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Motorizing (“Bratcamming”) a focus block or microscope

 
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JGVilla



Joined: 27 Dec 2007
Posts: 62
Location: Netherlands

PostPosted: Mon Mar 30, 2015 12:58 pm    Post subject: Motorizing (“Bratcamming”) a focus block or microscope Reply with quote

Introduction

Last year I started considering the possibilities of using a stepper motor with my focus block.
I found especially the “electric-bradcam” project presented by Chris S. very appealing (see here).

I carefully studied all his information and - being totally new to “robotics” - I did some research on the internet which equipment to use and where to find it.
Beginning of March I was ready to order the equipment and had made technical drawings for my “fabricator”.
The whole design looked (not surprisingly) remarkably like Chris S’ bradcam project.

At the end of January Rik Littlefield started a new thread about How can I harvest and adapt a focus block?.
I found that a challenging thought but also had no answer to the question. Until I noticed a thread by Gembro: Rig II – ‘Bamboo’
Especially his use of “U-bolts” rang a bell. For a couple of years I’m using Item profiles as guide rails on my sawing/routing table.
U-bolts and aluminium profiles might be the answer to the problem.

I will present my solution in three parts:
1. motorizing a focus block,
2. motorizing a microscope, and
3. making a universal stage.
I stopped my original idea of “Bradcamming” my focus block and started instead this project, still making use of a stepper motor with timing pulleys and a timing belt.

Part 1 of 3 - Motorizing a focus block

In his thread Rik referred to my focus block Olympus CHC focusing block which I had made quite some time ago. Here it is again:


1. Original focus block mounted on an Item Profile 5

Underneath the Item profile (type 5) is a cheap Chinese 200mm quick release (QR) plate and some Chinese quick release (QR) clamps for mounting the set-up on a multi-function rail.
Originally there were two QR clamps underneath the focus block for which two M6-threaded holes were provided in the bottom part of the “U-brace”.
These holes are now used to mount both the QR plate as well as the Item profile to the focus block.
First the QR plate is bolted to the Item profile and then the two of them are bolted together to the focus block.

As probably not many people will use such a construction I will leave this for what it is.
Later on – in part 2 – I will give full details how I mounted the Item profile and the QR plate on a microscope.
In this part I concentrate on how to mount a stepper motor (from Cognisys) to the focus block.
That operation is easier to explain here. For the microscope I use basically the same construction.


2. Stepper motor mounted on an Item Profile 5

I refer to the construction that holds the stepper motor as the “side car” (see further on).
As a picture is worth more than a thousand words here are some more pictures with views from different angles.


3. Stepper motor mounted on the side car

The QR plate is 200mm long and because of the position of the threaded holes in the bottom of the “U-brace” the profile is 206mm long to make a symmetrical construction.
206 mm is also the length needed for the (calculated) required length of the timing belt. Here I use a 132t MXL timing belt.


4. View from right behind showing the side car

The horizontal cross profile - mounted to the main longitudinal profile - is only 40 mm long and the standing profile is 45mm. The profiles are closed with Item cover plates. More about these later.
Mounted to the side of the standing profile is a Nema 17 (size of the stepper motor) bracket with quite some mounting flexibility. However the bracket is made of 3mm aluminium and can easily be bend if handled carelessly.


5. View from left behind, the manual control side

This construction provides freedom of movement along 3-axis. Seen from the position in figure 5:
A: left-right: only needed to prevent the stepper motor from touching the focus block;
B: up-down: the position of both shafts in relation to each other is not critical and has only minimal effect on the required length of the timing belt,
C: forward-aft: by just slightly releasing the two fasteners in the bottom cross profile, you can push the side-car with stepper motor towards the pulley on the fine focusing shaft to mount the timing belt.
By pulling the cross profile aft (with your finger) you can tighten the timing belt, taking care not to ‘over-tighten’ the belt.


6. Different views of the side car

In figure 6 several views of the side-car are presented, which clearly show the design. The automatic-fasteners from Item provide a very sturdy connection.
You have to position the fasteners in the profile yourself with a hex T-handle (size 3mm).
They have a self-tapping counter-clockwise external thread. The fasteners are made of bright zinc.
Although this profile is made of black anodized aluminium the fasteners stand out very clearly.
I already started to paint them black as it will take several layers of paint until they are not shiny anymore.

