What to use for rails? Jackshaft, And some Campbell thc

[KKamel]

mjello

untill yesterday iw used 25x25 flat bar as a rail for my plasma, however i have discovered that it was bent and deflected were easy. What is the "best" rail to use? (dont go nuts) im thinking of switching to something like 50x25x3 or a round tube for rails to get a straight rail out of the metalshop and also to help with the deflection.

Im also thinking of adding a shaft so it drives the x axis on both sides instead of just one side, good/bad/wont make a differens?

And lastly i was looking at the campbell thc, reading the user guide it referes to the second parallel port. Does the thc needs an entire port on its own?

Well thats about it for me excuse the poor english, now im off for work

[Torchhead]

Port 1 on the PC for MACH needs mostly outputs. You have 5 inputs. From those you need inputs for homes, limits and e-stop. The THC needs 3 inputs and 1 output to operate. At one time Campbell had a single port THC/breakout but you only have two inputs for all other inputs.

A lot of tables use angle iron that has been milled on one edge for the V groove wheels like are sold by Bishop Wisecarver. Turn the milled edge up and run the wheels on top. Some let gravity hold things down or cam follower wheels on the bottom of the angle.

[Weldtutor]

Originally Posted by KKamel What is the "best" rail to use? (dont go nuts) im thinking of switching to something like 50x25x3 or a round tube for rails to get a straight rail out of the metalshop and also to help with the deflection

Standard wall (schedule 40) nominal size 1-1/4" pipe was used for rails in the table shown here.
http://www.cnczone.com/forums/showthread.php?t=16634

The bearings are positioned so that if deflection is still a problem with a similar set-up, additional supports could be used beneath the rails & between the table sides & the rails.
As shown, deflection of the rails is not a concern with the adjustable supports only at the ends of the rails.

The rectangular tube you suggest, or round tube of about 4 CM O.D. or larger with a wall thickness of 3 to 4 MM should also be suitable.

Keep up the good work on your table.