Thanks for all the responses - a lot of good point have been made and has given me things to ponder :)
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Thanks for all the responses - a lot of good point have been made and has given me things to ponder :)
I was recently trawling Youtube and came across a channel called Ades Workshop - this guy bought a Warco 16B machine which looks reasonable both in terms of cost and quality
His output looks ok from a hobbyist persepective - so my idea now taking on many of the above comments is to buy a machine akin to the 16B, fit a DRO and then use that to make a purpose but smaller CNC milling machine similar but Jazzcnc but smaller
Sounds like you have a plan.Quote:
Originally Posted by Monty_UK
Buy a mill to make a mill/router.
I'd draw up some of the new machine first. Then you'll know which size Mill to get. Don't want to end up with something too small.
Warco16b & Amadeal 25L are effectively the same machine.
I've recently been looking at TBI C5 ballscrews for my 25L. I better get some cutting done so the machine can pay for them. They're tempting.
Thanks DazpQuote:
Originally Posted by dazp1976
Just found my Zeus book from 1982 - well happy :)
I have just read this. I have a Harrison milling machine, I would buy a cnc replacement if I could find something of similar size, but they are all smaller, or hughr S?H industrial machine which will not fit into my workshop, even a Bridgeport is too big!
Have you thought about converting your Harrison?
Yes I have. I have already replaced the X axis acme screw with a ballscrew to eliminate excess play and chatter, I now have to do the Y.
In order to get my power feed back I am looking at NEMA hybrid stepper motors, This is where the fun starts.
I have searched the site for some answers. How do I get a readout of position from the stepper motor? or do I have to use a DRO and scales?
My understanding is that the linear scales can't be used for feedback, but perhaps I am wrong.
How does the machine know where it is, do i fit switches, perhaps hall sensors to find a zero position?
This type of control is all very new to me so a steep learning curve.
I am sure that there are others on here that have done this, but my searches don’t return any threads, perhaps I am asking the wrong questions.
FYI, "NEMA" simply means imperial (inch) dimensions in tenths of an inch, so a NEMA 17 motor has a 1.7" square face. Beyond that, it could be a stepper, a servo motor or even an induction motor. There are equivalent metric (IEC) descriptors but the motors are interchangeable eg an IEC 42mm motor will be a direct replacement for a NEMA 17 but be aware that the shaft diameter would most likely be a metric size.
You can use linear scales for feedback and they are arguably better than using the motor position, as they report axis position without backlash and spring in the ballscrew, belt etc. But most CNC controllers don't use closed loop positional control. You can do it with Centroid Acorn6 or Linuxcnc but the former isn't cheap and the latter pretty much requires a PhD in Linuxcnc (speaking from experience).
I have a lathe running Linuxcnc in closed loop with linear encoders and I wouldn't recommend it unless you don't mind getting very deep into the weeds. Open loop will deliver good accuracy on a conversion and fitting closed loop won't / can't magically transform the machine anyway - lipstick / pigs etc. I have another lathe and mill running Centroid Acorn and TBH they perform about as well as I could realistically hope.
You will need to fit half decent homing switches (and ideally limit switches) to each axis. Unless you have encoders that are kept alive when the machine is off, you will need to home the axes each time you power up. It's possible to use a servo motor or closed loop stepper drive to provide an index pulse when it is at its zero degree position after the home switch is tripped but really you would be chasing your tail at that point.
What @Muzzer said,
I have a Boxford VMC260 and is has homing switches but no limit switches. When you startup you home the 3 axis, if configured correctly it will know the extent of your axis travel
Caveat, I'm new to all this and still finding my way around
If you are looking to convert your Harrison mill to CNC, this might be worth a read https://www.mig-welding.co.uk/forum/...achine.109112/