Conect 121 lathe retro

[Hood]

Just got a wee lathe yesterday, have been looking for one for a while just to play around with and got talking to Graham Waterworth and he mentioned he had one so I bought it

Its based on a Myford ML10 and had a 1/2HP DC motor on the spindle and a couple of steppers for X and Z axis. I have stripped things down a bit and have replaced the spindle motor with a 1HP AC servo I had lying around. I have a 400w AC servo for the Z axis and I am hoping to pick up a 100w or 200w one for the X.

At the moment the motor on X sticks out the front but I am hoping I can redo things so it sticks out the back, time will tell if thats going to be easy or not.
The toolpost is a Dickson quick change but I am thinking of doing a gang tool setup at the moment and maybe in the future I will make a turret.

Anyway heres a few pics of the lathe as was , the lasttwo are the original spindle motor and the servo I have fitted.

[budman68]

What a fun looking project, Hood, look forward to seeing it move along- 

Dave

[Hood]

I am looking forward to seeing what it can do with the servos Think I will have to modify the ballscrew bearings a bit as at the moment they are only thrust bearings and on the Z the other end is just an oilite bush. Would be fine for steppers I suppose but think they may heat up a bit with servos, then again maybe I need some heating as its not exactly a tropical climate here

Hood

[RICH]

Hood,
Welcome to the world of small and you will certainly have fun with it.
I put bearings on both sides of the Z and X axis on mine with one side able to adjust preload of both bearings.
The problem on having the X motor mounted to the back side is that there is not much to grab onto for mounting. I made a bracket
and things worked out. Another pain is ball screw size on the X axis since it's small in size ( small and accurate means expensive you will find ).
My x axis screw has a rather fine lead and didn't need any reduction / stepper is directly attached. Actualy it's a positioning ball screw and i was
after accuracy. Both of the screws have backlash adjustment for the nuts....so post tweaking the bearing preload i could then refine the nut preload.
For the x ball screw a tapped hole in the top of the carriage provides for getting to the nut adjustment. With both ends of the ball screw anchored / rigidly supported allignment becomes trial and error. Not much problem for the Z, but the x axis is very short and no give .......have gibbed x axis slide ...so the bearing mounting plates  can be shifted some to provide for gib adjustment. In the end all this paid off.

I use a 1/2 HP motor on mine and when using the back gearing get plenty of torque and no spindle slow down when threading. Draw back
here is spindle speed though. But with CNC you can always use a fine feedrate to get surface finish.

A small accurate CNC lathe is just a joy to use,

RICH

[Hood]

Rich, its already got ballscrews on it, X is tiny as you say, its 8mm dia 2.5mm pitch. Z is a bit bigger think 12mm and 5mm pitch but not really looked closely as I have not had much time.
Mounting shouldnt be an issue at the back if I can do what I am thinking. The topslide had the motor at the front as in the second pic above, I reckon I should be able to just spin the top slide around so that the mount will be at the back. I have seen a few pics of the later versions of this lathe and they have the motors at the back so I think thats probably what they have done.


Hood
 

[Overloaded]

Hey Hood, is that the 3016 at the spindle ? 5000 max rpm ?
Curious, what is you planned ratio .... motor to spindle ?
Thanks,
Russ
 

[Hood]

It is indeed Russ
Plan on keeping the ratio as is, 2:1 so 2500 max although I may limit it depending on how it sounds or if it sounds good may put it 1:1 

Hood

[mc]

I've got one of the later ones with the x-axis motor at the rear.

Mine had had very little use, and I got it for a very good price from somebody who bought it from auction but couldn't get it to work.
I retrofitted mine with a SmoothStepper and C23 that I had doing nothing, and I bought a couple Gecko G251s to go with it.
One weird thing was the X-axis ball screw is imperial (3/8 x 10tpi), and the Z-axis is metric (12mm x 4mm)

Still not used it in anger yet, as I've had a rather hectic spring/summer so still not got past playing with Mach's built in wizards.

Full details of the woo's I had with mine can be found at http://www.mycncuk.com/forums/showthread.php/2619-Conect-121-Lathe-The-toy-collection-grows!

[Hood]

I have already seen it
Looks good
Where about are you, think its somewhere in Lothian if I recall.
I am up the coast a bit in Carnoustie but my workshop is in Arbroath.

You said your X ballscrew was 10TPI, is it definitely that as mine seems to be metric 2.5mm pitch.

Have the mounting brackets all worked out for the X motor, not sure if I have Alu to make it from, plenty steel but might be too heavy.
Heres some pics of what I plan.

Hood

[mc]

I'm about 10miles east of Edinburgh.

The X-axis is definetly imperial, as it threw me for a while as to why I couldn't figure out the pitch in mm, until I dug out the micrometer and checked the diameter, at which point the penny dropped.
Althought I'm pretty sure I had to tweak the Steps per unit quite a bit from the calculated figures to get it accurate. If I get a chance, I'll check what figures I ended up with (I'm of on holiday next weekend, and I've got quite a lot of stuff still to do before I go!).