[ALABAMA]

ANYBODY HAVE EXAMPLE PROGRAM FOR SPIRAL INTERPOLATION?
GROOVE STARTS AT 3.00" DIA GOES 360° +90° ENDS AT 3.375" DIA .030 DEEP. THANKS

[txcncman]

How many revolutions to cover the 3/8" distance? How close to a true spiral do you need?

[Kiwi]

This code arcs 450 deg. This should be within 0.001"
G01 X1.5 Y0. Z0.
G03 X0.3441 Y1.4929 Z-0.0051 R1.5162
G03 X-1.5084 Y0.4295 Z-0.0108 R1.5502
G03 X-0.7077 Y-1.4367 Z-0.0161 R1.5847
G03 X1.3243 Y-0.959 Z-0.0214 R1.6185
G03 X1.5942 Y0.4502 Z-0.0248 R1.6459
G03 X0.4449 Y1.6212 Z-0.0287 R1.6688
G03 X0 Y1.6875 Z-0.03 R1.6913

[txcncman]

"1 REV, NEEDS TO BE VERY CLOSE TO A SPIRAL"

Very close? +/-0.015"?

Here is some code to do it increasing diameter counterclockwise with X0. Y0. being center of spiral with line segments:

G0 X1.5 Y0.
G1 Z-.03
X1.4984 Y.1
X1.4969 Y.131
X1.4873 Y.2278
X1.4823 Y.2614
X1.4606 Y.373
X1.4564 Y.3903
X1.4266 Y.4948
X1.4193 Y.5166
X1.3799 Y.6194
X1.3713 Y.6394
X1.3232 Y.7382
X1.3126 Y.7578
X1.256 Y.8522
X1.2437 Y.8708
X1.179 Y.96
X1.165 Y.9776
X1.0928 Y1.0608
X1.0772 Y1.0772
X.9979 Y1.1539
X.9809 Y1.169
X.8952 Y1.2386
X.8768 Y1.2522
X.7852 Y1.3141
X.7656 Y1.3261
X.6689 Y1.3798
X.6482 Y1.3901
X.5471 Y1.4353
X.5255 Y1.4438
X.4208 Y1.48
X.3983 Y1.4866
X.2908 Y1.5135
X.2677 Y1.5182
X.1581 Y1.5357
X.1346 Y1.5384
X.0238 Y1.5462
X0. Y1.5469
X-.1112 Y1.545
X-.135 Y1.5436
X-.2457 Y1.532
X-.2695 Y1.5285
X-.3788 Y1.5073
X-.4024 Y1.5017
X-.5095 Y1.4711
X-.5326 Y1.4634
X-.6368 Y1.4235
X-.6592 Y1.4137
X-.7596 Y1.3649
X-.7813 Y1.3532
X-.8771 Y1.2957
X-.8977 Y1.2821
X-.9882 Y1.2164
X-1.0077 Y1.2009
X-1.0922 Y1.1276
X-1.1104 Y1.1104
X-1.1883 Y1.0299
X-1.2049 Y1.0111
X-1.2755 Y.924
X-1.2906 Y.9037
X-1.3534 Y.8107
X-1.3667 Y.7891
X-1.4212 Y.6909
X-1.4326 Y.668
X-1.4784 Y.5654
X-1.4878 Y.5415
X-1.5245 Y.4352
X-1.5319 Y.4105
X-1.5592 Y.3013
X-1.5644 Y.2758
X-1.5821 Y.1646
X-1.5851 Y.1387
X-1.593 Y.0262
X-1.5938 Y0.
X-1.5919 Y-.1128
X-1.5903 Y-.1391
X-1.5786 Y-.2515
X-1.5747 Y-.2777
X-1.5532 Y-.3886
X-1.547 Y-.4145
X-1.5159 Y-.5233
X-1.5074 Y-.5487
X-1.4669 Y-.6544
X-1.4562 Y-.6791
X-1.4066 Y-.7809
X-1.3938 Y-.8047
X-1.3354 Y-.9019
X-1.3205 Y-.9246
X-1.2538 Y-1.0165
X-1.2368 Y-1.0378
X-1.1624 Y-1.1236
X-1.1435 Y-1.1435
X-1.0618 Y-1.2226
X-1.0412 Y-1.2408
X-.9528 Y-1.3125
X-.9306 Y-1.329
X-.8362 Y-1.3927
X-.8125 Y-1.4073
X-.7129 Y-1.4626
X-.6879 Y-1.4751
X-.5837 Y-1.5216
X-.5576 Y-1.5319
X-.4497 Y-1.5691
X-.4226 Y-1.5772
X-.3118 Y-1.6049
X-.284 Y-1.6106
X-.1711 Y-1.6285
X-.1428 Y-1.6318
X-.0286 Y-1.6399
X0. Y-1.6406
X.1145 Y-1.6387
X.1432 Y-1.637
X.2572 Y-1.6251
X.2858 Y-1.6208
X.3984 Y-1.599
X.4266 Y-1.5923
X.537 Y-1.5607
X.5647 Y-1.5515
X.6719 Y-1.5104
X.6989 Y-1.4987
X.8022 Y-1.4484
X.8281 Y-1.4344
X.9268 Y-1.3752
X.9515 Y-1.3589
X1.0447 Y-1.2913
X1.068 Y-1.2728
X1.155 Y-1.1972
X1.1767 Y-1.1767
X1.2568 Y-1.0938
X1.2767 Y-1.0713
X1.3494 Y-.9817
X1.3674 Y-.9575
X1.432 Y-.8618
X1.4479 Y-.8359
X1.504 Y-.7349
X1.5176 Y-.7077
X1.5647 Y-.6021
X1.5759 Y-.5736
X1.6138 Y-.4639
X1.6225 Y-.4347
X1.6503 Y-.3234
X1.6567 Y-.2921
X1.6673 Y-.2329
X1.6785 Y-.1468
X1.6855 Y-.044
X1.6875 Y0.
G0 Z.1

