Sieg X2 CNC conversion

[spuddevans]

For the last year or so I have been gradually gathering up various bits and pieces to do a CNC conversion on my X2 mini-mill, just as and when I have had the spare cash and when I see things on offer.

Now I have got my Paddleducks  engine running my attention has turned to working on my machines, and the first thing I wanted to so was to get started on my CNC conversion.



So for the last few days I started working on the electronics side of things.

A long time ago I played Bass in a little band, and I also did the PA duties. Anyway, the point of this seemingly pointless story is that I built myself a stereo 150Watt per channel PA amplifier for the band and mounted it all in a nice 19" rack case. Now this amplifier has been serving very usefully as a footstool under my desk for the last few years, so I decided to recycle it.

I stripped out the 2 150watt amplifier modules and all the wiring and pre-amp section, and this left me with a nice big 6U 19" rack case with a toridal transformer rated at 500VA, 35V. Once rectified and smoothed that will give me approx 40-45V at about 14amps, and that will provide that power for the stepper drivers.

Here is a pic of the transformer fixed in place, along with the stepper motor drivers placed roughly in the position that they will be fixed. Also pictured are a couple of small transformers that will be used for powering low voltage stuff.




The reason I have 2 little transformers is to give me 4 power supplies that are completely isolated from each other. Why do I need this? Well, to protect the controlling PC from any voltage spikes and surges from the steppers, I have a isolated interface that goes between the PC and the stepper motor drivers, but this requires a 5Volt supply that is seperate ( ie, isolated ) from the PC's power supply.  ( that's one isolated power supply )

I also have got one LCD voltmeter and one LCD Ammeter for monitoring the main power supply voltage and current demands ( not really needed, but I like dials and displays ), and each of these displays needs its own power supply that is exclusive to each LCD meter. ( so thats 2 more isolated supplies )

Then I have one more that I'm not totally sure if I need it at the moment, but it may well come in handy.



Anyway, I have also done some metalwork on the front and back panels of the case. It has been interesting trying to cover up all the holes originally made for the amplifier with the new holes for the new application.

Here you can see that I have installed a fan, this is positioned so that it will draw the heat away from the stepper motor drivers as seen in the 1st pic.

Also you can see the cutout for the 25way "D" connector for the connection to the PC, and the 4 4way XLR sockets that will connest to the stepper motors ( X,Y,Z and A (for the rotary table) ), these are of a locking type because if you unplug a stepper motor from its driver while it is powered then most likely you will have to replace the blue smoke in that motor driver, they really dont seem to like that. So hopefully having locking connectors will prevent disconnection thru vibration or pulling of cables.





Moving on to the front panel, I have got the 2 lcd meters to mount, and also I have 4 moving coil ammeters and 5 switches to mount.

This is as far as I had got up to yesterday.




Then today I milled out the holes for the LCD's and also another hole for a switch.


And this is what I ended up at the end of today.




So on the front panel I will have a master Voltage and current readout on the 2 LCD's, and individual readouts for each of the stepper motor drivers. I will also have a switch for each stepper driver to easily isolate any motor ( especially helpful for swapping the Rotab for say another axis without having to power down the whole system.

There is also a master power switch ( the green switch )


Anyway, that's as far as I have got. That is pretty much all of the metalwork done on the electronics box, now I will be working on wiring it all up.


Tim

[John Stevenson]

I stripped out the 2 150watt amplifier modules and all the wiring and pre-amp section, and this left me with a nice big 6U 19" rack case with a toridal transformer rated at 500VA, 35V. Once rectified and smoothed that will give me approx 40-45V at about 14amps, and that will provide that power for the stepper drivers.


Tim

I make that 49 volts output, too close to the max of those drivers, think you need a bit of buck boost winding to get the voltage closer to 30 v AC.

dare say someone else will chip in with more accurate figures.

John S.

[spuddevans]

I make that 49 volts output, too close to the max of those drivers, think you need a bit of buck boost winding to get the voltage closer to 30 v AC.

dare say someone else will chip in with more accurate figures.

John S.

