Myford 7, 3 phase motor other CNC questions.

[EddyCurrent]

I use https://www.inverterdrive.com/ myself, most inverters will allow external 0-10v control and as Neale said with the right interface board your away. I suppose it should be easier to install using the kit but I don't know what's involved with the Myford.

[magicniner]

I fitted a standard 3 phase, foot mount, TEE branded motor to my Super 7 about 10 years ago, I had to file/cut the mount holes in the plate and use thick washers on the nuts but it's held up for those 10 years (and so has the second hand Siemens drive that runs it), it will take 4mm OD reductions on 2" stainless with (using indexed carbide tooling) little curly blue chips flying everywhere, all for £165 ;-)
I'm using a Siemens Inverter Drive but on other machines I have ABB and Mitsibushi, any of the big industrial names should give good performance, documentation and life.
All my drives either have a potentiometer built in or have front panel buttons to give speed, jog and direction control, these can alternatively be set to external controls.
If you buy a decent drive and read the documentation the programming isn't Rocket Science, if you buy a drive with a Chinglish manual you might struggle,
Regards,
Nick

[Jconway651]

Went for this package from transwave on ebay. It's about the same price as the newton tesla kit but it has a "better inverter" in the sense that it can be cnc controlled whereas the standard package from newton tesla didn't have this ability.
http://www.ebay.co.uk/itm/1hp-IMO-Ja.../161503539660?
Lets hope it arrives over christmas whilst i have time off to play..

[Web Goblin]

Main thing to check would be the shaft size on the existing motor and make sure the new one has the same diameter to fit the pulley.

[Jconway651]

The new ones a 5/8" shaft, so should be a direct swap. Saying that i didn't actually check the one that's currently fitted.
Ill have a look in the morning...

[JohnHaine]

Hi Joe, I've converted my Super 7 to CNC with a ballscrew on the cross slide so far. These two pics show the fitting. I made a new bracket to fit on the end of the Xslide as I wanted to be able to convert the lathe back, so not start hacking any Myford bits. I think the PXF S7 is easier because the normal feedscrew is larger than the standard ML7 or non-PXF S7, so there is quite a large "tunnel" through the slide body which will pass a 12mm x 5mm pitch ballscrew (from Arc). In order to mount the nut I milled up an ali block which you can see at the back of the nut - this is first screwed onto the saddle using the normal feednut mounting holes, then the flange of the ballnut is bolted to it. This was an interesting job for my little CNC mill. What you can't see is that on the back of the block is a spigot to locate it in the feedscrew tunnel. As I'm using a 12 mm screw I think I can get away without a support bearing on the other end. At the drive end the screw is turned down to 8mm, it's direct driven from the motor through an Oldham coupling, and runs in a needle roller bearing in the end plate with a couple of roller thrust bearings either side of the plate.

I'm using the standard leadscrew at the moment, with the stepper bolted to a 6mm ali plate in turn bolted on another 12 mm plate that picks up the row of machined holes along the back of the bed. There are slots to allow for belt tensioning. The stepper drives the leadscrew through a 1:2 toothed belt. It's crude but effective! I generally followed Tony Jeffree's conversion on the leadscrew but didn't bother with boring out the hole in the bearing, just fitted roller thrust races which self-align quite happily.


There was a chap exhibiting at the Midlands exhibition who had a very nice conversion of a non-PXF S7, and I believe he is planning to make a kit available. You can see it on YouTube at cncyourmyford, and his email is cncyourmyford [at] btinternet.com. He does a proper job on the cross slide with bearings at both ends of the screw but has to use an 8mm ballscrew since the non-PXF slide has a smaller hole through it. He also fits a ballscrew in place of the leadscrew, by dropping off the Apron and fitting a new one from an alloy casting. I am thinking of doing something similar but fabricating a new apron.

[kingcreaky]

thanks for sharing this JohnHaine; very much enjoyed reading it.


Jconway651 I have nothing much useful to add; other than keep the thread posted with whatever you decide.

F*ck it, Im way out my depth here but I have seen one of these cheap huanyang vfd's used to power a 3 phase motor.. You would have to read up on whether its a suitable application for you but may save you some money. Im not sure if it would be any use.... I think there are some ways of controlling the speed via mach aswell.

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http://www.ebay.co.uk/itm/NEW-VARIAB...item3a76ff32da

[Jconway651]

John Haine: Those are some useful pics, my setup will be similar im hoping.
Im assuming you were talking about ArcEurotrade? Is that where you got the ballscrews? They dont have them in there catalogue or online anymore it seems.
The leadscrew on my myford was bent when i got it so i will be going to ballscrews on both axis straight away.
Ive seen the cncyourmyford youtube videos and was quite impressed, although im assuming for his screw cutting he has spindle driven by stepper motor, like in Tony Jeffree's where he has an electronic division master.

Kingcreaky: Im sure this is similar to the inverter ive ordered, and im not to pannicked about the initial wiring and getting it running. However im sure the process of controlling spindle speed through mach will confuse me plenty.

[EddyCurrent]

Kingcreaky: Im sure this is similar to the inverter ive ordered, and im not to pannicked about the initial wiring and getting it running. However im sure the process of controlling spindle speed through mach will confuse me plenty.

No, if you ordered same as you said earlier you have a Jaguar drive, quite a good brand actually. Have you ordered a breakout board etc. yet ?

[Jconway651]

Na i havent ordered a breakout board yet, was waiting for it all to arrive before ordering anything else.
Im not really sure what i need to be buying in terms of the breakout board.
I had planned to just get the motor fitted and working so i can continue to use lathe whilst i buy other bits ill need.