Centering microscope - Prototype

Web:
gtwr.de/
Instagram:
/ stefan_gtwr

[@daveticehurst4191]

Stefan, I made one over 20 Years ago, so heed my advice. I worked for Philips Research Labs who had an optical Department, and gave me all the help I needed. You NEED to have angle adjustment on the mirror / Prism. Light will reflect at 90 degrees only, ANY misalignment of the 45 degrees will give you a centering error between your spindle centre and your cross hairs. Good luck with it. When the Philips workshop closed I got hold of 2 Isoma centering microscopes with W 20 shanks on for Aciera F 3's. As you say, megabucks on e-bay £ 400 + You may also want to increase the focus distance, 8 mm is too small, you need 25 mm + otherwise you can not pick up an edge down a recessed part.

[@choefken424]

Dave is right, this is extremely important. The vertical field must be aligned with the spindle so the hair line does not move when you move up and down the quill.

[@rwmtube]

Hmm...Are you guys sure? There are commercially made centering microscopes that do not have 90 deg optics. A lesser angle is common. How do those work then? I want to build one of these so please advise. Robert

[@choefken424]

100% sure. Let's say you have a center drill on the spindle and drill a small center mark. Then replace the center drill with the optical device with the quill down, for sure the hair line will not match the center mark. So you need to adjust the mirror to "move" the hair line. Then repeat with the quill up, and it will not match again. So adjust the mirror and repeat again until the hair line is aligned with the quill up and down. The optics need to match the mirror angle, otherwise the field of view could get out reach when adjusting the mirror.

[@rwmtube]

OK but...for the workpiece to be in focus doesn't the quill have to be at the same height for every meausrement? Or at lease very close?

[@rwmtube]

I think I see what you are getting at. You can easily center the body of the microscope and the central ray of the optics to the center or the spindle. However, if the central ray is not precisely parallel to the spindle axis (Z axis) any vertical movement of the quill will create error. Having said that, I don't see how this creates a problem in this application. Lets say you center on a mark. Since the mark has to be in focus you only have about .5mm of height variation in the objective-target distance. I have verified this on the bench. Lets say your microscope is off axis to the Z by 5 deg (which would be a lot.) That would introduce a centering error of .04mm or about 0.002 inches. ( Sin 5 x .5) That's plenty accurate. What am I missing here? Carlos- Your reply discusses moving the quill up and down and the marks not matching up? Not possible. The quill will always be at the same fixed distance from the work. That distance being the distance required to get sharp focus. I think you guys are way off here.

[@ThisOldTony]

Excellent project! Really like the narration, seems to work. Did you find it any easier / harder?

[@mikemorris8065]

now Back on Subject more or less , I don't know where you can get all these details and Idea's from but yours is the first channel i look at any time i look at KZbin machining video's So I want to Thank you so Much for your Time and sharing your skills with us

[@joseguzman9448]

Realy outstanding job,i am retired now but i would have loved to come up with such brilliant idea and execution of it myself !BRAVO!!!

[@MikeHenry362]

Just found this while research center scopes and wanted to comment about how much I enjoy your videos and your style. The commentary in all of your videos is always very clear and understandable, for both your design and fabrication approach. You are an inspiration to those of who strive to do better in our home shops.

[@ShevillMathers]

The microscope 'ocular' or eyepiece used is a simple Huygens eyepiece, the internal lens is the Field Lens, and the front one is the eye lens. The 10 x microscope 'objective' is a plain achromat. Instead of a prism a semi-silvered flat could be used same size as the diagonal in the square housing. Nice to see, I made a similar unit many years ago for a machine shop engineering friend. I am used to these devices in various forms in my telescope applications. Like your cross hairs. Also many surplus optical sites sell a variety of graduated gratucules /reticule, with cross hairs, if you ever wanted to measure distance offsets from the centre. Nice project with your usual finese.

