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Thread: A little beauty - maybe...
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26th February 2014, 07:12 PM #1Philomath in training
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A little beauty - maybe...
I've been very Stuart-esk lately in my purchases. (and isn't he an inspiration to us all?) Optics and measurement gear.
This one came home today
P1020126 (Large).JPG
It is a Japanese Tiyoda inspection microscope dating probably from the '70's. It's been grafted onto a Newport base but from the black base parts up it is original I believe. It is though missing a small screw to secure the eyepiece. Magnification is 45 times I think (anyone know how to check that?). Everything is stiff and needs cleaning but the view through is good. The plan is to remove the base and make up a spindle mount so it can be held in the mill spindle and used for locating features and measurement.
The optics look high quality though - I can't see a mirror in there anywhere, so I'm guessing that it is prism driven. Focusing distance from the end of the objective to a work piece is around 30mm (rough measurement).
Michael
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26th February 2014, 08:55 PM #2GOLD MEMBER
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Glad to help Michael
Google came up with this
"
- for microscope, the magnification is the product of the lateral magnification of the object, Mo and the angular magnification of the eyepiece, re thus;
M=-(di/fo)*(25/fe) ; di=image distance, fo=focal length of objective, fe=focal length of eyepiece "
Now how you go about measuring the focal length of the eyepiece I'm not sure, so even if the above is correct its not a huge amount of help.
A way I just came up with that will get you a ballpark. How easy it is do do might depend on how dominant your dominant eye is. Set your scope on a rule, work out how much of the rule you can see in the eyepiece. Then set up the scope focused on a sheet of paper. Now if you can look through the eyepiece with one eye(say your right eye) keeping the other eye open. Then with a pen make the paper make both sides of the circle you see with yo right eye... with the pen position on the edge of the circle with your left eye(sorry if that makes no sense at all lol). Measure the distance between the two pen marks, divide that by the distance you can see on the rule. thats your power. Well it worked on a sample of one(the Marcel)
Does the the image move "the same way" as the scope or is it inverted?
Got a theory why the big slot is cut in the base?
Stuart
p.s. does it have a reticle? (I assume so)Last edited by Stustoys; 26th February 2014 at 09:06 PM. Reason: p.s.
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26th February 2014, 09:25 PM #3Philomath in training
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The image moves the same way (which is nice in itself)
The slot in the base is for position adjustment. There is a screw that bridges the gap - tighten it and put the gap in which in turn tilts the scope back. Newport is a name I vaguely associate with lab type optics so I think this scope may have been used on a test bench.
45x seems odd to me though (15x eye piece, 3x objective). 3.5mm side to side through the eyepiece.
Michael
PS - Standard cross hairsLast edited by Michael G; 26th February 2014 at 09:26 PM. Reason: Stus's PS
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27th February 2014, 12:13 AM #4GOLD MEMBER
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Whats wrong with 45x? Depending on the recticle you should be able to get 0.01mm.
https://www.woodworkforums.com/attach...6&d=1377249995
Thats a picture of a 0.01mm lined slide through the 20x Marcel
Doubt you can do much about it(properly), the recticle will (I assume) be built into the eyepiece and the objectives will likely be unobtainable. I did add a 60x cheap scope to the front of my tool makers scope for wire checking the straightness of my lathe, seemed to work ok
Didnt you like my power check idea? lol
Thats what I figured the slot was for, it just seems strange to make such a big solid part if you're going to cut 90% away.
You've reminded me to get my finger out on a cheap optical project I have going.
Stuart
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27th February 2014, 02:05 AM #5
Hi Guys,
Michael thanks for the picture. That looks to be a very nice inspection microscope.
Actually I could use help with some thoughts I've had about trying to build something similar that I can use in a collet on the mill for centring and such. As it happens I have some pieces of optically flat mirror but don't have a reticule of any description. So I'm a bit stuck for that. I've also various lens that I can play with. I do have a very old cheap toy microscope that I could cannibalise for bits if needed.
Thanks:Best Regards:
BaronJ.
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27th February 2014, 06:58 AM #6Philomath in training
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Baron, have a look at the Hemingway kits catalogue - I've actually got one of their centering microscope kits 95% machined in the shed - I just need to do the mirror holder and work out a finish for it. (The instructions suggest anodising but I'm not ready to set up for DIY and commercial I think would cost $$$). They may be able to supply some of the parts for you.
Getting this one is cheating really but it seemed a bargain at the time.
To mount this one I was just going to make up a cranked shaped bracket and screw the raise/ lower mechanism onto it. Nothing special.
Stuart, agreed that there is nothing wrong with x45 as such, but for general inspection and location of feature work it is probably higher magnification than needed. On the other scope I have it is x10 and that seems good to me. Spare Tiyoda parts are out there on eBay but have silly pricing so I'll live with it.
