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-   -   Going to Maker Faire: New Bolted Base Table - Rome, Italy (http://www.mechmate.com/forums/showthread.php?t=4152)

silverdog Fri 19 July 2013 06:15

Going to Maker Faire: New Bolted Base Table - Rome, Italy
 
I started talking in my original building thread about the invitation I had to partecipate to the next european Maker Faire in Rome the 3-6 Oct with the Mechmate. The Idea is to transport my Machmate there, and to show a big DIY CNC produce a Wikihouse. I thought that instead of spending money for the transportation of the whole Mechmate, it would be a good idea to build a partially bolted table if the prices of materials to build a new base are similar to the cost of transport.
The new base at the end of the show will be moved to the Fablab Rome which will soon be inaugurated, and there be completed as a new Mechmate.
The idea of helping the Fablab to build a Mechmate, excite me. I think after 7 years from Gerald's project start, Mechmate is the still best project, the more affordable for a production machine and, if I'm not wrong, can be considered very close to an open source project (it was for years open source isn't it ? ).
So I think for many reasons it's the perfect fit for the Fablab idea and I hope that others Fablab around the world will follow.
Now after this brief :o prologue ... let's start the project.
The Idea is to build this new base to fit my gantry which as a 1700 mm cut ability. The total lenght will be extended to permit the cut of a full ply sheet which in Italy is long 3100-3150 mm so 3200mm it's the choice for X axis.
As I discovered that the max Y cut should be best 1830 mm ... I would like to find a way to fit my gantry and then extend the Y axis to 1830 mm cut.
I can dimension the longitudinal beams to 1830mm cut and make holes also for my gantry (100 mm difference +-).
With my 3 years experience, now I know that I just have to do what Gerald did ! no questions, no fancy ideas :) ... just follow instructions, and examples ... so:
http://www.mechmate.com/forums/showt...5&postcount=12
Flattening the tubes 5 cm each side more could be a solution ...
Anyway, waiting the metal quotes ... I will do a nice sketchup draw !
Ciao

Gerald D Fri 19 July 2013 11:24

Sergio, you have to very careful with safety if you are going to be at a public place. It will be best to check with the organisers about their rules before the time. I suspect they want barriers to keep the public fingers out, emergency stop buttons, fire extinguisher, ground fault current protection for the main power. They might also have noise restrictions. (I have twice taken machinery to exhibitions in Germany, so I have a little experience there)

silverdog Fri 19 July 2013 11:53

Hi Gerald,
Yes we will discuss the safety very soon. My Mechmate has all the emergency stop all around, We will put barriers to keep every part of the public body far from the machine :), we will have for sure dust extraction ! But I'm going to check everything next week when I will present the quote for the base table. (yes the noise is a problem but they told me that the exibition stand will have noise insulation, but we have to check)
(Did you brought the Mechmate to exibitions ?)
thanks for thr advices

silverdog Fri 19 July 2013 16:19

:) no it's not ! I know that Mechmate it's just a hobby and I know all the legends about you :) is it true that you were in the south african military navy ?
... so, this may be the first Mechmate public exibition ?

Gerald D Fri 19 July 2013 20:58

All white males over age 16 had to spend 2 years in military service - I went to the navy at age 23 after studying engineering. It wasn't actually my choice to be in the navy, but I really enjoyed it. As far as I know, it will be the first MechMate on show to the public.

silverdog Sat 20 July 2013 02:47

Quote:
Originally Posted by Gerald D View Post
As far as I know, it will be the first MechMate on show to the public.
So I have a big responsability ! :o

silverdog Sat 20 July 2013 03:45

Some questions ...
 
3 Attachment(s)
The goal is to replicate Gerald design ...
http://www.mechmate.com/forums/showt...5&postcount=12
but this is what I got:

silverdog Sat 20 July 2013 03:49

My otions are:
1 - to offset the legs on the left of the main beams
2 - to change the distance between the legs until I find the corect position
3 - to solder the diagonal braces in the position indicated by the arrow in the pictures
4 - ? :o

Gerald D Sat 20 July 2013 09:43

Left picture is okay.

In center picture, move the top of the diagonal to the 81.8 position.

The diagonals do not have to be exactly vertical. They do not even have to be close to vertical. Your middle picture will be 100% strong, but it will look better if you go to another cross-channel.

silverdog Sat 20 July 2013 13:37

4 Attachment(s)
Quote:
Originally Posted by Gerald D View Post
...but it will look better if you go to another cross-channel.
I'm sorry but I don't understand :o
Here what I did ... (same color = welded)
When everything is ok I will post the sketchup model maybe can help somebody else ...

Gerald D Sat 20 July 2013 20:45

That is 100%

Red_boards Sun 21 July 2013 19:43

Sergio,
I'm guessing you are putting flanges on the top of the legs, vertical supports and cross supports and bolting them all to the beams?
A lot of holes to drill on the underside of 3.8m beams!

