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KEJR
09-05-2011, 09:21 PM
Hello,

I have a 9x42 bridgeport with variable speed head and am thinking of converting it to a manual/CNC mill (2 axis) using Mach3 and steppers (for simplicity and cost). I bought some stepper motors a year back but haven't gotten any further. I have some questions:

- Does anyone have drawings of mounting plates for the motors/pulleys?
- Any problems noticed by stepper cogging when used in manual mode?

I am thinking of using the stock lead screws for now and upgrading to precision ballscrews down the road. I am very competent at the electrical controls design so that doesn't bother me at all.

I realize that purchasing an old trak or prototrak would be easier, but one hasn't surfaced and quite frankly I am not sure it is worth the hassle of moving the machines in and out of my shop. I may change my mind down the road but for now I'd like to stick with my machine. I'm estimating another $500 worth of electronics and $1000 for the ballscrews down the line and a running prototrak can go from $3500-$8000 depending on condition. I know that changes depending on if the controls are dead, but I don't see those much.

Thank you,
KEJR

macona
09-08-2011, 01:29 AM
Oh, believe me, it will be worth the hassle. Moving a machine should not stop you, my mill is 50% bigger than the standard bridgeport and I can move it around my shop by myself.

One thing is you kill the value of the manual machine. Nobody will even pay what the manual version was worth let alone what you put into it in time and money.

A machine with a real control is sooo much better than any of the PC conversions. If I could put a real control on my mill I would do it in a heartbeat (And I am still trying to do that). Almost all simple jobs can be done in conversational right on the machine.

John Stevenson
09-08-2011, 05:12 AM
One thing is you kill the value of the manual machine. Nobody will even pay what the manual version was worth let alone what you put into it in time and money.



Yabut you could always fit a decent machine light on it and double the value :p

macona
09-08-2011, 03:42 PM
Yabut you could always fit a decent machine light on it and double the value :p

No, its best not to see what you are doing when you are using a BP. ;)

KEJR
09-08-2011, 09:40 PM
I guess I'm not looking to resell my $500 manual mill. The guy was either going to sell it to me or see what the scrap yard gave him. :o Its not a bad machine so I'm hoping to convert it for my use. I don't plan on selling it, but I've said that before about other projects I've had to sell off for various reasons.

I'm looking to do a conversion really similar to a Prototrak as I'd like to maintain manual hand wheel operation. The X axis can easily go back to stock [or nearly so] by removing the motor from the left side. The Y axis nearly the same situation. I hear you though, sometimes someone sees that a guy in his home shop monkeyed with something and they don't want to touch it with a ten foot pole. Alot of that depends on how well it is done and if the project is complete. I cringe when I see listings in want ads that say "Partly converted to CNC!"

As to "homebrew PC" vs commercial "conversational" programming goes, I thought that Mach3 could be had with the wizards to do pockets, arcs, circles, etc.? Is this kind of hodge podge in Mach? I know its probably not nearly as nice as a Prototrak, but at least halfway there? The thing I like about theMach/ PC avenue is that you aren't tied into a vendor that wants $1000 for a repair/replacement controller part, assuming they even make it anymore.

I'm afraid my $11 department store desk lamp on my mill won't double its price. Maybe some day I'll buy or rig up something better. :o

thanks,
KEJR

macona
09-08-2011, 10:35 PM
Believe me, once you start using cnc you will never, ever, use the hand wheels. I had hand wheels on my mill as well figuring I could used it manually. Never happened. Just as easy to pop in commands in to the MDI and no counting turns or whatever.

A real controls is just better. The plugins for mach kind of work but there is just no standards so one thing may call something one thing and another something else. Software like that is what makes apple look good. Consistent interface.