just another plasma build and then some :)

just some more progress pictures after a rough week due to my junk not running right when i am working on something big

my X axis and Y axis are running on a 4:1 ratio due to stepper motors not having good torque speed curves so this ratio will get me where i need to be hopefully.

i had the motors doing nothing for me sitting around and gecko G201x drives with a PDMX-134 mother board along with a 70VDC power supply for everything. my gantry has some weight since i wanted to have a router head option available to me as well.

i did go with those leveling casters i mentioned in a previous post.they look pretty nice and should work well. I also ordered some drag chain this weekend and went with a 25 x 77 internal size with a 150 mm bend radius. i'm hoping the size i picked works well? never messed around will the stuff in the past but never had a big table like this either. i tried to get material for the frame for the table but they were almost out of that size material so i will have to make another trip to the steel distributor this week when they get some more material in.

i'm getting anxious to start on the table and get this thing off the floor already also what to see some drag chain in place across the gantry and have it look like something almost done

I use 25 x 77 drag chain and its a good fit. I had to google how to open it though!
8" outside dimensions seems to be a good radius in practice.

i did a little bit of research on it and came across someone who was using 25 x 50 and had problems with torch wires not bending and cracking eventually so i figured the bend radius was to small so went for something close to 6" on a bend radius. i thought i dodged a bullet but since your using it and not having issues i feel better about it now. i try like heck to get things right the first time but since i never built a table this big or a plasma table for that matter it's only a matter of time before my luck runs out

started working on the table and then the Bridgeport mill i have started with it's issues So i spent some time ripping the upper head down on that so i could see what was going on. the low range was not working and the mill was not staying in gear so working bow out of steel was not going very fast at all, i picked this mill up several years ago from a previous employer for next to nothing and they had rebuild the head so it had all new bearings with next to no hours on them.

once i got in there i found some issues. first thing i found was a key laying on top and was like how did you get there and where do you belong? but looking into it deeper i found another issue. the bull gear assembly has a shaft nut on the end that holds it together the nut was off the assembly all together and sitting on top of the upper most bearing on the spindle shaft. so needless to say i will pull my spindle bearings and clean those out and re pack them with new grease. they feel alright but i know if there is any metal floating in the grease they won't be in a short period of time.

back to they key i found on top, i looked all over the place and nothing obvious was being seen as were it went so i had to do some research and finally figured it out, Here the thing is actually the key that hold the large bull gear in place on the assembly. there is no way it could have come out the way this thing is made so who ever did the last repairs on this thing mess up big time on that one,

getting good finishes on things has always been tricky with this mill and i think this could have been why. i just wanted to make a table and now it looks like i have to play repair guy so i can actually get some work done with this thing, .

stupid machines

i have watched a few builds and it seems the gantry seems to be the hard part for most. i would say the table is far worse to get right
first off it is a pain to get a 10 foot bar machined straight in a free state with no stress on a Bridgeport mill , second it is such a pain dealing with travel issues and constantly relocating each section you are working. and finally it's just a slow process doing everything manually.

i took note of how long it took me to center drill, drill and power tap the 47 holes needed to mount these 2800 mm long rails and it takes about 2.5 hours each. i was not keep track of time but i would say i have at least 16 hours in the pair and they are still not done yet

i'm guessing 10 to 12 hours each buy the time i get the rest of the holes and counter bores in them. almost 3 months of working probably at least 20 hours a week on this project is where i am at. good thing i don't making a living building these things otherwise i would probably be homeless

What I am going to do next time is to use a plate mount for the linear rail that I will have laser cut. Then all I need to do it tap the holes and weld it to the table frame.

thefabricator03 wrote:

What I am going to do next time is to use a plate mount for the linear rail that I will have laser cut. Then all I need to do it tap the holes and weld it to the table frame.

I declare that as cheating!

And its exactly what I did!
I hand tapped the holes using a magnetic tapping jig from Hare and Forbes. Some M4 holes they could not cut but they scribed and centre marked position with the laser. M6 holes in 12mm were tap ready. To be perfect, I should have machined the rail and rack mounting surfaces but that was beyond my little SX3 mill. I did use it for the gantry rail though (1600mm on a 400mm table....)