Hi everyone. I'm looking at picking up a Grizzly G0704 mill to convert to CNC for hobby use. I have a budget of $4000 but would love to stay closer to $3000. But before I get into all the technical specs I'm looking for I'll give some background information on myself.
I just graduated with a B.S. in Mechanical Engineering and have my E.I.T. I'm currently an engineer at Keystone automation in Duryea, PA. (We do a lot of cool projects. Here's our website if you want to check us out Keystone Automation.) We specialize in automated machinery for mostly manufacturing and do a lot with Fanuc robotics, PLC programming, and other machine design things. However, I don't do any of the normal machine design stuff yet. We have a few bridgeports, a Haas VF4, another CNC mill, a CNC lathe, a manual lathe, a huge lathe, surface grinder, etc. My dad also has a large Grizzly round post mill/drill, a decent size DoALL lathe, and a ton of other tools common to a garage atmosphere.
I'm looking to build various gun parts such as AR uppers and lowers, bolt carriers, milled AK receivers, AK trunnions, reweld jigs, tube gun receivers, muzzle breaks, etc. Now the majority of these parts are steel, and I don't have any CNC experience on anything other than plastic. So here are my questions:
1. Are the dovetails and table in the G0704 accurate to keep a tolerance of +/- 0.001" over 12" cutting steel? I'd love to have +/- 0.0005" over 12" but I don't think i could afford that kind if precision.
2. Are there any actual numbers in accuracy in the servo vs. stepper motor debate? I'm about to do the calculations to figure out what kind of torque is required for this setup.
3. I would like to use NSK ground ball screws, 15mm diameter with a 5mm pitch for the x and y axis. With a 200 step/ Rev motor that 0.00984". Is it possible to machine to the 0.001" with a step size like that?
I'd really appreciate some input on these.
I just graduated with a B.S. in Mechanical Engineering and have my E.I.T. I'm currently an engineer at Keystone automation in Duryea, PA. (We do a lot of cool projects. Here's our website if you want to check us out Keystone Automation.) We specialize in automated machinery for mostly manufacturing and do a lot with Fanuc robotics, PLC programming, and other machine design things. However, I don't do any of the normal machine design stuff yet. We have a few bridgeports, a Haas VF4, another CNC mill, a CNC lathe, a manual lathe, a huge lathe, surface grinder, etc. My dad also has a large Grizzly round post mill/drill, a decent size DoALL lathe, and a ton of other tools common to a garage atmosphere.
I'm looking to build various gun parts such as AR uppers and lowers, bolt carriers, milled AK receivers, AK trunnions, reweld jigs, tube gun receivers, muzzle breaks, etc. Now the majority of these parts are steel, and I don't have any CNC experience on anything other than plastic. So here are my questions:
1. Are the dovetails and table in the G0704 accurate to keep a tolerance of +/- 0.001" over 12" cutting steel? I'd love to have +/- 0.0005" over 12" but I don't think i could afford that kind if precision.
2. Are there any actual numbers in accuracy in the servo vs. stepper motor debate? I'm about to do the calculations to figure out what kind of torque is required for this setup.
3. I would like to use NSK ground ball screws, 15mm diameter with a 5mm pitch for the x and y axis. With a 200 step/ Rev motor that 0.00984". Is it possible to machine to the 0.001" with a step size like that?
I'd really appreciate some input on these.