[RainMan 2.0]

Great post Richard , and congrats on making such a heavy duty machine at such a reasonable price .
You certainly scored when you sourced the aluminum extrusion, wow!
I see I made the post too lol .

I am liking the idea of building your own CNC . I would cheat in a few areas , like buy the Z axis already assembled .
I'm wanting to go with linear rails , those block type style like there now using at CNCrouterparts on there Pro version . But I would like to go with larger extruded aluminum on the Y axis as you did .
Thanks for posting , that's a great looking machine

 

[RainMan 2.0]

Richard , do you have and profile shots of your rack and pinion drives on the Y axis ? I can't get a good look at how you designed it , or if there directly connected to gear rack ?
I was going to buy CNCrouterparts pro version rack and pinion if I end up building one .

I'm also liking the front hinged spoil board idea . Very clever

 

[RainMan 2.0]

Thanks for the info Richard . I have to say I'm very impressed by this build and your talent , and I like how you think out of the box

 

[RainMan 2.0]

Richard , I think the electronics being mounted on the gantry has its advantages, but my concern would be the potential of getting a cold solder joint in the electronics from long term vibration .
I'm not an optimistic, so maybe I worry to much sometimes.

I was wondering how you get the proper engagement on the gear rack from the pinion on the stepper motors on the Y axis . Are the holes elongated where the steppers are mounted in order to rotate it to put the appropriate pressure on the gear rack ?
The reason I ask is , if there's not perfect engagement there would be the potential for backlash , which would obviously cause poor repeatability.
I've noticed most systems have a spring that can be tensioned to get the right pressure between the stepper motors pinion to gear rack contact

 

[RainMan 2.0]

One other question lol .
When the pinion on the stepper spins , in theory it would try and climb out of the gear rack .
Of course it doesn't , because the bearings on the rail are holding it true , but I've noticed that the weakest part of the bearing (the bottom) would be taking the brunt of the force from this stepper as it's creating torque .
Not sure without firing up photoshop and illustrating this , that my concern makes any sense .
I'm sure I'm overthinking this , but I think the gear rack should be mounted so that the stepper puts force the other direction, pulls the gantry down , not forcing it up .
Like if the gear rack was mounted above the steppers pinion , not above it?

But I do love the simplicity of your design

 

[RainMan 2.0]

Good points Richard . I never realized that the round linear rail you are using are attached threw out , as I thought they were suspended from each end like a lead screw , but it's making it more interesting as a alternative to the other over priced linear rails that I was looking at .
Btw you've done one heck of a job creating this machine

 

[RainMan 2.0]

Richard , as much as I have my heart set on linear guides (the square blocks ) , I was wondering where you sourced your round linear guides ?
I'm sure they would work well , and as you say the cost is is less.

This is the place where I was going to order from in Colorado, but I don't see the round style like you have there

https://motionconstrained.com/store/hiwin-linear-guides/hiwin-hgh25-square-block-linear-guides/

 

[RainMan 2.0]

Wow looking at all that extruded aluminum is unreal Richard !
You guys in the US have some of the best perks . That's one heck of a drive for me , but again , thank you for the info .
I can't believe the score you got there , and those round linear rails are ten times cheaper than what I'm looking at

 

[RainMan 2.0]

That photo looks like all the (good) parts from an abandoned profession exhibit. I've been at trade shows where company booths were made from just such parts, and left for scrapers for being too expensive to store and/or ship to the next exhibit.

Wow and ouch at the same time :|

 

[RainMan 2.0]

Richard , the more I look at your machine, the more impressed I get . I would change a few small things , but each to his own . (Not big on direct drive ).
That must be great having a cnc club , wish we had something like that around here . Guess I gotta start it myself lol.
I have to say the guys at cnczone are an awesome group too, as they've been very helpful