4' x 4' mdf router first timer

[4nak8or]

Gday all,
I've been reading all the info on this site and am halfway through building my first cnc router table. I started building after reading phooddaniel's cnc build site and then found this excellent forum. My design is loosely based around his ideas with some ideas of my own and a few ideas ive seen on here added in. I am open to suggestions on how I could improve it as hopefully I will be able to use it to build a second larger one soon (if SWMBO allows)

[4nak8or]

brief info on table
table size (X x Y x Z): 1220mm x 1540mm x 1450mm (48" x 60" x 57")
cut size : 800mm x 1300mm x 100mm (31" x 51" x 4")
laminate trimmer 400w (approx 1/2 hp)
will be used to engrave mdf and acrylic maybe cut mdf up to 3/4"
homemade bearings
mdf and aluminium angle construction
originally allthread leadscrews now looking at belt for x and y axis
looking at using keling 425 oz/in 4 axis package (2 motors for x axis)
still considering different software options??
maybe EMC (not sure how I'll go with linux) if not mach3
CAD/CAM still to be determined (to many trial downloads to try out)
anyway heres a few pics to give a better idea of what ive done so far, I look forward to receiving feedback and ideas/advice from all

[aolshove]

Looks like it has potential but personally, I wouldn't run steel bearings against aluminum rails.

[4nak8or]

I was just following what a few others have done, apparently its a case of at the price of aluminium angle you just replace them as needed, what would you reccomend I use for my next one as I plan to build a similar design next

[aolshove]

Steel angle I think. I would just worry about steel bearings rolling against aluminum angle over several thousand iterations. I would predict that the aluminum angle would groove and possibly cause alignment or accuracy issues eventually. Just a thought.

[epineh]

I am going through the same process at the moment, I built my first machine (still working on it btw) using steel bar (not pipe) and angle iron/bearings. I am happy as it turned out but for my next machine I am thinking of doing better. I have seen commercially made machines using square bright steel bar and bearings that have been used 12hrs/day for the last two years without problem, I was thinking of doing that.

It also may be worth looking at buying linear rail, while it seems like a lot at first, by the time you have bought bearings, made all the fittings etc I wonder just how much difference there is, and the bought ones move SOOO nicely

As for software, I am hoping the latest release of TurboCNC comes out soon, I used it at first but found the lack of constant velocity cutting a problem, so I went with others (DeskCNC, EMC). When I heard the latest version of TurboCNC was coming out with Const. Vel. Cutting I was very happy, minimal hardware requirements, solid performance and did I mention FREE !!

I was working on servo drives to work with EMC (just H-Bridges) but have decided to make them step/dir to work with TurboCNC.

Nice work on your machine btw.

Russell.