Is there a basic primer on stepper motors for a newbie?

**merlin777** · 06-28-2018, 05:23 PM

I'm planning a spindle cutting machine for cutting rope twists and so on. I have no experience (yet!) in building a machine or use stepper motors so I wondered if there was a 'stepper motors for CNC for dummies' somewhere?

At the moment I'm just seeing a lot about 'nema' 17s and 23s and don't dont what they are so I know very little.

I attached a plan of my early design for comment. My impression at the moment is that I don't need huge stepper motors because I'm just rotating a small piece of work (wooden spindle max 2" x 10") and positioning a router bit but as you can tell i dont really have the first idea!

For reference, the second photo is a small (90mm x 300mm) xy table which I intend to cannibalise for the cross slide and maybe the bed.

Any thoughts VERY welcome!

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**ger21** · 06-28-2018, 08:14 PM

Just dont buy anything until you've spent a few months doing research.
Im in a hurry right now, but I'll try to lock later.

**merlin777** · 06-29-2018, 06:00 AM

Originally Posted by ger21

Just dont buy anything until you've spent a few months doing research.
Im in a hurry right now, but I'll try to lock later.

Thanks for that. Any help greatfully received. I don't. Know where to start with stepper motors I've got a learning curve to climb before I get any!

**A_Camera** · 06-29-2018, 07:12 AM

I think NEMA23 will be good enough for what you plan to do, but carefully consider everything before you commit to buy anything. The XY-table you have on the picture looks for example pretty weak to my eyes. It looks as it is made of pretty thin aluminium and probably 6mm screws driving simple nuts, maybe plastic nuts, maybe brass. It looks very similar to the one I have but mine is a bit smaller and is a Proxxon KT70. Anyway, it is far too weak for anything other than playing around with it, or maybe as a drill stand positioning system for small and light objects, not as a mill XY table. The eBay versions are not better (probably worse) even if the seller call it "precision XY table". I also think that modifying such table takes longer time than building one, and the one you build is probably better than the one modified. I had similar ideas some years ago, but gave up after some time.

Anyway, as Gerry said, don't buy anything just yet, consider carefully what you want to do and what you can do. The advantages of making mistakes is that you learn, but mistakes costs money, so if you have a limited budget you should try to avoid them and learn from others mistakes instead. Spend time on studying what others have done or how people solved their own mistakes. Set up a budget, especially if you are on limited resources, but also set up a goal and define what you want to achieve, quality, space, rigidity... That's where you should start. There is no limit in this hobby, you can spend any amount of time and money on it because you can always make it a little better, which takes a little more time and costs some more money in an endless loop. So it is important that you have a clear picture of what you can do and how much you can spend (time an money wise) on this hobby.

**ger21** · 06-29-2018, 11:44 AM

You are much better off overbuilding and going with bigger components. The cost increase won't be that much, and you'll end up with a much more capable machine.
Nema 17's are generally not suitable for any cutting machines, so you'd want Nema 23's.
Most of the cheap Nema 23 rotary axis setups from China are not that strong, so be careful before you buy.

**merlin777** · 07-02-2018, 04:03 PM

Originally Posted by ger21

You are much better off overbuilding and going with bigger components. The cost increase won't be that much, and you'll end up with a much more capable machine.
Nema 17's are generally not suitable for any cutting machines, so you'd want Nema 23's.
Most of the cheap Nema 23 rotary axis setups from China are not that strong, so be careful before you buy.

OK - quick update. I received my xy table and I ordered a rotary table and 3 jaw chuck..

The plan is to put something together to test the principle and find the critical factors. Most componenets I should be able to use elsewhere if they aren't going into the 'MkII'.

I inverted the xy table and removed the green base to reduce height. I now have a long bed I can bolt to a solid baseplate for the helical lathe prototype and a cross slide for the tool.

They'll both be useful for my dremel drill press if they dont get used in the MkII.

I'll wait for advice on the motors and control system. The aim is to use something compatible with the MkII.