That's a good point John, would you have a recomendation as to a safer voltage to run with?

I could just drop a couple volts pretty easily using a couple or 4-6 diodes in series.

I will have to fire up the transformer with caps and see what the unloaded voltage is.


Tim

[John Stevenson]

I'm running these exact same drivers with an RS transformer rated at 30v AC and according to my reckoning that should put 42 volts out with a 10,000uf cap and under test it does exactly that.

I know you have all your bits so more of a heads up for the UK guys.
This guy on Ebay located at Swindon has rakes of these power supplies.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=380071301709

These power supplies are rated at 50.5 to 56.5 volts which is a bit too high but to get these voltages you need to feed a signal to a sensor pin on the PS.

If you don't connect the sensor up just feeds mains in , they put 42 volts out all day dead stable. If you can collect at the door he sells them for £10 each, which is an absolute snip, I bought 50 

John S.

[spuddevans]

Well that really is a great price for those psu's John, if I didnt already have this transformer ( and another 300VA one, same voltage, in case I want to expand to more axis's for a future lathe conversion ) I would def get a couple of those.

I just did the calculation for rms to peak voltage dc and it seems to work out at 35Vac gives 49.49Vdc, a bit too close for comfort. So if I can drop about 3-4 volts I will be ok ( I hope )

Anyway, I can drop the voltage by just using 4-5 diodes in series, a bit wasteful I know, but it is the easiest way that I can think of to reliably drop 3-4 volts without losing any amps. ( but I am open to suggestion if anyone else can give any other ideas )


Tim

EDIT:

I've just found some high power diodes that drop 1.5volts, so 2 maybe 3 of these will drop the voltage to a safer level for the drivers.

[John Stevenson]

A while ago I bought what i thought was a 50v xformer from RS, wired it all in and just did a quick test, wanted 72 volts, and finished up with 78 volts which was a bit close to the 80 volt max on the large drives.
Turned out I had ordered a 55v xformer 

Not knowing about the diode trick I wound some heavy flex hookup wire round the torroid, 10 turns, switched on and that gave me 1.6 volts, so wound another 20 turns and got 5 volt.

Connected one the end of new coil to the existing one and took a reading over the two windings and got 60 volt. Reversed the termination and that got me back to 50 volts. Wrapped some of that white packing tape round it, the type with like a glass fibre weave and it looked just the part. It's still working like that today.

John S.

[spuddevans]

Not knowing about the diode trick I wound some heavy flex hookup wire round the torroid, 10 turns, switched on and that gave me 1.6 volts, so wound another 20 turns and got 5 volt.

Neat trick, I would never have thought of that 


I dont have a whole lot to show for todays work, I spent most of this morning arranging and then re-arranging all the components to try and get them fitting with enough space around them, and with enough airflow thru to the exhaust fan to ( hopefully ) keep the drivers cool.

Then it was just a case of bolting it all down and then this afternoon I set about wiring up the drivers to the 4pin XLR sockets. And that's all I got done.

But I did finish off by probably doing the most important step, I took a photo of the progress.

So here it is, I've added a few labels to hopefully make clear what some of the bits are for.




I still have to mount the smoothing capacitors, mount the bridge rectifier and wire them, wire the breakout board, make up a rectifier and regulator for the breakout board, and a whole bunch more too!!


Stay tuned for more updates,


Tim

[DMIOM]

.......with enough airflow thru to the exhaust fan to ( hopefully ) keep the drivers cool.....

Tim,

Just an observation - you may be better rigging it as a slightly pressurised case by having an inlet fan, with a filter, rather than an exhaust fan.  Most cases "leak" (and I guess your metal pegboard base plate will let most of the air in) and you can't have those multifarious apertures filtered.  Even if you don't have, say, any wood-dust, general environmental dust will gradually accumulate.  Many consumer PCs rely on exhaust fans, and when you open up a PC that's been in an office environment for a couple of years you'll usually find lots of gunge & dust around all the gaps in the front of the case.

(good re-use of the 19" case though   )

Dave

[spuddevans]

Thanks Dave for your thoughts and suggestion

I have thought about reversing the fan, and I may well give it a try and your suggestion of the filter is a great one thanks, I hadnt thought about that.