[@puddingpimp]

You introduce a centering error by wrapping the ends of the wires in contrary rotation. It's better to pull them in opposing directions (same rotation around the optical axis) then any difference between the thickness of the wire and diameter of the whole is negated. Also if you pull all the wire corners around the same way, you would negate any centration error in the drill centering (though not from the collet block), because you would be using the same registration respect to your mill and vise for all 4 bends. Rather than tying a knot, it would be better to pull them under tension with weights and pulleys, and set them in place with epoxy (not CA). Personally, I think that crosshair is too thick, it would be better to use very thin black nylon wire which pulls straighter than metal wire, is very cheap, and won't corrode like copper. Epoxy optical cement is guaranteed not to fog, so that would be the best bet.

[@BluesDoctor]

Great work Stefan. I worked for many years in designing and developing night vision equipment for the defense industry. Had occasion to add a reticle to the nvg. My wife loves to tell the story of taking some of her hair, darkening it to black and fabricating an assemblly similar to what you did. In fact it worked very well and was used in early rifle scopes for the military. Modern times we use photolithography with many features. But simple always works! Great project and enjoyed.

[@ROBRENZ]

Excellent work as always Stefan! Love the voice over and condensed editing ; ) I second changing to a 30 or 45 degree eye tube idea. ATB, Robin

[@faaf42]

Narration is excellent! Thanks.

[@AmateurRedneckWorkshop]

A great build and something I would have never thought of. Keep on keeping on.

[@rwmtube]

I just finished mine and calibrated it. Works great! No inaccuracy in centering except that my mill was not trammed correctly. It makes it easy to find a tramming error by rotating the spindle. This will get a lot of use in my shop.

[@Gkuljian]

I have wanted one of these for ages. I've got a Deckel, and the Centricator, and telescope are not cheap by any means. Thanks for giving us a sense of how to build one.

[@johannfr]

Great work, as always! Also, I can't recall if you've done it before, but this format where you narrate the video afterwards is great. Less machine noise while you're talking, etc.

[@danielwerger5641]

Excellent project Stefan...! Thanks. Another source for surface mirrors is old overhead projectors... I always salvage the mirrors and lights out of them.... Cheers, Daniel...

[@petergregory5286]

Stevan, This has turned out to be a very interesting project. Judging by the quality of the advise you're being given the final version should be a very useful tool. The information about the surface mirror took me back to physics lessons at school and measuring the refractive indexes of various pieces of glass. Hope you'll show us the final result. Regards.

[@ShadonHKW]

Well done, your results speak for themselves.

[@rupertpowell]

One last ting. Superglue outgasses and will fog your optical surfaces. Use something other than cyanoacrylates for anything optical.

[@StefanGotteswinter]

Whoops, thats a good tip, thanks! Will it still outgas after it cured? I know the effect of the white debries while it cures.

[@rupertpowell]

I think it reduces over time, but still does outgass, even after curing. NASA has a total ban on cyanoakrylates on any space craft for this reason.

[@roleic7246]

to fix the wires a drop of 5-min-epoxy might do as well. Usually epoxy is better concerning outgassing. A bake-out could also enforce out-gassing early on so it will happen much less later. Superglue maybe at 70°C several hours. 5-min-epoxy at maybe at 90°C for several hours. Bake-out is also a standard procedure for space and high-vacuum applications.

[@StraightThread]

Try a drop of shellac. That's what they mentioned in the video about using spider webs for crosshairs that Rupert provided the link to. It takes a bit longer to dry, but shouldn't outgas.

[@roleic7246]

Shellac is a resin secreted by the female lac bug, on trees in the forests of India and Thailand. It was used for polishing furniture in the last 2-3 centuries. Nowadays it's almost only used for refurbishing old furniture. I have never seen that stuff on an outgassing property list. It seems to be better than superglue. But if it is the best and most practical I somehow doubt. But I have no facts to back that up.

[@pierresgarage2687]

Nice prototype, I like some of your ideas... enjoyed.... ;)

[@maxg8815]

Well done, Stefan! Highlights and narration, very professional. Sure beats half an hour of watching a lathe turn. Lose autofocus and we'll nominate you for videographer of the year. Keep the good stuff coming, we love it.

[@RRINTHESHOP]

Loved the project, fun to build and develop. Great job.

