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#1
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Why so little triangulation for strength under a workbench?
Everybody goes to great lengths to make their woodworking benches heavy and
strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - |
#2
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I've often wondered the same thing and, like you, have added angled braces
in many structures. The only thing that I've changed over the years is to fortify my attachment points (more screws. bolts, or whatever than normal). Other than that, they work extremely well. BruceT "Owen Lawrence" wrote in message ... Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - |
#3
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As a retired structural analyst, I've noticed the same lack of wracking
resistance. It would seem especially important if the bench is to be used for tasks such as hand planing where the forces are applied parallel to the top surface and not important if the bench is being used primarily for tasks where the forces are oriented vertically. I would also suggest, as an alternative to angled members, the use of plywood shear panels on the back, sides (and front if no drawers or shelves are planned). The panels, when rigidly attached to the legs, would provide wracking resistance in the same manner as does plywood sheathing on house framing. Many other workshop tables, tool bases and stands could benefit from the same treatment, e.g. router tables; many of the designs I see in woodworking magazines, and commercial offerings as well, appear to completely ignore wracking resistance. Shear panels can easily be retrofit to existing benches and stands that lack them, greatly increasing their rigidity. David Merrill "Owen Lawrence" wrote in message ... Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - |
#4
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Owen Lawrence wrote:
Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. snip See my comment about 1/2" CDX gussets in "wood for work bench" post. Lew |
#5
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I believe the reason you do not see triangles on the back of well built
benches is the same reason you don't see a large 2" pipe bumper surrounding a new Jaguar. After all, this would prevent dings, which we all know Jag owners fear more than death it self. It's looks, looks, appearance, style, staying with the old look, etc . . . "Owen Lawrence" wrote in message ... Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - |
#6
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Steve DeMars wrote:
I believe the reason you do not see triangles on the back of well built benches is the same reason you don't see a large 2" pipe bumper surrounding a new Jaguar. After all, this would prevent dings, which we all know Jag owners fear more than death it self. It's looks, looks, appearance, style, staying with the old look, etc . . . .... And w/ most old, original benches, well crafted, significant sized mortise/tenon joints that eliminate the need... |
#7
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Owen Lawrence wrote:
Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - My bench was built from 4x4 legs and 2x4 everything else. I used M&T joinery throughout. The top is bolted to the undercarriage with 3/8" bolts (just happened to have a supply). No angled supports at all. After 8 years, still no movement of any kind. mahalo, jo4hn |
#8
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You say "staying with the old look". Why didn't people centuries ago
incorperate those things? They knew of the advantages then. "Steve DeMars" wrote in message news:C8oLe.470$Sj1.89@okepread04... I believe the reason you do not see triangles on the back of well built benches is the same reason you don't see a large 2" pipe bumper surrounding a new Jaguar. After all, this would prevent dings, which we all know Jag owners fear more than death it self. It's looks, looks, appearance, style, staying with the old look, etc . . . "Owen Lawrence" wrote in message ... Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - |
#9
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I think that the massive approach builds a bench that is strong, steady, and
.. . . dead! The cross-braced approach tends to build a bench that is lighter, strong, steady, and . . . resonant! I like a bench that doesn't vibrate so that when something bumps everything on the bench doesn't dance around. A real monolith would be ideal. Tim Ellestad "Owen Lawrence" wrote in message ... Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - |
#10
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On Sat, 13 Aug 2005 08:58:15 -0400, "Owen Lawrence"
wrote: Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. Because they are heavy enough and strong enough already. Mine's solid maple, 9' by about 2' 6", 12 drawers, plus two upper wide thinner drawers, handed to me when I was moving one time. In fact, I'd made myself a couple of lighter models, and when this was offered, threw them out to take this one in the moving van. What more do you need if you have what you need? |
#11
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On Sat, 13 Aug 2005 15:07:15 GMT, "David Merrill"
wrote: As a retired structural analyst, I've noticed the same lack of wracking resistance. It would seem especially important if the bench is to be used for tasks such as hand planing where the forces are applied parallel to the top surface and not important if the bench is being used primarily for tasks where the forces are oriented vertically. I must be weaker than you? My planes are sharp enough to not meet so much resistance and are used with a smooth application; certainly not even remotely close to the forces needed to pull my solid, well-built workbench apart. If your planes are dull and you try to gouge off half-inch thick shavings you might have a point. |
#12
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Are you really an asshole or do you just play one on the internet?
