Centering microscope

[simonl]

Hi all. Ive always been keen on the idea of a centering microscope (optical centre punch also on to do list) but given my needs are not high and their prices its clear ill probably never aquire one. BUT I have to ask, has anyone ever thought about making one using a S/H low magnification microsope? Good quality old scopes are a dime a dozen can be had for under $20 - $30 in the U.S. An objective/eyepiece combo with 10X would do nicely. Challenging part would attaching a post to fit in collet and align along optical axis. Even more chellenging would be the cross hairs being in focus with the workpiece.

Thoughts?

Simon

[simonl]

Replying to my own thread. How desperate am I!!!

Anyway feel free to shoot me down on a silly idea. Im in hospital with my son. He just had his tonsils out and I been here all day. Theres only so much stuff you can look at on ebay. Gumtree. Grays etc. Etc. Now im making up more projects.....like I dont have enough!

[Stustoys]

Gimme a minute! I type slow lol

[simonl]

Take all the time you want. Im here till tomorrow!

[Master Splinter]

Aldi have some camera/USB based microscopes on sale this weekend for $50...would you like an electronic solution? Probably better if you're talking CNC, though.

[Michael G]

If all you want is 10x (and for basic work I think anywhere between 10x and say 25x is all that is needed) there are probably relatively cheap examples on ebay (mainly in the US) that pop up every so often. You could make a microscope but with the move towards digital cameras old school optical 'scopes are going for less than the cost to produce them.

Michael

Olympus VMF 2X Stereo Microscope Body With 15X NEW Eyepieces | eBay (http://www.ebay.com.au/itm/Olympus-VMF-2X-Stereo-microscope-body-with-15X-new-eyepieces-/261546174362?pt=LH_DefaultDomain_0&hash=item3ce55de79a)
C Baker Measuring Microscope in Montmorency, VIC | eBay
http://www.gumtree.com.au/s-ad/maidstone/miscellaneous-goods/scientific-microscope-with-wooden-carry-box/1052584545 (http://www.ebay.com.au/itm/C-Baker-Measuring-Microscope-/121391494815?pt=AU_Business_Industrial_Medical_Scientific_Equipment2&hash=item1c437f369f)

[Stustoys]

Well of course I have lol

I have a couple of projects on the go to do with them.

Been out to the shed to grab a scope along the lines of what you are talking about.
First on microscopes its not just the eyepiece you have to add the objective lens. The smallest eyepiece I have is 15x the smallest objective is 8x thats 120x thats a lot for a centering scope. You only have about 1mm field of view.
20x can see to well less than 0.01mm. with a 6mm field of view. there is a pic somewhere on here I'll try and find it.

Next problem is the image will be up side down and back to front. Now a mirror might fix half that problem.

Alignments aren't to much of an issue as along as you don't want adjustable focal length, the depth of field is to shallow for you to be to far out.

cross hairs are more of a issue, focus is easy. you use the eyepiece movement for that. Work piece focus is easy you just use the Z axis.

One project I play with now and again starts with one of these

Mini Outdoor Compact Adjustable Pocket Monocular Telescopes Scope 8X 20mm BAG | eBay (http://www.ebay.com.au/itm/Mini-Outdoor-Compact-Adjustable-Pocket-Monocular-Telescopes-Scope-8X-20mm-Bag-/130579756799?pt=AU_Cameras_Telescopes_Binoculars&hash=item1e6728f6ff&_uhb=1)

I'm thinking about using one of the Porro-prisms are the mirror.
Also by changing the distance between the objective and ocular you increase the power.

I have another monocular on the way that uses a roof-prism

Though, I am liking the microscope idea as somewhere to steal a focus slide.

Parallax error if there is anything is something I'll have to worry about later.



Stuart

[simonl]

Hi splinter I would prefer a purely optical system and do away with the need to fire up a pc or even a screen.

Michael. I have steered clear from stereo scopes thinking it may complicate matters. Agreed there are some nice microscopes out there going for a song.

Stuart. Thats why I figured on canibalising a microscope. You already have a quality optical system with objective and eyepiece, focus and prism. I qas half hoping the optics would be correct way round already on a microscope?

Seriously considering this:

Lot of Three AO American Optical 60 Sixty Spencer Monocular Microscopes | eBay (http://m.ebay.com/itm/271558593306?nav=SEARCH)

Simon

[Stustoys]

Might have been over stating "well less" than 0.01mm a little. Make up your own mind.....of course its better than the picture.

http://www.woodworkforums.com/174817-stuarts-fault-optical-acquisition/?highlight=marcel

Stuart

[Michael G]

Seriously considering this:

Lot of Three AO American Optical 60 Sixty Spencer Monocular Microscopes | eBay (http://m.ebay.com/itm/271558593306?nav=SEARCH)

There is no objective though. If buying in bulk, why not this -
LOT 3 Perkin Elmer TLSM 1 Hand Held Measuring Reticle Inspection Microscope | eBay (http://www.ebay.com.au/itm/LOT-3-PERKIN-ELMER-TLSM-1-HAND-HELD-MEASURING-RETICLE-INSPECTION-MICROSCOPE-/360908909868?pt=LH_DefaultDomain_0&hash=item5407d8ed2c)
Look to be complete and you could probably sell off the other 2 to recoup some cost.

As well as toolmakers' microscope, look for "inspection microscope" as well. I found this one this way
http://www.woodworkforums.com/182394-little-beauty-maybe-post1751671.html#post1751671

Michael

[simonl]

Thanks michael. No objective... I missed that! Those reticle inspection scopes look the go.