[@andrewdolinskiatcarpathian]

A really fascinating video Stefan, with great cross over appeal. I am restoring a precision travelling microscope. You have provided some interesting ideas. Thank you.

[@MegaCountach]

Hi Stephan, you pretty much blew my mind with this video!!! Absolutely brilliant! I love the way your mind operates. Keep up the fantastic videos. Cheers, Doug

[@crjpetersutube]

55 years ago I restored the crosshairs of a rifle telescopic sight with spider's web strands - from the long ones that support the main web. Optically excellent and VERY fine. They still work!

[@LogicIndustries]

Bad ass project, sir. Very interested to see what your next iteration looks like. Keep 'em coming!

[@dougbourdo2589]

Nice piece Stefan. Regarding the mill mount flange: How about making the top side thicker, boring a relief for the flange & putting adjustment screws similar to an adjustable chuck for ultra fine centering? What's next? a fusion reactor? Fantastic stuff Sir.

[@rupertpowell]

Stefan, If you use paint stripper on the mirror backing you can remove the paint on the rear of the mirror. This reveals the silvering (aluminuum) and you then have a surface silvered mirror which is far more preferable than a back-silvered mirror..which gives ghost images. Nice vid. Keep em coming!

[@StefanGotteswinter]

Thanks, I will try that - Acetone should do the trick. Today I got a nice glas prism in the mail, that seems to be of excellent quality, lets see if that works out for the next prototype :D

[@rupertpowell]

MIrrors are generally proffered to prisms when there is not much light as prisms attenuate more and they need to be multi-coated to prevent internal reflections etc. Mirrors work at all bandwidths and do not require any coating. At least not exotic ones like lenses and prisms do. The best mirrors to use are those sold as telescope secondaries for Newtonian scopes. You can get them for a couple of euros from surplus places (SurplusShed) or on ebay.They can also be harvested from import optical devices like this www.ebay.co.uk/itm/90-Deg-Zenith-Mirror-Astronomical-Accessory-for-1-25-Telescope-Eyepiece-trackco-/221942394907?hash=item33accc301b:g:RIYAAOSwhcJWMDht.

[@RexusKing]

Wow, thanks for the valuable information! I'm building a camera and was just searching for cheap reflex mirror!

[@daki222000]

just was gonna say that!

[@rupertpowell]

Rexus King Usually for reflex camers you need thin ones so they are light and can move more quickly. The ones for telescopes tend to be thick so their surfaces are curate to at least a 1/4lambda. (sub 1uM). For a camera viewfinder this isn't completely necessry...nor for a centering scope...unless you want to use high mags. Stefan is only using 100x so any old mirror will be sufficient.

[@thaiexodus2916]

Reinventing the wheel with the wire a little. Use single film magnet wire and a drop of motor/magnet wire shellac. Once cured the shellac is inert. Magnet wire goes down to 56 gauge, .00049 with the film bringing it up to .00052. Front surface mirrors degrade over time due to oxidization. Hermetically seal the chamber and flood with nitrogen gas or make the mirror easily replaceable.

[@razorworks9942]

Hey Stefan, another home run! This is very impressive. I need to get a magnetic chuck too. I really enjoy your video's, and need to do mine in such a way to keep the interest of whoever is watching. Job well done my friend!! Razor!

[@christopherbarnes6976]

Stefan you do some amazing work, but wow that cross hair was over the top. Great stuff, thanks as always for the inspiration and great videos. Chris

[@stefanrichter9162]

Very fine project ! I like it. 1. You have seen that you have to adjust the focal point of the first Eyepiece-lens to the crosshair. That is necessary and depends on your own eye-prescription. So in case another person wants to use your device he needs to make this adjustment previosly before using the eyepiece. Have this in mind in case you want to make a device to be used by different persons at the same place. (Make the first eyepiece-lens adjustable , thats all) 2. I prefer standard prisms rather than firstsurface-mirrors. (bathroom-mirrors make ghost-images at the first glass-surface) The reason is price and they are easy to mount in such devices as yours. 3. One cheap source of eyepieces and prisms are russian made binoculars. You find them at fleabay. Don´t spend money buying high end binos for this purpose , the costly part at a binocular is the mechanics and the alignment. In this case you are going to cannibalize it. The advantage of cannibalizing a binocular is you find 2 eyepieces , 4 prisms and as bonus 2 fantastic achromatic mainlenses to build luxury-magnifiying glasses for your workshop , and all is multicoated.

