The 4x4 Altmill is a big machine and I’m wondering what kind of precision one can expect on cuts, in the X, Y , and Z axes. Are we talking about 1mm, 0.5mm, 0.1 mm precision? I don’t think I’ve seen these numbers in any of the specs.
Specifically, I would want to use the Altmill with a drag knife to cut small but intricate shapes in vinyl or paper. If I have a good drag knife, can I expect the same kind of cut that I would get from say, a Cricut machine?
As an example, if I were to cut a 10 mm circle, would the end point meet exactly at the start point ?
FWIW, once I get my Altmill, I will try to adapt a Cricut or Cricut-clone knife. The clones are relatively cheap and the Cricut brand is currently on sale (at Michaels). The blades are tiny and rotate in the housing so they don’t need to be attached to the spindle collet.
For larger, less-precise cuts, I’d try the home-made drag-knife that gwilki posted about in another post.
Simple Drag Knife for Thin Stock - Community Discussion / 
Tools & Speeds - Sienci Community Forum
There is also a drag-knife similar to the Cricut sold by Carbide 3D but it’s way more expensive if you factor in shipping to Canada.
I can’t answer any of these questions but Robot Shop sells carbide 3D products and they’re based out of Canada. I don’t know if they sell that drag knife anymore but I know they used to. I got a few etching tools through them, and I purchased my original shapeoko 3 years ago through them as well. Shipping was very reasonable.
1 Like
Hi Chucky,
On precision on the altmill, there might or might not be a direct spec, but I found a hint in the upgradfing to SLB section that might give you an idea on how precise an altmill - At least - can be, when it’s perfectly calibrated.
I know, there’s no such thing as no slop in our kind of machines, but even my clunkmill - Not calibrated and I don’t care much for a wee deflection - will stay below your lowest estimate.
I think you will end withing 0,05mm from where you start in your circle with a well calibrated and oiled up altmill.
1 Like
Thanks for the info. I think I can live with 0.05mm
I don’t have any numbers but before I bought the AltMill I emailed support inquiring if the specs were tight enough for PCB milling and was told yes.
I have not tried yet, still on my roadmap, but it was a deciding factor in my selection of the AltMill.
1 Like
I can’t find all the info needed but not counting any play in the system you should be able to calculate the precision.
I think it’s screw pitch / (steps per revolution X micro-steps). The screw pitch needs to be the pitch for one thread if it has multiple starts. I’m not sure how they are usually labeled. If the pitch is still measured by adjacent threads then you need to multiply by the number of starts.
1 Like
Once I receive it, I’ll put a real small value in the precise jog settings and then confirm movement with a dial gauge.
1 Like
