Newbie- Best Iron for retrofit?

[RP Designs]

Ok, I am leaning 90% on the side of a retrofit instead of buying a turnkey hobbyist machine. I am looking for a bigger envelope, and basically a more sturdy machine. It seems that starting with an existing CNC mill and retrofitting that is probably the way to go, especially considering I don't have a way to make brackets, etc. So I have been Looking at the series 2 Bridgeport with the boss 8 or newer controls and a few others, (tree, Clausing Kondia, Atrump etc).
I must admit that this is a new subject for me and there is a sea of information to sort though. What I am looking for is the ease of retrofit, quality and price. Value, basically. So what does everyone think, what should I try and find?

[TOTALLYRC]

Hi RP,
From my own experiance I would look for a solid machine with good motors, ways and ballscrews.
All of the electronics will be pretty much tossed if it is an original Boss control. IMHO

If it has analog servo amps and a useable tranformer, you should take a good look at the DSPMC/ip as a controller. The upfront cost looks steep, but if you don't have to buy 3 servo drives and a new transformer, you are hundreds ahead of the game. Plus all of the I/O is great.

See my Build thread for what I did and how I did it.

http://www.cnczone.com/forums/showthread.php?t=66994

If you are starting with a base machine and nothing else, and don't have a tool changer, then the smooth stepper is another great option. You could go p-port and a BOB or 2 but it depends what you are looking for in the final outcome.

Good Hunting.

Mike

[RP Designs]

Man, I will give you credit, looks like a hell of a job. I am a little lost though in what you added, re-used or just discarded. Of course it looks like the tool changer seems to add a great deal of complexity to your retrofit. I was looking to do a little more simple version, BOB to PC sort of thing, and re-use as much of the existing control as possible. I am searching for a later boss system, although I have run across a couple dynapath equipped mills. Of course I have also looked at a kit such as the AjaxCNC kit, but I would need to get a real bargain on the machine to make it economically worth while.

Is there any way you could make a basic list on the parts needed for a retrofit?

[RICHARD ZASTROW]

Would you consider a Bostomatic 300 series machine? There's one for sale on the opening page of the 'Zone. Serious machines.

Dick Z

[RP Designs]

Originally Posted by RICHARD ZASTROW Would you consider a Bostomatic 300 series machine? There's one for sale on the opening page of the 'Zone. Serious machines. Dick Z

I would and did, unfortunately that mill is a little out of my reach. Couple that with shipping and it blows my budget entirely. It looks like a great machine though.

[TOTALLYRC]

Originally Posted by RP Designs Man, I will give you credit, looks like a hell of a job. I am a little lost though in what you added, re-used or just discarded. Of course it looks like the tool changer seems to add a great deal of complexity to your retrofit. I was looking to do a little more simple version, BOB to PC sort of thing, and re-use as much of the existing control as possible. I am searching for a later boss system, although I have run across a couple dynapath equipped mills. Of course I have also looked at a kit such as the AjaxCNC kit, but I would need to get a real bargain on the machine to make it economically worth while. Is there any way you could make a basic list on the parts needed for a retrofit?

Hi RP,

Thanks for the kudos.
The tool changer is not at this time working since I haven't tried to connect it yet.LOL. It is on the todo list right after the lathe is done.

The problem with a list is what are you starting with.
If you have a working Boss system, hillbilly makes a bob that interfaces with it and Mach3. IIRC. But it may be for stepper driven sustems, not servos, but I am not sure.

If like my machine, it was upgraded to something else in the past, you might have analog servo drives and motors.
Your motors might be shot or the encoders. You may or may not have a useable power supply. If you decide to go the BOB and pc route, you will either need to change the drivers to step and direction which may men a power supply change as well.

In my case, I had good high voltage servo amps and a useable transformer. The cost of the dspmc was about the same as a set of geckos, new power supply, breakout board and smooth stepper. Plus I can run the motors at their rated voltage.

Had I opted for Gecko drives, I would have had to change the drivers, the ps to a max of 80v, and possibly changed the motors unless I wanted to put up with running the motors at a lower voltage and the associated lower rapids that would have resulted and so forth. I also would have opted for a smooth stepper as I like the smoother pulse train that it provides.

The dspmc also reads the encoders back into Mach3 so you could use it as a dro in manual mode if needed. Since the encoders are always powered in my system, even an e-stop doesn't cause a loss of position.

In the end, I used the input transformer and the dc power conversion stage, which together make up a dc power supply. I was also able to save the servo amps, the VFD(until I blew it up), some of the wiring, the pair of 24v power supplies, and assorted tidbits.

Mechanically the machine was sound with a fairly new z ballscrew and good x and y ballscrews. The spindle and spindle motor were also good and reused.

All of the castings were reused as is. The Yaxis has some visual wear on it but so far it is doing fine and any play was adjusted out of the gibbs.

Hope that answers a few more questions.
Mike

[RP Designs]

Well, I won't know what I'll get until I get it. The search is on, though I have to admit it seems like there are people who seem to find some really good deals and I have yet to find something close to a "Smoking deal". I did find one machine but I think I would need a tetanus shot before I even go and look at it.

[RICHARD ZASTROW]

There's a Boston Digital 1440 0n e-bay for under $2,000 with (4) spindles. At least one of the spindles should be useable.

Dick Z

[RP Designs]

Originally Posted by RICHARD ZASTROW There's a Boston Digital 1440 0n e-bay for under $2,000 with (4) spindles. At least one of the spindles should be useable. Dick Z

WOW! that thing is massive! I am trying to fit it into a smaller nook in my garage which is 10'x10' and that machine fills up the whole space!