Surface Plate Calibration and Conditioning

In this video we see the process for inspection and reconditioning granite surface plates. The plates are inspected and calibrated with an Autocollimator and a special instrument called a repeat meter sensitive to millionths of an inch. The plates can be resurfaced in the field using diamond charged cast iron laps. For more information or to get your plates calibrated check out the links below.

[dunoon]

In the mid-60's I was on a Polaris Submarine repair ship and I worked in the Fleet Mechanical Calibration Lab. We had 2 black granite surface plates a 4'X8' and a 2'X4', we calibrated our own using a procedure from Metrology Engineering Center in Pomona, Calif. we measured every inch and plotted it using a Davidson D638 autocollimator and a precision front surface mirror. It would take as about 2 days to shoot the big plate and about a half day to shoot the small plate. Then we would enter all these measurements into a Frieden mechanical calculator and it would set and crank out for about 8hrs to give us our high and low spots as I remember it was a AAA plate but we used it for everything from a bed to ironing our uniforms on. It was mainly used to calibrate all the optical equipment we serviced, when I went back in the Navy in the early 70's nearly all the optical stuff had been replaced by electronic equipment. I really loved working on and calibration optical instruments. Those days are long gone.

[MattsMotorz]

I like that guy, you can tell he loves his job, which is something I always like in people.

[spookypen]

You watch one video on surface plates... and now the algorithm's got you.

[billdlv]

I was surprised at the simple equipment too. You can tell those guys have a solid understanding of the concepts, and are not just following steps.

[danarrington]

25+ years in manufacturing and I have never seen this done. Thank you so much for posting this video. It's not at all what I had imagined. Great stuff!!

[RyanWeishalla]

Interesting work.  It was nice that the guy was into talking about what he was doing and let you video it for us.  That story about the lady who only wanted the B certification was hilarious.

[joseluissoto]

The kindness of the field techs walking us through the process... thumbs up! Thanks Ox!

[FredMiller]

Wow what a treat! How many of us would ever have seen this on our own. Thanks for sharing Tom!

[Ujeb]

Tom, thanks for sharing this with us! The process of flattening granite surface plates isn't seen often by machinists. I saw the tail end of a calibration about 30 years ago but that's all. Funny story - when I first began working in the engineering department where I'm working now (25 years ago) I found under a huge pile of junk, a pink granite surface plate, a monster size 6 foot by 10 foot. After I cleared it off and tried cleaning it, I found globs of hardened epoxy all over it's surface! It turns out that a bunch of students were using it to make composite panels on it! That stone must have cost 10's of thousands of dollars and was used as a table! We have since gotten rid of it and I replaced it with a 4 x 4 foot pink stone that I use to set up fixturing for my new wire EDM.

[TheChipmunk]

Great to see folks who are enthusiastic about their work, happy to be filmed, and happy to explain for everyone even though they probably weren't expecting it. It says great things about the company and the professionalism. Big thumbs up to Precision Granite for this (and you of course Tom!)

[RookieLock]

Man, I've watched this like 3 times over the last few years, and it's still as entertaining as the first time I saw it. You can really tell these guys love what they do. Love how they took time to educate you and us. Thanks again Tom!

[jpkk]

I'm coming into contact with precision plates for the first time and this is completely blowing my mind! I love how so many precise things come from such a simple tool... a surface!

[russhellmy]

"your granites are actually improving my laps" OK then let's just do a contra, you don't bill me, I won't bill you. hahaha

[Kruglord]

Man, I'm a geomatics engineer (formerly know as a survey engineer) and these guys are talking about 1/4 second precision and all that, that's incredible! You've got to have some pretty fancy equipment to reach that precision, I'm gaining some new appreciation for the measurement precision needed in machining.

[ChunkyMonkaayyy]

"Under promise, over deliver." Really cool video!!

[Alistair_Spence]

Particularly enjoyed this video Tom. These guys obviously know their stuff. It's always good to see professionals doing their thing. Thanks.

[joer]

It's nice to see such a young guy getting into this kind of old-school technical work. Hopefully they'll be able to keep the skills alive!

[imdeplorable]

I'm with you --- I found this fascinating. I have no use for this knowledge but, I love learning so, I watched this from end to end.
Thank you for making this video.

[crusader]

Wish I had 50 millionths of this dude's energy

[danielwerger]

Tom, you blew my mind with this one. Never have I seen this process, and its amazing how (relatively - given that young guys expertise) simple it was.... I'm still digesting this video. Absolutely useful.... Thanks a million, Daniel.