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broken 10x comparator lens

SRuss

Aluminum
Joined
Mar 26, 2010
Location
New Hampshire USA
Hi everyone....

I came into work this morning to find that the lens on the shop comparator has a bullseye right in the middle. :( It looks like something was dropped on it when it was standing on end.

I checked it all out; the shadow is crisp and clear, and it's measuring fine (I compared a part on my inspection comparator).

My question is this: do you suppose with heating and cooling it will get worse? (although it's awfully thick glass). Could it over time change the measuring accuracy?
We don't measure anything on it past, say, +/-.003

I have looked all over online for a ballpark price for a new one, to no avail, just in case we really need to replace it. Right now, funds are low, so I'm hoping we can get by with this one for now.
 
If your lens is a free-standing magnifier, there are lots of options for a replacement.

If it's attached to a calibrated traverse mechanism, your options are limited.

As long as the grid or scale on the comparator ground glass is sharp, it will work fine as is, although you may have discontinuous lines/edges.

- Leigh
 
Thank you Leigh.

As a machinist-thrown-into-QC (I'm the whole department! :eek: ) I still have a lot to learn about metrology equipment. I never had a lot of time with comparators, anyway.

It is free-standing, and turns out to have cost $575 in 2003 (I found the old catalog). I just wondered if the constant heating and cooling from the light might make it worse over time. Right now the lines still look good.
 
Magnification lenses should not get hot under normal operating conditions so if the lens has a chip it will not get worse. Your image will certainly be distorted in the area with the chip but everywhere else on the screen should be fine. If you have the instrument calibrated, the calibration tech will normally add a note about it on the calibration form but should not fail the machine. I dont know what brand of comparator you have but if its a J&L or OGP they both still make their own lenses here in the USA and you can have just the outer lens element replaced by the factory. The other brands of comparators use imported lenses and they dont sell parts. Try EBAY for those. Good luck
 








 
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