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Manual to cnc lathe retrofit? feaseable?
« on: February 23, 2008, 09:03:39 AM »
Hi Guys
Im new to this forum, and would like to hear your opinions on an idea i have. Whilst admiring a haas tl2 lathe and thinking how much i would like one, it occured to me that for the price of one i might be able to get my manual lathe reground, and retrofitted to cnc, and mach3. The lathe will be used for gunsmithing work, and like the fact that it has a short headstock so that i can get both ends of a barrel bore clocked, and add coolant through the bore whilst chambering. I would like to be able to clock a barrel blank in, and let the cnc thread, counter bore, then bore the chamber undersize, and finaly finish off the chamber manualy with the tailstock. Also it would be nice to profile a barrel blank between centers. I know as a rule converting a manual to cnc is going the long way around, but i realy do like this lathe. I know its going to be expensive too, but want to hear your thoughts on it, and tell me im not mad ;D
Its a cazeneuve 590 by the way, and hopefully the pics will attach.
Thanks
Kev



Re: Manual to cnc lathe retrofit? feaseable?
« Reply #1 on: February 23, 2008, 09:44:42 AM »
Compared to haas it will not cost that much to retrofit and is very doable.  Here are videos of a person that did the same thing you want:
http://www.youtube.com/profile_videos?user=westchagnon
Re: Manual to cnc lathe retrofit? feaseable?
« Reply #2 on: February 23, 2008, 10:39:07 AM »
shouldnt be any problem at all, I retrofitted my 14x40 enco with ball screws and servo motors a few months ago and its working perfectly, I am turning and threading bbls with it no problem. I can cut , face and thread both ends of 65-70 suppressor tubes in an 8 hour shift. I have been very happy with the brakout board and spindle encoder from cnc4pc , pendant is very nice also. Only thing left to do on mine is finish up the 8 station auto tool turret.

I would say go for it , very rewarding outcome
Re: Manual to cnc lathe retrofit? feaseable?
« Reply #3 on: February 23, 2008, 12:24:23 PM »
Thanks
For your input guys, it puts my mind at rest, and gives me lots to think about now.  8)

Regards
Kev

Offline jimpinder

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Re: Manual to cnc lathe retrofit? feaseable?
« Reply #4 on: February 24, 2008, 04:57:23 AM »
All you honestly need is two stepper motors and drivers. ArcEuroTrade in the UK has some large steppers that would do it.

Don't try to get all singing and all dancing straight away. If you drive the cross slide and the main leadscrew that is all you need.

The advantage is the LATHE is the same, it is the one you are used to, so any little problems will be easy to deal with.

Mach 3 provides many configurations for backlash and other little things to get the lathe set up correctly.
All I did with my lathe was take off the operating wheel, and substitute a drive via a tooth belt.
Not me driving the engine - I'm better looking.

Offline DAlgie

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Re: Manual to cnc lathe retrofit? feaseable?
« Reply #5 on: February 24, 2008, 11:21:07 AM »
Don't underestimate how much power it takes to run the Z axis, the saddle. My experience is that it might be three to four times the amount needed to power the cross slide, the X axis. A decent ballscrew will help a lot if you can afford it or find one used from a larger CNC machine as I did. I see Jim's lathe here has a large reduction on the Z axis, this helps a lot but reduces the rapid speed down that amount too. So, if you use a large motor on the X axis along with the Z axis, then the power supply will match better, if you go with a smaller one for the X axis then you need to be careful that the higher voltage power supply that the Z axis motor needs is not too high for the X axis.
     DaveA.
Re: Manual to cnc lathe retrofit? feaseable?
« Reply #6 on: February 24, 2008, 02:00:26 PM »
Thanks
For the sound advice guys. When the time comes for this retrofit, im going to let the experts do it, and look for somebody who can do the full works, grinding, repaint, ballsrews, etc..., there will be no expense spared on this, but i think i will end up with something along the lines of a haas tl2, but perhaps more versatile, and i think certainly more rigid. and probably less the cost of a haas.

Kev
Re: Manual to cnc lathe retrofit? feaseable?
« Reply #7 on: May 18, 2008, 11:47:51 AM »
Ok guys
A little update, I have had a quote to do the above work, but in the price was the heidenhain conversational controller, and they came back with a rough guess of £30k  :o. Now i am not afraid to spend some money on this, but that is just rediculas!. So my thinking is i would like to still get a complete regrind of the ways, and turcite added, so that i know everything is good from the start, and have a go retrofitting it myself, or have somebody, whos done it before do it. Please bare with me and the following stupid Qs, but i am old school and a total newby when it comes to cnc, but i want to get into it and learn it. Can you guys tell me EVERYTHING that i will need to convert this machine to cnc? and if possilbe give a brief explanation of what things are? from what i can gather i will need mach turn for the controler,ballscrews, servo motors to drive them, dro? glass scales? for mach to read what the servos are doing? and what about the spindle motor? does it changed to a vfd, or servo motor? i dont know? .When i am ready to go for this i will have a budget of £15k, so if you were in my shoes, what route would you go.
All advice appriciated.
Kevin

Offline jimpinder

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Re: Manual to cnc lathe retrofit? feaseable?
« Reply #8 on: May 18, 2008, 01:23:37 PM »
Kevin -
The first thing is you have to decide what you want at the end of it. To me 15K is a lot of money and several of my CBC friends have got rid of CNC machinee centres for a lot less than that. I don't have the space, unfortunately.What are you seeking to do with the machine. You have talked about the firearms work etc, but that doesn't seem all that much (to me), unless you are a registered dealer.

