just another plasma build and then some :)

i'm sure there are easy ways to go about for sure. welding things in place would save time no doubt but even laser cut parts get a lot of heat put into them and you get stress thrown into your parts from the process.if your going strictly air plasma then i'm sure you can get away with more. but if you would get into a high definition cutter you might want to avoid welding linear parts to the table. in a precision build you would need to get into welding thicker frame work together so it can be machined after in a precision build application.

part of the reason why i have avoided welding anything is because of stress in the frame caused by all the heat. another part is me working with what i have on hand as far as the tools i have to work with.

it would have probably been easier for me to go with CR flat bar but the cost is a lot more than HR flats. it all depends on what your budget is? for me i am working on a shoe string budget so i fight with cheap material issues to save some money. CR is not straight either but it is better than HR.

once i get the sides done the rest will go much faster the sides that the rails are attached have to be accurate since everything ties into them as a whole.

if plan A fails plan B will skimming the table top with a mini mill head to bring it in closer if need be

I guess it comes down to how accurate you need your machine to be.

I would not say my build was a precision build by any means but I am able to achieve tolerances close to 0.5mm easily which is more than suitable for the work I do.

Air plasma really is a blunt axe, even hi-definition is not that precise compared to say laser or water jet.

I know its not in your budget but a machine like yours really deserves a laser head on it. It would be interesting to see what kind of tolerances you would get with such a precise machine.

I think the biggest shortcut would be to get some 4" x 4" SHS cut and drilled for tapping to mount rails and mounts with one of these:
www.lasercentral.com.au/services/tubular-laser-cutting/
These guys cut some parts for me on their laser tube cutters.

Then you could skim the rail in a mill before assembly. I don't think welding would bother accuracy much this way as the whole frame would be cut to 0.01 tolerances or better. But the better way would be to bolt these down on the floor and square them with a laser and have your water table or downdraft between them as a separate structure. You see a number of high end machines built this way.

even with all the extra attention to precision at the end of the day the machine still has rolled ball screws and those are going to only be accurate to .003 to .005 per foot at best.

i think .1 mm would be a good guess at the level of precision on this build. obviously the bigger the part the more error you accumulate but on average i would guess .1 mm

once you know where you are at that number can always be dialed in closer. that just requires more work getting set up. so it boils down to what is needed once again

So what do you plan to use the machine for? Production or just a hobby?

something that make me money hopefully this is a plan to have a shop set up at home for retirement. i have a ways to go before i'm at that point but i am sure it will be here before i know it at the same time

Job shop or do you have a product you want to make.

I could see some very accurate art work being cut out

when i get done building i have a very good friend that is high up with a construction firm that does work all over the country. so seeing if i can get my foot in the door with this company is priority # 1 plan #2 would be to see if the local fab shops have a need to form work out and # 3 would be work on my own products to sell myself.

my friends employer would be a good bread and butter customer if i can get in with them. they do several million a year in business.

i have an artistic side but seems like everyone and their brother does that sort of work so not sure how profitable it would be? commercial contracts seems like a better way at steady income?

Making your own product would be the ideal thing to do it you had a market for it.

Commercial work can be a race to the bottom depending on the customer. If you can get in to a decent company you would be set.

We were spending around $40,000 a year outsourcing our plasma cutting and we were only getting base plates and cross brace cleats cut.

It can be profitable if you get the right client.

being at home you get limited on the power supply end of things. 1 - 50 amp breaker is a large portion of the supply for your home. one reason a multi function machine is attractive to me.

this is why i am going through the trouble to make a machine base that is as accurate as possible. +/- .003 is over kill on plasma but if you are working on sheet work that requires +/- .005 a milling head on the universal table is needed. a sure fire way to not get a job is to not have the equipment to make it in the first place.

usually the bigger the parts being made means the more money you can get for making them. not everyone can do large or really long parts.

i see a lot of people trying to cut aluminum on a router and wondering why they trash the spindle bearings. it's more about having the right kind of spindle bearings in the spindle and having a machine heavy enough to absorb most of the vibrations that go with those cutting forces. even HP on the spindle is not as critical as you would think. a Bridgeport mill has 1 to 2 HP motors on the spindle but they can cut 1/4 of an inch depth of cut in aluminum or better.

why because they weigh about 2,220 pounds and the spindle is designed to take that kind of cutting force.