[txcncman]

Here is some code to do it increasing diameter counterclockwise with X0. Y0. being center of spiral with arc segments:

G0 X1.5 Y0.
G1 Z-.03
G3 X1.4823 Y.2614 R1.5
X1.4606 Y.373 R1.5008
X1.4193 Y.5166 R1.5051
X1.3799 Y.6194 R1.5094
X1.3126 Y.7578 R1.5137
X1.165 Y.9776 R1.518
X.9809 Y1.169 R1.5232
X.7656 Y1.3261 R1.5283
X.5255 Y1.4438 R1.5336
X.2677 Y1.5182 R1.5388
X0. Y1.5469 R1.5439
X-.2695 Y1.5285 R1.5492
X-.5326 Y1.4634 R1.5544
X-.7813 Y1.3532 R1.5596
X-1.0077 Y1.2009 R1.5649
X-1.2049 Y1.0111 R1.57
X-1.3667 Y.7891 R1.5752
X-1.4878 Y.5415 R1.5805
X-1.5644 Y.2758 R1.5856
X-1.5938 Y0. R1.5908
X-1.5747 Y-.2777 R1.5961
X-1.5074 Y-.5487 R1.6013
X-1.3938 Y-.8047 R1.6065
X-1.2368 Y-1.0378 R1.6118
X-1.0412 Y-1.2408 R1.6168
X-.8125 Y-1.4073 R1.6221
X-.5576 Y-1.5319 R1.6273
X-.284 Y-1.6106 R1.6325
X0. Y-1.6406 R1.6378
X.2858 Y-1.6208 R1.643
X.5647 Y-1.5515 R1.6481
X.8281 Y-1.4344 R1.6534
X1.068 Y-1.2728 R1.6586
X1.2767 Y-1.0713 R1.6638
X1.4479 Y-.8359 R1.669
X1.5759 Y-.5736 R1.6742
X1.6673 Y-.2329 R1.7348
X1.6855 Y-.044 R1.7954
X1.6875 Y0. R1.856
G0 Z.1