One reason I have been leaning towards an exhaust fan is that with a pressurised system I would be trying to force the warm (hopefully not hot) downwards thru those little holes. That seems a little bit kinda the wrong way to me

That is why I positioned the stepper motor drivers ( the main source of heat ) next to the fan so that the heat could be extracted from the case instead of being blown into the case. ( the stepper driver that is positioned further in the case is the "A" axis driver which will be driving at a lower current and thereby run a bit cooler )

The lid does have a series of vent slots in it, but I want to cover these up as with life in a metal-munching workshop there could well be tiny metal fragments that could settle on it, or even in it, and that could spell disaster in blue smoke.


I appreciate what you are saying though, I may well try running it in either direction and see how it works out.


Tim

[John Stevenson]

Tim,
Who's breakout board is that ?

John S.

[spuddevans]

Tim,
Who's breakout board is that ?

John, it's justs a generic chinese made unit like this one linky  (I didnt buy this particular one, but it looks identical to mine )

I dont know if it is brillient or not, I guess I'll find out 

As this is all a new field for me I am completely open to all suggestions and hints/tips and help offered, so if anyone spots something that could be done better, please speak up


Tim

[John Stevenson]

Tim, One thing to note with this board is there is no charge pump for Mach fitted.

The Charge pump circuit prevents the machine from moving / glitching whilst the computer starting up. As a computer starts it polls the various ports etc to check if they are all active, this can cause an active machine to move off zero or even start the spindle, if so controlled.

No big deal if it's your own machine and not for resale, just make sure the computer is up and running with an open copy of Mach on the screen BEFORE switching the machine on.

John S.

[spuddevans]

Thanks for that John

I had read about using a charge pump, but like you say this particular breakout board doesnt have that feature. I was considering using one output pin to power a relay.

This is where it gets a little confusing, but stick with me ( otherwise it'll just be me who's confused here  )

This relay ( controlled by Mach ) feeds power (the 45V supply from the transformer ) into a second relay, this 2nd relay is set up to be a latching relay (it will latch on until power is removed ) and it is controlled by the little green switch on the front panel. ( This is a momentary switch )

So the circuit works something like this, When 1st switched on, the power is not applied beyond the 1st relay ( the one controlled by the pc ), then when Mach is run and it sends out the signal to the 1st relay to turn on, then and only then can the 2nd relay be turned on by pressing the green button. Any time that the signal is inturrupted from mach then obviously the 1st relay will cut power to the 2nd relay which will also cut power to the drivers. The power will remain cut off until the signal from Mach is re-established AND then the green button is pressed again.

 Hopefully this may make a heath-robinson charge pump replacement.


Tim

[spuddevans]

Well I left you all hanging on the edge of your seats, ( you were all on the edge of your seats, weren't you? if you weren't on the edge of your seats, please could you do so now or the whole effect will be ruined  )

Anyway, I have not been completely idle since the last post, I have been working on the wiring and fitting a few more little bits into the box.


Here's a pic of the whole progress as of today.




Here's a few closer shots.

This is a closer shot of the bridge rectifier. I mounted it on a piece of Ali heatsink that I had left over. I drilled and tapped it M8 so that it would be able to fit it onto the bolt that secures the transformer to the case. Then I drilled and tapped a M4 hole to mount the bridge rectifier to it. That should keep it cool even when under full load.
I have yet to hook up the positive to the smoothing caps, this is where I will be putting 3-4 diodes to drop the voltage to keep it within the limits of the stepper drivers.




This is the next part of the power supply chain, the smoothing capacitors, 2x 10,000uF. Also beside it you can see the power relay that will switch the transformer on and off as described above in my post about my substitute for a charge pump.




Here is the bank of 4 relays that are switched by the front panel switches, these feed the 45V dc from the smoothing caps to the actual stepper drivers. The reason for using relays for switching instead of just using the front panel switches are, firstly, the switches are illuminated, but they need to be switching 240Vac in order to light up (ok, not a really important reason, but I like lights and dials), and secondly when the main transformer is switched off the relays will immediately isolate the stepper drivers without waiting for the caps to discharge.
Also you can see a ferrite choke to hopefully suppress any interference.




