this is wired1's excellent build of the ob1.4 with a larger build envelope of about 380x380x380mm.
I wanted to use half of the 1m openbeam length for the base.
I used the ob1.4 original diameter rods and placement, I just made them longer.
I replaced the front y axis gt2 pully with a larger one from sdp-si.com : 6Z51M036DF0605 , so it would clear the openbeam rail.
this pulley has 36 teeth.
I also had to buy more gt2 belt due to the larger build envelope, this is sdp-si.com part number: 6R51MC060 , I had to use 3meters total for x and y axis.
using a lazy susan bearing for the filiment feed.
tried a bed made from granite tile 12" x 12", but it cracked at 70deg C.
so I'm now using 0.25" x 15" x 15" t6061 aluminum plate over 0.375" x 15" x 15" plywood connected directly to the standard ob1.4's y-carriage.
printing on blue painters tape and if needed hairspray.
the tape is applied directly to the aluminum plate.
using hossman's dial indicator attachment the aluminum plate is level to +-0.010" over it's surface, ie front to back and side to side; it was easily adjusted using the spring setup showed in the pictures.
I'm using plastic zip ties to put the electronics and power supply on the ob1.4 frame so it all moves as a unit.
I'm using hossman's long lcd cable configuration and I've had no issues.
I'm using repetierHost in ubuntu 12.04 linux and really like it.
I'm using slic3r which comes with repetierHost.
I was having globing issues on printed parts as seen in the pictures on z height over about 12mm, this turns out to be an issue where repetierHost needed to have the ping-pong communication turned on, DOAH ! I suspect repetierHost was not waiting for the marlin software and just throwing g-code away.
The printer is working very well now at 50mm/sec print speeds.
after some more finer calibration I'll try to up that speed to see what margin it has.
thanks again to wired1, hossman and nate for all their help.