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Teardown, Cleaning, and Reassembly of the Miscellaneous Parts of the Olympus BH-2 Microscope Frames 

Revision 1 

Page 8 of 45 

Introduction 

The microscopes in the Olympus BH-2 line have largely 
been  replaced  in  the  professional  and  clinical  world, 
due  to their advancing age  and the lack of repair parts 
from  Olympus.    A  great  many  of  these  microscopes 
were  produced  in  their  day,  and  because  of  this  they 
are  readily  available  on  the  used  market  for  very 
reasonable  prices.    Thanks  to  their  excellent  build 
quality and solid optical performance, these scopes are 
now  very  popular  with  hobbyists,  providing  an 
affordable  and  high-quality  alternative  to  the  Chinese-
made scopes prevalent today. 
Problems  that  might  be  encountered  when  purchasing 
one of these scopes is that various mechanical systems 
may be stiff, sluggish, or even completely seized, due to 
the  decades-old grease  in the  microscope.   Procedures 
for  servicing  the  major  components  of  the  Olympus 
BH-2  stands  are  covered  in  other  documents  in  this 
series.    This  document  describes  the  complete 
teardown,  cleaning/lubrication,  and  reassembly  of  the 
various minor sections that are not covered elsewhere.  
This  should  allow  a  hobbyist  with  reasonable 
mechanical  abilities  to  service  these  portions  of  the 
applicable microscope stands.   

Scope of this Document 

This  document  describes  the  complete  teardown, 
cleaning/lubrication,  and  reassembly  of  the  various 
minor  sections  of  the  Olympus  BHS  (including  BHSP), 
BHSU,  BHT  (including  BHTP),  and  BHTU  microscopes, 
covering the following components. 

 

Viewing-Head Lock Screw (two versions) 

 

Nosepiece Slide Mount (two versions) 

 

Field Diaphragm Assembly (two versions) 

 

Light Inlet Assembly 

 

Light Exit Assembly (two versions) 

Tools Needed 

The tools listed in the sections below will be needed to 
service 

the 

various 

minor 

sections 

of 

the 

BHS/BHSU/BHT/BHTU stands. 

 

Pliers, needle-nose 

 

Pliers, soft jaw 

 

Screwdriver set, JIS (item 7 o

Appendix 1

 

Screwdriver set, slotted 

 

Lens-Handling Suction Tool (item 9 o

Appendix 1

) 

 

Lens Spanner Tool, bent tips (item 8 o

Appendix 1

) 

A Few Words about JIS Screws 

Screws  with  JIS  heads  are  found  in  much  of  the  older 
equipment  designed  and  manufactured  in  Japan.    JIS 
screws look very much like standard Phillips screws, but 
they differ in that JIS screws were designed to not cam-
out  under  torque,  whereas  Phillips  screws  were 
designed  to  intentionally  cam-out  as  a  means  to  limit 

the  torque  applied  to  the  fasteners.    Because  of  this 
crucial  difference  in  the  geometry  of  the  two  screw 
types,  JIS  screws  will  be  damaged  by  standard  Phillips 
drivers  if  too  much  torque  is  applied.    JIS  screws  can 
usually be identified by the presence of a single dot, or 

by  an  “X”,  stamped  into  one  of  the  four  quadrants  of 

the cross-point depression (se

Figure 1

). 

 

Figure 1 

 Head of a typical JIS screw 

Supplies Needed 

The supplies listed in the sections below will be needed 
to  service  the  various  minor  sections  of  the 
BHS/BHSU/BHT/BHTU stands. 

 

Cleaning Solvent (se

Recommended Solvents

 section) 

 

Cotton Swabs 

 

Grease (se

Recommended Lubricants

 

section) 

 

Pipe Cleaners 

 

Tissues, oil-free (item 5 o

Appendix 1

) 

 

Lens Cleaning Solution (item 4 o

Appendix 1

) 

 

Lens Duster Bulb (item 11 o

Appendix 1

) 

 

Light Oil, PTFE (item 3 o

Appendix 1

) 

Recommended Lubricants 

Plastilube®  Brake  Grease  (medium  consistency)  can  be 
used  on  the  various  minor  sections  of  the 
BHS/BHSU/BHT/BHTU  stands  (item  1  of 

Appendix  1

)

.  

Molykote 44  Light  (item  2  o

Appendix  1

)  can  be  used 

on  the  knurled  field-adjustment  ring  of  the  Light  Exit 
Assembly.    Both  greases  will  remain  serviceable  for 
many years to come.    

Recommended Solvents 

Some type of cleaning solvent will be needed to remove 
the  old  grease  from  the  various  minor  sections  of  the 
BHS/BHSU/BHT/BHTU  stands.    Solvents  that  can  be 
used  are  acetone,  diethyl  ether,  heptane,  hexane, 
mineral spirits, turpentine, and xylene. 