A closeup of the stepper driver wiring.



Showing the wiring of the ampmeters and switches. Each meter is wired across a shunt ( a short, extremely low resistence link, in this case about 0.015 ohms ) You cant see the shunt directly, but in the picture above of the stepper driver wiring you may have noticed a single terminal block sticking up. The reason it is sticking up is that the shunt is inbetween the terminal block and the terminal of the driver. ( the actual shunt I had to make myself out of some resistence wire I had, it turned out to be about 14mm long was the needed length )




A closeup of the back of the LCD displays.




So that's as far as I have got, I have just been taking my time trying to keep the wiring as tidy as I can, it makes troubleshooting a bit easier ( I hope )


Stay tuned for more updates ( you dont have to stay on the edge of your seat this time  )

Tim

[spuddevans]

So here's a little update on this.

I fitted a bigger transformer for powering the breakout board and for powering a speed controller board that I just got from the states, and possibly a spindle speed monitor circuit that I also just got. The original transformer only gave me 0.3Amp output, but this one gives me 1.3Amp, plenty to play with.

I also made up 2 sets of Bridge-rectifier and 5volt regulators along with electrolytic capacitors. I just hard-wired all this lot together, mainly as I had mislaid my vero-board ( which will no doubt appear as if by magic when I have finished doing all things electronic ).

You also might note a little yellow blob attached to the regulators in the pic below, these are Tantalam (woeful spelling) Bead capacitors, like electrolytic caps they are polarized and will go bang if connected the wrong way. A little cap mounted close to the regulators will help to supress interference.




I also modified the wiring on the back of the ammeters. Because I am using home-made current shunts which may differ slighty from one to another, I need some way of adjusting and setting each meter to read a true value. So I got some 100 Ohm 10-turn trim pots and fitted them in-line with one lead of each of the meters. (100 Ohm is a lot higher than I need, probably 30 ohm would do, but I only got 100 Ohm ones, but being 10-turn should give me the range of adjustment I need )




Then I had to create a little relay driver circuit to interface between the breakout board and the main power relay (my poor-mans charge pump system). The problem I faced was this, the breakout board's output ports are active low. What that means is that when the computer sends a signal to turn a particular pin on, the breakout board will actually connect that output to ground. This would not create a problem if the breakout board could handle the current to operate a relay, but alas it cant so I had to come up with a little circuit.

It is a very simple circuit, just a PNP transistor, a 1k resistor, a diode and a relay. The PNP transistor will turn on when the base pin is brought low, ie ground. Then the current can flow through it and into the relay, turning it on ( which will then allow the main psu relay to turn on ). The diode is there to suppress the back EMF when the relay is de-energised.

Again, not having any stripboard or veroboard to mount the circuit to, I mounted the diode to the relay, secured it with a dab of hot-melt-glue. then I hot-glued the transistor to the side of the relay, and then soldered the whole lot up. By mounting it all together it meant that I only had to bring 3 wires to the relay from the breakout board, then I could position this relay close to the main power relay, thus saving having to run 240Vac lines all over the place.

Here's a couple of views of the relay and associated circuit.




I then ( very tentitively ) plugged the power in, but before switching it on I unplugged the power supply wiring that goes into each stepper driver ( handily these stepper drivers have easily unpluggable connectors for all their wiring ) Then I switched on, and ....... well nothing went bang. Then I realised that my poor-mans charge pump circuit was doing its job, preventing the main transformer from switching on until Mach sends the signal to the right pin.

Not wanting to ( potentially ) fry my pc, I bravely decided to just over-ride the need for connection to a pc and just used a little piece of wire to link the output pin to ground, thereby energising the little relay. Then I was able to press the power switch on the front panel and ....... again, no bang or flash, just the Lcd's lit up showing 0.00v and 0.00A ( because I havent connected up the main Positive from the bridge-rectifier yet ).