[@rok1475]

A suggestion for next version: you can buy optical graticules made for microscope eyepiece that are etched with precise scales ( 0.01/ per div). Some have concentric circles etched on the glass that make centering on small holes quite easy. If you place the graticule/cross hairs in front of the lens looking down and align the center point with the center of the spindle you will virtually eliminate the parallax error the the optics and mirror above introduce. The center marker may appear a bit off center in the view, but if aligned correctly, it will in fact be in line with the spindle. The challenge though is very shallow depth of field. You need to compromise and balance the focus on the graticule against the focus on the scribed line or the edge. But the up side is that the center of the scope is always in line with the spindle, no matter what happens to the mirror or the eyepiece. The downside is that this approach requires a redesign of the scope... Check out the scope based on this principle made by KZbinr from Japan named Miki Ono. kzbin.info/www/bejne/rZXGnoOoi9KJfrs

[@ChrisB257]

Love that mag chuck. The Al machined very nice. The .3 mm drill was tricky - I have some of those tiny drills... they break if you even sneeze! :) Second cross hair was lovely... works excellent. Human hair instead of the Cu wire - or maybe it's thicker! As usual, you are a patient and precise man. Congratulations. Hard to think that's ''just'' a prototype... it sure does a super job. What make is that nice edge finder Stefan?

[@Thunderbelch]

Awesome work as always! Was also thinking of HDD platters for 1st surface reflectors... Adjustment screws for centering the shaft would be a great upgrade.

[@noelrieusset3952]

Loved it, I need one for wheel cutting for clock making. I have a hint for you... For the cross hairs, I fixed a rifle scope with broken cross hairs, I used a black womans stocking thread, its stretchy held in place with super glue and very thin. It worked great. Cheers Noel

[@mustgetlife]

Stefan, if you use a beam splitter you can get coaxial lighting, let me know if interrested, I'll make a sketch to explain. If you've already ordered the prism though I think it's not worth the hassle, ring lighting will work. You can get front surface mirrors on ebay easily I think. Aluminium is better for the visible range than silver and make sure it's protected (has a SiO2 coating on top). Hard drives are a good idea, but they might be slightly lossy and not sure about longevity. Old SLR cameras will have both front surface mirrors and pentaprisms I think. Overall - I like your direction, thank you for the video and keep it up.

[@mgbrv8]

Excellent work as usual. I have two centering scopes and once u install your prism you might want to paint the internal with flat black paint to avoid any refraction. also some thumb screws for fine quill mount adjustment for centering would be handy Great work Dave

[@wolfitirol8347]

Stefan nobody surprises me like you do with this excellent job you showed why the best KZbin metal guys like old Tony and so on mention you in the first row.... Unbelievable good and easy job if you make it :-)) for us "Normalos" a good origin for ideas.. Thanx

[@hermankrijnen6409]

Stefan, a fantastic new item that I have been looking for for a long time. I plan to cut gear wheels for a clock and in order to make them any accurate you need to centre the gear cutter. This the perfect tool to do this and I cannot wait for the definitive design. Meanwhile I will start scrounging for the optical parts. Keep up the good work!

[@Watchyn_Yarwood]

Very interesting project, as always! I see you have received a lot of good comments and ideas. I look forward to you re-visiting this in the near future.

[@stepcorngrumbleteats7683]

Very nicely made. Thanks for sharing this build.

[@fochall1]

Hi Stephan, I have been a camera tech for 20 some odd years and the best surface plated mirrors are in poloroid sx70 cameras and 35mm slrs. they are very thin and un tempered. Also 90 degree slr viewfinders could be handy as well. check your local thrift stores.