Your power check method made my head swim, so I may come back to it later...
Michael
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27th February 2014, 12:25 PM #7GOLD MEMBER
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Thats the optical project I'm talking about(like I dont have enough things half done already)
I bought one of these for the prisms. http://www.ebay.com.au/itm/8X20-Adju...c09d1f8&_uhb=1
Although the prisms are used as 180deg, but you can use them back to front as 90 degs. Extend the tube 4ish inches ups the power and shortens the focal length. The focus becomes your recticle focus for a fix focal length scope. Added and making the recticle will be a little trickier, but I have a couple of ideas.
I take it the "eyepiece tube" can be rotated 180 so the mount is at the back?
I thought you were complaining it wasnt enough...... You could most likely add a 0.5x lens to the front without much trouble. From China of course. http://www.ebay.com.au/itm/0-5X-Barl...b7d01be&_uhb=1
Its a little on the huge side for your needs. I'm hoping the "Doubling Total Magnification power of your Microscope and reduce the focus length" is a copy and paste from his 2x lens add.
I'm sure I made the test sound much harder than it is. I might try and explain it better later.
Stuart
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27th February 2014, 02:52 PM #8.
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Reticles
Michael,
How did you make the reticle in your Hemingway?
Available Z for you isn't the issue it is for me but with the steep angle of the eyepiece barrel you'll be gobbling up a fair bit of yours. Would you be better off finishing off the Hemingway with some black wrinkle paint and using the Tiyoda for close inspection work?
Bob.
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27th February 2014, 03:08 PM #9.
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An quick and easy way to do this for short focal length lenses is while inside a dark room to focus the image of a window onto a wall opposite the window.
The formulae for working out "fo" is, 1/fo = 1/di + 1/do, where do = distance to object. Since do >> di , di ~ fo .
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27th February 2014, 07:11 PM #10Philomath in training
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http://www.hemingwaykits.com/cgi-bin...71X#aHK_20171X
The kit comes with detailed construction notes, drawings projected from a 3D solid model and all necessary material including standard microscope eyepiece, objective lens, silvered prism, graticule, fasteners and aluminium bar and tube.
- One of the main selling points for me was that the optics came with it as they can be hard to find. Hemingway might be open to the idea of selling the optics and some plans on the basis that Al bar and tube are available here and would otherwise add substantially to the shipping cost (my kit was purchased when I was in the UK in 2009).
My rough eye balling says that I'll lose around 120mm of Z for the scope plus 30 for the focal length. The body of the Hemingway is around 80mm long but the objective focal length is 70mm - about the same although if the objective focal length of the Hemingway were shorter then there would be a slight saving. There may be an opportunity to crib a little if you revised the design with that in mind. The bend in the tube is deceptive as it is expanded there for the prism - it's around 45 degrees off straight. I am thinking about paint for it though.
Yes, the tube will rotate in the mounting ring
Michael
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28th February 2014, 12:32 AM #11.
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28th February 2014, 12:50 AM #12
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28th February 2014, 07:01 AM #13Philomath in training
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I guess one mod that would minimise the Z taken up is to move the mirror - If the scope was made as a straight item and the mirror mounted after the objective the Z could be down to very little - most of the focal length could be pushed out horizontally. If only I knew someone with a half made kit who already had a scope so was not too fussed if the mod did not work. (But who?...)
Michael
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28th February 2014, 09:26 AM #14GOLD MEMBER
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Hi BobL,
I had a play with your eyepiece idea. Its a little tricky. When I get a minute I'll have another go. Thank you.
One thing remember about a SSZCS*. They are only any use if you have a tool/holder set up that short. The prototype I made for Bob as had a total Z length(from spindle nose to workpiece) of 40ish mm(maybe as low as 35mm?). Thats really only likely to be useful if like Bob you have direct mount collets. An ER32/BT30 chuck is way taller than that on its own. I can also imagine a short focal length being painful at times. So of course the answer is either two scopes or an adjustable one .
Talking about that I think they would be much easier to make if you only had one line on the reticle(as I think some might??).
Stuart
*Super Short Z Centering Scope
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1st March 2014, 01:52 AM #15
Make a centering scope.
Hi Michael, Guys,
I went and had a look at "Hemingway's" web site. The price seems a bit steep ! The only unique thing I saw was the graticule. Thanks to the kind person that sent me a PDF of the original article. That describes exactly how to make your own. The technique I've used before drilling holes in bottles to make table lamps. I'm sure that I can devise some method of scribing two lines at 90 degrees to each other.
Thanks.Best Regards:
BaronJ.