Nearly time to start building!!!

[itsme]

Hi there everyone,

I'm finally getting my Sieg X1 mill on Saturday. I've got some NEMA 17 180Ncm stepper motors that will be running in unipolar mode with a Xylotex board and of course I've got the Xylotex board (which I have already assembled). When I get the machine it'll all start with a complete rebuild and then the CNC conversion can begin!!!

The motors will be running in unipolar mode (as I said before), so I would imagine that they won't make their full rated torque, but there should still be enough torque to drive the leadscrews with a one-to-one ratio. The motors do have double shafts and I would like to keep the manual controls for the machine. What I would like to know is how I should mount the motors.

If I were to use a 'solid' coupling (aluminium or steel) that connects the motor shaft to the leadscrew directly, I fear that I may have alignment issues. I also think I would have some problems when it came to manual machining and all the 'sideways' force on the handles was being transmitted through the 4 small stepper motor mount screws. What does everyone think of this method?

The alternative (more expensive) method is to use a toothed belt drive to the leadscrew (still keeping the one-to-one ratio). This way the motor would be offset and all alignment issues would be sorted. The handles could then be mounted on the leadscrew side of the arrangement, so that no forces would be transmitted through the stepper mounts in manual mode. What does everyone think of method number 2?

Which method do you think is the better one (I'm leaning towards belts at the moment). Are there any other suggestions?

Regards
Warren

[JRouche]

Granted the toothed belt would be a little more expensive but flexability for mounting the motors is increased and as you said mounting the handwheel will be simple. Think about hand wheels without the crank, just the round section. Less sticking out to clobber your body parts. They also make hand wheels with folding crank handles.
JRouche

[JFettig]

Those little steppers probably wont have enough torque for that mill.
Youll want to look into flexible couplers, you can get them at many places, I have some from mcmaster and had some from reidtool
mcmasters are a little cheaper and are clamp onto the shaft rather than with set screws.

Jon

[itsme]

Hi there,

Thanks for the replies. Belt drives are definitely looking good at the moment.

About the stepper motors. I did quite a lot of research on the stepper size before I went out and bought them. If anything, they should be a bit on the big side. I have been reading on the Yahoo groups and people have succesfully converted this mill (it's the same as the Micro Mills available from Harbour Freight etc in the US) using motors of about 150 ozin of torque. Now, if I've got the conversion right (which I think I have), then my 180Ncm motors are about 250 ozin, which should be more than enough.

*SIGH* I've just read my first post. I can now see why you think they'll be a bit small. I said they are NEMA 17's, they are in fact NEMA 23's. My mistake. Sorry for that. I don't know where 17 came from...

Regards
Warren

[MIKE JEFFERS]

hello
is this the same as the clarke mini mill? if so iv'e fitted 180 oz motors to mine and
it cuts okay but the z axis is slow, needs a bigger motor. just fitted as your method 1
an upgrade to ball screws & stuff wil be on the cards , or maybe a bigger machine
will be sought ( x3 or similar). i never missed the manual operation but the quil z is
useful. just build it,get it running and mod it as you se fit.

[JFettig]

itsme, your correct if they are 250oz-in, I just assumed that 180Ncm is a very low torque because of the nema 17 frame.

Jon

[MIKE JEFFERS]

itsme
i thought i'll post some pics of my cnc's so here they are (i hope) i appologise about the mess but ...well....you know.
the mill is a machine mart micro mill £240 on vat free day and the same china mill as a lot of others motors from e-bay (180 oz i think) running 12v from a battery charger
as compucutters.co.uk site controllers built by my mate pete
the gantry router was built first , out of plastic sheet 12 mm in 2 (long) days then
used it to spot drill aluminium (6063 t6) and replace most bits (a machine building itself
freaky or what) same controllers/supply etc
as i said in an earlier post just build it then work out the problems
regards
mike

[itsme]

Hi Mike,

Thanks for those pictures, your mill looks pretty decent. The Sieg X1 that I have got (or rather 'had' :frown: ) is just the same as the Clarke Micro Mill, except it has got the extended base for more Y-axis travel.

I also looked at the Clarke Micro, but then found this X1 for £255 (cheaper than the normal Machine Mart price) with the bigger base (brand new). The reason why I 'had' this mill, is because it has gone back to the shop- not because I don't want it any more, but rather because it doesn't work. The place that I bought it from has been very helpful and they are going to sort the problem out. Of course, they make thousands of these machines, and I get the one that doesn't work...

I've decided that I'm going to go with toothed belts for all axes. It'll be more expensive, but I think it should be worthwhile.

As for a machine making itself, well it sounds good to me!!! My micro is going to make a lot of its own CNC conversion parts, but not quite to the same extent as your first machine...

Mike, how have you found the rigidity of this machine and also its performance with your setup?


Regards
Warren

[MIKE JEFFERS]

warren
the mill is surprisingly good , i'm a toolmaker and used to big machines but this little mill is better than i anticipated so much so that i've bought another one oan i'm going to use this to try some mods and ideas from the first one .
the biggest headache has been the z-axis (i even thought about lying the mill on its column to gee it up a bit) but tweaking the settings has it running okay
bolt it to a bench (even better would be a granite slab see your local stonemason/funeral guy) as this will damp the vibes. feeds and speeds also come into it as will cutters and your expectations ,remember its only a £250 machine
lapping in the bed ways and fitting brass gibs are benificial and keep it well lubed
both machine and job and i think you'll be happy with it.
then you'll want a bigger one .
what are you going to do on it?
mike

[itsme]

Hi Mike,

At the moment I've got (well, my Dad) an Emco Compact 5 lathe with milling attachment (manual version). This little machine has been excellent, but sadly it is definitely better suited to turning work than milling work. When it comes to milling, anything more than about 0.4mm per cut and the vibration is horrible and often causes the tool to wave all over the place. It's fine for small jobs though.

The X1 was bought to take the strain off the Emco and also to have the CNC capabilities. I'm fairly sure it will be a lot more rigid than the Emco for milling (and the travels on all axes are much bigger). The X1 will be used mainly for model engine parts. I'm just busy trying to finish off an engine now, and after trying to mill the steel conrod on the Emco, I'm particularly keen to get the X1 going. I also can't wait to get the CNC conversion going, because I want to make some crankcases from billet. That should be fun!

All I need now is the working machine...

Regards
Warren

[MIKE JEFFERS]

got your mill yet?
mike