[@Engineerd3d]

HDD platters as mirrors, I would not. The ones that actually good optically are already made of glass. The rest of them actually are coated and they do have a good bit of hue to them. Your best bet on a mirror would be to find an old projector or a rear projection TV and steal the mirror out of that. Those have very good quality and are basically free if you go to a recyclers. For the cross hairs, if you have the patience you can get some fiber optic strands and drill the eye piece itself while gluing and exposing the ends of the fibers out to the environment. This should net you a glowing cross hair. High quality sniper scopes have this kind of setup.

[@arnljotseem8794]

Really cool build Stefan. I'm drooling over a Leja centering microscope on German Ebay now for my Schaublin 22, but its €400. I don't really need it at this stage, but its cool...... That magnetic chuck of yours is really impressive, and it looks like you trust it completely :-) Nice job.

[@BrianDaleNeeley]

Excellent prototype. The problem with doing too good a job on the prototype is that there is less incentive to build a final model. ;-) I don't know how crosshairs are normally adjusted, but I would think some fine threading in the tube and on the crosshair assembly would be better than a friction fit. That would probably make it more bump resistant. Initial alignment would take a little longer, and fine tuning even more, but that is something you should only need to do it once. Thank you for all of your informative videos.

[@timtrott4145]

Very nice effort,fine job .I remember reading somewhere That they used spider silk for sniper rifles in WW2. For the cross hair I have found that stretching the wire till you can just feel it give a little will leave the wire dead straight, take out all the kinks. makes threading it through a hole a lot easier.

[@outsidescrewball]

Another great video/build.....really enjoyed/learned

[@petertinning5886]

A centering microscope or a laser crosshair centering light are as good as the method used to produce the center mark in the first place. An easier, quicker and less complicated way to produce accurate holes is to make yourself a drill nest, one that can be set up using a vernier caliper negating the need to mark the hole center. The 3D Warehouse has some examples.

[@jeffkurtock6726]

if you use a Penta Prism, the optical path is always 90°; no need to align. New they are about 70$USD, but you can find "parts" for SLR cameras with a Penta, or even a Penta Roof, prism.

[@69camaoZ28sc]

You make some really good and useful videos. You get the inventiveness in my brain motivated. I was thinking of buying a Fowler 10X Optical 21mm Comparator lens set with the 8 piece reticle scales that are photo etched into glass. Your single piece machined housing is genius. I've been looking to do something similar to this. I only expect hobbyist accuracy out of my device. I probably will use and old 35mm single reflex camera Prism on a little fabricated seesaw for fine tuning of the angle (spring on one side and screw on the other). I also want to add an old USB camera because my vision is no longer 20/20. PS Hard Drive Platters are reflective. however I've made Hard Drive clocks in the past and If they are in a humid area they tend develop spots and make a nice home for some molds to bond to. I need to get a camera and start doing videos.

[@cavemansmancave9025]

Very interesting project. I can see a camera adapter as a useful addition for those of us who have horizontal mills. I'm curious. Do you post in German as well as English? I don't speak German, I'm just curious. Thanks, John

[@dumitruhociung856]

A prism will be a big improvement over a bathroom mirror. If you can't find that, get a telescope diagonal mirror, even the cheapest and smallest will be much better optically.

[@gerardobelink2568]

Cool stuff you create. Congratulations Stefan!

[@caltick]

I find mirrors in old scanners which I take apart for the smooth rods and bronze bushings inside. Probably good quality. Awesome video too. I may 3D print one of these devices.

[@whitehoose]

I think traditionally the cross hair (reticule) used either a silk or spiderweb filament. When using wire, Ideally a single (silver) thread is passed in an "S" through all four holes and fixed in a single knot secured with shellac to avoid differences in tension. Probably not a significant issue at 5x ... just splitting hairs :). Agree about providing adjustment of the mirror also, at such small scales it doesn't take much to throw in big errors. Forensics use superglue vapour to find latent fingerprints in an enclosed space it's very invasive - plus the acid used to keep it liquid is extremely corrosive the vapour is insidious and gets everywhere.

