5'x15'x24" shopbot

[Howard Andersen]

Is anyone running a "lights out operation"? - i.e. is it feasible/safe to feed the shopbot some wood, turn off the lights and go to bed, come back the next morning and find the work done? How safe? Anybody created extra safety devices for this kind of circumstance? Any help is appreciated.

[broscott@gaius.org]

Desiring a cutting area of 20 to 24'long, 6'wide, 36" tall.
How difficult is it to build the shopbot to these measurements?
broscott@gaius.org (mailto:broscott@gaius.org)

[tlempicke]

I am currently buiding a Shopbot that will be 24 inches wide by 30 inches long. Question is - why do you need a Z axis that is 30 inches tall? How about building the machine with a big hole in the center if you just want to machine on the top of a tall piece? Actually you could simply cut a hole in the table of a regular size Bot and get the same thing.

[tlempicke]

Sorry! Just re-read your post and realized that you said 20 to 24 FEET not inches!

Tom

[flyboy]

I'm still working on the table for mine for aboyut 9 months UUUUGH. 12'x5' x 24"Z plunge. Man, what a project for me. At the time they did'nt have the longer tables available. Anyway, I hope someday to be running it. Hopefully you will not have such a hard time to get your table made or whatever. It hasn't fit into my schedule well even though it's not that hard of a task.

[cmrtom]

I made my own table with 10 inch steel channel for the legs and primary cross member and those funky little tapered washers from McMaster Carr. It was a simple idea. I have a 12 inch channel for the horizontal side member. I now know that my using a 20 inch channel for that piece I could have had a much larger z axis. I used 2 by 2 by 1/4 inch angle to connect the two side rails together. Then placed two sheets on top of each other of melamine coated particle board for the table(really took 5 sheets). I initially thought the I would just machine down the 2 sheets, but found that I have a much easier time with a seperate piece of material that I machine the surface flat. All materials move over time. I have to resurface these disposable sheets every couple of weeks. My table is 5 ft by 10 ft with a z capable of traveling 20 inches. Building your own table is a matter of preference and up to your skill level. I really enjoyed the building process

[shawn_xof1]

My 2cents about a large table..... My bot is 6' X 18' with a 24" Z. The z axis is not very good for cutting wood when it is fully extended at it's 24 inch travel. as well it is hard to make your table sturdy enough to get rid of the vibration. There is no room under the table for large angled supports. What I did to overcome the problems is two things...

To Keep the table sturdy I had to fix the side rails with cross members from the rails to the floor.

To allow for wood carvings I built a second table which is 6' by 10' and 12" down from the z axis. this also adds a ton of support to the entire table. Granted it is a fair amount of work when you want to remove or install the sub-table, but it is rare that I need the bottom table 24 inches away from the z axis.

Also you have to be sure to accomidate the length of bit you are wanting to use on a 24" z axis... For example if you have 24" of Z travel you need to drop your table about and additional 6 inches so you can take advantage of the full extent of the Z travel.

[chip]

Howard,

We run our 'Bots while we are gone on a routine basis. There are a few precautions to take.

First, hook your computers up to a UPS. This will keep the positioning alive if power shuts off. DO NOT hook the router or the control box to the UPS unless you have a mighty BIG one that can handle the amperage of the router or control box for an extended time. The PC router draws up to 15 amps, and the motors draw a bunch (don't have the figures at this time) too. It is quite a big load. You would almost need a motor generator behind the UPS in order to handle it. Protect the computer, that is paramount.

Second, install a safe router shut-off switch controlled by the controller. This will shut off the router if power fails to your building. MAKE SURE that the control box is not on the UPS. There may be plans for the circuitry kicking around somewhere....

Think about what you want. You do not want to waste the wood, break a bit or burn out some circuitry. In case of a power problem, you want everthing to stop dead in it's tracks.

The other thing is that it would be good if the routers shut off after the piece was done, instead of wasting the router brushes.

Hope this helps.

Chip