Spindle Swap to Light Work Steel

[verhoevc]

I’ve done a lot of reading on shopbots (especially the desktop) and working with steel. I’d like to get some vise style hold downs and tackle some light stainless (think 416 and 17-4) work. Think full cutter width passes 0.080” deep taking as many passes as needed to get there.

Best I can tell from this reading, the limiting factor may be the spindle, not the gantry and drive train?

Thoughts on swapping to a low-RPM/high-torque spindle to tackle jobs like this without resorting to buying a mini Tormach or similar?

[coryatjohn]

I think you'll find three problems inherent in the standard ShopBot when it comes to machining steel.

1. The gantry and entire structure is just too weak and wobbly. To machine steel, you need a solid machine made from heavy steel, not aluminum extrusions.
2. The motors that come with the standard SB, even an Alpha, have steps too large to work with a material like steel.
3. A spindle or router spins too fast and a spindle has too low torque at the lowest RPM's to do anything but make a mess.

It's very likely that you'll twist your machine with each step and the results will be just terrible. You'd be better off getting a mill or farming out the work.

[verhoevc]

Yeah, I thought it might be the case that the spindle wasn’t the only constraint. Sigh… looks like I have to buy more tools. OH NO! Lol

[Rob Gunn]

Yeah, wood, foam and even alumaboard is doable. I would never think to try steel. Look on your local craigslist or market place and you can probably find a used cnc mill that would work for what you want to do. I picked up a older cnc Bridgeport a few years ago for $1000.

[coryatjohn]

Wood, plastic, brass, aluminum, copper, non-ferrous only. That's what your SB is capable of machining successfully.

[verhoevc]

Yup, done all of those quite successfully!
Thanks for the replies folks.