[Geof]

Back home again so I can continue meandering through this thread and respond to some of the comments and questions.

Maxine; thank you for the thank yous. Part of the reason I spend time on the zone is to pass on experience and show how things can be done.

Adobe; The pillow block you see is just an ordinary pillow block and I did not get vibration, which quite honestly surprised me. I still use that same pillow block on the machine that I use for prototyping in the home shop but all the production machines use the Haas tailstock support for the rotary. A possible reason I do not get any vibration is that I machined the boss to be a neat fit, i.e. slightly larger than 2.000"; I have to tap the pillow block into place with a plastic hammer. This setup is no longer used, it was only double sided with three parts per side; the production setup is four sided with four parts per side and I will get to that later.

PBMW; I did refer you to a different thread on G52's and gar gave you some description. To use the same phraseology you use; G52 is an alternate way to get inter-coordinate relationships with adjustability. I like to use multiple offsets for the adjustability they allow. Nearly all our parts have holes and my approach is to place the work offset at the hole center. Often parts have intersecting holes and when these are done on a rotary fixture having a different work zero for each hole means it is dead simple to tweak the intersection spacing. However, as I mention in the first post now I would use G52 rather than separate G54, G55, G56, etc., but really there is not much difference. The way I have it figured out if you have fixtures that go back to exactly the same location on the machine it makes no difference. We have one machine which has three Kurt double lock vises permanently mounted on the table and for these vises we have sets of custom jaws for holding different diameter stock; twelve parts per load. This machine cycles through the same range of parts and because the vises do not move the individual work zeroes for the different parts remain the same. This means we do not have to manually enter any work offsets; each part program has its own work offset program; the work offset program is just a string of G10 commands that enter the work zeroes for the custom jaws used with the part program. We also keep dedicated tooling for the different part programs with the tool offset values in a tool length program. Changing a setup on this machine is a case of; mount the custom jaws on the vise, load the tools, call up the tool length program and run it to enter the tool length offsets, call up the offset program and run it to enter the work zeroes, load the parts into the vises and push Cycle Start. If the vises are moved and replaced it is necessary to change all the work offset values in several work offset programs; needless to say we avoid moving the vises. On other machines we change between vises and a rotary fixture and this is where G52 becomes valuable. G52 defines subsidiary work zeroes, or child coordinate systems, with reference to whatever main work zero is active. The G52 command includes X, Y (and Z, but we rarely use it) coordinates that give the location of the child coordinate relative to the main work zero. All these G52 commands and coordinates are in the part program. When the rotary is setup it is only necessary to find and enter the main work offset location for a reference hole located at the center of the base that holds all the part fixtures; rather than entering 12, 16 or 32 individual work zeroes. It is still possible to individually adjust the G52 offsets but this is done in the program rather than on the offset page.