Regarding the black cover plates, they are put in place by a light hammering force and are not easily removed by hand.
You need to tap them on the back to drive them out.
When placed in the profile for the first time the two pins on the back are slightly shaved off and make a tight connection.
After taking them out again you can further shave the two pins with a sharp knife until they just fit the two holes to be taking out by hand when needed.
Take care not to shave off too much of the pins. They will then loose retaining force and will easily fall out.

The pictures also give a clear view of the stepper motor bracket.
These brackets offer very flexible connection possibilities and under normal operating conditions they are sturdy enough,
but care should be taken not to inadvertently deform them.

The strain relief is mounted on the profile in a profile 5 zinc nut M5 with a button head bolt cut to the required length.


7. Top view of the construction

From the above view you can see why I use a 90 teeth (90T) timing pulley. With the focusing knob removed it nicely covers the open housing case.
Furthermore the 90T pulley gives a further reduction in step size of 66%.
Minimum step size with the 90T pulley is 22.2 nm (nanometre) while with a 1 to 1 gearing (32T pulleys on both shafts) the minimum step size is 62.5 nm.
I will probably never use the minimum step size, but having it in place doesn’t seem to hurt the operation and
to my (subjective) observations the stepper motor runs more smoothly and makes less noise in “HI-precision” mode.
As can further be seen the focus block can still be operated manually from the right,
albeit with the stepper motor controller powered up only the coarse knob can be manually operated.
The fine knob can only be operated electrically from the controller or manually when the controller is powered down.


8. Installing a timing pulley on an Olympus CHC microscope

If you want to mount a timing pulley on the focusing shaft of the Olympus CHC microscope you have to dislodge the fine focusing wheel on the left side of the microscope.
Make sure you have the timing pulley ready for installing.

Under the fine focusing knob with the graduation marks on the right hand side (viewed from the front of the microscope) are the reduction gears.
You will definitely want to stay away from opening that side; the timing pulley must be mounted on the left side as shown above.
Best thing to do is to get a copy of the Olympus CHC maintenance manual in which the internals (with pictures) are described:

From the repair manual page 10 and 11:
3 5 Disassembling procedures for coarse and fine adjustment knobs.
3-5-1 Disassemble the fine adjustment knobs in the procedures given below:
a) Detach right and left Plates AA 785000. They can be detached with tweezers fitted into the notches formed in the plates.
b) Remove Screws AB3x6SA from the right and left fine adjustment knobs.
Contrary to the manual only remove the left hand knob (if viewed from the front)
To remove the screws (remove only one screw, just hold the other one in position), fit the allen wrench into them and turn counterclockwise.
c) Pull out the fine adjustment knobs in both directions (remove only the left adjustment knob).
3.5.2 Detach Washer AA784400.
3-5-3 Detach Spring AA 795500.

If all else fails, read the manual here.

First you have to remove the cover plates on both knobs with a pair of bended tweezers.
Carefully pry through the small hole in the plate and gently apply some outward force (to the side not to the centre of the plate) to remove it.
The plates are held in place by some sort of sticking tape.
On the right hand side you will probably want to replace this plate, so try to keep them intact and store them for later use.

Set the microscope so that you face the back side. Now use two Allen keys of the appropriate size (M4 hex screws – 2.5mm Allen key) to unfasten the hex screws.
The one on the right (as seen from the front) should just be held in position while the one on left (viewed from the front) should be turned to loosen the hex screw on that side.
By unfastening the left hex screw the focusing shaft is free to move sideways, so be careful to prevent the shaft from moving out.
Keep it in place at all times by pushing it in with your hand!

While holding the knob and shaft in place with your hand, pull out the knob on the left hand side.
Under this knob there are two washers.
A plastic one (probably stuck to the underside of the fine focusing knob by the grease) and a metallic spring.
Lay them aside for possible future use.
Now you can clean the inside housing of the fine focusing knob of excessive grease.
Then, while still holding the shaft in place, push the pulley over the shaft and tighten it with the set screws (M3 screw – 1.5mm Allen key).

Note: All references with regard to left and right are made while facing the microscope from the front.

Material used:
206 mm Item profile 5 size 40x20
40 mm Item profile 5 size 40x20
45 mm Item profile 5 size 40x20 (on the microscope I use Item profile 5 size 20x20)
6x automatic fasteners for Item profile 5
4x Item profile 5 size 40x20 cover plates
2x Item profile 5 nuts M4 (to fasten the stepper motor bracket)
2x short M4 low profile cylinder bolts
2x M6 bolts to the fasten QR plate to the Item profile 5
2x M6 bolts to fasten the QR plate and the Item profile 5 to focus block
1x Item profile 5 nut M5 for the strain relief
1x short M5 button head bolt for strain relief.

