Is this a possibility. I'm thinking more in terms of moving the machine, a 4*8foot table is gonna be quite heavy and rather impossible to move when first welded together. I'm just worried that the table top would flex to much without the legs on it. Or do I just have to make do with the table needing to be moved by crane when I'm moving. :-D

And by the way, the rails, do they really need to be hardened...???

Yes, This would be a good option to have. I too was looking at the table wondering if the table could be altered a bit for this same reason. In my case I would want to make it here at my the shop, then bring it to my home shop. What is your take on this Gerald?

My table will not be completely welded, in order that it can be taken with me every time I move.

That's excactly the same reason why I'm trying to figure out a way to build it without welding it together, I'm thinking of making it so that the legs can be taken of so It's a little easier to move around.

Suggest you weld 2 pieces as per drawing 1010310W, but then bolt drawing 1010300W instead of welding. Fabrica seems to be following this bolted style - see his pages. I know of a table like this in Romania that has already been dis-assembled, moved and re-assembled successfully.

Just give a few hours I will uplaod some pictures which shows you the way i did it.

The only advantage I can see for taking the legs off would be to get the table through a doorway if my building did not have a large enough door to take a 4 foot + wide table through. The reason for bolting a table like ShopBot does is you can ship it in a smaller box. I picked one up at the factory (4X8) with table and took it back to Minnesota inside a Dodge Caravan. Would I do it again? No,I would use a 3000 lb capacity utility trailer. I could move the whole machine assembled with that.

The MechMate table should be very stiff. As for heavy it should be easy to move with timbers and pipe rollers and or a pallet jack or two. Now before someone says I am nuts I will tell you I have moved (buy myself as in just me alone) machines that I could not pick up with my 8,000 pound capacity forklift using timbers, pipe, bars and a 2 ton come-along. That is in and out of the shop and on and off tilt deck or beaver (drop tail) trailers. I still have all my fingers and toes and no broken bones. It takes more time to disassemble and reassemble machinery than it does to just put your mind and back to it and move it. It goes alot better if you bait some friends to help with a little free beer. Just don't let them have the beer till you get it moved or you may wish you had just done it all yourself. Sometimes thinking about doing something is harder than just doing it.

You could also bolt removeable casters on the legs. Larger ones roll over power cords, welding rod stubs and air hose better than small ones.

This is just the way I look at it. Other ways may work better for you. One of the nice things about building your own machine is that you are the one who has the last say on how it should be.

Ted, our big table is one floor up from ground level. The doorway into that section is 6ft wide by 8ft high. The table had to be stood on its side before it could be "inserted" with a crane. But, being one piece all-welded, it coped quite well.

Sometimes you just have to use a crane or lift. Have you done a drop test yet? If anyone does get photos. When I get in the position where I need another machine I am going to build one of yours in my size. I need to drop you a e-mail about another issue some day soon.

Kim, I didn't notice your question until now "And by the way, the rails, do they really need to be hardened...???". That point is discussed in this archive, but the short answer is that they need not be hardened.

No Ted, no drop tests yet, not even planned, but that doesn't mean it won't happen...http://www.mechmate.com/Forum/clipart/happy.gif

Our mix of welding and bolting for table 3 (X=2750mm):

There is value in a bolted table. I have been thinking of bolting the leg and brace assembly to the main beam as well. The main beam seems to make the sub assembly top heavy(in theory). If the machine gets unbolted and moved it might be easier to protect the rails and gear track from damage. What is your thougths about something like that Gerald?

I must add that I was thinking to make it easier for myself if I had to assemble the table on my own. The four legs with the bracing can be set up first before lifting the main beams in position. Me Crazy?:)

I want to stop the main beams from rocking/flexing/tilting in the y-direction - that is the main reason for keeping the legs and uprights welded under the beam. (I didn't actually see the purpose of the vertical uprights as helping to stop the beam from sagging - the beam is strong enough by itself.)

When the y-car makes sudden movements on top of the gantry, it kicks the beams sideways, and this is the direction in which I have noticed most "hum" from a table. Ideally I would want every single single cross-support welded under the beam - and I probably am still going to do that in addition to the bolts. That would be a very easy weld to cut if the table must be taken apart.

Carrying a side-frame the correct way up is actually easier than the other way around. Just make sure you have 2 trestles to park it on - one at each point and legs simply hang down.

I have decided to stick to your bolting arrangement. I still can't grasp the forces the spindle/ router is appling to the table structure to its full extend. This is something one must experience more than calculated before hand I think.

The first thing one must recognise is that the major forces are in the horizontal plane. The dynamic "vibration inducers" are horizontal.

In the vertical plane the thing is more static. We want long term flatness and repeatability of the z dimension. But there isn't anything that really causes up and down bounce.

Assembly is going well, albeit with some minor problems. This being a bolt together, I assembled the complete table, got it squared up and plumb then tacked in the lower cross supports and braces...I did not complete all the welds in place, but finished them after I had taken the whole thing apart - big mistake, everything moved (even areas where i did not weld) and not all of the threaded holes in the frame structure lined up with the holes in the bottom web of the main beams (if the first two bolts were inserted, the other end was off by as much as 15mm :eek:) However there was enough flex in the side frames that I was able to pull the flanges into position with a ratchet load securing strap (the type used on big trucks to secure the load). My Father did not think I would be able to move it that much with only a strap and he was getting ready to start cutting and re-welding to get things to line up, but after some terse words best not repeated he let my try with the strap and was left speechless ;).

Here is the sequence of assembly:

Attachment 2422 Attachment 2423 Attachment 2424 Attachment 2425 Attachment 2426 Attachment 2427 Attachment 2428

. . . . . . the pieces all over the yard getting paint.