"Guess who" wrote in message ... I must be weaker than you? My planes are sharp enough to not meet so much resistance and are used with a smooth application; certainly not even remotely close to the forces needed to pull my solid, well-built workbench apart. If your planes are dull and you try to gouge off half-inch thick shavings you might have a point. |
#13
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On Sat, 13 Aug 2005 19:53:42 GMT, "CW" wrote:
Are you really an asshole or do you just play one on the internet? No, but you surely are. I was being serious, and my reply was not to you in any case, so mind your own damned business. He seemed to think that it was necessary to state being a structural analyst, as if that made a difference. That was not at all necessary, since the forces are in fact so relatively small, so what in hell does force of planing have to do with the strength of a well-made workbench, and why do you need to be some sort of expert to explain it? I have a degree in math and physics, and that makes no difference either. Anyhow, I need not explain myself to someone so obviously too stupid to understand. Stick to your woodworking, if in fact you do any. I'm done here. |
#14
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David Merrill wrote:
As a retired structural analyst, I've noticed the same lack of wracking= resistance. It would seem especially important if the bench is to be u= sed for tasks such as hand planing where the forces are applied parallel to= the top surface and not important if the bench is being used primarily for = tasks where the forces are oriented vertically. =20 I would also suggest, as an alternative to angled members, the use of plywood shear panels on the back, sides (and front if no drawers or she= lves are planned). The panels, when rigidly attached to the legs, would pro= vide wracking resistance in the same manner as does plywood sheathing on hou= se framing. Many other workshop tables, tool bases and stands could benef= it from the same treatment, e.g. router tables; many of the designs I see = in woodworking magazines, and commercial offerings as well, appear to completely ignore wracking resistance. Shear panels can easily be retr= ofit to existing benches and stands that lack them, greatly increasing their= rigidity. =20 David Merrill I added those shear panels to one bench I made -- they actually formed a = "drawer box -- complete with drawers :-) " -- and they certainly do=20 increase the rigidity of the table. I also added them to the saw=20 out-feed table -- it allowed me to use light materials and have a rigid=20 table. It makes a big difference if the bench is built with "light" materials=20 -- 2X4's and MDF as was my original work bench. The panels do increase=20 the "stiffness" greatly. Not so sure it would do much for a properly=20 made work bench -- which my first one wasn't. "Owen Lawrence" wrote in message ... =20 Everybody goes to great lengths to make their woodworking benches heavy= =20 and =20 strong for stability. But one thing I've always wondered is why there = are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the =20 legs =20 and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in =20 additional =20 boards on the sides going from the front bottom to the back top. It wa= s very strong front to back, but wobbled a very little bit side-to-side. = I put an additional angled piece on the back (couldn't do the front becau= se =20 of =20 the drawer and retractable wheel mechanism) and now it behaves as if th= e whole thing is made of one block of steel. Super strong! Cabinets wor= k this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of =20 steel =20 truss rods. I wouldn't think those would be needed at all if there wer= e a few well placed wooden pieces added to the design. All chance of racki= ng would be completely eliminated. When I build another bench I plan to add these pieces to the design, bu= t since I've never seen it like this before I seriously wonder if I shoul= d. You thoughts please? Thanks. - Owen - =20 =20 =20 --=20 Will R. Jewel Boxes and Wood Art http://woodwork.pmccl.com The power of accurate observation is commonly called cynicism by those=20 who have not got it.=94 George Bernard Shaw |
#15
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Yep, you really are an asshole. Thanks for the confirmation.
