Question on 4th axis

[sirbean]

I have a question on the 4th axis. If i have a project that is longer than 16 inches on the x, is it possible to move jig over and pick up where you stopped? I am new to cnc and dont even own a tormach yet but am on the fence. Have any of you guys tried using a router on your spindle. Im thinking of gunstocks here. Thanks all.

[Al_The_Man]

You could use a work shift offset one of the G55 and up positions.
Al.

[TXFred]

I've had to do something similar on a lathe, turning a four foot piece of 2" aluminum with no steady rest. I broke the program into five sections, and made sure that each program left a smooth face that I could use to indicate in the part for the next operation.


(Ignore the ugly guy in the picture. The part I'm holding is the one I'm referring to.)

At each step, I had the lathe create the step, with its very small radius on the corner, then move 0.05" farther along the part, then make a facing pass. You can do something similar at the end of each section by rotating the A axis through 360 degrees while an end mill cuts the face.

If you're making a rifle stock, the real challenge is going to be keeping the part from rotating when you shift it, or re-indicating the A axis.

You should plan on there being some error when you shift your part. Make sure that it's in an area where you can do some blending with sandpaper. You could try and perfectly indicate it, but if it's a choice between an hour of setup or five minutes with sandpaper, I know what I'd choose.

Frederic

[sirbean]

Thank you. Just what I needed to know.