[@scopeboy66]

I have repaired scopes for years. You have done an awesome Job. You can find a crosshair for your scope that will fit in the eyepiece pre made

[@2tooberu]

When dad was in the military he was taught to use spider silk for the cross hairs

[@lifuranph.d.9440]

Very strong too.

[@WildmanTech]

As always you've done a skilled job of craftsmanship. I just clamp a Laser pointer into a collet.

[@BundyBearsShed]

Great video, concept is good and it works well. Thanks.

[@BuildSomthingCool]

Wow! that is great idea. keep up the good work.

[@mcnultyfp]

Isn't necessary to make all the wires exit their holes clockwise (or anti-) to compensate for the holes being three times larger than the wire? I'm wide-eyed with wonder - stunned, really. Brilliant work

[@5steve55]

Hello: You might have good luck with a piece of front-sided mirror; often found in an old photocopier; that would avoid any doubled imaging. Shiny discs from hard drives are good too. Agree with Rupert P about spider webbing. Very nice project.

[@johncarruthers5020]

you can purchase a reticle for an astronomical polar scope very cheaply, they often come in a cell. usually 3 grubscrews would allow centring and colimation. As the NCP wanders some astronomer fit a new current Polaris reticle, the old ones are given away (Y)

[@philoso377]

Nice presentation and good stretch. Use a isotopic flash light source of a flash light or a laser pointer beam transmit from behind the eye piece can tell tales of how our design and finishing may be. When set up and focused the cross hair center onto a test cross hair center then rotate the scope one quarter turn to see eccentricity. We will be surprised with our result in the first cut. Scope like this must have alignment capability to compensate production error. There are two types of error concerning these scopes, optical - 1) axial tilt offset and 2) axial drift offset. The symptom of 1) can be mistaken as caused by alignment of 2) and vise versa. Do verify before entering an open loop task in refinement. I was am frustrated with one of mine it only have y axial correction. I decided to crack open it to regain the x alignment. Will trash it if failed. I love to wait for your next center scope project some day.

[@boelwerkr]

To make the crosshair don't glue it, melt it into the plastic with electric current. This way your much more accurate and you don't need additional glue that can be problematic in long term. Make two pieces so you can put the wire between them. Then put the wires into position and in tension. I've done it by soldering small pieces of iron sheets as weights to it. This will also help with the positioning. You can put in scratches in the right places to guide the wires. Then put the other half on and hook the wires up to a variable power source. The wires between the plastic half's are isolated so they can heat up. The exposed wires get cooled by the air moving around them. While heating up the wires will expand a little bit and contract while cooling down putting tension on the wire. I've done this with very very fine wires.

[@lorenlieder9789]

Very nice job on your centering scope Stefan.

[@russhellmy]

the hole for the wire is on centre and dia 0.3mm, but the wire is dia 0.09mm and pulled to one side of that hole. so wouldn't the wire now be 0.105mm off center? Obviously you can't really make a hole much smaller than 0.3mm and still really thread a 0.09mm write through it. however there are 2 possible solutions to this 1. you could pull the wire 90 deg from the way you did it. so the wire ends up offset along the axis ( which doesn't matter) instead of a across the axis. 2. you could pull the vertical wire to the right at the top and to the left at the bottom, then for the horizontal pull up at the left and down at the right. cheers

[@0RDClark]

Hard drive platters make excellent mirror surfaces. Thy're optically flat and easy to machine. I use them in optical benches for laser work and can be more versatile and durable than their glass alternative. I cut mine on a pillar drill using a good quality hole saw with the arbour drill removed. As long as everything is securely clamped they cut very well, just make sure you cover the surface with at least 3 layers of masking tape, as the chips can score and damage the surface.

[@bertr5650]

Great project Stefan. Thanks for sharing. Without an optics clue in my brain, would it be possible to have it at a larger angle to save you getting down to look at 90degs?

