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  #1  
Old Tue 29 May 2007, 11:12
Loren Gameros
Just call me: Loren
 
Costa Mesa
United States of America
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Wood base table option

Hi Gerald and everyone,

I was looking at the thread titled:

"Websites that inspire (and get the budget approved!)"

Specifically the "Because we can" website.

In doing so I noticed that the "Because We Can" people have a Shopbot that they are very proud of has a wood base table. I also noticed that they chose to use what "appears" to be rough construction grade fir. Not the best type of wood option but very cheap.


What is your or anyones thoughts on constructing a really nice and strong base table out of wood? Using for example marine grade ply (apple ply) to contruct the table?

Is it out of the question or just a matter of giving it a go?

I would appreciate any or everyones opinion good or bad.

NOTE: I got this inspiration from the thread titled "Websites that inspire (and get the budget approved!)" and that's all I am trying to do, GET BUDGET APPROVALE! I am not trying to redesign the Mechmate.

Last edited by Gerald D; Tue 29 May 2007 at 20:49.. Reason: quick change
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  #2  
Old Tue 29 May 2007, 13:41
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Loren, hope you don't mind that I put the link & picture into your post.

A wood table is 100% for 2D work, where fine control (repeatability) of Z-axis depth is not needed. The table surface tends to "cup" or "bow" a lot more than a good steel table. This movement due to moisture and heat reactions.
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  #3  
Old Tue 29 May 2007, 16:47
normand blais
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montreal
Canada
Hi Loren Gerald
If you build a table like that pic ,you need cross bracing both axes, your table top act as stifener for the top . and bolt it down .
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  #4  
Old Tue 29 May 2007, 21:35
J.R. Hatcher
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Wilmington, North Carolina
United States of America
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Loren several years ago I considered building a wood base. In the US we have a product called a microlam, they come 2" thick by various widths and 50 , 60 feet long. they are made in a factory by gluing plywood (not marine it's to expensive) together and staggering the joints. the resulting beam is very stable and very strong. In construction these beams take the place of steel beams. We can buy any width and length needed. I was going to use these in place of the C channel and cross members. But if desired steel could be used for some parts, I guess it would be called a hybrid. If the entire base was wood, there are ways to fasten all of this together that is super strong. Make the cross members microlam too, maybe 2" X 6" then you would drill two 1" holes near both ends, leave 3" of wood to the end and 1" to the top and bottom. Now drill a 1/2" hole from the end of the cross member straight into the center of each 1" hole. Mark and drill the 1/2" holes through the main beam to match. Then cut some 7/8" steel rod 2" long, drill and tap a hole through the 7/8" way, 1" from the end, this becomes the nut. Screw a 1/2" X 6" hexhead machine bolt w/flat washer from the outside of the main beam into the cross member into the 7/8" rod nut, that is now in the first 1" holes you drilled, when tightened up it makes a very good joint. Anyway that's the gest of it, more or less. It would be a lot easier to understand if Gerald would do a drawing. If most of this can not be understood we will try again.
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  #5  
Old Wed 30 May 2007, 05:56
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
http://s154.photobucket.com/albums/s...ighttoolworks/
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  #6  
Old Wed 30 May 2007, 09:12
Loren Gameros
Just call me: Loren
 
Costa Mesa
United States of America
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Hi Gerald,

I looked at the wood table from Knighttoolworks. Yes it is a nice looking table but do you still think that making a base table out of wood is a mistake?

Before you answer let me say why I am considering the wood base table option:

1. I am sticking this monster in my two car sized garage so I am short on space.

2. This is strictly for fun and I have no intention on using this for a production shop (I might eat those words).

3. If I make a very strong and solid welded table I really have no upgrade options in the future.

In closing I would like to add that I am trying to seek out opinions either for or against a wood table verses a metal one.
I am not looking for approval.
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  #7  
Old Wed 30 May 2007, 10:11
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Loren, I would not argue that a wooden table is a mistake. If you recognise the limitations, then it is fine. I argue strongly against a wooden table when people want to believe it will be just as good as a heavy steel table.

Above it was said: "the resulting (wood) beam is very stable and very strong. In construction these beams take the place of steel beams. " That is a big misconception if we apply it to router tables (and most other applications too.....). We are looking for stiffness and not strength. There is no risk of us breaking the table (wood or steel), so strength doesn't come into play at all. Steel is very hard to beat for stability and rigidity - wood is probably one of the worst materials in these areas.

If you have a wooden table, you will have to cut "busy" parts slower - stops and starts (or lot's of direction changes) shake a table around. On the stability issue, you will have to calibrate the z-position often, have to skim (surface) the spoilboard often, and realise you can't leave a complex job on the table overnight for fear of it moving....
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  #8  
Old Wed 30 May 2007, 10:17
Marc Shlaes
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Cleveland, OH
United States of America
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Loren,

I too am short of space and therefore, I am also sure that the "monster" will be moved. So, a one piece welded table is just not possible. I am not considering wood however. Some type of bolt together table out of metal is in my future. I started playing around on CAD and have been weighing two drastically different options.

1) Welded subassemblies with triangle corner gussets in the "UniStrut" fashion.

2) 8020 Extruded t-slot fabrication. This is much more expensive but also much more "erector set" and therefore easily modified later.

I haven't submitted any drawings or discussed these with Gerald yet because, for me, it is yet too early. Given your postings recently, I thought I would add my thoughts.

Something to think about...

Marc
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  #9  
Old Wed 30 May 2007, 11:01
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
One-piece welded is very easily cut and re-welded
Did you know that the modern practice for overhauling submarines is simply to cut them into slices, slide them apart into modules with easy access, and then weld the whole thing together again. You can't cut and re-join wood that easily!

Bolt-together (wood or steel) is an option. The table is a pretty dumb dead part as far as the MechMate is concerned. The only things asked of it are rigidity and stability - concrete is probably the ideal material
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  #10  
Old Wed 30 May 2007, 11:10
Marc Shlaes
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Cleveland, OH
United States of America
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You know that sounds so obvious and yet, it actually never even slightly occurred to me. Good thought.
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  #11  
Old Fri 08 June 2007, 14:29
Loren Gameros
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Costa Mesa
United States of America
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Ok, metal it is!

I have some scrap 1.5" x 3" Channel that I was thinking about using?

Any advice before I start cutting would be greatly appreciated.

Here is a pic.
Attached Files
File Type: pdf Metal Base 3-D pdf.pdf (66.8 KB, 359 views)
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  #12  
Old Fri 08 June 2007, 22:43
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Started a separate thread for the metal route here
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