Suppliers list:
Cognisys Stackshot controller & stepper motor
Item (USA) catalog
Pololu Nema 17 stepper motor bracket
Makeblock list of worlwide distributors
Makeblock 32T timing pulley
Makeblock 90T timing pulley
Makeblock 90T timing pulley slice
Makeblock 4mm shaft connector
Timing belt calculator
Gates MXL timing belts
Motionco (UK) 133T MXL timing belt
Technobots (UK) 132T MXL timing belt
Technobots (UK) 32T MXL 5mm timing pulley

Part 1 (stepper motor on focus block) remains an on-going project.
Now I’m painting everything as black as possible. Next I will re-install the black “flocking” material on the focus block, which was removed for this project.

9. part 1 remains an on going project

Work on part 2 of this presentation is also proceeding very well.
I will have to take some more photos to be used for explaining and then start writing.
This will take a few more days.

10. in part 2 - stepper motor mounted on an Olympus CHC microscope

Part 3 of this presentation is also nearing completion. However I found an improvement in the design which I like to complete before posting. That will probably be next week or so.

11. in part 3 – a universal stage for both vertical as well as horizontal use

to be continued . . .


Last edited by JGVilla on Sat Apr 11, 2015 2:32 am; edited 4 times in total
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Charles Krebs



Joined: 01 Aug 2006
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Location: Issaquah, WA USA

PostPosted: Mon Mar 30, 2015 1:59 pm    Post subject: Reply with quote

Impressive project and beautifully documented.

Thanks for posting this.
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ChrisR
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PostPosted: Mon Mar 30, 2015 3:15 pm    Post subject: Reply with quote

Excellent. That's a lot of detail to digest .
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abpho



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PostPosted: Mon Mar 30, 2015 4:54 pm    Post subject: Reply with quote

Looks very well put together.
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Chris S.
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PostPosted: Tue Mar 31, 2015 1:23 am    Post subject: Reply with quote

Jan,

What a wonderful post, and substantial contribution to the art! Very Happy

I well know that this sort of post takes a long time to create, and appreciate the time you clearly put into it. (This in addition, of course, to the inventiveness in the technology documented.) I'll be considering your work, here, in detail--and will surely be far from alone in this.

Great job!

--Chris
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JGVilla



Joined: 27 Dec 2007
Posts: 62
Location: Netherlands

PostPosted: Fri Apr 03, 2015 9:43 am    Post subject: part 2 of 3 - Motorizing a microscope Reply with quote

part 2 of 3 - Motorizing a microscope

A picture of the “converted” microscope has already been published in part 1 (picture 10).

In this part I will use the side car construction which has been presented in the previous part.
Scrutinizing the picture below you may notice the following differences with the set-up in part 1:

1. The vertical profile is now made of a 20x20 profile 5 instead of a 40x20 profile 5.
This gives more room at the top of the longitudinal profile, which is here 270mm long.
Using a 20x20 profile gives as much stability as a 40x20 profile and it saves two connectors,
and if you want everything to be cut by Item then it does not matter which profile(s) you order.
If you order a length of profile to be cut by yourself than it is cheaper to stick to one size.
2. The pulley on the fine focusing shaft has been changed from a 90T pulley to a 32T pulley.
Note that the diameter of the fine focusing shaft is 4mm while the diameter of the stepper motor shaft is 5mm.
My pulley on the stepper motor has been carefully bored out from 4 to 5mm.
I advise against doing that yourself. Even the smallest misalignment will result in a wobbling pulley.
I have been looking for a 32T pulley with a 5mm bore and you can find one in the product list in part 1 (last line).
This pulley is visible in pictures 26 and 27.
3. The timing belt is now a MXL 100t timing belt (1/4“ width).
4. Also new is the “home made” U-bolt, but that is part of this presentation .


12. Final assembly of the microscope

The objective of this project was to motorize a microscope without causing any damage.
This objective has almost been reached; but not quite!


13. Two 5mm holes in the bottom case of the Olympus CHC microscope

First of all I could not resist drilling two holes in the bottom case of the microscope.
The attachment of the longitudinal profile is then much simpler and elegant as when using e.g. another U-bolt.
Diameter of the holes is 5mm for two button head bolts.


14. Scratch marks on the back of the Olympus CHC microscope

Some more “damage” to the microscope is caused by the four (4) set screws in the Item longitudinal profile.
These set screws are needed to stabilize the back of the microscope on the longitudinal profile as the microscope back is slightly rounded.
Using 4mm set screws nicely fixes this problem.

