Printed from Kezuriba (kezuriba.net/en/nc/g87/)
G87
Machining center, LatheModal, group 09Back boring cycle (reverse spot facing)
⌨On machining centers
G87 X_ Y_ Z_ R_ Q_ (shift amount) P_ F_ K_
- The spindle orients and the tool is shifted so the cutting edge clears the hole, passed through, then shifted back on the far side and cuts upward
- The R point is below the hole, etc.; the points are defined the opposite way from the other cycles. G99 (R point return) cannot be used (Siemens ISO supports initial point return only)
Diagram: G87 motion (side view)
◎On lathes: Side deep hole drilling cycle (live tooling, systems A/B)
The same number means something different on lathes (FANUC-type G-code system A). Group 10.
≠Differences between controls and machines
The same code can be written or assigned differently depending on the CNC control and the machine builder. Always check your machine’s manual.
| Source | Machine | Item | Detail |
|---|---|---|---|
| Haas | Machining center | code | G77 (Back Bore Canned Cycle)Haas mills use G77 for back boring. G87 is not in the list |
| NIST | Machining center | Format | G87 X_ Y_ Z_ R_ I_ J_ K_NIST: I/J give the shift position and K gives the top of the counterbore |
📚Sources
The meaning shown agrees in at least two sources (agreement confirmed). Explanations are written in our own words.
- Siemens AG — SINUMERIK 802D sl/840D/840D sl/840Di/840Di sl/810D Programming Manual ISO Milling, 04.2007 Edition (6FC5398-7BP10-0BA0) cache.industry.siemens.com
- National Institute of Standards and Technology (NIST), USA — The NIST RS274NGC Interpreter – Version 3 (NISTIR 6556, 2000) nvlpubs.nist.gov
- Haas Automation, Inc. — Mill Operator's Manual – 17 Mill G-Codes (online version) haascnc.com
- Siemens AG — SINUMERIK 802D sl/840D/840D sl/840Di/840Di sl/810D Programming Manual ISO Turning, 04.2007 Edition cache.industry.siemens.com