Dividing head is splitting mine.

[kenny6486]

I am interested in making model camshafts (4 – 8 inches long)  for small engines Traditionally it appears you use a dividing head/ rotate table and tail stock on a mill to make camshafts. If so, is it necessary to automate the dividing head or does it work fine hand turning?  I want to buy one that can obviously index, maneuver both vertical and horizontal, and have ability to be automated. Regarding automation, I am thinking about attaching a variable speed Sherline motor or CNC with step motor eventually.  What I need to know is which rotating dividing assembly  are your favorites. It has to enable me to attach a motor though. Also  is a 6 inch rotating table adequate for my work or do I need a larger rotating table? My price point is under $900 preferably. My mill (to be purchased this fall) is PM 935 TV
 

[sssfox]

Hi Kenny, you may want to make an entry in the Introduce Yourself section before you go any further.

That being said, you sure ask a lot of questions.  I'm not sure the size of of the rotary table should be at the top of your list.  Machining a cam shaft is an involved process, but straightforward.  The size you are proposing could easily be done with a 4" table.  A 6" table adds some versatility for future projects.  Sherline makes a CNC controlled 4" table that I hear works well.

How much experience do you have machining and electronics? There are a couple of very good threads on another forum concerning making a CNC rotary table using an Arduino board for control.  Do a google search on "Arduino CNC".

Once you learn electronics to that level, adding the stepper motors to your mill isn't that difficult.  The rotary table becomes the fourth axis.  CNC machining of a cam shaft is fairly uncomplicated, once you settle on the design.  You program the data into the cotrol software and the machine does all of the work.

Machining one manually consists of determining the designs of the individual lobes and getting the relationships among them correct.  Basically that involves matching a table of height data to the angular positions of the lobes.

There are also small machines that do it for you, if you plan on making a lot of them.

I hope you are successful in your endeavor.  We can always use more machinists.

Steve Fox

[Allen Smithee]

Where the lobe profile consists of four circular arc segments (one for each flank, a longer one for the back of the lobe and a shorter one for the tip of the lobe) there is a method from Chuck Fellows that cuts the arcs directly using just a boring head and a rotary table in the mill which he described in this thread. This is much quicker than the alternative series of tangent cuts.

AS