Servicing a BH2 BHTU microscope

[Harold]

I've got an Olympus BH2 BHTU that I'm very fond of. However, it's coarse focus is pretty stiff eve with the tension control backed off as far as I'm comfortable with. So I'm thinking the focus mechanism(s) could use some attention. I've read through Carl Hunsinger's excellent documents covering service/cleaning of the focus block and coaxial focus mechanism. Looks reasonable straight forward for someone with decent mechanical skills. However, I'm a little uneasy about performing surgery on my only microscope. For that reason, I'm going to try to find a stripped stand for sale that I can use as to "practice" on. I've got the tools and supplies recommended by Carl either on hand or on the way. But before I dive into this project, can anyone who's gone through this exercise before off any additional tip/hints?

[deBult]

I now have done 4. The use of the JIS screwdriver set is mandatory: you will ruin some of the screw-head’s using a Philips set.

Recommend to start cleaning and relub the gearbox: this usually already helps a lot and may suffice.

Step 2 is clean and relube the coaxial mechanism part but SKIP the removal and lubrication of the pinion assembly (the pinion assembly is the toughest part).

Step 3; Additionally do the relub of the sliding focus block.

The videos are a great addition to the written parts.

Alternatively: request a serviced stand at Carl H. and move your optics to this one.

[Harold]

The point about the JIS screw driver is well taken. I went to the extreme of buying the brand Carl suggests. Since my first "victim" will be a more or less "sacrificial lamb", I'm going to go ahead and try giving the assembly the full treatment, paying close attention to the cautions offered in both the PDF and the video. My motivation for this project comes from the knowledge that BH2 parts are no longer in production, necessitating cannibalization of existing equipment. Which means I'll need to know how to take things apart and put them back together on my own.

Just FYI, I've worked on motorcycles and high end bicycles for years, and I'm comfortable enough around a machine shop to chamber and fit barrels and actions on rifles used for 1000 meter benchrest shooting.

[deBult]

Just FYI, I've worked on motorcycles and high end bicycles for years, and I'm comfortable enough around a machine shop to chamber and fit barrels and actions on rifles used for 1000 meter benchrest shooting.

Then your starting point is way better than mine

BTW: you will require 2 strap-wrenches for the pinion assembly (plus I used a burner for making Crème brûlée for heating the one end of the pinion “glued” with lock-tight.

I ended up with a box of spare parts, screws and all, plus sufficient refurbished parts to rebuild an extra BH2, so your reasoning on spares is well understood

[Harold]

I think I can get by with the pair of soft jawed pliers for the pinion assembly, but I ordered a couple strap wrenches as a fall back. I'm really looking forward to this project. One lesson I learned a long time ago is to break the job down into small steps and take my time. Saves a lot of frustration. Carl's directions are well suited to that approach. So I've made a catalogue of the tools solvents and lubricants he recommends, ordered what I don't have on hand, and dug the stuff I do out of the repository we call a garage. Now it's just a matter of looking for my "guinea pig" BH2 stand. More than a few on Fleabay that look interesting.

[deBult]

I never managed to find soft jawed pliers on this side of the pond, so mis-use the strap of the strap-wrench combined with pliers

Well, now I now the proper name /expression (non native speaker here) I was able to find 2 on amazone with shipping to my neck of the woods.