Gerald D Sun 21 July 2013 21:08

Flanges are not needed. A single bolt at each contact point is enough.

silverdog Mon 22 July 2013 02:18

1 Attachment(s)
Red, the right and left side are all welded. At the end I will have 4 basic pieces ....
9(main beam)+2(legs) bolts on one side and the same on the other .... this shoud explain better:

silverdog Mon 22 July 2013 02:33

The calculated Weight for the main side is +-130 kg .... not a plesure to carry :) but with some tricks (support wheels ... ecc.) 2 (better 4) people can handle :)

silverdog Tue 23 July 2013 11:29

Sketchup model
 
1 Attachment(s)
Here my Sketchup model of the bolted base.
It's for a 3200x1830 cut area.
main left and right sides are approx 130 kg each ...

silverdog Mon 05 August 2013 09:09

I am ready to by the iron, but as usual some of the part are not available:
C channel 76x38 not available but 80x45 is ! so adding weight to the base it's not a problem (unless you have to carry it :) )
The pipe 50x4 is not available, the only similar pipe they have is 48x3mm. If it's not enough I have to go with a square profile ...
Would be a problem the 48x3 pipe ?
Thanks

KenC Tue 06 August 2013 06:56

for trusses, 3mm pipe is plenty. but not for the bottom beam. will look a lot nicer if the bottom beams are square or rectangular.

Fox Tue 06 August 2013 15:26

I would use square profiles with I profiles anyway, easier to cut/weld/align, (won't roll away, etc) plenty of examples of MM's this way.
Gerald only used round tubes originally because he had a big pile of them anyway, and it's nice that the dust will fall off... as he wrote somewhere.
Having said that, a circle is always stronger (torsional) than a square obviously, so construction can be more lightweight hence most bicycles are round tubular frame but more complex to join (lugged joints when thin walled)...and most lorries and skyscrapers are build from square, rectangular and I-profiles.

silverdog Wed 07 August 2013 01:36

Thanks Ken and Fox,
My fist Mechmate was done with square tobe 40x4 mm. The main reason was to avoid the crush on the pipe ends ... because I thought I need a press, now I know a big hammer will do the job.
My experience now tell me that if you do what Gerald said you can never be wrong ... that's the biggest lesson :-).
But I think I have no chances to change the pipe tube for squares tube.

Fox Thu 08 August 2013 07:43

If you insist on round tubes Tubemiter
The hammer method is quicker, but this is nicer ( and if your get really into the details it is a better way, as hammering the pipe flat makes that the weakspot, although one can discuss if you will notice the differnce in your MM ).

silverdog Fri 09 August 2013 01:36

Yes I know Tubemiter, very nice program, I use it for PVC pipes, in this case I will use the "hammer system" ... it's much easier not only the cut, but the main purpose of crushed ends is becase it's easier to weld ...

silverdog Tue 10 September 2013 13:27

1 Attachment(s)
.... The dummy hit again !!! :o
Well my brilliant idea was to build a bolted Mechmate base for the maker faire that will serve as a base for the FabLab Rome later. I thought that the best dimensions are those of the commonly available plywood ... 3150x1830 ....
So you ask: is such a so "brilliant" idea ?
Well I tell you: if you plan to use on this base my smaller gantry and you succeed .. isn't brilliant ?
You say: wait !! a smaller gantry on a bigger base ? you look somewhat less brilliant than you think !
And I tell you: I have a solution ! as I am building a bolted base I can do a row of holes on one side on the cross beares to "tighten" the base to fit my gantry. then when the base will be reassembled in the fablab it will have the bigger size.
Don't ask me why I thought that the difference from my gantry and the future gantry will be 100-110 mm .... as I discovered today the difference is 230 mm !!!
this is the conclusion:

silverdog Tue 10 September 2013 13:35

2 Attachment(s)
.... What a beaty ... isn'it ? :mad:
I have also the problem that the support boar doesn't fit inside ... so I have tro drill different holes on the cross bearers ....
Another solution is to center the cross bearers an make 2 rows of holes ....
..... It could work ... but I'm not happy I'm not proud is this what I have to show to so many people ?

silverdog Tue 10 September 2013 13:39

Please tell me what you think .... the only other solution is to give up the idea of enlarging to 1850 mm and cut the cross bearers to fit only my size ..... :(

smreish Tue 10 September 2013 19:18

Sergio,
I am trying to understand what is happening here.
Have you or have you not fabricated the base or gantry yet?
Ideally what you should have is about a 100mm perimeter on the sides of the spoil board for the spindle/y-car to over run the board for surfacing/bigger cutters and clamp clearance.

If the 200+ mm difference is on one side only...you could..depending on your cable chain bend radius, use that "shelf" that is created by the cross bearers to support your chain.

So...what part of the fabrication are you at? Gantry done? Table done?

parrulho Tue 10 September 2013 21:15

At that point, I would go with a new gantry fitting the big table.

silverdog Tue 10 September 2013 23:56

Paolo,
new gantry is not possible, no time no laser cuts ecc. ecc.

Sean,
No I am still in the process of making the base, at moment I have prepared everything and the rails are done. I miss some welding and the holes on the cross bearers. I thought to have the difference on one side and use it as support for the chain, but 200+ mm would not permit to attach the support board in the correct place . Technically speaking both the solutions are possible .... but the real question is: Can a Mechmate like this be showed (for the first time) to a large amount of people (80k-100k) ? What kind of pubblicity would it be ? (for me and for the mechmate).
My answer is not positive, my solution is to cut the bearers.

KenC Wed 11 September 2013 01:28

For displaying to the public, I would stay 1 fixed size. You can put in more time for the cosmetics. Change the base size to fit your misfortune gantry.

Make a 1220x2440 table area for wood routing on the front end, at the extra length end, set up a separate table area for metal milling or the A-axis or plasma cutting or whatever you can think off to con the audiance that wasn't there by mistake :D

MetalHead Wed 11 September 2013 09:33

Can you give us real pictures?


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