This thread reminds me that I need to grab some spares for my MIG. It's been years since I've welded, but I was doing okay at the time.

There's definitely a typo in one of the messages. Unless time is measured differently in Scottish

/you/ are pulling me up on a typo? Oh the irony.

Hahaha. Fair point. I think I'm doing better recently.

Got my stepper motors today. Don't have the proper drivers yet so only running them at 750mA (instead of 4.5A) but even at that piddly current I can't stall them by hand. Well impressed.


CNC4You Nema 23 3.1Nm stepper motors: http://youtu.be/4ZhwKfWf3iY

The stepper motors are for controlling the movements along the axes?

Have you bought a router for it yet?

Yup, steppers for x, y and z axis. Would have made more sense to get a smaller one for the z, but the three were together in bundle for a nice price.

The cutting head is going to be kind of modular. Probably start with one of my face dremels and upgrade as I learn more about how to use it. I'd love one of those 3kW water cooled spindles on aliexpress. Or a plasma cutter!

Sounds promising.

I have been modelling on NX for most of the day, designing a bracket for our new force monitoring equipment.

I have no idea what a face dremel, but it sounds painful.

NX scares me. We have to use its little brother, Solid Edge, at uni and that's frustrating enough. Especially as they never actually teach us properly, so you end up having to work stuff out by yourself and invariably this leads to learning to do things the wrong way, or leaving big gaps in your knowledge.

I am teaching NX8.5 to our engineers next week. Having proper training makes huge difference.

I'll give that a watch tomorrow.

I am getting ready to do this as well.  I am using an old table as my starting point.  It's about 4' x 4', I want a decent size working area.  I'm going to be using a Dremel as the cutting tool and an Arduino as the controller.

I have a lot of the parts I need already, but I'm only in the hunting, gathering phase right now.  I have two stepper motors but I don't know if they will work yet.  I have a parts list started and am getting ready to start buying/making the needed things and get this project going!  I am going to do a time lapse of the project if I can get my camera to cooperate.

How is yours coming along?

No progress, the real world has been getting in the way. Still waiting for my motor drivers to turn up. Still. Need to order my linear rails. Still need to grind my shirty welds off. Still need to finish designing the y and z axes.

That's what keeps happening to me.  Sounds like a Matchbox 20 song.

Well today is the last day of the 'expected delivery' time frame on ebay for my stepper drivers. Shame they only got dispatched at 3am. From Hong Kong.

That sucks.  I have a digital soldering station I'm waiting on but I'd say with the weather it won't arrive today.

Is there a place that suggests what steppers to use?  I have two from printers or something, I think they will work for this project but I'm not sure.

I highly doubt that steppers harvested from printers will have enough grunt to run a CNC mill. They'd probably manage a laser cutter gantry, as long as it was light weight. I've also found (although this might be because the printers I nicked mine from are /old/) that printer steppers are relatively low resolution, at 7.2 degrees/step. The printers tend to use a gearbox to increase resolution, but for a CNC extra gearing means extra backlash and should ideally be avoided (Backlash can be compensated for in software to an extend, but if you want decent repeatability it's best to minimise it from the outset) . General rule of thumb (can't remember where I got this or how valid it is...) is you want at least 1Nm to be able to use a dremel effectively to cut wood. The motors I've just received are 3.1 Nm, cost about £30 each and they need a hefty 5 amp driver. In terms of how much torque you need: to cut a straight line in the X axis, you need enough grunt to both move the y/z gantry and enough left over to push the tool through the material. Additionally, your y/z motors need enough torque to prevent the tool deviating in either of those two directions. It soon mounts up to needing quite a bit of force. Furthermore, when you look at a stepper motor torque rating what you get given is the holding torque - i.e. how much torque it has to hold its position. As the RPM of the motor increases, the torque decreases. If you use microstepping you can also reduce the available torque by a large chunk. Also also, there is seemingly no properly reliable way to calculate a linear force from a screw torque. Due to the number of variables in a setup (particularly the friction between your screw and nut), the normal formulas used can be out by 25% or more. Some US building code I saw says that if a particular clamping force is required, you must measure it directly with a strain gauge rather than using a formula to find out how much torque to put on a bolt.

If you don't mind and have time can you point me to some of the guides you consider the better ones for this project?  And link me to the motors you ended up buying?

I got these motors: http://www.ebay.co.uk/itm/111412185294?_trksid=p2057872.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

I think the guy selling them has a pretty sweet setup - he's put his own stickers on them, with a model number. If you look up the model on alibaba/express there's only one place selling them - for slightly more than this guy is in the UK. I suspect he's struck a deal there, somehow :D

Anyway, I think the price is pretty fair - they seem to be very strong (see video up there ^^^ ) and they're dual shaft so I can stick a rotary encoder on the back end for feedback. 

As for guides, well I've been wanting to do this project for about 6 years or more. I've read countless forum threads, instructables, hackaday articles etc. There's not really any one guide I've followed, more a case of trying to understand the various theories of operation and then design my own system. CNCZone.com is a pretty active forum.

To be honest, if I was in teh USA I'd probably just have bought a Shapeoko 2 machine. But the shipping costs to the UK are ridiculous. I think the unit costs about $600 delivered in the US, over here it's about £680 (plus potential import duties etc.)