[@harveydix7611]

Possibly an etched crosshair out of an old rifle scope? Great video and an interesting build. Thanks for posting!! HD

[@marceltimmers1290]

Hi mate. I'm still fascinated by the build of this project. I have a few questions/suggestions tough. What if you would use fishing line for the crosshairs and instead of glueing them, melting the Delrin closed with a tiny soldering iron? I think the fishing line might be more easy to centre and will be less obstructive in the field of view. While you might have already have finished this project, I had to stick my big fat nose in.

[@StefanGotteswinter]

I push that thing around in cad back and forth, I will build a proper version of it for sure :) The cross hair itself is definetly the least of a problem, even the copper wire I used was fine enough. I wont use a delrin ring in the next iteration, but something in the line of a plastic that takes glue more reliable. Maybe a phenolic or PEEK...stay tuned :D And for the crosshair itself I am going with carbon fibres..

[@marceltimmers1290]

Thanks mate.

[@marksinden4156]

If you are using a prism, you could build a sighting laser into the spindle where it is clamped into the mill head, and be able to line up the light spot with the desired target. Might be less fiddly than the crosshairs.

[@petek210]

Brilliant idea to use the hard drive as a mirror.

[@roleic7246]

Very interesting and different project. To add another layer of perfection you could put the eye piece pointing upward by 30° or 45° to be more ergonomic. And uninterrupted cross hairs cover up the center spot e.g. a weak center punch mark. An interrupted and possibly dashed cross hair like in your Isoma microscope would help fine adjustments. Of course that is hardly possible using wires. It might involve some etching or engraving of a glass or transparent plastic disc. Or you could glue a copper foil on a glass or plastic disk and etch away the copper where it is not needed like with PCBs and wash the remaining glue off. This way you could also leave concentric rings to center on holes or pins. It's an inspiring project, thanks.

[@adamhutyra4142]

nie

[@jimbit22]

nice project..! one suggestion for a cheap front surface mirror is removing the protective paint from the back of regular mirror with a good paint stripper.

[@StefanGotteswinter]

Haha, good tip, thanks, I will try that.

[@pierresgarage2687]

Car mirrors are also front surface reflective surfaced, dirt cheap at the scrap yard. You can also get one with defrost if you feel it ever comes needed... lol

[@Rubin5342]

Stephan, this is just sweet work. I am going to try this. I love the precision. I don't agree with some comments regarding mirror angle error because once this device is zeroed by trial and error, the mirror angle will not come into play, I think. Dave T. Obviously has experience under his belt so this is my inexperience thinking out loud. Should very much improve precision in the average drill press also. Thank you. //John in Oregon

[@thatoldbob7956]

Great idea, excellent workmanship. Question: as I noticed, the mirror with its thickness, is centered between rounded corners ( if I saw it right). In this case the mirror surface is closer to you than the center of your mill. What the real situation is?

[@geneelliott3230]

I have terrible eyesight even after cataract surgery and corrective lens. I use a microscope camera that plugs into a USB socket and it has internal lighting with good focal adjustment lens. I can now see the finest detail on my laptop screen. Might be worth a try for your project? Cheap ebay / China purchase but works a treat for under $20.00 US.Cheers

[@DoRC]

very cool. it seems though that a .0035 in wire viewed at the 5x mag you have would appear as almost .020 which seems awfully wide for something that is used for such a precision alignment. maybe I'm wrong though.

[@jamwaffles]

Excellent video as usual! What size shank does your edge finder have? Is it 6mm? If so, do you know where I could get one? I have a mill that uses ER11 collets so something more common like 10mm is out of the question unfortunately :(

[@larrysperling8801]

really enjoyed the build. thanks for another great video.

[@WeaponsMachinist]

Nice work on that optical piece. I guess everyone else has over shot the purpose.

[@ianbertenshaw4350]

Hi Stefan, Nice work ! What if you made the mounting spigot flange sit in a recess and tapped 4 holes in the main housing so you could use some small fine thread screws to push on the periphery of the flange to fine tune its position ? Works a little bit like a 4 jaw chuck . So where to next ? Shop made 3D taster ? Maybe a profile projector ? :-)

[@richkellow1535]

Nice one Stefan, but I had to smile when you said it was a piece from a "shaving mirror" considering that you are very rarely clean shaven on video. 10/10, as usual.