So if you have a very expensive state-of-the-art microscope I would advise against going this way,
but if you’re trying to get a cheap second hand microscope for high precision focus stacking this might be the way to go.

Enrico Savazzi in his book “Digital Photography for Science” has published some valuable information about this subject:
8.5.2 Precision focusers
10.9. Focus stacking
10.9.1 Optimal stack parameters and practical advice
10.9.2. Focus stacking software
10.9.3 Focusing racks for focus stacking
10.9.4 Automated focus stacking
10.9.5 Building an automated focus stacker

Please note that apart from the two above described minor “alterations” the microscope remains fully intact and can be re-established to its original state in about 20 minutes.
In fact by working on this project I completely stripped the microscope of all external attachments, laid them aside carefully and afterwards put everything back together for this write-up.


15. Fully serviceable microscope, turned around for a better view of the attachment of the profile

Picture 15 displays the original microscope with side car and stepper motor attached.
The microscope however has been turned around to present a better view of the attachment of the longitudinal profile, the QR plate and the home-made U-bolt.


16. Home-made U-bolt

Very noticeable in the design of the motorized microscope is the use of a home-made U-bolt.
On the left side are the single ingredients and to the right is the assembled U-bolt.
The U-bolt consists of 2x M4 threaded rods which are squared by carefully hammering them down in a vice.
Over each rod are 5 rounded connection nuts. A single piece of M4 threaded rod with 2 rounded connection nuts are used as cross bar.
The M4 threaded rods (is that the correct English term for these things?) are not yet cut to size.
On the right hand side the total assembly is shown.

I cut the last of the five rounded connection nuts which make up one side of the U-bolt to just 2mm short of the M4 eye bolt set at the correct angle in the profile.
I put this shorted connection nut lower down the line so that the last one is full length (20mm).
Cut the M4 threaded rod to halfway the last connection nut to make room for the M4 cylinder head bolt through the top.
This bolt has to sit on of a washer, otherwise it will slip through the eye.

The eye bolt is tightly fastened at the correct angle in the longitudinal profile by use of a plier.
By doing so you are able to loosen and turn a rod on one side only and slide the side car in or out without having to disassemble the complete set-up.
If a rod turns very lightly in the cross bar you can give it a drop of (Loctite) glue. Figure 26 shows how the U-bolt is used.


17. Front and back view of the Item longitudinal profile

The upper picture in figure 17 shows the side of the longitudinal profile against which the QR release plate will be mounted.
For that purpose two M6 (or ¼”-20) threads can be made in the centre part of the profile (see further on by “mounting the QR plate”).
Also visible are the 4 set screws. When the profile is mounted to the microscope the set screws can be adjusted from this side.
The two M4 eye bolts have already been mentioned above by the U-bolt assembly.

The lower picture shows the side of the longitudinal profile that will be mounted to the microscope.
From left to right in the T-slots: 2 profile 5 M4 nuts each holding a set screw, next again two M4 nuts with set screws and all the way to the right two profile 5 M5 nuts
which will hold the screws through the holes in the microscope base plate or the holes in the aluminium L-bracket (or alternative connection bolts, see figure 22) whichever option is chosen.


18. Aluminium L-bracket

The L-bracket is a standard size 70x50 mm, 5mm thick aluminium profile.
I thought it would be nice not to have to cut the L-bracket,
however for the universal stage I needed to cut off 8mm of the long side to let the stage pass (see part 3).

It might be tricky to drill holes in the L-bracket at the exact position. As you can see I had some problems here.
Fortunately I got the holes in the short side and the inner holes in the long side just right.
The two outer holes I had to clear for about 1mm in one direction. Not visible after assembly and
these two holes are not needed for alignment, they merely further tighten the L-bracket to the microscope.

I keep the short side of the profile at 50mm because that corresponds with the bottom case of the microscope.
By doing so, the same longitudinal profile can be used with the stripped down microscope used as focusing block or as a stand alone microscope.


19, Longitudinal profile mounted on the focusing block

Mounting procedure for the longitudinal profile when the microscope is used as focusing block:
1. Turn the set screws back into the T-slots so that they do not stick out;
2. Put the M5 button head bolts through the L-bracket and attach the two M5 nuts lightly,
3. Bolt the L-bracket to the underside of the microscope stand with M6 cylinder head screws (shorter than the originals);
4. While holding the microscope, slide the M5 nuts into the longitudinal profile;
5. Align the base of the L-bracket with the end of the longitudinal profile. While keeping the profile aligned with the microscope tighten the two M5 button head bolts;
6. Turn the 4 set screws so that they just touch the back of the microscope;
7. Slip the U-bolt over the head of the microscope and fasten it with the two M4 cylinder head screws with washers.
Make final adjustment to the alignment of the profile and the microscope so that they are nicely aligned (done by sight) and
then tighten the two screws through the eye bolts;
8. Gently tighten the set screws against the back of the microscope.

