I have been tasked with purchasing the gage block sets for the company I work for. It's been a while since I've worked the linear side of the house so I have a few questions. We plan on calibrating your run of the mill micrometers and calipers so. . . . . .
1. What grade gage block set do I need to purchase?
2. Can I use a rectangular set or is square my best/only option?
3. Is one manufacturer better than another or all they all pretty similar?
Any information would be greatly appreciated. Thank you in advance.
I'm partial to ceramic blocks...easier to handle and keep clean...they ring better and no corrosion. They don't burr, but they do chip, so you gotta be a little careful with them.
How big are we talking? Are the calipers and mics small or do you get into the bigger sets? This is kind of vital information to have. How many calibration events are we talking about per year any idea? Also are we talking high end mics here or just your run of the mill =?-.001 accuracy?? If just the "normal" mics I would buy a cheap used set why blow a wad on new ones? Maybe the boss will give you a raise for saving the company money??
Mostly your low end equipment and probably looking at 100 or more items a year.
Right now I do not believe that we are looking at anything over what a standard 81 piece set could do. I was interested in the differences between square and rectangle blocks because there sure is a price difference.
Just a reminder,
Theres more to calibrating mic's than just linearity of the spindle. Be sure to check parallelism and flatness of the anvil and spindle. You will need some Optical Flats/Monochromatic Light and Precicion Spheres(for larger mics) also. Really the 81 pc Grade AS-1(prefered) or Grade AS-2 should be fine to use for mics of an accuracy of 0.0001" or worse. Get the Grade 0 or Grade 00 if your mics have an accuracy better than 0.0001".
Personally Id stay away from the ceramic blocks. Not that they are bad but Im guessing you have a small lab that has good temp control but not great temp control. Prolly +/-2 or 3 deg Im guessing. Reason being is that the ceramics are less sensative to temp changes than steel. Bringing your gages into the lab 24 hours prior will allow them to settle to the temp of the steel gage blocks. They will have similar expansion coefficients giving you a truer reading on the mic.
Try this vendor, best prcing I have found for gage blocks
http://www.jwdonchin.com