[@paulshedleski7063]

rarely clean shaven because he doesn't have a shaving mirror anymore

[@joedellaquila9766]

Wow. I never knew they made magnetic chucks for the lathe. What is your experience with it Stefan? Does it hold well while spinning around? How accurate can you get with it. Great video by the way. Very interesting. I probably will never require a centering microscope but it's really informative to watch your build process.

[@StefanGotteswinter]

Thank you - I wrote a short text about the magnetic chuck on my website: gtwr.de/rant/magneticchuck.html

[@andrewmawson6897]

Excellent Stefan, but would be far easier to use with the eyepiece at (say) 45 degrees to the spindle axis so you don't have to kneel down to use it !

[@stacysimon8864]

As always Stefan, unparalleled work Sir. You make me feel like an apprentice... LOL. Keep up the excellent work Sir!!

[@CJ_LEGAN]

As always, Well Done!!! Thanks for the videos, CJ

[@aserta]

You should buy a military pair of binoculars. Those, already have many of the components you need like the crosshairs, threads, and prism.

[@sharpx777]

very interesting, got a couple of questions though: - can you adjust the focus by moving the eye piece in and out? - how do you adjust tilt? (as in the spindle axis with the close-up piece to be in the same line and the mirror axis to be at 45 deg with the spindle) reason I'm asking is what about if you want to center on a point inside a part that prevents you from dropping the quill down close to it and you can't focus that way? It would also throw the point off if the assembly is tilted once you are at a different height.

[@docpedersen7582]

Very nice project! I think a front surface mirror would serve better, certainly more than a shaving mirror. (Obtainable from Laser/optics bench surplus stuff. Or your equivalent of Edmund scientific.) Alternately look for an old set of binoculars from a thrift shop and use one of the prisms out of them. Might even find an old battered microscope at thift shop to reduce parts cost (for those starting from scratch.) I don't see need for prism adjustment screws. Not talking about angstrom precision here, just reasonable machine tolerances.

[@juanrivero8]

A magnificent prototype, Herren Zeiss and Leitz are patting you on the back. I would have liked to see you line up a center-punch mark. I have an optical center punch and the crosshairs are built in. Which brings me to the point that people do make eyepieces and even objective lenses with crosshairs built in. This would get you out of the business of making crosshairs. Whether one could afford them is another matter. Sometimes you can find old microscopes at bargain prices, though, and repurpose them. An alternative is a laser center-finder and for this consult Dan Gelbart's channel; it's in the video on the mill at about 2:15. I built a knock-off and that is what I use. Good to about .02mm. Anyway, bravo!

[@steveloomis9022]

One of the coolest things I'v seen, love this idea

[@EdgePrecision]

Stefan, Why don't you check into buying a Optical Reticle for a rifle scope. You may be able to find one you can mount in your eyepiece.

[@masaakiarai3669]

Nice job!You can find thin copper wires from earphone cable. Most of them are bundle of 0.055mm standard wires. Old amature astronomer makes their corsshair from nylon thread or teethbrush handle. Heat some nylon thread on fire and pull it suddenly, it turns thin thread.

[@riaandewinnaar5040]

Looks like a telescope colimation tool. Well engineered.

[@peterbaynes5804]

Great work Stefan... I really enjoyed this video.

[@pauldorman]

Rather than wires, why not a measuring reticle? There are very many different kinds designed for microscope eyepieces, with all sorts of scales and grids to suit your optics. They aren't cheap (around ‎€150), but much more precise.

[@andrewkitchens]

careful with the hard drive platters, some of the newer ones are made of coated glass not aluminum

[@RyanRettinger]

Excellent work- Have you considered using this centering scope in the tail stock of the lathe to set the height of lathe tools? I would love a video of this. I’ve also thought about using this tool as a substitute for an optical competitor to measure parts by picking up edges and recording the DRO positions. Any Comment?

[@RyanRettinger]

Autocorrect got me- *a substitute for an optical comparator