Mounting the longitudinal profile to the stand alone microscope:
1. Turn the set screws back into the T-slots so that they do not stick out,
2. Put the M5 button head bolts through the holes made in the back of the bottom case and attach the two M5 nuts lightly,
3. Bolt the empty bottom case to the underside of the microscope stand with the M6 cylinder head screws,
4. While holding the microscope with the bottom case, slide the M5 nuts into the longitudinal profile,
5. Align the base of the L-bracket with the end of the longitudinal profile. While keeping the profile aligned with the microscope tighten the two M5 button head bolts,
6. Turn the 4 set screws so that they just touch the back of the microscope,
7. Slip the U-bolt over the head of the microscope and fasten it with the two M4 cylinder head screws with washers.
Make final adjustment to the alignment of the profile and the microscope so that they are nicely aligned (done by sight) and
then tighten the two screws through the eye bolts,
8. Gently tighten the set screws against the back of the microscope.
9. Re-install the bottom assembly to the bottom case: one screw for the ground wire and four M6 attachment screws.


21. Assembled focusing block with aluminium L-bracket

Mount the QR plate to the longitudinal profile. I use M6 bolts but make my own sliding bolts.

Sliding bolts are bolts with just under the head no thread. About 6mm of the thread is removed.
After you screw the bolt through a (¼”) thread you can then slide the bolt through the slot.
If you use M6 sliding bolts you also have to clear the ¼” entrance thread to 6mm.


Alternatively if you don’t want or can’t make M6 threads in the longitudinal profile,
make four 4mm holes 10mm on each side of the centre line of the QR plate (aligned with the T-slots).
Make sure that these holes do not interfere with the position of the set screws already in the T-slots.
You can put M4 cylinder head screws through these holes to be fastened in 4 more profile 5 nuts M4.


22. Alternative connecting bolts

While finishing this write-up I did not feel happy about the aluminium L-bracket.
The intention was to describe possibilities to assemble a home-made motorized focusing block or microscope without significant damage to the microscope.
The cutting and drilling requirements for the aluminium L-bracket might well be beyond a - not ‘super-equipped’ - DIY’er.
Based on the U-bolt technology presented by Gembro (see part 1) the following can be a possible alternative.

The alternative connection bolts consists of 2x 70mm M5 threaded rods positioned in a profile 5 M5 nut and fastened to the longitudinal profile with a washer and a M5 hex connection nut.
Placed in the upper two M6 threads of the microscope stand (which normally hold the microscope bottom case) are now two M6 eye bolts.
Below the eye bolt are a M5 hex connection nut and 2 washers (a small one with a hole of 5mm and a big one which covers the hole of the eye bolt).
On top of the eye bolt are again two washers and a M5 hex nut to fasten the whole contraption.
On top of the hex nut is another M5 connection nut used for holding the anti-slack rubber band.
Everything is readily available in a good hardware store and only the threaded rod was cut to size.


23. Parts used for one alternate connection bolt

The eye bolts do not line up with the rods and the nuts in the t-slot, but they do pass through the eye bolt.
By adjusting the two connection nuts on either side of the eye bolt you can adjust the back of the microscope to just touch the centre of the profile.
Then tighten the screws of the connection bolts to make a solid connection.

In my original design I have the QR plate on the longitudinal profile aligned with the underside of the focusing block.
Using the longitudinal profile with the QR plate attached you can find this position again to mark it on the profile for future use.


24. Assembled focusing block with alternative connector bolts


25. Assembled focusing block with connector bolts

Setting-up of the two connector bolts must be precise.
Because of the misalignment of the M6 eye bolts and the T-slots the M5 threaded rods end up off-centre in the eye bolt.
To prevent an offset of the focus block on the longitudinal profile the two connector rods must be placed exactly perpendicular to each other
so that they touch the side of the eye bolts at the same relative position otherwise the focus block will line up with a slight offset:
not critical as long as the focus block and the longitudinal profile are kept parallel to each other.