What about bolting 10.10.322 to 10.10.302, and then bolt 10.10.330 to 10.10.302.

I'm thinking about having more than just 4 legs (2 on each side). Probably as many as the number of cross members i have.

Then horizontally bolt 2 long angle bracket to all legs on each side. Add diagonal L bracket between each legs.

For horizontal squareness bolt L bracket diagonally to the bottom face of each cross members, connecting 2 neighbouring cross members.

Can you sketch your ideas and give us a picture?

Here they are, Sir..... :o

Nikonauts,

- why so many legs? How can you be sure that each one is firmly carrying a share of the load? It will need a perfect floor

- the horizontal diagonals directly under the table top are a waste, the table top itself does that bracing.

- that table will be flimsy in the y-direction because there is no bracing to stop the legs from swinging in that direction.

Those drawings are meant to clarify my suggestion on what could be done to make a bolt assembled table. I myself have not decided yet how it'd be, but i'd really love to have my table transportable.

well, some people will have a lot of extra steel if they buy in stock length. can put it to use as extra leg so extra Y-direction bracing could be placed. I didnt include vertical y-direction bracing into the sketch, forgot it, my bad. Maybe not as many as there are cross members, but really, is it counter productive to add more legs? I'm an inexperienced in this kind of thing, it's all a hunch.

Adjustable leveller foot attachment solve it, yes? no? Will the table be too heavy for a leveller?

Didn't occured to me, that's brilliant. I agree. Plus, it's ugly.

Gerald, what do you think about bolting 10.10.322 to 10.10.302, and have the leg (10.10.330) bolted to the cross members (10.10.302) (refer pic #3)? Which means, the leg does not support the longitudinal beam directly, but rather the leg supports the cross bearer, the cross bearer supports the longitudinal beam. If one really need bolted table, i guess this is how it could be done. Each member could be dismantled. Does the "superman underwear" (last pic, sorry i don't know the proper name) help?

"is it counter productive to add more legs?"

Yes. More expensive, more stuff to transport, more levellers, more complicated levelling procedure.

I think you should ponder for a while exactly how often you think you will move the table, and what your expectations are around the setup time afterwards.

I built a partial bolt together table, then disassembled it to paint, then reassembled it. I'm happy with it's transportability in eight pieces (*) , but
honestly I expect to move it somewhere between zero and twice in my lifetime. If I hadn't built it to break down, it would have required moving every other major tool (starting with the cabinet table saw) out of the shop
to get the manuevering room to move it in, and I still can't fathom how I'd have tossed around that thousand pounds of steel, short of inviting a dozen friends over for a beer.

During the reassembly, the bolting was a much larger nuisance than I anticipated. For example, you discover that you have to start leveling parts of the table before it's assembled enough to really take leveling measurements. It's not an erector set, and it I suspect I may have taken almost as long in reassembly and realignment as I spend on the initial welding.

I built mine to meet the spec of going through a standard single doorway and up and down stairwells carried by two men. I'd probably do it again that way for my needs, but it certainly requires the same skill level to reassemble as it takes to build in the first place.

If I thought I'd be moving it every three months or so, I'd likely have welded the entire lower frame as a unit, and then made provision for putting wheels on the side. I'd pull off only the beams/rails, and gantry.

If I thought I'd be moving any more often than that, I'd start looking at cheap trailers from Harbor Freight, and figuring out how to weld a mechmate on top of one so I could just roll it into any old shed or garage bay. Hmm. And then adding a removable set of side panels and a roof, and it could be it's own shed. Maybe that's what I'll do if I ever built another ;-)

In none of these scenarios would I alter the basic table design, because you realize after you've built it that all of the elements work together to solve the needs of the machine.

(*) The eight pieces are: Gantry+Car, Deck w/ middle six cross beams, 2x Rail/Beam, 2x side leg unit, 2x end brace w/ end cross beam. There are flanges with twin bolts between each leg and end brace. There are flanges with twin bolts at the top of each leg attaching to the major beams, and there are single bolts holding each end of all 8 cross beams to the major beams. That totals out at 32 bolts to dissassemble my table. About 24 go in painlessly, 6 require a little convincing, and 2 I don't really want to talk about <shudder>

I have copied posts by Brad and Alan into the thread above. Two good examples of bolted tables.

My table is also bolted together for easy trasport. A couple hints on the way I did it might help. As was mentioned, you still need to weld flanges on the different sections to allow bolting together. Before welding, I clamped the various flanges to their mating part and drilled all the holes thru both at the same time. This aided the assembly and made the whole drilling process easier (and believe me, all of the drilling is a bit of a pain). Also, drilling 1/2 inch holes is MUCH easier with a drill press than free hand.

Then, all of the flanges were bolted in place as I welded the sections together. This kept things very precisely aligned. The reassembly of the table was very quick and easy after painting. I did it by myself in about 3 or 4 hours. I did also stamp each section with an orientation code, because you will never get the holes exaxtly the same in each flange.

Another hint is that I built the entire table upside down. This not only let me keep the heavy parts (the main beams) close to the ground, but it also let me "level" the table from the very beginning.

Kevin

This is a smart piece of advice. In many cases the pieces can be drilled, bolted then welded. Just make sure the welds cool before disassembling.

As a suggestion - once you have a breakdownable (is that even a word?) table set up and leveled/squared/etc., and before you attache the MDF bed, drill two holes though every bolted joint and drive hardened dowel pins flush completely though the assembly. That way, if you ever need to move the beast, you can drive out the pins, unbolt, and move it. To reassemble, loosely bolt it together and drive in the dowel pins (always use new ones) and finally torque down the bolts. It won't be perfect, but should be more than good enough for woodworking.

Brian