need to be fairly tall to provide support. My gut tells me at least 300 mm. The color might match the wall to visually hide it.

You could do something with steel rods to make cross braces from corner to corner.

Just some ideas. It's an inherently weak structure, but it could be very dramatic if it could be made to work. If it were me, I'd make a mock up and try to break it. You might need to use wenge for the joints to control for the wood type. That may lead to some ideas.

$.02

Niels J. Larsen
02-13-2009, 4:32 PM
Hi Neils, the stretcher will help for certain, however if you're only placing a couple of printers on it, where would the racking come from?

Well, my 2½ yr old daughter would probably be the first to push it just for the fun of it, if it just wobbles a little bit :cool:

So, to save my daughter - AND printers :D - I'll take the measures necessary to make this as stable as possible without sacrificing the simplicity of the design.

John Schreiber
02-13-2009, 4:36 PM
Another idea is to attach it to the wall in back. If that would work in your situation, it would make it strong enough.

Niels J. Larsen
02-13-2009, 4:37 PM
If this is going to be against a wall, is there any chance of making a solid back? It could be out if 1/4" ply rabbeted into the back to hide the edges. That will add a LOT of dimensional stability.

You can also just use more rods, spaced closer together. Extend them deeper into the leg if you wish.

Alternatively, you could just use wooden dowels - through and flush with the top or concealed.

A solid back is not an option (for me) as I want it to be as open as possible.

Is the stringer/stretcher I added not enough?

Niels J. Larsen
02-13-2009, 4:39 PM
Another idea is to attach it to the wall in back. If that would work in your situation, it would make it strong enough.

Thanks for all your ideas John, however they don't suit me (sorry :)).

Do you also think the table is too weak - even with the stringer attached as shown in the latest pictures?

John Schreiber
02-13-2009, 4:49 PM
Do you also think the table is too weak - even with the stringer attached as shown in the latest pictures?

My gut tells me that the stinger would have to be quite a bit taller, but it doesn't have to be very thick. But I've never worked with wenge. You could make a mock up of the geometry of the table in two dimensions with construction lumber. It's plenty strong from front to back, but the concern is from side to side. You could just use building studs (2x4s in the US), bolt them together at the corners and experiment with the thickness of the stringer.

40 mm has a very solid appearance. Somebody is going to climb on top of it one day to change a light bulb. If the actual strength doesn't match the appearance, it's going to go crunch.

M Toupin
02-13-2009, 7:21 PM
It's a low table/bench which will be used as a printer table.

Everything is 40mm thick Wengé. The table top is 500mm deep and 1200mm wide.

The legs are 500mm deep and 500mm high.


You'll be fine IMO. I think some folks are being thrown off my the metric so let's convert (roughly);
20mm = 3/4"
40mm = 1 1/2"
500mm = 20"
1200mm = 47"

Keeping in mind this a a printer stand and it shouldn't get a whole lot of abuse, Let's look at this:

The top will be Wengé approximately 20" (500mm) deep, by 47" (1200mm) wide, by 1 1/2" (40mm). that's a very substantial piece of lumber! It's not going to flex under any reasonable load, much less the weight of two printers.

Now you need to look at the legs/sides and the attachment. While you don't specify, I'm guessing from your pic that the sides are the same thickness as the top, 1 1/2" (40mm).

I'd not waste the time or money on 20mm (3/4") stainless steel pins, hardwood dowel rods would be more than adequate. If it was me, I's sink the dowel 1" (25mm) into the top and about 2" (50mm) into the legs. With glue you'll have a very strong joint for the purpose. The stringer across the back would be a good idea and will add a god deal of sideways stability. If it was me, I'd make it about 4" (100mm). With the 1 1/2" (50mm) wide legs, 3/4" (20mm) dowels and the 4" (100mm) stringer it's going to be very stable.

Mike

Niels J. Larsen
02-14-2009, 6:42 AM
You'll be fine IMO. I think some folks are being thrown off my the metric so let's convert (roughly);
20mm = 3/4"
40mm = 1 1/2"
500mm = 20"
1200mm = 47"

Keeping in mind this a a printer stand and it shouldn't get a whole lot of abuse, Let's look at this:

The top will be Wengé approximately 20" (500mm) deep, by 47" (1200mm) wide, by 1 1/2" (40mm). that's a very substantial piece of lumber! It's not going to flex under any reasonable load, much less the weight of two printers.