"Guess who" wrote in message ... |
#16
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On Sat, 13 Aug 2005 23:34:16 GMT, "CW" wrote:
Yep, you really are an asshole. Thanks for the confirmation. You are merely confirming your own character. Now, I'm not here for your rubbish; you're kill-filed. |
#17
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Oh the pain. Will I ever survive?
"Guess who" wrote in message ... On Sat, 13 Aug 2005 23:34:16 GMT, "CW" wrote: Now, I'm not here for your rubbish; you're kill-filed. |
#18
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On Sat, 13 Aug 2005 10:28:17 -0500, Duane Bozarth
wrote: Steve DeMars wrote: I believe the reason you do not see triangles on the back of well built benches is the same reason you don't see a large 2" pipe bumper surrounding a new Jaguar. After all, this would prevent dings, which we all know Jag owners fear more than death it self. It's looks, looks, appearance, style, staying with the old look, etc . . . ... And w/ most old, original benches, well crafted, significant sized mortise/tenon joints that eliminate the need... Yep. As a poor boy, most of my benches are made from framing stock, and the racking resistance comes from using a 1.5" x 3" through tenons mounted through the legs (doubled up two by fours) that are bolted into place with big lag screws. Solid enough for just about anything- a M&T joint that size doesn't submit to racking forces very easily. That being said, I've got some older ones that do have cross-bracing because I just screwed some single two by fours to the corners of the tops, and the things wobbled like crazy until they were braced. It all just depends on how you've built it in the first place, and whether or not you like the look of the bracing in the back- everything has it's place. |
#19
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In article ,
"Owen Lawrence" wrote: Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. Those diagonal braces interfere with the nice cabinetry that you build under the bench. Its storage space, in the most convenient place. Mortise and tenon construction makes it stiff. I used that, plus the Lee Valley threaded rods under tension to keep it stiff for my lifetime. John |
#20
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On Sat, 13 Aug 2005 10:32:01 -0400, Bruce T wrote:
I've often wondered the same thing and, like you, have added angled braces in many structures. The only thing that I've changed over the years is to fortify my attachment points (more screws. bolts, or whatever than normal). Other than that, they work extremely well. BruceT So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - Here's the reason ... the full reason: the braces and sheer panels aren't used because they aren't needed. The massive construction typically used provides inertial resistance to sudden loads and the rigid joinery privides resistance against sustained loads. If you build a light weight workbench you may need braces. If you build a bench with so much wood that it leaves a gap in the forest visible from space, bracing is probably wasted effort. Since the wood is subject to a lot of different stresses, such as being used as a vise from various angles and having lots of things whacked on it, I opt for a workbench so heavy it leaves marks in my concrete floor. Bill |
#21
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On Sat, 13 Aug 2005 08:58:15 -0400, "Owen Lawrence"
wrote: Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - Owen, I wonder exactly the same thing. The work bench I built used doubled up two by fours for strength but I used diagonal bracing on three sides for rigidity. See http://tinyurl.com/bqd4k This bench doesn't move when it's not lifted on its casters. TWS |
#22
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"TWS" wrote in message ... On Sat, 13 Aug 2005 08:58:15 -0400, "Owen Lawrence" wrote: Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers. When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one). So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated. When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please? Thanks. - Owen - Owen, I wonder exactly the same thing. The work bench I built used doubled up two by fours for strength but I used diagonal bracing on three sides for rigidity. See http://tinyurl.com/bqd4k This bench doesn't move when it's not lifted on its casters. Nice. How do the casters work? - Owen - |
#23
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On Sun, 21 Aug 2005 08:35:37 -0400, "Owen Lawrence"
wrote: Nice. How do the casters work? - Owen - The short answer is that the lever in the front of the workbench twists an angle iron under the bench, which, in turn, pushes up on 4 2x4s that act as lever arms to press the casters to the floor. When retracted the casters fully retract so the bench is sitting on solid wood feet. When lifted up the feet are raised a little over 1/4 inch and the bench is moveable. If you want the gory details, email me and I'll send you a more detailed description. You can find my email address on my website. TWS |
#24
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Nice. How do the casters work?