So, the only thing left to do before testing with actual stepper motors and pc attached, is to work out how many of these power diodes are needed to bring the voltage down to a safe enough level for the stepper drivers. Then I will be able to do initial testing and setting up of the ammeters, and then the electronics side will be complete.  ( barring a complete meltdown and explosion !!! )


Tim

[raynerd]

Looks pretty damn good to me! Look forward to seeing it run some motors!!

[spuddevans]

Thanks Chris 

I hope it'll work ok, if it does work then the real work starts. I have to get some ballscrews, Angular Contact bearings, oldham couplings, couple of timing belt pulleys and belt, a bunch of Ali plate to attach it all together, plus I am toying with the idea of a One-Shot lubrication system for the mill.

That's not to mention making a set of brass gibs for the mill too, and the possibility of making an enclosure for the mill to keep the chips and coolant managable ( did I forget to mention the thought of flood coolant, but that will def' be a later thing, I dont intend going into full-scale production with this, just for my own enjoyment )


I think I've caught it 


Tim

[fatal-exception]

Yep, definitely a nice control box. I often wished I had an ammeter on my spindle driver. It would have saved quite a few end mills over the last few years.

What do you have in mind for spindle control? That's one thing my X2 has never had. I have a servo driven spindle on my gantry milling machine and I'll tell you, its nice to have the spindle fully controlled. This guy sells some speed controls that work with the X2. http://www.cnc4pc.com/Store/osc/index.php?cPath=25&osCsid=ce2a646b9ab3911fd1210250cff9b211 I should get one, but I don't use the X2 enough now to justify it.

So what do you have in mind for the mechanics? Are you upgrading to ball screws all around? I can take some pics of my machine if you want some general ideas as far a motor mounting / coupling to the screws, ect. What size motors are you using?

You won't regret the conversion...

Paul

[spuddevans]

Thanks Paul 

Yep, definitely a nice control box. I often wished I had an ammeter on my spindle driver. It would have saved quite a few end mills over the last few years.

Actually, you have given me a great idea. All the ammeters on my control box are just for the steppers. But adding another ammeter to the mill itself to monitor the current going to the spindle motor. 1st class idea, thank you 

What do you have in mind for spindle control?

I got the C6 from CNC4pc

So what do you have in mind for the mechanics? Are you upgrading to ball screws all around?

Yea, I'm planning on converting all the axis's to ballscrews. I intend to use oldham couplings for the X and Y, and then use a timing pulley setup like Hoss on cnczone has for the Z axis.

I can take some pics of my machine if you want some general ideas as far a motor mounting / coupling to the screws, ect.

Yes please, the more info I can look at before hacking into my mill the better.

What size motors are you using?

They are the "350Ncm - 10mm Shaft - Hybrid Stepper Motor" that are part way down this page ( hopefully these are strong enough, if not I guess I will use a 2:1 reduction via timing pulleys as I already have these motors )

On the Z axis I'm going to get a 2:1 reduction using the timing pulleys, and I will still have my air-spring to support the weight.


Tim

[spuddevans]

Just a little update, I dont have anything by way of pictures to show, but I have had it powered up tonight without letting any of the blue smoke out, so that is a bonus.

I ended up using 3 diodes to bring the voltage down to a safer level which turned out to be 47 volts with no load attatched. Now that the power supply was complete I set about calibrating the analogue ammeters, an easy job as I was able to apply a load to one channel at a time and then compare to the Lcd ammeter.

Then, just for laughs, I plugged the power leads back into the stepper drivers, hooked up all 4 steppers, donned an upturned saucepan on me head, stepped away and bravely switched it on with a wooden broom handle.


Well actually I didnt use a broom handle, but I did switch on and nothing went Booom.

Buoyed by this tremendous and overwhelming success I progressed on to switching on each individual channel, and with no smoke emerging I switched all the channel switches off.


It was at this point that I realised that the main Lcd ammeter was still giving a small reading I pulled the cover off the box and saw that 2 of the stepper drivers Power LED's was still lit.

The problem is that a couple of the relays that are for isolating the power to each stepper driver are tending to stick in the on state. Not good!!