Safety Considerations with Solvents 

Regardless  of  which  solvent  is  chosen,  make  sure  that 
adequate  ventilation  is  present  during  the  cleaning 
process,  and  that  any  necessary  personal  protective 
equipment is utilized to minimize exposure.  Consult the 

Summary of Contents for BH2 Series

Page 1: ...mail com Permission is hereby granted to distribute this PDF document in its entirety for personal non commercial purposes only provided that the contents are not modified in any way including the cop...

Page 2: ...Clean Threads for the Locking Thumbscrew BHS BHT ____________________________________________ 18 Servicing the Old Style Slide Mount BHS BHT ___________________________________________________ 18 Cle...

Page 3: ...d Tools Referenced in this Document ___________________________________________ 45 Parts Supplies and Tools____________________________________________________________________ 45 Sources for Parts Sup...

Page 4: ...the locking thumbscrew 18 Figure 55 Clean threads of locking thumbscrew old style 18 Figure 56 Thoroughly clean slide mount base old style 19 Figure 57 Slide mount parts ready for use old style 19 Fi...

Page 5: ...nstall screws to secure the retaining plate 28 Figure 108 Reinstall plastic gear collar onto the rotor 28 Figure 109 Secure the gear collar with two screws 28 Figure 110 Reinstall the slotted stop pin...

Page 6: ...ed retaining ring 37 Figure 161 Unscrew and remove threaded retaining ring 38 Figure 162 Lift and remove the glass field exit lens 38 Figure 163 Blow loose dust from the glass lens 38 Figure 164 Clean...

Page 7: ...us BH 2 Microscope Frames Revision 1 Page 7 of 45 Figure 190 Secure filter holder in recess of knurled ring 43 Figure 191 Light Exit Assembly ready for service 43 Figure 192 Dust cap for BHS BHSU ligh...

Page 8: ...set slotted Lens Handling Suction Tool item 9 of Appendix 1 Lens Spanner Tool bent tips item 8 of Appendix 1 A Few Words about JIS Screws Screws with JIS heads are found in much of the older equipment...

Page 9: ...used on the BHSU BHTU stands The BHS BHT locking thumbscrew includes a spring loaded plunger and consists of six separate parts This locking screw can be identified by the presence of the slotted end...

Page 10: ...Figure 7 Mounting disk from an old binocular head Carefully place the circular dovetail of the mounting disk see Figure 7 into the dovetail recess for the viewing head using the circular dovetail to d...

Page 11: ...e in the end of the plunger shaft see Figure 12 Figure 12 Carefully remove e clip from the plunger shaft Remove the clamp holding the mounting disk in place and remove the mounting disk from the dovet...

Page 12: ...nt acetone to remove any grease or other contaminants from the bore of the stationary inner barrel of the locking thumbscrew see Figure 18 Figure 18 Clean the bore of the stationary inner barrel Use a...

Page 13: ...igure 24 Figure 24 Insert plunger into bore of the inner barrel Apply a light coating of a suitable grease item 1 of Appendix 1 to the exposed threads of the stationary inner barrel of the locking thu...

Page 14: ...t end Use a suitable clamp with non marring jaws to hold the mounting disk in the slid over position to keep the end of the plunger shaft exposed see Figure 30 Figure 30 Clamp mounting disk to keep sh...

Page 15: ...locking thumbscrew the locking thumbscrew must be removed from the pillar arm so that any thick or hardened grease or contaminants can be removed from the threads and then reinstalled into the pillar...

Page 16: ...nd a suitable solvent acetone to clean any grease or contaminants from the threads of the tapped hole in the pillar arm see Figure 41 Figure 41 Clean the threads of the tapped hole Reinstall the Locki...

Page 17: ...w ready to provide many more years of trouble free service see Figure 35 Figure 47 Refurbished thumbscrew is ready for use Nosepiece Slide Mount There were two versions of nosepiece slide mounts used...

Page 18: ...Figure 53 Figure 53 Remove the slide mount from the pillar arm Clean Threads for the Locking Thumbscrew BHS BHT Using a pipe cleaner and a suitable solvent e g acetone clean the inner threads of the t...

Page 19: ...le slotted screwdriver loosen and remove the stop screw for the nosepiece slide mount locking block see Figure 58 Figure 58 Remove the locking block stop screw Using a suitable slotted screwdriver loo...

Page 20: ...unt base making sure the bearing surface of the locking block is in contact with the mount base see Figure 64 Figure 64 Position locking block under slide mount base Align the pivot screw hole in the...

Page 21: ...Using a suitable JIS screwdriver reinstall the three m2 6x5 screws to secure the nosepiece slide mount to the BHS BHT pillar arm see Figure 70 Figure 70 Secure nosepiece slide mount with screws Reinst...

Page 22: ...sembly from the base casting see Figure 77 being very careful so as to not damage the Light Exit Assembly with the field diaphragm assembly the two assemblies are very close in proximity and the refle...