26. Attaching the side car to the microscope

With the longitudinal profile and the QR plate attached to the microscope, attaching the side car is relatively simple and in fact already dealt with in part 1.
The pictures above show how to insert the side car in the longitudinal profile:
Take off the left cover plate, remove the bolt from the top of the leg, turn the leg upwards and remove the bolt and washer from the longitudinal profile.
Slide the side car in all the way to the housing of the fine focusing pulley and install the timing belt.
Slide the side car backwards to tension the timing belt and fasten the side car with the two bolts in the bottom cross profile.
Insert the eye bolt with nut again, fasten the arm of the U-belt and attach the cover plates. Now you are all set to go.

This setup is for a second hand Olympus CHC microscope which probably had a hard life. One of these days it might just die on me.
With this setup that should not be too big a problem.
Another one is still relatively easy to find and you only have to transfer this setup to the “new” microscope.
Use the old base plate for the two holes (if you need those) and that’s all there is to it.

On the stepper motor I now have installed a 32T timing pulley with a bore of 5mm.
It has only one very tiny set screw which I replaced immediately for a standard M3 set screw (length 5mm), otherwise it functions well.


27. Final assembly of focusing block

Here part 1 and 2 nicely merge together. Note that the original stage plate holder remains in place.

In part 3 I will show the Universal Stage, how to attach it to the stage plate holder and
how it can be used both horizontally as well as vertically both with a camera or as subject stage..

to be continued . . .
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JGVilla



Joined: 27 Dec 2007
Posts: 62
Location: Netherlands

PostPosted: Fri Apr 10, 2015 6:31 am    Post subject: part 3 of 3 - Making an universal stage Reply with quote

part 3 of 3 - Making a Universal Stage

The previous part ended with a paragraph about alternative connections bolts.
Working with both set-ups (regular L-bracket and alternative bolts) I came to the conclusion that I prefer the regular L-bracket.
It is easier to install and does not require so much “tuning” by the set screws.



28. Connecting the profiles to the stage plate holder

The original stage plate holder should remain in place.
If you want to replace it for something else, you have to take into account the small ridge at the bottom. A flat piece of aluminium will not work here.
The ridge is provided to make sure that the stage place holder can run freely with the focusing block.
Instead of designing your own plate it is much easier to leave the stage place holder in place and work from here,
especially as there are already 4 holes provided to connect the profile. These holes line-up very nicely with the profile.

I cleared the 4mm holes to 5mm for M5 bolts which are stronger.
These holes have a slight recess where the original M4 bolts (or any M4 cylinder head bolt) will fit in for lining-up the original Olympus stage plate.
Clearing these holes from 4mm to 5mm has no or little effect on the use of the original stage plate.



29. Mounting the Universal Stage

First mount the two side profiles to the bottom profile with Item automatic fasteners
Then mount the bottom profile to the original stage plate holder by the 4 bolts indicated.
Now the top 4 profile nuts can be slid into the top profile.



30. Top profile mounted on the universal stage with automatic fasteners

I had a piece of profile 5 size 60x20 available and that makes a beautiful stage,
however the L-bracket had to be trimmed down a bit as indicated in figures 30 and 31.



31. Finished Universal Stage assembly

The 60x20 profile now clears the L-bracket nicely (figure 31) while there is still room for the rubber band, if needed when using the focusing block in a horizontal setup.

Picture 31 also gives a good overview of the Universal Stage.
The automatic fasteners take up most of the cost of the Universal Stage.
Each costs approximately U$$ 3.50 and you need 8 for a stable construction.
Apart from the profiles, the cover plates and the fasteners you also need 8x profile 5 nuts M5 and 4x profile 5 nuts M4.
Each nut costs about US$ 0.60. Total cost for the Stage is about US$ 50.00.



32. Extending the side profiles

When working in a horizontal set-up the stage is more than adequate,
but in vertical mode the two side profiles could be extended about 20mm,
so that the top of the 60x20 profile – even with the focusing block in its lowest position –
will stay just above the side of the focusing block.

If you use the alternative connection bolts (mentioned in part 2)
you can make the same set-up but then you have to extend the side profiles a further 15mm.
For me this is stretching it a bit too far as the Universal Stage is only fastened on one side to the original stage plate holder.



33. “Extended” stage assembly for vertical use in highest and lowest position

Figure 33 shows the extended final assembly. The 60x20 top profile is not available in black anodized aluminium so that will be made black later on.



