Thread: Warco Major CNC build log
Any further news?
I have the smaller Machine Mart one made redundant 6 years ago, very accurate.
Was rather intrigued by the lead screws, i broke mine 9 years ago and close on £200 and 6 months delivery from MM.
I always left a ratchet and socket at the back for the two nuts.
I did inset 18" of 10mm square gauge plate along the back of the bed to set things square against and it is proving incredibly useful.
It was a very tight fit, had to tap it in with a hammer, half expectied the back of the table to split off but I seem to have got away with it.
Haven't done the splashguards and pneumatic spindle lock yet.
Next I want to wire up the 1 micron tool locator. Hopefully this will let me set the tool position exactly where I left it the day before and autoset the height following a tool change.
I have read this thread (more than once) on the work you carried out converting your Warco Major to CNC.
I too have the same machine and I am contemplating doing the same thing. (but I am new to the CNC field, but do have some local backup on seting up using Mach3 etc)
I do have a couple of questions for you that are specifc to this conversion, if you would be so kind.
Was the overall expendature and effort worth it, in terms of the usefullness of the machine when finished?
I am perticularly interested in the Z axis arangement you came up with. How is that working out for you now?
Which motors and controllers did you finally go with and on what voltage do you run them. Do still you consider them to be the correct choice?
With hindsight, is their any aspect of the project you would change and why?
Overall expendature and effort worth it? For me, yes. I had already CNC'd it without the benefit of CNC and as a budget job I got what I paid for. If you want to get the tolerances down, and keep them down, I think preloading nuts and screws is a good idea. The mill has 2 problems when you try to cut better than .001". The column flexes, the quill is sloppy. Grease the quill, try to keep the head wound right down when milling. Value for money? I did it because I became obsessive about seeing a couple of zero's after the decimal point on my calipers, value for money depends on how freaky you are.
The 'Z axis arangement' works well. Setting up a mill is a time consuming business, so putting in two 8mm screws to lock the Z is not exactly onerous.
Motors and controllers? I used 3.5Nm NEMA34's and Garys 240 volt drivers that come straight off the mains with no seperate PSU. The motors were rated 3A wired in series, the lowest setting on the drivers was 3.18A RMS, 4.5A peak. They seem unstallable, snapped a 12mm end mill like it wasn't there when I had a whoopsy. Not sure how fast they go, my computer can't keep up. I'm quarter stepping at 200 steps to the mm. They run a bit hot but it doesn't seem to worry them.
Anything I would change? Yes, I would mount the Y axis nut 12mm towards the front so I could have gotten the tool centre in line with the front of the bed when I cut it flat. The bolt heads collide at the back. Also a few annoying clearance errors. The Z axis digi scale top interferes with one of the bolts holding the cheeks in place, had to miss the bolt out. The Z axis handle comes very close to the Z stepper conduit clamp. I was slightly concerned that the heat from the X axis motor might be getting on to the lead screw but it doesn't seem to get above blood heat so probably okay.
Thanks for the swift reply.
That is all very usfull info.
May I just stretch you a little more on a few points.
Do you have any suggestions on how to "stiffen" up the column
Which motors exactly did you use ( part numbers would be extremely usefull) and were did you get them from?
What is the voltage at the motors?
Gary was no stock on the motors at the time so I got them from ArcEuro. I think they are the same motors wherever you go.
I never measured the actual voltage at the motors, I soldered and shrink wrapped everything before I plugged it in. Not sure I want to measure it at the driver end either, I am a bit nervous about exploding voltmeters. I used fat wires with fat insulation, had to cut part of the wire core away before it would go in the driver connector. Overkill perhaps, but I don't expect much in the way of losses even on the long run to the Z so probably around 200VDC.
The drivers aren't cheap but as they plug straight in to the mains you save on the PSU, also you can be fairly sure you won't have to replace everything later due to a lack of volts at the motors like I did.
Not sure you can stiffen the column. I thought about concrete but the movements are so small, thermite? Also I can't be sure the flex is actually in the column, may be the whole thing bending, may be where the column joins the base where I shimmed it to cut square. It is practically impossible to measure.
I have read the whole build and it brought back memory's as i have a similar mill, i hope Robin does not mind me adding some info of how i tackled the problems.
My biggest issue was the Z axis namely the play of the quill in the headstock. I also made three failed attempts at cnc'ing the Z
My own quill had just over .1mm slack which is abysmal, i had a quote to hard chrome the quill and grind it to size of £300 and thought there must be a better way.
I cut through the front of the headstock with an angle grinder also at the top of the headstock to allow the quill bore to become flexible in diameter.
So now the quill was too tight, so i have adjusting screws that allow me to open the bore for the quill this allow me to get a beautiful fit of the quill in the headstock tight enough that there is no play but free enough that there are no issues with lost steps.
To CNC the Z i based my design on a Bridgeport mill (Getting the Nut As Close To The Quill As Possible) which i have also, by machining a slot in the quill i have mounted a custom housing that takes the ball nut it is made in steel and by using two strips of steel in the headstock i can take all the wobble out of the quill.
In fact i have the quill rotated 180 degrees in the bore as that was where it seemed to slide as easy as possible so now the the teeth for the gear are at the front.
It has two steel cheeks attached to the headstock and looks very similar to Robin's in that respect.
I do not suffer from flex in the column and my belief it that the flex in Robin's machine in fact comes from the poor fit of the quill.
Although clamping the quill will minimise problems it will not eliminate it completely.
Robin is correct. I would love to see a more indepth view of this too. (PLEASE).
Well as I was asked so nicely I will start a new thread.
Here are some pics to whet your appetite.
The first is the complete assembly.
The second shows fine lines on the quill that emphasises the smooth but tight fit.
The third shows a close up of the ballscrew way deep inside the housing.
Don't forget that estop button in a convenient place
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Last edited by M250cnc; 08-12-2010 at 02:37 PM. Reason: Pictures Added
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