The short answer is that the lever in the front of the workbench twists an angle iron under the bench, which, in turn, pushes up on 4 2x4s that act as lever arms to press the casters to the floor. When retracted the casters fully retract so the bench is sitting on solid wood feet. When lifted up the feet are raised a little over 1/4 inch and the bench is moveable. If you want the gory details, email me and I'll send you a more detailed description. You can find my email address on my website. I think I understand your explanation. I will definitely have some sort of retractable wheel mechanism on my next bench, and your way gives me one more possible approach. One thing I also want to add is an easy (really easy) way of levelling the table. No floor I've ever encountered is completely flat, so if you move your bench (and if it's got wheels, you will), you have to level it again. I haven't thought about it much, but I worry that anything like extensible feet would just ruin the structural integrity gained by all those triangles. - Owen - |
#25
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On Sun, 21 Aug 2005 21:45:48 -0400, "Owen Lawrence"
wrote: snip One thing I also want to add is an easy (really easy) way of levelling the table. No floor I've ever encountered is completely flat, so if you move your bench (and if it's got wheels, you will), you have to level it again. I haven't thought about it much, but I worry that anything like extensible feet would just ruin the structural integrity gained by all those triangles. - Owen - Owen, I wanted the bench top to be flat but I see no reason why it needs to be absolutely level. If it were used to align with another piece of equipment or table then I could understand why that might be useful but, to me, the value of having a rock solid feel is significantly higher than having the table level. As you point out, it will be very difficult to make levelers that will be as solid as the base with the diagonal bars. While it is possible I don't see that it is worth the extra effort. TWS |
#26
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One thing I also want to add is an easy (really easy) way of levelling the
table. No floor I've ever encountered is completely flat, so if you move your bench (and if it's got wheels, you will), you have to level it again. I haven't thought about it much, but I worry that anything like extensible feet would just ruin the structural integrity gained by all those triangles. - Owen - Owen, I wanted the bench top to be flat but I see no reason why it needs to be absolutely level. If it were used to align with another piece of equipment or table then I could understand why that might be useful but, to me, the value of having a rock solid feel is significantly higher than having the table level. As you point out, it will be very difficult to make levelers that will be as solid as the base with the diagonal bars. While it is possible I don't see that it is worth the extra effort. TWS Don't let the semantics distract you. It's flatness that I'm really interested in. If the table support frame is absolutely rigid, unless it only has three legs it's going to rock until the fourth leg's length is adjusted to meet the floor. It's an overconstrained system. If the frame isn't absolutely rigid, it's going to change its shape to match the floor, which is also bad. I already experience this with my new router table. I'm always moving it around, and it's very rigid over its four legs. When I need to lower it from its wheels I just shim one of the legs (or keep moving it until I find a better spot, which is a pain). But a router table is a lot lighter and takes less abuse than a workbench so it's not a huge problem. I expect I'll get away with an extensible foot if I ever get around to adding one. - Owen - |
#27
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On Mon, 22 Aug 2005 01:22:45 -0400, "Owen Lawrence"
wrote: Don't let the semantics distract you. It's flatness that I'm really interested in. If the table support frame is absolutely rigid, unless it only has three legs it's going to rock until the fourth leg's length is adjusted to meet the floor. It's an overconstrained system. If the frame isn't absolutely rigid, it's going to change its shape to match the floor, which is also bad. I already experience this with my new router table. I'm always moving it around, and it's very rigid over its four legs. When I need to lower it from its wheels I just shim one of the legs (or keep moving it until I find a better spot, which is a pain). But a router table is a lot lighter and takes less abuse than a workbench so it's not a huge problem. I expect I'll get away with an extensible foot if I ever get around to adding one. - Owen - Ok, I understand. You're right, if the floor is not only tilted but also not planar then you have lost the advantage of the rigid base - the rigidity actually works against you. In my case the garage floor is reasonably planar so I can always find four points of contact by jockeying it around. Let me know when you've finished your bench and what you come up with. TWS |
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