Now you need to look at the legs/sides and the attachment. While you don't specify, I'm guessing from your pic that the sides are the same thickness as the top, 1 1/2" (40mm).

I'd not waste the time or money on 20mm (3/4") stainless steel pins, hardwood dowel rods would be more than adequate. If it was me, I's sink the dowel 1" (25mm) into the top and about 2" (50mm) into the legs. With glue you'll have a very strong joint for the purpose. The stringer across the back would be a good idea and will add a god deal of sideways stability. If it was me, I'd make it about 4" (100mm). With the 1 1/2" (50mm) wide legs, 3/4" (20mm) dowels and the 4" (100mm) stringer it's going to be very stable.

Mike

Thanks for your reassurance Mike! :)

I had the same impression and you're probably right - people are thrown off by the metrics. Sorry for that, but I don't do imperical :D

I will use the stainless rods purely because of the look, so no wooden dowels for me..
I think it'll make a great contrast to the black wengé.

Thanks!

M Toupin
02-14-2009, 11:17 AM
I will use the stainless rods purely because of the look, so no wooden dowels for me..
I think it'll make a great contrast to the black wengé.

After re-looking at your original picture, maybe I misunderstood... are you going to mount the top flush with the sides, or do you intend to have the separation with the pins exposed? I assumed it was an exploded view, but now I'm wondering.

Mounting the sides flush will add a lot of strength due to the extra support, much like a M&T joint gains strength from the shoulders. If you intend to have the pins exposed, then I'd reconsider my endorsement. I think it would work, but It's going to be a lot more fragile and subject to side loads. I'm not sure I'd try and pull that off myself, but on the other hand, you can mock it up and see how strong it is before you glue it up. If you have any question in your mind, then you could always drop the top down flush.

Mike

Niels J. Larsen
02-14-2009, 5:01 PM
After re-looking at your original picture, maybe I misunderstood... are you going to mount the top flush with the sides, or do you intend to have the separation with the pins exposed? I assumed it was an exploded view, but now I'm wondering.

Mounting the sides flush will add a lot of strength due to the extra support, much like a M&T joint gains strength from the shoulders. If you intend to have the pins exposed, then I'd reconsider my endorsement. I think it would work, but It's going to be a lot more fragile and subject to side loads. I'm not sure I'd try and pull that off myself, but on the other hand, you can mock it up and see how strong it is before you glue it up. If you have any question in your mind, then you could always drop the top down flush.

Mike

I guess you misunderstood - the top will "float" 20mm or so above the legs/sides, so the stainless rods are exposed.

If the rods were not exposed I don't see a point in using them.

Perhaps you're not the only one that misunderstood my intention, as others have also suggested that I use wooden dowels.

So, to clarify once more - the top will NOT sit flush with the legs as that would "just" be a simple butt joint and that's NOT what I'm after.

John Sanford
02-14-2009, 7:17 PM
Since you want to float the top, yet keep the back as open as possible, howzabout something along these lines:

A stainless steel arch. It runs from about an inch above the floor at the back of each leg smack dab up to the underside of the top in the middle. It still gives you access to 98% of the wall behind the unit, continues the stainless theme, and it provides near maximum triangulation. Getting really fancy would involve tapering the arch, but that may be a bit much as far as fabrication goes. Get stainless fittings from a marine supply place and you can simply fasten the fittings to the wenge and then put the arch into them. The most difficult part of "metal working" would be bending the arch, and that shouldn't be too problematic.

Chris Schoolland
02-14-2009, 10:46 PM
I think you can flush the legs with the edge if you do something John alluded to, as I tried to show in this model. Look around and either hide parts or turn layers on/off to see what I mean. You would reduce the need for a stringer, as well. It should be no problem for a welder to make something like this.

I like your design.