I should have known that they could be a problem area, the inrush of current at switch-on tends to weld the contacts shut. So I will just do a little re-wiring and run the power straight to the front panel switches.


Oh well, only a minor setback that will be easily fixed.


Tim

[Brass_Machine]

Great job so far Chris. I read the whole thread this morning and took the determination to finish my CNC controller board. Thanks for the inspiration!

Eric

[spuddevans]

Great job so far Chris.

Thanks Fred  


I took the camera out to the workshop today, so here's a pic of where I put the 3 diodes to drop the voltage for the main Stepper drivers.





I got a bit more done today, I started on taking out the faulty relay and it's 3 companions and just wired the power feeds direct to the front panel switches. That done I turned to mounting the speed controller board into the case. I fabricated a few brackets out of Ali.





And I also made up a couple of ali brackets to mount the little spindle speed detector board in the case.





I then wired the 2 boards up as seen in the pics above.

I was thinking of mounting both the speed controller board, and the speed detector ( tach ) into the mill's own electronics enclosure, but then I realised that if I convert my lathe over to cnc too, then I'd need to buy or make a 2nd speed controller and Tach. But if I had the 2 boards mounted in the stepper driver case, then I would only need to have a switch to change over between lathe and mill.

Anyway, I think I am now at the point of bringing a pc out to the workshop to hook up to it, and then hopefully make the steppers turn according to my command. Then I will have to have a tidy up ( as the workshop is looking like a bomb has gone off in an electronics dump ) before starting on the modifying of the mill.


Tim

[spuddevans]

Just a little update on this. I brought out a PC and hooked it all up, installed Mach3 and then set about working out how to configure Mach3.

What is a little overwhelming is the shear amount of options and customisability ( I think I just made up a new word ). At 1st when I tried to move any of the axis's all I got was a quiet squealing noise from the steppers, but a quick trip into a connections menu to change the "active low" setting on each axis to being on solved that. And so I have motors spinning on my command. I have to say that I was really pleased that I had managed to wire all the stepper motor phases up correctly for each axis, I was half expecting to have to re-wire some of my leads.

Anyway, I spent the rest of that afternoon playing with Mach3 and it's settings.


That being done and found to be working ok, I have now turned my attention to the task of working on the mill itself. Over the last few days I have been gradually breaking it down into it's componant pieces with a view to cleaning them, setting them up better, and also seeing just how I am going to mount the Ballscrews and nuts when they arrive.

I have spent this afternoon working on aligning the head of the mill with its upright column so that the spindle axis is parallel with the dovetails. I ended up having to shim the bottom of the head casting by 0.16mm to get it close.( I say close because I have still got a runout of about 0.08mm over 12 inches of travel, but I got fed up with taking the head off the dovetail to adjust it. The error when I started was over 0.3mm over the 12 inches of travel)


I have a number of parts coming in the next week or so for this, some oldham couplings, some Angular contact bearings a few other bits that escape my memory at the moment. So until they come I am a little stalled. I have to re-assemble the mill though, so I'll be getting on with that, as well as working out what sequence I need to follow to make the various brackets and fittings for the conversion.


Tim

[spuddevans]

I havent done much today ( well nothing actually ), but Krymis' post asking about tramming a X2 and so I went out with my camera and took some pics of what I did yesteday.

As I "almost" described above, I have currently got my X2 mill in bits and spent the afternoon tramming the head to the column.

This procedure is much easier if you have the column laying flat on your bench, not that it would be impossible to do while the column is attached to the base, but it involves taking the head off and on again a number of times.

This is a photo showing the initial setup of the column lying on it's back with the head in place ( I have removed the pinion from the head so that it can just slide up and down unhindered ) at the top of the column. I have adjusted the jibs until I cannot feel any slop or side to side play, but not so tight that the head cannot be moved. Then I chucked a 12" 10mm piece of silver-steel into the chuck, mounted a Dti on the bottom end of the column and aligned the dti with the bar.




Now just before you think that you dont have a perfectly straight "test" bar to use, there is a work-around. Just rotate the bar thru 360 degrees, note the high and low readings, find the middle of the 2 readings and then make a note of that reading.

Then slide the head as far down the column as you can towards the Dti to take a 2nd reading, and repeat the above "averaging" reading.




If (without any adjustment) you have an identical reading as the top then double check it. If it is still identical then quickly think of 7 numbers for next weeks lotto!!!

But most likely it will not be the same, on mine I had an average difference of 0.30mm lower at the bottom than the top reading.

So now we have to shim the head to correct it. So loosen the jib screws a little to make it easier to slip off the column, and slide the head off the column and place it upside down and loosen the 4 screws that hold the 2 castings together that make up the head.



If, like mine, yours is painted over you might have to remove the 4 screws completely and then give the top casting a little tap with the handle of a screwdriver to break the paint seal. I then discovered that the paint was also covering some of the mating surfaces, so I very gently used a file to get the worst of the paint off, but I didnt file down to expose bare metal, then I put a sheet of wet-and-dry sandpaper on my surface plate and with some light oil for lubrication I rubbed the mating surfaces of both halves of the head until I got rid of all the offending paint.

Having done that I wondered if I had made it any better, so I put it all back together and mounted it back on the column, adjusted the jibs again, and went through the same checking procedure as I described above. Amazingly there wasnt much difference, just a bit worse than before

Anyway, I took the head off again, loosened the 4 bolts shown above, and got my very expensive shim material (tinfoil), and folded up 4 thicknesses of it and inserted the shim at the bottom edge of the casting, tightened the bolts, remounted the head onto the column and adjusted the jibs again, and re-checked it.

On mine it reduced the difference to 0.20ish mm, so I removed the head and folded up 12thicknesses of foil and re-mounted and re-checked... difference was down to 0.08. So it was "Off with it's Head!!" again and this time tried 14 thicknesses of foil.

This time it was close enough for me, actually a little over, but at a later point I plan some other mods that will give me an easier way of adjustment, so I am happy to be within 0.04mm over 12 inches.


Here's a pic of the shim in place, sorry the pic isnt great quality, this is a really well cropped fragment of a closeup, you can just see the shim at the bottom.




Now, once you have got the shim to the right thickness, this time only tighten the 4 bolts slightly ( loose enough to make rotational adjustment ) Then remount the head, adjust jibs, and then move the Dti round to measure the side-ways movement of the bar.



Make a note of the reading as before, and then



Note reading as before.

This adjustment is much easier than the 1st one. Very importantly, retract the Dti before making any adjustments. Then just use a deadblow hammer to GENTLY tap the relevent top head casting corner in the relevent direction, re-introduce the Dti and then check again.

Once you have it aligned to your satisfaction then loosen the jibs and very gently remove the head, and really really gently put the head upside down again and then tighten the 4 mounting bolts up fully. You have to be really gentle with it so as not to disturb the settings before you tighten the bolts.

Then it is just a case of re-mounting the head onto the column and checking it one (hopefully) last time to make sure it is still ok in both ways.


And there you go, the head should now be aligned with the column.


Some may wonder just why go to all this bother, what difference does it make? Well imagine that you have to drill a hole, maybe 1st you chuck up a spotting drill or centre drill to start the hole. Then you raise the head up and chuck a full length drillbit and then you notice that the longer drillbit is not perfectly lined up with the spotting drill's hole. This is because the head is further up the column with the drillbit than the short centre drill or spotting drill, and so if the head is not totally in line with the dovetail ways of the column this will introduce this error.

There may well be other implications of not having it fully aligned, but I'll leave it for other to add them. Suffice to say that a properly alligned and trammed mill should work a lot better than one that is not.


This is just the 1st part of tramming the X2, but there is plenty of info on the 2nd step, especially Bog's tramming tool build thread, well worth checking out. That's on my To-Make list


Tim

[Brass_Machine]

Good info on tramming the head to the column. Many thanks Tim! I am going to be doing this within the next 4 weeks or so. Because of this thread, I have been encouraged to start my CNC conversion again. I just finished soldering up my controller and order a power supply (don't feel like making one).

Eric