Denford Software & Machines

HI Can anyone help? We have inherited a starturn 4 Lathe when we merged schools. The lathe was originally connected to a BBC computer. Can I connect this to a PC? What software do I need and any other bits and bobs ( cables ect. ) where can I find these or make them.
Would be very greatful for any help as the machine is just sitting there collecting dust and would like to use it with the pupils.
Thanks John H
Duncanrig Secondary School

Yes it's possible, but quite a bit of work - see details of my conversion - viewtopic.php?t=452&highlight=starturn

Cheers

Dave

HI Thanks for getting back to me so quickly. You look like the man who can help. Can you please give me a ful description of how you achieved the conversion. I have some electrical knowledge and I'm not scared of some grafting. That is if you still have all these details.
Thanks John H

Hi John

Well I can't really give you a step by step guide - I just made it up as I went along ! Most of the info I have is on the thread I mentioned but I can try and guide you wherever possible.

Try and consider the job as 3 different areas -

Stepper motors
Switch gear and Estops
Spindle

Stepper motors - the best place to start. I would trace the step and dir lines for each driver. Then cut the terminal strips at the top to the mainboard to release the two wires for each driver. Then build the interface circuit, hook it up with a breakout board to the PC and see if the motors will move. By only pulling out the driver step/dir lines you can leave all the Estop / power circuitry connected and there is no need to mess with it yet.

Switch gear/estops. You will need to look at which starturn version you have - the earlier ones like mine had the control relays on the mainboard so I had to source and fit new ones. Newer starturns have them on a seperate board so I suspect you could re-use them. All the switch gear is on a big loop that runs on 12v (apart from spindle index). I split the switch gear into individual switches run off 5V to make the interfacing easier. I left the Estop on a 12V circuit to power the big relay, but uused one set of the estop contacts fro a 5v estop signal to the breakout board.

You will probably also find that the aux transformer puts AC straight into the mainboard. To get around this I put 2 reg/rec units in for the 5V /12V supplies.

Spindle. Two areas here, the control voltage, which is basically 3 connections for a potentiometer. I used a Digispeed from Peter Homann and it was a doddle to setup. Then there is the spindle on/off. You have a second big relay that switches the 240V supply to the spindle drive. The digispeed has an onboard on/off relay that you can use to switch the main relay. You can also retain the front buttons but you will need to build some latching electronics to switch on each button. I retained the front buttons, but in hindsight I wouldn't bother as it is just extra complication and my implementation is not perfect - I can confuse and in the wrong combination of buttons and switches the spindle can start when not wanted.

Hope that is some help

Cheers

Dave