Niels J. Larsen
02-15-2009, 7:02 AM
Since you want to float the top, yet keep the back as open as possible, howzabout something along these lines:

A stainless steel arch. It runs from about an inch above the floor at the back of each leg smack dab up to the underside of the top in the middle. It still gives you access to 98% of the wall behind the unit, continues the stainless theme, and it provides near maximum triangulation. Getting really fancy would involve tapering the arch, but that may be a bit much as far as fabrication goes. Get stainless fittings from a marine supply place and you can simply fasten the fittings to the wenge and then put the arch into them. The most difficult part of "metal working" would be bending the arch, and that shouldn't be too problematic.

Sounds plausible, but to understand fully - what type of profile of the stainless are you thinking of?

Roundbar or flat stock that is bent into shape or are you talking about something completely different?

Niels J. Larsen
02-15-2009, 7:06 AM
I think you can flush the legs with the edge if you do something John alluded to, as I tried to show in this model. Look around and either hide parts or turn layers on/off to see what I mean. You would reduce the need for a stringer, as well. It should be no problem for a welder to make something like this.

I like your design.

Thanks!

So you're basically talking about a flat plate routed and screwed into the top, with the round stainless rod welded onto it?

Should the rod still go into the table top or should it "stop" at the stainless plate?

That would probably work - thanks for the idea!

Samuel A. Livingstone
02-15-2009, 1:17 PM
A possible solution would be 4-5-inch steel "L" brackets 1/8 or so thick put a pair near front and a pair towards the rear. A setin of 6 or so inches should work. If you mortise them in would be practicly imvisible unless they stuck their head under the table and looked up.

If bolts are needed you can always cut a few face plugs from the scrap or even on the underside of the top with 1.5 inches of thickness.

Build it strong or fore ever have wood breaking. kWho knows what it will later be used for.

Sam, NY;)

Niels J. Larsen
02-15-2009, 2:38 PM
A possible solution would be 4-5-inch steel "L" brackets 1/8 or so thick put a pair near front and a pair towards the rear. A setin of 6 or so inches should work. If you mortise them in would be practicly imvisible unless they stuck their head under the table and looked up.

If bolts are needed you can always cut a few face plugs from the scrap or even on the underside of the top with 1.5 inches of thickness.

Build it strong or fore ever have wood breaking. kWho knows what it will later be used for.

Sam, NY;)

Sam, I don't understand fully what you mean.

I understand that you suggest to use "L" brackets at the front and the back, but do you mean that I should use them instead of the stainless rods or in addition?

Please elaborate :D

John Sanford
02-16-2009, 12:43 AM
Niels,

You could use whatever profile you want. Simplest of course would be to use flat bar. Using marine fittings would likely be simplest with round stock. My concept isn't just little "angle brackets", I'm referring to a full arch.

Chris Schoolland
02-16-2009, 1:13 AM
Thanks!

So you're basically talking about a flat plate routed and screwed into the top, with the round stainless rod welded onto it?

Should the rod still go into the table top or should it "stop" at the stainless plate?

That would probably work - thanks for the idea!


Niels, Look at my model in x-ray mode, or turn layers on and off to see what I drew as far as interior construction. You could also click on any part and hide it to see how the parts interact.

Don Eddard
02-16-2009, 1:18 AM
Thanks!

So you're basically talking about a flat plate routed and screwed into the top, with the round stainless rod welded onto it?

Should the rod still go into the table top or should it "stop" at the stainless plate?

That would probably work - thanks for the idea!
The stainless rod welded to an inlaid steel plate was my first thought, too. Chris' sketch is almost exactly what I was thinking. I think you'd gain a little strength from having the rod protrude into the table top, but if the welds were strong and the plates were relatively thick, maybe 10mm or so, I don't know that the extra strength would be necessary.

I like the looks of the design.

Niels J. Larsen
02-16-2009, 12:14 PM
Niels, Look at my model in x-ray mode, or turn layers on and off to see what I drew as far as interior construction. You could also click on any part and hide it to see how the parts interact.

I see now what you mean.

Yeah, that would probably work!

Shannon Kruse
04-22-2009, 1:35 AM
This is a little off topic, but still on topic.

Could someone take that same general idea with an arch in the back (6" tapering to 3") attached to the sides with a mortis and tenon joint and the entire bottom frame attached every three inches or so with rods (similar to mission style appearance) to make a computer desk? Or would it need more structural integrity?