34. Stage plate for vertical use in highest position with attached x-y slider in forward position

I have attached to the 60x20 profile a piece of 10mm thick HPL (high pressure laminate),
the same thickness as the Olympus stage plate, so the original x-y slider could be re-mounted.
Two positions are created for the x-y slider: a forward and an aft position, exactly 70 mm apart.
The x-y slider is fastened from above (but using the original threads in the slider) and can be easily repositioned or removed.
The HPL plate itself is fastened with 4x M5 short bolts to the profile 5 nuts in the 60x20 profile.
Below the stage plate there is quite some room for future expansion e.g. recreating the bright field illumination as in the original microscope
(using continuous light as well as flash).

This is a very stable fully motorized vertical rig with lots of potential for future development.
Note: the “head” of the microscope is contributing to the stability as it rests (via a leftover 20x20 profile) on the base plate.
For extreme stability it could even be fastened with a bolt and a big washer to a QR clamp on the base plate.


35. Vertical stage plate in lowest position with attached x-y slider in aft position

The difference between the highest and the lowest position is of course the 30mm free travel of the Olympus focusing block.
With the x-y slider in the aft position it runs (partly) in front of the Olympus fine/coarse focusing assembly but stays well clear of it.



36. Sliding stage plate for use with camera

For use with a camera I made a “sliding” stage plate with a QR clamp. The stage plate is again made of (16mm) HPL.
It is only half the width of the profile stage holder thereby leaving the knob of the QR clamp free to be turned.
The stage plate is attached to the profile stage holder by 4x profile 5 M4 nuts which can easily slide in the T-slots.
By releasing the 4 cylinder head bolts on top you can slide the stage full forward or fully aft.
In these positions the nuts in T-slot also function as stops for alignment of the stage plate.
You can fasten the stage plate in between but that requires additional action for alignment.

Depending on what kind of equipment you are using you can position the camera either full forward or full aft and facing left or right.
Due to the QR plate underneath the focusing block you can mount the total construction either horizontally or vertically.

For reference a few examples of equipment in different positions:



36. Nikon D800 with 105mm VR

With sliding stage in aft position a Nikon D800 with 105mm VR just fits but sliding it forward, or attaching extension tubes, will collide with the head of the microscope.



37. Nikon D800 with 105mm VR reverse mounted on sliding stage: unrestricted use



38. Nikon D800 on Novoflex M42 bellows with extension tubes

The underside of the Novoflex bellows resides about 1mm below the rim of the microscope head,
but due to the alignment of the sliding stage with QR clamp: unrestricted use.



39. Nikon D800 with Nikon PB-4 bellows and 52mm extension tubes: unrestricted use



40. Vertical set-up with Nikon D800 and M42 extension tubes

I’m not a fan of using a focusing block with heavy equipment in a vertical position, but it can certainly be done.

Below is another project. For my next assignment I need a vertical copy stand.
It is in first instance not mend for macro work, but during the development this aspect will certainly be taken into account.
The Stackshot will here be mainly used as a very convenient camera lift.
Focus stacking can be done with the Olympus focusing block below.
Need to make a switch so that both Cognisys stepper motors can be operated from the same controller.


41. My favorite set-up. Work in progress


Hope this presentation contributes to the art of automatic focus stacking . . .


---oo000oo---

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Last edited by JGVilla on Sun Apr 12, 2015 6:05 am; edited 3 times in total
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ChrisR
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PostPosted: Fri Apr 10, 2015 12:18 pm    Post subject: Reply with quote


This is something I will be looking at a lot, Jan.
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JGVilla



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PostPosted: Sun Apr 26, 2015 9:04 am    Post subject: Update Reply with quote

Update

From just below figure 34 in part 3 above:
Quote:
The 'head' of the microscope is contributing to the stability as it rests (via a leftover 20x20 profile) on the base plate.
For extreme stability it could even be fastened with a bolt and a big washer to a QR clamp on the base plate.

As an experiment I did just that. I took a cheap Chinese QR clamp put a 1.5” ¼-20 flat head bolt through it and tightened it with a washer and a ¼-20 hex nut.
On top of this hex nut I placed two more hex nuts for spacing and placed the microscope head over it.
Locked it up with a large (30mm) washer, a regular washer and a ¼-20 cap nut.

I placed the microscope focusing block on the QR rail of my base board and it turned out to be quite a sturdy construction even by just using this bolt.


42. Head of microscope fastened to QR plate using a QR clamp with bolt and a big washer

The disadvantage of this construction is that the microscope focussing block can pivot around the ¼-20 bolt on the QR clamp.
From picture 42 the solution is obvious: place a second QR clamp underneath the longitudinal profile.


