# Thread: cutting circle on side of part without G132 option i.e. using G1 Z C only. Possible?

1. ## cutting circle on side of part without G132 option i.e. using G1 Z C only. Possible?

I need to mill a circular counter bore recess on the side of a part with live milling tool on an Okuma lathe with OSP7000L that has only X, Z and C (no Y and no G132/G133 option). I'm sure there is a way to make Z and C move in sync to cut a circle using some fancy user task code with tiny G1 Z & C increments. I did it roughly using G1 and C and Z small movements (1% increments on C and guessed Z plus tweaking points) but it's not very round
Ideally 0.1% increments in C and Z 0.1 or less increments would be nice
Any ideas?

2. It will not be cylindrical, the walls will be tapered
- as you don't have Y axis, any holes on a cylinder perifery must go thru the axis centerline
( wall taper depends on how deep you go, the face will not be flat as soon as you move C-axis )

IMO - Your only option is to drill and C'bore with the canned cycles only ( tools would need to be correct size )

3. ah yes!
so no counter bore with smaller tool. will use correct size tool and plunge
so now I just realized the G132/G133 is mostly useless. Tapered sides on a hole or slot would be unacceptable unless the drawing called for tapered sides.

so how about a more practical use, deburring.
let's get some numbers happening..... here's the relevant part of a program I wrote that deburrs a 5/8" hole using a 3/8" 45 degree cutter. I'm deburring the inside of the hole of course
all the Z's were totally guessed and tweaked with trial and error for one quadrant then just mirrored for the other 3 quadrants.
it works but it would be nice to have the cutting smoother and/or have the C and Z auto-calculated using some kind of mathematical formula given cutter dia. (0.375), hole dia. (0.625), center position (Z-2.059) and X cutting position (X2.95)
Probably not so simple

Code:
```N172 M110
G0 X20 M15 G94
T0404 M8 (3/8 45 DEGREE CUTTER)
G0 C0 X3.9 Z-2.059 M13 SB=3000
G1 X2.95 F30.0
C[0+7.0]
M16
C[0+6.0] Z-1.976
C[0+5.0] Z-1.954
C[0+4.0] Z-1.929
C[0]     Z-1.900
C[0-4.0] Z-1.929
C[0-5.0] Z-1.954
C[0-6.0] Z-1.976
C[0-7.0] Z-2.059
M15
C[0-6.0] Z-2.142
C[0-5.0] Z-2.164
C[0-4.0] Z-2.189
C[0]     Z-2.218
C[0+4.0] Z-2.189
C[0+5.0] Z-2.164
C[0+6.0] Z-2.142
C[0+7.0] Z-2.059
M16
G0 C0 M12
X4.0 M9
X20 Z20 G95 M15
M109
M1```

4. it's two axes synchronized interpolation - easy for Okuma. must be with IGF, right?
You choose side machining and coordination system change to flat from default. Then you draw just a circle an see, how M code looks.
If you do manual programming, you need two arcs making a circle. One doesn't works on old machines.

5. no not with IGf. There is no G132/G133 option on the machine.
The idea is to re-create that using User Task code.
It's impossible to use G02/G03 in only Z and C.
It has to be done with G1 I think and is not so simple.

6. The difference is a cylinder (couterbore), and an elipse (deburring edges). As the c-axis rotates the tool remains alligned, so you would get tapered walls, in a counter bore. For de-burring the edges the C and X axes can work together in 2D. Wothout a Y axis it can be done but it is very slow, and depending on finish requirements may not be to print. For example you could use a very small tool with .01 imcrements

Robert

7. yes, 0.01" increments is what I need. But to do that it has to be generated by a formula, its impossible to do manually.
slow? well maybe to program it yes, it's all trial and error. but the machine does the work real fast. I deburred the inside of the hole in about 5 seconds. The boss watched it and I think he came in his shorts in the excitement