Setup alignment

[ozzie34231]

Sometimes setup is the most difficult/interesting part of a job, especially CNC.
Can someone give me their idea on the best way to setup an indexing head on a milling machine table at a specific angle to the X axis.
The head is a C-5 collet fixture with 360 rotary settings. I want to set its longitudinal axis at an angle with the X axis of my machine.
I'd like it to be rather accurate because I'm making a carbide insert cutting tool.
I have an idea or two, but I'd like to see what all of you come up with.

Thanks,
Jerry

[Mcgyver]

ahh a puzzle...but first, an angle to the x axis is a cone - what direct you want to angle it – in a plane with the y axis or z axis? Ie tilting the dividing head or bolting it to the table at an angle?.

First the low tech minimal tooling idea (I guess only for small angles at angle in the xy plane) put a 1" piece of drill rod in the dividing head and an indicator in the spindle. By moving the quill, take a reference reading near the head, the move the table along the x axis a set amount and measure again. Pythagorean theory and trial and error tapping with brass hammer get you there.

To be more precise, we dust off the sine bar and gauge blocks. If its xz, just gauge block, sine bar and parallels in contact with a piece of drill rod in the head. If its xy, Clamp a largish tooling block to the table and indicate it to the x axis. Then gauge blocks, sine bar, against the block and drill rod in the head, by bringing them into contact you are at the right angle.

If you don’t have gauge blocks and sine bar, you can do an accurate job of making them. Use Pythagorean theory, all you really need as two round bars held a constant distance apart and instead of actual gauge blocks just machine a piece the required height of the stack. Maybe a PITA, but you wanted accuracy

So what super easy way did I miss??

[Kmed]

ANother way is to get it to the rough angle then use a dial indicator over say 1" the calculate the the angle by using the indicators reading. I dont know how you want the angle, but you can use this page to figure it out using a little trig.



Right triangle trig

[ozzie34231]

Okay, I should have said in the xy plane. My best idea was to get close with a protractor to the table edge and then refine with a 1/2" or 3/4" bar about 3" long in the collet and two computed locations along the line, 0,0 and the computed coordinate.then a wiggler or my laser edgefinder.

A sine bar on edge would be a good idea too.

Any other ideas?

Jerry

[lerman]

Originally Posted by ozzie34231 Okay, I should have said in the xy plane. My best idea was to get close with a protractor to the table edge and then refine with a 1/2" or 3/4" bar about 3" long in the collet and two computed locations along the line, 0,0 and the computed coordinate.then a wiggler or my laser edgefinder. A sine bar on edge would be a good idea too. Any other ideas? Jerry

Since we have a CNC machine, clamp a piece of scrap plate to the table. The drill/ream some holes for dowels at the proper angle and a useful distance. Put a straight bar against the dowels for alignment.

The precision is as good as your mill.

Ken

[ozzie34231]

Excellent!

[Mcgyver]

I think Ken takes the prize!

[Geof]

Just to horrify the purists! In the next month or so I will be drilling a pattern of alignment holes directly in the machine table to simplify setups.

[Ken_Shea]

Geof,

Can we see pictures

[Geof]

Originally Posted by Ken_Shea Geof, Can we see pictures

Yes, just give me until the end of September.

[miljnor]

well its a hobby machine and I have bought used machines with dimples in the table. But I make it a point to fire anyone who drills into my milling tables. While your doing it intentionaly most of the time its a careless accident, and I can do without careless accidents into my 30k to 150k machine tools.

Just out of curiousity is this a purpose build machine? becuase you can't take those holes back! ahhhhhhhhh the horror of it!

[ozzie34231]

Thanks to all,
During the night I was thinking about this and the pegs seem the perfect answer. Actually I only need one hole, the other peg can be held in the machine spindle. That way if I ever want to set up for a similar job, even a different angle, no problem.

Jerry