[moto21]

Hey all. First post here but log time site user. I recently bought a Boss 4 r-ram. I want to retrofit it because I want to improve accuracy i.e. cnc heads and custom bike work, and I like the new gcode better than the old boss code. I want to spend as little money as possible. I was trying to decide if it would be cheaper to build my own retrofit or just buy a kit and get the control features I want. I want a system that would use encodes and the stock limit switches on the boss. I would like spindle speed control using the stock spindle controller alone with the auto brake and auto spindle on/off. I’ve heard of people doing this with the Larkin system, any info on this. Also with the Larkin system a lot of people seem to use stock stepper motors would this be possible with my system. I just want some input form some smarter people so thanks for the help
~Brad

[masspfei]

www.linuxcnc.org is a retrofit and they say they have support for all you are saying. What kind of accuracy are you looking for? A boss 4 will need to be totally rebuilt for improved accuracy. If it is running with the old control you would be better off trying to use it. If not mistaken, should have accuracy and repeatability of .001. Be warned, retrofit and a little money don't go together.

www.geckodrive.com also has encoder feedback on some of thier stepper motor drives. That would make sure it would not skip using the right software.

Steven

[moto21]

When I say low cost I mean under 4k becuase I can buy a ajax retrofit kit for 4k that has all these features and no messing around.

[machintek]

You get what you pay for. The stepping motors and pulleys on the BOSS 4 give it a resolution of .001 inch. Thus even with encoders, it would be hard to dial in accurate backlash. By now this machine is 20 years older or more. Depending upon the use it saw and the care it received, it may be that the center of both X and Y axis axis are more worn than the ends of travel. It would be hard to do incremental pitch error compensation. How accurate do you want the spindle speed to be? Do you expect to rigid tap? This has the same vari disc drive of a series 1 standard. The BOSS 8 and 9 and V2XT used an air motor to turn the speed control. A varialble resistor (volume control) was used for an approximate speed output to the control.
Therefore do you want to get better than .001 resolution? That would mean either changing the motor to ball screw ratios or new motors (and drives). Very expensive.
This is in addition to the cost of the control.
I have heard of people using a direct drive to the spindle and using a new motor and drive. Again, this would put you over your limit.
Perhaps you should consider a used EZTRAK 3 axis or a used Milltronics. All the work has been done, all the bugs worked out and total outlay of money may be within reason.

George W.

[moto21]

Thats y Im thinking of just going with the ajax kit. That includes servos instead of steppers and most of the work is easiky done. As for wear my machine hasn't see much use. Its been in storage for a while and from what I hear it wasnt used much in the shop it was in. If only thing I could get out of this machine was .001 I could live with that but .0001 would be perfect.
Thanks for the replys
~Brad

[claudiod]

let me know how do you like the ajax kit, Im in a similar situation such as you I have a 4x8 table that i would like to retrofit. But my problem Im not too good at electronics. so let me know how hard it is to do the installation yourself.

[moto21]

I let you know and I plan on doing a little project plan here as I go. Just saving for the last of the money needed. Hard because Im building a new shop this year and saving for this to.

[harolda]

a wizbanger down the road wants to take of the motors and run a boss machine manual can you al beleive that??it is true i put a stepper drivers
on one machne from ebay :argue: