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Three B&L “Model” microscopes UPDATE

Posted: Fri Feb 22, 2019 4:42 pm
by Radazz
I thought collectors Might be interested in these variants of the Bosch and Lomb “Model” microscope.
My only source for data is the internet, and the last thing I want to do is spread disinformation, so any other B&L affectionados (there might be two or three) please feel free to add comments or corrections.

From what information I can find, I believe this Gundlach style stand was manufactured from 1883 to 1889. The fine focus racks are somewhat fragile, and of these three stands only one does not creep across the field of view after 130 some years.


None of these stands has a serial number, and cannot be nailed down to a year of manufacture, but there are a few clues.
This first stand has no patent dates engraved on it. The other two show 2 patent dates engraved on the focus assembly, the latest of which is Oct. 13, 1885.
This stand could have been manufactured between 1883 and 1885. And has an open 2 barrel nose piece.

This second stand is engraved with two patents; Oct. 3 1876 and Oct 13, 1885. So cannot have been manufactured before then.
Presumably, one is for the course focus and one for the fine focus, but I don’t know which is which.
This stand has a compound objective which is ~10x with the front piece screwed on and ~5x with it removed

The third stand has the above mentioned patents engraved on the rack. This is the only one with a perfectly functional course and fine focus rack.
Someone seems to have added an enclosed two barrel nosepiece at a later time; It bares a patent date of Dec. 1, 1908. It is also the only one with the original lacquer still on it. (Mostly intact)

I personally feel these beautiful brass microscopes are as enjoyable to look at as they are to look through, and I like to gaze at an antique slide through them now and then musing on who might have used them in the past.
I hope this is interesting to someone.

Re: Three B&L “Model” microscopes

Posted: Fri Feb 22, 2019 8:42 pm
by apochronaut
Those are really beautiful. An enormous amount of precision hand labour went into them. Jackson stands too. I think B & L abandoned Jackson stands after 1905 or thereabouts.

Re: Three B&L “Model” microscopes

Posted: Sat Feb 23, 2019 3:16 am
by apatientspider
Beautiful! Do the lenses still produce acceptable images after all this time?


Re: Three B&L “Model” microscopes

Posted: Sat Feb 23, 2019 5:16 am
by Radazz
I can see no de-lamination at all. All three produce clean images. The only real problem is with two of the three fine focus assemblys. The design used a leaf spring to resist the fine focus screw, but it is a weak point. Time seems to have defeated two of these scopes. Needless to say I am very careful with the working stand.
I have an early Investigator which is older than any of these and still works splendidly.
While I do look through these now and then, they don’t get lots of heavy use.
The Twentieth Century stands are much more substantial in construction, and most of the examples in my collection are still very usable. The fine focus on the Bosch and Lomb 16033-433 stands has one of the finest touches I’ve experienced.
Still, I spend most of my viewing time in front of the twenty first century equipment. There is no comparison for photography. Digital photography has made it much easier, as well. I can’t say I would have pursued the hobby as avidly if I still had to use film and a wet darkroom.

Re: Three B&L “Model” microscopes

Posted: Sat Feb 23, 2019 5:28 pm
by Bufo Bill
The pictures are as well made as the objects in them. As beautiful as any industrial item, be it steam engine or sports car. The wear and age only add to to the beauty of such items.

Re: Three B&L “Model” microscopes

Posted: Sat Feb 23, 2019 6:50 pm
by Radazz
Writing this post inspired me to look through each of these again.
The oldest one has become too fragile to play around with :( . Sadly is just for display now.
The dated stand that has been stripped has a functioning course focus, but the fine focus creeps around the center of the fov. Bent needle, I know but I’m afraid to try to “fix” it any further.
Clear image, though.

I might be slow, but staring at these it occurred to me that the original nosepiece on the stand that still has the original lacquer and still works perfectly would be the most valuable use of resources.


Re: Three B&L “Model” microscopes

Posted: Fri Mar 01, 2019 4:02 pm
by Radazz
Not trying to bump this one but I wanted to include some observations.
I got all three of these working again. I disassembled them to try to understand how they were supposed to work, then try to make them work correctly.
I also didn’t want to mess with the stand that was working fine, even for reference.

What I found was very interesting.
The two stands with the patent dates engraved on the focus racks seem to be production stands manufactured between 1885 and 1896.
The stand without patents engraved on the focus rack is different enough to possibly be a prototype.
Outside, it’s hard to see any difference, but on closer examination, the fine focus knob is smaller.
The real difference is internal.

The ‘production’ stand has a leaf spring mounted in the socket of the limb that puts upward pressure on the whole rack block, while the fine focus knob pushes down on a pin that engages a dimple in the spur thrusting back at the bottom of the focus block. The coarse focus knobs hook over a right angle slot on either side of the limb socket and are tightened to stabilize the focus block. The fine focus knob has the double duty of slowly allowing the whole assembly to rise by backing off the knob, and holding the entire assembly in the limb!

This is nothing like 20th Century B&L fine focus mechanisms with two millimeters of travel. They work well enough to roll focus through a mounted specimen. But the remarkable thing about the dancing bear isn’t how gracefully it dances, but that it dances at all. This is not an especially “user-resistant” design as evidenced by the failure of two out of three of them after only 130 years or so. ;)

The other stand, has the leaf spring mounted on the focus block which sits on top of a ledge inside the limb socket. This requires holding the leaf spring up while inserting the assembly into the limb. Only there’s no space for a tool. Whatever is used to hold the spring up must be whipped out while the block is shoved home. The rest of the assembly works the same. This takes three times as long to install the rack assembly into the limb, and its no wonder they changed it for production.

I wonder if this really is a prototype. Any thoughts from the experts?