MadModder

The nice thing about 5c collets is you can get not only round, but also square and hexagonal ones 

If you are running high speed it is probably worth machining the few thou body run out off to get better balance

( no point if your work is all low spindle speeds)

Hardwood in almost any form is always very welcome Pete 

@eskoilola
if you haven't read the link I provided, <snip>

Actually I DID read the article(s) and this seems to be somewhat what I want to do.
- I want to maintain the manual controls touch and feel as much as possible
- I want to have the thing to be a "fly by wire" - probably G-code compliant
- I want to do this as far as possible with the original controls
- I want to have sex with my lathe ....

What I would really hate is a big bunch of buttons and some reverse polish notation aka Sinclair scientific calculator from the 70's - it was a really sexy gadget at it's time. Had one and hated it all the way.

For example. At the moment there is a automatic feed on/off lever. That lever would be really easy to modify to be a forward/reverse feed control. On center position (positive lock) it would allow manual control with apron handwheel or the handwheel at end of the lead screw. When away from the center the feed would be equally faster to the desired direction.

Same kind of thinking would go with the cross slide. This time the feed would be controlled with the ex-half nut lever which would now be repurposed for that function.

That Slo Syn motor can do (per spesification) 10.000 steps / second (aka 2500 Hz) - quite amazing for a large stepper like that. I am pretty sure that the torque is an overkill - which is not bad. That 10.000 steps/second amazes me as I also have done my fair part of stepper drivers. The best ones had a switching power supply with constant current output. This means that the voltage rises with the drive frequency. These could easily do 2.000 steps/second but after that most of the steppers went berzerk. That sort of speeds also require acceleration time. Assuming that the ball-nut I have has a 3 mm pitch (same as the current lead screw) the max speed would be then 150mm / second. It is enough for most purposes. I have never measured the pitch of the ball-screw but if my memory serves me correctly - it is more.

When it comes to accuracy there is one unspoken element in the lathe, the compound. You figure it out from there. Auto-feed in the compound ... Hmmmm ..... Maybe a angle sensor and whatnot.

As PK very nicely put it - all this is really cheap - one just needs 10.000 worth of equipment to do it 

Further more - all this is purely academic as long as I am on my assignment here and my home is there. That being said - well thought is halfway done.

@eskoilola
if you haven't read the link I provided, there is provision for and a design for an "electronic half nut" for this ELS controller. It works just as you describe: you move it a certain amount in either direction and it moves the apron at a preset cutting speed. You can move it a bit further and it accelerates progressively to a defined 'jogging' speed. Pretty much like you would use the apron handwheel. He used the analogue input of the control chip to achieve this with a simple potentiometer. I used an electric wheelchair handle with pot to do this.
Finer control is provided by the manual pulse control on the panel. The whole thing is very functional.
It also has a port to connect it to a full CNC controller, should you want to use MachIII, G-code or whatever to operate the lathe.
The ELS by itself just gives you better control over feeds and cutting depth, and includes all common threads, all common tapers and taper threading in memory. It withdraws the cutting tool at the right time and allows nice consistent cutting and threading at the correct speeds for the tools used. Cutting threads a high speeds with nice fine depth of cuts automatically is very nice - and a bit exciting when they finish against a large shoulder!

Matthew,

Look at the date it was posted, April 1st, All Fools Day