Page 23: ...ar from the diaphragm rotor if it will come loose See Figure 81 Figure 81 Lift and remove the plastic gear collar Using a suitable JIS screwdriver loosen and remove the four m2 6x5 screws securing the...

Page 24: ...to clean them If the leaves are plastic do not use acetone but instead use a plastic safe solvent such as alcohol Figure 88 Thoroughly clean the diaphragm leaves Using a suitable solvent thoroughly c...

Page 25: ...he pivot pin on the end with the relief notch see Figure 90 if applicable into one of the pivot holes in the metal diaphragm stator See Figure 92 Figure 92 Reinstall first diaphragm leaf into the stat...

Page 26: ...ighth leaf the end with the relief notch if applicable under the lifted ends of the existing leaves and place the pivot pin into the appropriate hole beneath the lifted leaves Use the pencil markings...

Page 27: ...e metal diaphragm stator The two orthogonally located holes for the screws should be in the position shown in Figure 105 Figure 105 Orientation of the screw holes in the rotor If the two orthogonal sc...

Page 28: ...tor Using a suitable JIS screwdriver reinstall the two m2 6x5 screws to secure the plastic gear collar in place on the diaphragm rotor See Figure 109 Figure 109 Secure the gear collar with two screws...

Page 29: ...tator See Figure 115 Figure 115 Lift and remove the plastic rotor from stator Beneath the diaphragm rotor there are 10 diaphragm leaves positioned within the circular recess of the metal diaphragm sta...

Page 30: ...ate with the four tapped holes in the stator See Figure 118 Figure 118 Reinstall brass retaining plate onto stator Using a suitable JIS screwdriver reinstall the four m2 6x5 screws to secure the brass...

Page 31: ...nlet Assembly BHT BHTU Using a 1 3mm or 050 hex tool loosen and remove the two m2 6x3 setscrews securing the Light Inlet Assembly into the bore of the base casting see Figure 125 Figure 125 Remove set...

Page 32: ...and remove adiabatic glass disk Remove the upper spacer tube from within the metal barrel see Figure 130 Figure 130 Remove the upper spacer tube Use a suitable lens suction tool item 9 of Appendix 1 t...

Page 33: ...the lower retaining ring Use a suitable lens suction tool item 9 of Appendix 1 to carefully lift and remove the lower frosted glass disk from within the metal barrel see Figure 137 Figure 137 Careful...

Page 34: ...onto the lower retaining ring within the metal barrel see Figure 141 Figure 141 Place collector lens into metal barrel Carefully place the lower spacer tube into the metal barrel and press it down un...

Page 35: ...aining ring to the glass disk The Light Inlet Assembly is now ready to be reinstalled into the microscope stand see Figure 148 Figure 148 Ready to reinstall the Light Inlet Assembly Reinstall Light In...

Page 36: ...ons are shown in top view in Figure 153 and in bottom view in Figure 154 with the plastic metal version on the left and the all plastic version on the right in both figures Figure 153 Top view of the...

Page 37: ...he filter holder in place in the recess of the knurled field adjustment ring see Figure 156 Figure 156 Remove screws securing the filter holder Lift and remove the filter holder from the recess in the...

Page 38: ...f Appendix 1 to remove as much loose dust and debris as possible from the glass field exit lens see Figure 163 Figure 163 Blow loose dust from the glass lens Use a suitable lens cleaning solution and...

Page 39: ...ws securing the frame of the Light Exit Assembly to the base casting of the stand see Figure 168 Figure 168 Remove screws securing frame to the base Carefully lift and remove the frame of the Light Ex...

Page 40: ...ush item 10 of Appendix 1 to carefully clean the wetted reflective surface of the mirror by gently wiping the surface with the soft bristled brush see Figure 175 Figure 175 Carefully clean the primary...

Page 41: ...n the base casting making sure you do not touch or damage the fragile primary surface mirror see Figure 180 Figure 180 Re install Light Exit frame into base cutout Align the three holes in the Light E...

Page 42: ...oil to the plastic filter holder Place the filter holder into the center recess of the knurled field adjustment ring see Figure 186 Figure 186 Place the filter holder into recess of field ring Rotate...

Page 43: ...Although this collimation is not strictly required1 it should be done if you wish to obtain the best optical performance that your microscope is capable of providing A Few Words About Dust Protection...

Page 44: ...available for download at various microscope related hobbyist sites on the internet These can be found by searching for the titles in an internet search engine such as Google Olympus Research Microsco...

Page 45: ...3 Super Lube Synthetic Oli w PTFE 4oz Super Lube 51004 Amazon 10 99 4 Sparkle Lens Cleaning Solution CLS Amazon 18 43 5 Lens cleaning Tissue 50 sheets Tiffen Amazon 8 95 Table 1 Supplies for servicing...

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