Check out my build, I build a Z Axis just as you are describing, might help you out some.

HD CNC

 

I don't know what you mean by Belt drive. The Sphinx is leadscrew driven.

-The bottom plate doesn't really serve any purpose other than looks.
-1/4" is plenty good for the back plate. You need to remember that weight is a concern. Depending on your span of your X axis, and the spindle choice, you could be talking serious weight.
- The holes were in the plate when initially machined. I have since abandoned the hall effect limit switches. The product is fine, but requires you to orientate the sensor so it must sit in a real specific way. I am using standard roller limit switches, but honestly this is one area I would like to improve upon, given that mounting is not a huge undertaking.

More pics of my machine can be found at: CNC Studio (@cncmaryland) • Instagram photos and videos

 

Ahhh, gear reduction drive. I just not a fan of that, to me the more parts, the more chance of something going bad. To each their own. Good luck with your build!

 

Came across this when I was looking for Z-assemblies for my machine. Right now its somewhat like the OX and the Workbee but my machine is made from Plywood plates and its just not stiff enough. Maybe I'll replace the linear bearings with slides. I'm having trouble with chatter too on my Y-axis while cutting in the Y- direction. I'll try the trochoidal milling path.

 

Andreas, you stated that you used a regular 3/4" wood router bit to face the aluminum. Please tell us the make and model number of that bit. I just started a build page here on Openbuilds now that I am starting to cut aluminum. BTW, great face job with that bit!

 

Very cool!

It looks like your old Z needed to be trammed a bit. That could also contribute to broken bits if you're cutting a slot that's deep enough. How are you handling chip evacuation?

 

I've also had success using typical wood bits for some aluminum tasks, but I'd be prepared to throw the bit away when you're done unless your F&S are just right. I made the stupid mistake of using a 3/4" straight bit to surface some 1/2" AL, then trying to use it on an irreplaceable piece of quarter-sawn red oak the following week. Fortunately, I stopped the job quickly. :|

On a slightly-related note, I encountered a couple of staples embedded in the middle of my Home Depot 3/4" MDF spoilboard while resurfacing. There goes a $35 surfacing bit.

 

So, rather than cutting a "slot" that's the width of the bit, leading to chip cloggage (not a real word), you're cutting it 50% wider? That makes sense. I wish EstlCAM provided an easy way to do that. Guess it's back to fighting with Fusion.

 

You don't need to 'fight' with Fusion's CAM Their own documentation and videos are very helpful and very informative. I spent a total of 2 days looking over the options, simulating it and it was surprisingly easy. There are a few nuances that you'll come across such as chatter with slots on less rigid machines. At that point you know what is happening and you have a specific topic you can seek advice on. At least thats what I did.

I used estlcam recently and cutting slots with it is very tiresome. For some reason, it does the trochoidal path and then reverses back to the start point doing another trochoidal path (essentially cutting air). This was very irksome since it doubled the machining time. Its great for cutting outlines from stock material and where you don't want to reduce the entire piece of stock to chips.

 

Your project seems interesting, any chance to get the files for cutting the aluminium? I would like to try it too