# 4th Axis Options



## angelfj1 (Feb 20, 2013)

I have been following the CNC conversions here as well as the CNC training.  I have a few questions.  

Some of the conversions have opted for a 4th axis, most only three.

Is the 4th axis generally used for rotary tables or are there other ways to use this axis?

Has anyone here converted a rotary table from manual to CNC?

I read a comment on another forum that stated that most hobby grade rotary tables have too much backlash to be successfully converted to CNC.  Is this true?

  Maybe a stupid question, but what is the difference between a horizontal and vertical rotary table and when would each be used?  

Some tables are dual vert./horz, is this a good plan? Is there a compromize in using the  dual type?

Is a rotary table tail stock an absolute necessity?

Thanks in advance, Frank


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## jumps4 (Feb 20, 2013)

hi frank
I ordered a rotary table from wholesale tool and converted it to my 4th axis. the information is in my build thread http://www.hobby-machinist.com/showthread.php/8187-rung-fu-clone-RF-45-ZX45-cnc-conversion/page4 and page 3.
 it was a really easy conversion and there are no backlash problems. every part of this table is adjustable and as smooth as silk. as far as using the axis it is no different than using it in manual mode, you can mount it horizontal or vertical and you dont always need the tail stock, that matters on the length of the part and method of mounting. the table is very ridgid with no play in any direction.
 as far as mounting there are so many different ways to use the table you will find yourself making all different kinds of mounts for each situation.
steve


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## angelfj1 (Feb 20, 2013)

jumps4 said:


> hi frank
> I ordered a rotary table from wholesale tool and converted it to my 4th axis. the information is in my build thread http://www.hobby-machinist.com/showthread.php/8187-rung-fu-clone-RF-45-ZX45-cnc-conversion/page4 and page 3.
> it was a really easy conversion and there are no backlash problems. every part of this table is adjustable and as smooth as silk. as far as using the axis it is no different than using it in manual mode, you can mount it horizontal or vertical and you dont always need the tail stock, that matters on the length of the part and method of mounting. the table is very ridgid with no play in any direction.
> as far as mounting there are so many different ways to use the table you will find yourself making all different kinds of mounts for each situation.
> steve



THANKS  STEVE !!!!!!!!!     :thumbsup:


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## jumps4 (Feb 20, 2013)

i forgot to address one other guestion you asked
the 4th axis in most applications is a rotary axis but does not have to be. the 4th 5th and 6th axis can be used for other things like rotation of the mill head from side to side or tilting it front to back. a tool changer, trunion table and trunion tables with rotary axis mounted on them. they can perform lathe functions with servo motors of high enough power and combine lathe and mill functions.
steve


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