[majsteve]

I'd like to be able to use Gearotic horizontally instead of as a 4th axis. I'm trying to find out if anyone has done the cnc for a rotary table horizontally on the mill.

The reason I'm interested is that I'm trying to cut a gear (almost 7" in diameter) that's over the limit for the x/y travel on the mill, even with extensions to the y-axis. Its for a clock project I'm working on. I was thinking if the rotary table was able to rotate, and then let the x and y cut the part, the rotate and repeat, it would be a nice way to cut a gear.

What I'm doing now is designing in Gearotic, CAD/CAM with BobCAD, then milling with Mach 3. To cut the gear within the limits, I can only cut 1/2 of the gear at a time, and then use the rotary table to move 180 degrees and repeat the milling. The same with cutting out the spokes. I have the blank mounted with a center bolt through a spoilboard and then into the threads of the rotary table. It worked, but its not "elegant".

I'm going to try surfacing using the rotary table by incrementally moving in y and then starting the cutter and MDI a-axis to +360 and then moving the y and doing -360. That, I imaging, will give a pattern of circles over stock.

Any thoughts would be appreciated, especially from someone who uses the rotary table horizontally.

Steve

[MasterSpoon]

I'm not entirely sure that I am following exactly what you are wanting to do, but if I am reading it correct at the moment you mill half the gear, rotate the A axis 180 degree's then run the program again so you can cut the whole gear.

Instead of doing that you want to cut 1 tooth, rotate A axis, cut another tooth, rotate A axis, ect ect

Being that the horizontal rotary table on a CNC mill is generally redundant I am not sure if there is any software that will spit out all the Gcode you want, What you may be best to do is manually edit the G-code, it opens fine in notepad and you can change whatever you want.

The change in the G-code would be easy enough to do
1 - create G-code for a single tooth
2 - open in notepad add a line above the cutting G-code to zero the A axis
3 - copy G-code from Zero A to end of tooth cut
4 - paste G-code after the first tooth but simply change the A0 to what ever degree it needs for the second tooth. (eg 60 tooth gear = 360 degree / 60 = 6 degree rotation per tooth)
each additional tooth you would simply need to add the next degree index to the A value, (eg for the 60 tooth, A0 to start, A6 for second tooth A12 for 3rd, A18 for fourth, ect ect)

Editing the G-code shouldn't really take you more then a couple of minutes.

[majsteve]

I got it cut adequately, using some y-axis extensions and some cussing. I think you're right that the a-axis is redundant for this operation and I could have probably just clamped some block to the table to index the stock and cut it flat on the table, reversing it when I needed to, but the a-axis rotation is totally more fun and I faced the sprocket using g00 a360 and g00a-360 to but interesting pattern with an end mill on the center section, and a fly cutter on the rim. More dumb luck than technique. I'm debating cnccookbook's G-Editor to see if it helps me learn what codes do what.