Greetings!
First post.......! Would have done this earlier, but technical difficulties wouldn't let me on board! Web Dude fixed me up thankfully!
I found this post when trying to take my Starrett #25-631 apart to replace the crystal assy.
First: I could not find a plastic crystal by itself to replace. Gone are the days of a $3 replacement!
Now it is an $8 piece that is a crystal and the surrounding black piece. Plastic, not metal. Your best bet is to go directly to Starrett dot com and purchase pieces there. I used a dealer and the transaction got all balled up with a higher price than stated, and a $22 shipping amount or some BS like that. Floored me! Good news that Starrett resolved it all and credited me back my entire shipping amount! As the guy said..... "we're an old company and slow to change!"
Second: In this post, guys have mentioned the "how to release the front face plate ring. Indeed there are three "high pressure areas" on a spring that encompasses the entire gauge face. Using a small pin, like a paper clip, one can depress this spring while applying upwards pressure on the ring. Here are the coordinate of the spring as I found it. (It is locked in place by a 90 degree bend in one end that is retained in the gauge itself.
These three points are oriented in a triangular shape, not equilateral. Two points on the bottom......and one at the top. You will want to try and release the top point and move the ring in the direction of the lower two points..... It can be a bit fiddly.....
Here are the point coordinates, using the dial as reference with the dial gauge oriented with zero at top and 25 at the 6:00 position at the bottom:
Top point is at the .002 mark Bottom two points are at .0105 and .031" There is probably a little lee way here but I believe that I marked my gauge case with the center point of each high spot on the spring!
Three: If you get a new crystal with the new plastic outer ring (held in place by three tabs as seen from rear of gauge when ring is snapped in place....more obvious when you have new ring in hand!!!) OK new plastic ring does NOT use the old spring. Remove spring and place with your old metal ring for good keeping in the junk drawer of your tool box......!
)))
Once you place the gauge dial in carefully under the main indicator needle, you can then snap the new crystal and retaining ring into position. Three tabs will snap into the recess around the gauge body. Test movement of the indicator ring and the faceplate and go from there!!!
Was glad to get this little gauge back in operational form! Used it already to check out face runout and bore runout on a new bellhousing for a transmission swap my son is working on! My old gauge was only good to .001 so having this new (to me!) gauge with a .0005" readout was great!
Hope this helps someone out! Your mileage may vary, but this is what I found with my #25-631 model which there are a LOT of out there in tool boxes across the planet!
(Thought I had pictures, but they're on my son's iCamera!)
Cheers!
Steve
Hollister CA
