ballscrew for IH mill

[KEYTEEM]

Hi everyone, i was wondering if anyone has purchased ballscrews for their
IH mill from a kit or seperately to see if anyone has dimensions easily avail?
i have done a lot of reading on this site and found what the dia. and
the pitch that i want to use but am confused as to what to do for,,

bearing size ?
total length per axis, should each screw equal what came with the machine?
how much shaft needs to be protruding from the bearing to place a pulley onto?

i know a few things that i am using will be,,
2:1 belt drive , 32/16 I assume with 1/2" belt, might need wider belt
rht 1200 stepper motors with geckos
3/4"d x .200p single start + double nut

or who might you recomend to call,nook, reid , rockford,
any help at all will be greatly appreciated since i am ready to purchase
but am spending to much time overthinking all this.
sorry if this posted in the area.

[MikeAber]

It looks like you need a little more planning for your project; you need to decide how you're going to mount the ballscrew, where the stepper motors or servos are going to be mounted, how thick the mounting plates will need to be and what size and configuration thrust bearings to use, how much room will you need for the double nuts on the ballscrew, etc.

Ask yourself if you have machinist skills to measure, layout and make the parts - ballscrew nut housings, mounting brackets, motor mounts, covers etc. and access to a lathe and mill to make the parts? If you aren't confident you can do these things then you are better off purchasing a kit. Even a kit can be challenging.

The mechanical end of things is just part of the project - the electrical end of things , limit switches, motor controllers, computer interface (breakout board), control software etc. is another dimension of the project.

The Industrial Hobbies kit is expensive; all of the engineering (mechanical and electrical) is included in the kit price including step by step instructions.

When you look at the quality of the materials used and the engineering needed - the kit really doesn't look that expensive at all - it includes all the NEMA enclosures, electronics, drivers, cables, connectors, lmit switches, motors, ballscrews, ballscrew nuts, mounting brackets, etc., etc. and technical support.

Mike

[KEYTEEM]

thanks for your feedback mike , i agree with you ,i definately need more planning,and am maybe going to save the conversion for down the road , not sure yet .
thank you .

[MikeAber]

KEYTEEM, I hope I'm not too negative on the DIY approach - it can be done and has been done by many - including myself.

I could answer your original question and say that conversions of the IH and other Chinese square column mills are using ball screws in the 5/8” to 7/8” (15 – 20mm) range and turning the shafts down to use a single 12 to 17mm double row angular contact ball bearing or two single row angular contact bearings in a back to back configuration with a preload washer for thrust bearings and a standard deep groove radial ball bearing to support the other end. Then to answer the question of what size to specify for length would be determined by what bearings you chose, the size of the thrust bearing housing, pulley, washer stack (if any), locknut, locknut washer, encoder mounting if using servos with the encoders mounted on the ball screw, length of the axis you’re working on, the support bearing size and support bearing housing size, etc.

None of this is rocket science; however, it does require planning and/or making a mockup of the assembly to validate your design. Look at other machines to get ideas of how to do these things. Mistakes with ball screws can be expensive.

1/2" timing belt and drive pulleys are very adequate.

The best advice I can give you is to go the Industrial Hobbies website and read all of the product instructions for installing the CNC conversion kit in the "How To" section of the site. The directions for assembling the servo drive will give you some idea of how the belt drive is interfaced to the ball screws. Aaron has spent a huge amount of time documenting the conversion process and he sells Rockford ball screws, ball screw nuts, and limit switches designed for your IH mill. http://www.industrialhobbies.com
I also recommend you read this thread about Balsaman’s conversion: http://www.cnczone.com/forums/showpo...93&postcount=1

Mike

[KEYTEEM]

No mike , your not being too negative , i would rather be safe than sorry
and have all my ducks in a row before making a foolish mistake and i
really do appreciate all your help, for now am puttimg the machine
back together and will use it as a manual machine and continue
planning for the conversion later, thanks again .