A CNC machine has two advantages. One is speed - but in actual fact if you add all the time it takes to program the thing, for a one off you could be better doing it manually. Having said that, I prefer to do the program in the comfort of my "office" (front room) and then transfer it to my workshop computer to run it, rather than be bunched up over the lathe all the time. The second is repeatability. If you are machining a number of the same parts, then CNC is the way to go. I think there may be a third - in that programing is easier to me that machining. I can program the machine, test the program, and then be confident the machine will cut it. Doing it manually, I could make a mess and spoil it.

My lathe is much faster now than it used to be, particularly on the rapid non-cutting moves (and it doesn't waste time thinking about it)
Cutting is much the same, you have to use the same cutting speeds anyway. To achieve this, I have not altered my balls screws, or anything, I have just installed stepper motors. Mine could be wired three different ways - see an earlier post - now thety are wired in parrallel, with the Geckos, they fly.

If your lathe is in reasonable condition then a regrind might be all that it needs. How is your backlash. Mine is a lot, but Mach 3 copes very admirably with it. Cutting ball shapes you cannot see the join.

If it were me, I would have the machine reground, and delivered back. Quite frankly, if you are a reasonable engineer, you can do the rest yourself.

If you are in UK - (you talk in £'s) - then purchase a motor from Arc Euro Trade. They sell a 650Ncm motor for £50. This is 3 times the power I use (my lathe is a large Warco combined lathe/mill - and I use the 220Ncm). They should drive anything and your machine looks like my friends Harrisson (of a similar size anyway). I would buy one motor for the time being, and see it's capabilities. Unfortunately I do not know of any simple way of calculating what power you will need, nobody on this forum has come up with any ideas.

To power this motor you need a stepper driver. Buy single units - do not be tempted to buy a three in one - if one breaks, it's easier to fix. If I were you I would buy Gecko drives - American - very good and the standard Gecko has the voltage and current capabilities to drive the 650 motor. All you have to do is fit them to your lathe. My photograph on the earlier post shows the one fitted to the lead screw. Yes, I have used a toothed belt drive, these are cheap, they transmit the power without slipping, and the range of sizes is enormous. The advantage is - if you fit your motor - say with a 1 to 1 drive - and you find you need a bit more power - then fit different cogs and you can scale up your power ratio (for a loss of speed I admit) - but you will be able to find the ratio you are comfortable with that gives you enough power - with a speed you can live with. Merely remove your handwheel, fit a toothed cog, mount the motor in a suitable place and then buy the correct sized belt. My belts are 9mm wide, 5mm pitch. On your machine I would use the next size up. These should be available from any bearing supplier - and haggle the price - they give up to 90% discount - I kid you not. I WILL fit covers on them sooner or later (probably later knowing me).

I don't have a problem with speed on a lathe. These lads that have aircraft carrier flight decks for their router tables like the thing to travel at the speed of light. I got mine up to 40 inches per minute ( with a 3 to 1 reduction) so with less than 20 ins travel, I could be up and down in no time. I have cut the speed to 20 ins so that I trade accuracy (less chance of missed steps) for speed.

If your leadscrew is in reasonable condition, then don't change it, unless you really want to - but I would try with it at first and see the results. As you gain confidence, you will decide how far you want to go. For the sake of simplicity I would use the same motor on the cross-slide - which is why I said only buy one to start with. A 650 motor should certainly cope with the cross-slide - and you can probably use a higher gear if you wanted, although again - speed isn't everything. If the motor is too small for your leadscrew, use it on your cross-slide. If it's OK then but another one.

For £500 you should be able to buy 2 motors, Gecko drives, gearing and belts to get started. The only other thing you will need is a power unit. For this, you have little option but to buy a professional power unit. The motors are rated at 5 volts - steppers are "over driven" so a 30 volt power unit able to give about 20 amps should do the job. This may be expensive, but we are still well short of the 15K

Don't get the idea that these "machine shops" can do any better at retrofitting a lathe than you can. All they do is cover it up so you can't see what they have done - and charge you a hell of a price for it. You can buy ALL the parts for £1000. Yes you could spend a lot more I am sure, and other people will probably advise you to buy something different. Certainly for £2000 you can get the best - certainly to do a two axis lathe - so where does the other 28K come in.

Have a try - very little will be wasted and you will gain a lot of knowledge, even if, in the end, someone does most of the work for you.



Not me driving the engine - I'm better looking.

Offline Hood

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Re: Manual to cnc lathe retrofit? feaseable?
« Reply #9 on: May 18, 2008, 02:02:53 PM »
Send it up to me and the 15K and I will get you sorted out ;)
 Seriously though, £15,000 would buy you a decent CNC Lathe, in fact probably half that. Big advantages is they will have toolchangers, ballscrews etc. You could then sell the old motors drives etc on eBay and fit AC Servos, unlike Jim I think speed is definitely important, with tool changes you will want serious rapids, my Lathe does 3.3M/min at the moment but once the  SmoothStepper has the threading sorted it will be getting fitted to the Lathe and my Rapids could be as much as 20M/min, but I think 10 will be what I settle on.
 Just my opinion but I was thinking along the same lines as you in that I was going to retrofit one of my manual lathes, glad I didnt :)
 Hood