I’m considering buying the Nomad 3 (when it’s back in stock) and was curious about this statement listed on the site regarding materials:
Cut Small Metal Parts…brass up to .25" thick cut well on the Nomad.
I have some brass projects planned that will be milling parts up to 2 inches thick. I assume this is possible with the Nomad, perhaps with some different feeds/speeds? Or should I consider the shapeoko instead?
I say this as an 883 Pro owner, the newer Nomad should be substantially better but I haven’t seen any real documentation of it yet so I can’t say for sure.
It can be done but you need to think about tool length, MRR and whether you want it to be possible or whether you want it to be easy:
Tool length: You’re limited in the depth you can reach by the distance from the spindle nose to the end of the tool (stickout). You really want to minimize stickout, especially on the Nomad, as the higher it is, the more leverage the endmill has against the machine. I generally try to keep stickout <15mm but I’ve gone as far as ~30mm when I’ve had to. This means some 2in thick parts will be possible but you’ll almost certainly have to machine it on multiple sides and some geometry may not be possible. You’ll need to go out of your way to find tools that will reach this far. The Shapeoko also has this constraint but you have the option of going for larger tools and larger spindles which can deal with the increased stickout better (I think, I don’t own a Shapeoko).
MRR: The MRR of the Nomad in Aluminium with recommended feeds and speeds is 0.16cm³/min, so if, for example, you wanted to make a 2in deep, 1in diameter hole in some stock, you’d be removing 26.4cm³, so you should expect it to take 165 minutes, or nearly 3 hours. The new Nomad should be able to cut that in half and these feeds and speeds are extremely conservative, so you can bring that time down with some effort. I think basically all the options for the Shapeoko can blow the Nomad out of the water.
Ease: The Nomad is very much not a machine for removing oodles of metal. It’s a machine for moderately small pieces or work with soft materials like plastics. If your intention is to frequently machine large metal parts and you don’t have stringent requirements on accuracy, you’ll probably be happier with a Shapeoko.
I’ll also add that I feel like Carbide 3D support treats metals on the Nomad like a bit of an edge-case. They won’t help you at all with feeds and speeds beyond pointing you to the aforelinked super-conservative recommendations. They won’t help with finding tools that work well or anything like that, that’s up to you and the community (and the community is fantastic).
The Nomad is also somewhat ill-equipped for dealing with chips. The official recommendation is to frequently clean the machine yourself or to come up with your own solution.
I don’t want to discourage you too much, the Nomad can mill metals for sure, I just wanted to tell you the stuff I wish I’d heard when I was making the same decision you are.
One thing I will say on the Nomad vs Shapeoko is that I’d expect a bit of time tweaking things on the shapeoko to get it right and then a bit to cut metal. Nomad should work for the most part out of the box.
2 inch part isn’t terrible, though you may run into some issues. Basically as described above, but the longer the tool, the less clearance you’re going to have.
This is great feedback, thank you! I’ve done a lot with 3D printers in the past, so I’m used to fiddling with settings to get things to work. Overall, I’m still leaning pretty heavily towards the Nomad 3 and think I can make it work for this project from all of your recommendations.
Cutting thick metal is much less of a problem if you control the design. Minimize any vertical walls and get familiar with Fusion (you are using Fusion right?) options for shaft/holder. Also simulations are very important to check.
The nice thing about brass is that it can tolerate a much smaller chipload compared to aluminum. However ive personally seen leadscrews with sprung anti-backlash nuts have a strong negative effect on how hard you can push in brass.
Like the others said, stickout matters. To minimize machine time its best to split up machine toolpaths with different stickout lengths.
Is it possible to share or get a snapshot of your design?
That’s helpful feedback. I’ve been using Fusion360 for 3D printing projects and am pretty familiar with the necessity of designing around the limitations of the tool. Good call on using the simulations – I’ve not done much of that for my previous projects.
I haven’t drawn up the design for this project yet, but it’s going to be a brass door knocker. In reality, the project will probably average around 1" thick, but possibly 2+" in some areas. Judging by what people have said, it should be relatively easy to taper the deeper cuts to make room for the shaft/holder and use the flip jig to cut from both sides.
The ultimate goal is to make a door knocker that knocks itself when someone presses the doorbell. It’s a silly gag that’s been rolling around in my head for a while. So the design will need to have room for some electromagnet coils hidden inside. There’s a lot of details to work out before I take my first cut, but that’s the general idea so far.