43. Microscope block with second QR clamp on another L-bracket

Directly fastening a QR clamp to the bottom end of the longitudinal profile is not possible, so I made a second L-bracket.

A ¼-20 thread was tapped in the centre of the short end of the L-bracket and a ¼-20 flat head bolt was cut to the required length.
On the long end of the L-bracket two 5mm holes were drilled 10mm on each side of the centreline so that they line up with the T-slots in the longitudinal profile.

To position the microscope focusing block unfasten the cap nut and remove the small and large washers from the ‘QR clamp with bolt’.
Put two M5 button head bolts through the long end of the (second/bottom) L-bracket and place the sliding nuts lightly on the bolts.
Slide these nuts into the T-slots of the longitudinal profile.
Place the ‘QR clamp with bolt’ underneath the microscope head and slide the longitudinal profile all the way down
until it rests on the short end of the second L-bracket and fasten the M5 bolts.
Unfasten the two M5 bolts in the top L-bracket and let the microscope focusing block slide onto the ‘QR clamp with bolt’.
Replace the large and small washers and tightly fasten the cap nut.
Finally re-fasten the two M5 bolts in the top L-bracket.

By tightly fastening the cap nut on the ‘QR clamp with bolt’ it turned out that the yaw of my cheap Chinese QR clamp was blocked by the head of the microscope.
The cheap Chinese QR clamps were replaced by two high quality QR clamps (figure 43).

As a last point I shortened the longitudinal profile about 15mm.
With the profile resting on the bottom L-bracket the profile now ends at the same height as the L-bracket on top.
On the other side the 200mm QR plate was mounted again on the profile and the bottom L-bracket was cut
so that it fitted while being attached to the QR clamp.

This construction is so rigid that you don’t need the home-made U-bolt anymore. 'Very Happy'


44. Microscope focusing block directly fastened on a QR rail

In order to maintain rigidity there must be a QR plate between the two bottom QR clamps.
Above (in figure 44) the bottom QR clamps of the microscope focusing block are fixed directly to the QR plate of my base board.
So no extra measurements are needed.

There are however two more possible positions to mount the microscope focusing block:
1. To a vertical multi purpose rail, and
2. In horizontal position.
Figures 45 and 46 show examples of both possibilities.
As indicated in figures 45 and 46 you have to place an extra QR plate between the two QR clamps.
A cheap Chinese 200mm QR plate nicely fits through these two QR clamps.


45. Microscope focusing block ‘with stabilizing QR plate’ attached to a vertical rail


46. Microscope focusing block used in horizontal position with ‘stabilizing QR plate’

The home-made U-bolt is now only needed when using the stand-alone microscope with a stepper motor.
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PostPosted: Sun Apr 26, 2015 10:28 am    Post subject: Reply with quote

Smile

Figure 41: It must be tempting to fix the microscope and the Stackshot to the same vertical extrusion?

I notice you change the diameter of the wheel on the focus knob. Is that decided now?
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JGVilla



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PostPosted: Sun Apr 26, 2015 12:11 pm    Post subject: Reply with quote

Hallo ChrisR

Quote:
Figure 41: It must be tempting to fix the microscope and the Stackshot to the same vertical extrusion?


If you mean something like this:

Yes it can be easily done, but what would be the advantage versus the focusing block on the baseboard and the Stackshot on the extrusion?
In my opinion putting them both on the same extrusion introduces more vibrations to both the Stackshot as well as the focussing block,
although it might be advantageous if they both vibrate exactly the same. 'Smile'
Also I see no advantage because with the Stackshot on the extrusion I can reach every position on (the stage of) the focusing block put on the baseboard,
while when they are on the same extrusion I'm more limited.
But time will tell.

Quote:
I notice you change the diameter of the wheel on the focus knob. Is that decided now?

That is of course just a personal decision.
When I start testing both focusing blocks I like to have them set to exactly the same setup.
Basically all the motorized setups I've seen so far use a 1-to-1 setup.
I'm interested to see which setup is the best (if that can be decided).

Regards

Edited for minor corrections
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PostPosted: Sun Apr 26, 2015 3:03 pm    Post subject: Reply with quote

Quote:
it might be advantageous if they both vibrate exactly the same.
Exactlly what I meant. Even with something apparently rigid I'm always surprised how much differential movement there is.
Perhaps the extrusion should be filled with lead shot (small balls) to stop it "ringing"!


I asked about the belt wheel (ratio) because I have a similar microscope to motorize. I may be picking your brain Very Happy .
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