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we have this old generator(FB, not available anymore) sitting there for a while, I want to bring it back to life, but the guy has left, anyone can share some idea of how to set the center thickness? every time it gets the interest of visitors, I figured we should set it up and show people the "high tech".
Do you know which model it is? If it's an 858 or 813, it's set like a Coburn 113 - effective front curve (that is, the sag of the lens in the blocking ring converted to a 1.53 curve) opposite the desired thickness.Quote:
Originally Posted by jameselex
Or are you actually interested in calibrating the thickness?
Thanks Shanbaum:
We are trying to set the thickness, not calibrating.
It is a 26-858A, I don't know does it mean anything; anyway, there are two wheels , left marked from 10mm to 170(for thickness?), right marked 0-17(base curve?), and there is a red arrow(pointing to the curve wheel) and greeen (pointing to the thickness wheel). I think once we figured it out but forgot totally later on.
Then, you just set the desired thickness opposite the front curve - but be forewarned, the front curve side of the scale is basically a 50mm sag gauge; if you're using some other size blocking ring, you have to adjust for that.
The "10mm" would actually be 1.0mm - so the thickness scale is 1.0mm - 17.0mm.
We are using a 50x9 ring, so it should work; my guess would be, put the green arrow on the base curve of the lens to grind, and start grinding untill the arrow hits the desired C/T?
Contact Mary Larson at Premeir Optical, she owns what is left of FB and may be able to help. 320-202-8704
It has only been about 20 years since I've actually looked at one of these - do the arrows move independently on each scale? If so, I think the idea is to set an one arrow at the front curve and one at the thickness. You make a series of cuts, ending up with the arrows aligned.
Thanks Jaqui! I lost their phone # and their website is not working , now can bug them agian:)
Yes, Shanbum , the two arrows can move independately, as I can recall last time we tried but the C/T came out right sometimes and wrong the other times, I will give another try and let you know what happens.