Advice on cnc conversion.

I`m a gunsmith I have two bridgeport knee type type milling machines. I was thinking of converting one to cnc. I looked online and found a kit by Microkinetics for 5500.00. I don`t know if this is a good price or if anyone has tried this brand. If not can you recommend one. I occasionally need a cnc to make cuts I can`t do on a manual mill. Thank you .

This comes up here regularly. The consensus is, that if you want to do it for the sake of doing it, and enjoying and learning from the experience, go right ahead. If you want a machine to use, especially for paid work, and if you have ANY value associated with your time, you're much better off buying a working machine.

Unless you are a hobbyist, do not waste time and resources with the CNC conversion. Just buy a used, proper CNC machine and only worry about making money.

5500 Clams for part of the kit. You still need X Y ball screw movement and their rolled ball screws are good for making you crazy chasing errors. Rolled screws are fine for some applications like a router.
Check out ALL that is needed.

Don't bother doing a conversion on a manual machine. I have done two retro fits on CNC knee types that had bad controls. I have about 6K in the pair including my time. They ended up only needing a control PC and amplifiers as the ball screws, servos, and encoders were fine. Dead knee types are great as a learning experience and can pay for themselves in time.

Scruffy has it right, don't mess with rolled ballscrews.

Ed.

atex57 said:

Scruffy has it right, don't mess with rolled ballscrews.

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Skip the ballscrews entirely and go with linear motors ...

(for that $5500 I have seen some decent running 3 axis Trees ...)

MachMotion for industrial grade machines, great support and proven tack record. That would be for a control update not a conversion however. I'd look for quality iron on the cheap like a Shizuka mill or something.

Fancuku said:

do not waste time and resources with the CNC conversion. Just buy a used, proper CNC machine and only worry about making money.

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I removed a portion of your statement.

My Fadal cost slightly more than the parts to your upfit kit, along with that cost increase came-

8000lbs more mass, an actual controller, lighted enclosure, 21t tool changer, coolant system, 20hp 2speed CAT40 spindle, enough axis thrust to lift your machine, the ability to threadmill, 900ipm rapids, rigid tapping...probably some other shit I've forgotten.

Keep (1) knee mill because everyone needs one, sell the other and buy a real mill.

EmanuelGoldstein said:

Skip the ballscrews entirely and go with linear motors ...

(for that $5500 I have seen some decent running 3 axis Trees ...)

Click to expand...

My friend told me today he wants to sell this machine 4500

mhajicek said:

This comes up here regularly. The consensus is, that if you want to do it for the sake of doing it, and enjoying and learning from the experience, go right ahead. If you want a machine to use, especially for paid work, and if you have ANY value associated with your time, you're much better off buying a working machine.

Click to expand...

Between 1993 and 2001 I converted over 100 of manual machines (turret mills, lathes, vertical lathes and bunch of specials) with late SERVO II CNC system. Unfortunately (or fortunately from my point of view) here in Israel there were no second hand "real" CNC machines for the prices other guys mentioned . I used rolled, zero backlash ballscrews from Rockford Ball Screw. Vast part of turret mills were already equipped with linear scales, which I integrated in feedback loop, and this way the positioning accuracy was acceptable. The unique QnE (Quick n' Easy) SERVO conversational package (which I translated to Hebrew) made this system ideal for guys who just made first steps into CNC world. From other side, the unlimited memory size of on board PC based control opened the door to producers of small complicated forms.
To my astonishment some of those retrofitted machines are still working until this very day.

Stefan

Retrofitting any old NC/CNC machine in the USA that you can pick up with a 15K fork truck is likely a bad idea.

Converting a manual machine to CNC in the USA was a '90's thing.
Leave it back there!


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