Stuart. I recently got one of those reticules calibration slides. For the price they are ok!

Who wants to go thirds in those inspection microscopes?

Simon

[simonl]

2 already spoken for. Who wants the last one?

[Stustoys]

ummmm If you're going to spend that sort of coin, you sure you don't want to just buy one?
Enco - Guaranteed Lowest Prices on Machinery, Tools and Shop Supplies (http://www.use-enco.com/CGI/INSRIT?PMAKA=240-0404)
Not that I have anything against making stuff just coz you can :)



"Stuart. I recently got one of those reticules calibration slides. For the price they are ok!"
They are but it wasnt so much about the silde. just showing what 0.01mm graduations look like at 20X.

Stuart

p.s. before you buy those other scope you'd really want to know power and focal length.

[simonl]

Party pooper! Yea alright you got a point but if we each buy one then we may get it for under $100 each delivered.

Ok refresh my memory. Power, is that magnification? so thats nof just the objective focal length x eyepiece focal length? The power may be a tad high but figured eyepieces are cheap and can be replaced? As for focal length, its going to be mm and not M surely ballpark for what we want??? Ok. Im really wrong aren't I??????

Simon

[simonl]

You've probably already loked but this is what it comes with:
TESTING & COSMETIC NOTES:

Please note that there are small dust specs on the eyepieces.

COMPONENTS INCLUDED IN THIS AUCTION:

• (3) - MICROSCOPE BODY
• (3) - SWIVELING EYEPIECE TUBE
• (1) - STARIGHT EYEPIECE TUBE
• (3) - 1:1/0,06 F 60 GERMANY OBJECTIVE
• (2) - 10XWF GERMANY EYEPIECE
• (1) - BAUSCH&LOMB 15XWF EYEPIECE
• (3) - MICROSCOPE ADJUSTMENT MOUNT
• (2) - HANDLES

F60 is that the focal length?

[Anorak Bob]

Simon,

The racks on the Elmers are probably superfluous because you can wind the mill table up or down to focus. You could sell the racks to Stuart and me to defray costs.:U We could use them to focus our Marcels.

Bob.

[Stustoys]

Power is magnification, that's objective X x eyepiece(ocular) X...... well sort of......if you change the distance between objective and ocular you also change the power and the focal length.
Focal length is the distance from the objective and the what you are looking at when it is in focus.

Now with those scopes you are going to need to mount them horizontally* and use a mirror/prism, that's going to use some focal length. WAG looking at those scopes if the focal length is less that 30mm you're going to struggle. Good chance the focal length is longer though, anything up to 100mm should be fine.

Changing the eyepiece isn't likely to be an option and that's where the retical will be(well it can be else where I believe but I doubt it will be). Next problem seems to be that there isn't any adjustment on the retical or anyway to lock it in the tube. This would mean being able to move the complete scope for alignment.


*unless you are happy to mount them vertically and use a lot of Z........this brings tram errors into play if you have a Z move of say 100mm between picking up your center and the cutter hitting your work.

Much of the above is best guesses and could well be wrong :)

Stuart

[Stustoys]

F60 is that the focal length?
It could well be......but I have a feeling F if normally something else in optics. thought maybe I am confusing it with F stop on cameras.


We could use them to focus our Marcels.
I'm looking at the slide on the microscope sitting next to me wondering if I can bring myself to cut it up............

Stuart

[Stustoys]

Just so I'm not putting a downer on the whole thing. If no one else is interested and you're still keen, I'll take the third.

Stuart

[Michael G]

The objectives look to be 1x, so with a 10x eyepiece, 10x magnification. (there is a 15x eyepiece so 15x magnification for that one). Based on that, I would expect focal length to be around 70mm or so? (getting close to a WAG)

Michael

[simonl]

Whats a WAG?

[simonl]

Hi stuart. I think I may pass on those 3 microscopes. I may have got a tad excited. No need for you to purchase since you dont really need either!

Simon

[Stustoys]

lol Whats 'need' got to do with it?


Whats a WAG?
wild a.. guess.
What do you think about the Marcel Simon?

Stuart

[MacPuddock]

This page discusses using a cheap pair of folding binoculars;


https://sites.google.com/site/pjoptical/home/centering-microscope

Findlay.

[Stustoys]

This page discusses using a cheap pair of folding binoculars;

Hey!!!! thats my idea!!!
I have a monocular on the way.
Beaten to it again lol:rolleyes:

Thanks for the link.

Stuart

[simonl]

Hey!!!! thats my idea!!!
Stuart

Ha. take that!

Well I'm home now and so much easier to type on a computer than the phone! Stuart, the whole issue of Z focusing distance and tram errors is a real consideration and one that I have not considered. Not much point having the potential to centre to within a 0.001" if it's off by a couple by the time you wind the head back down..

I just made an account with Enco. They will charge $14 tax and $7 delivery to my Nevada Shipto address. That's not a bad deal really. Also I couldn't help myself, I put in a silly bid of $US100 on those 3 hand microscopes. :doh: Dunno why.

Simon

[Stustoys]

Hi Simon,

Part of the reason for the "sliding" part of the prototype was to match Z length of the tool to the Z length of the scope for when one was being ummmmm lets call it "extra careful" :p. The major part was allow the shortest Z when needed for the Z impaired amongst us.*


lol you had me worried with "bid" you mean "offer". good luck. you never know.

Stuart

*the Marcels have more focal length to play with......about 75mm

[Anorak Bob]

Hi Simon,

............. The major part was allow the shortest Z when needed for the Z impaired amongst us.*

Stuart



* guess who that is !! :rolleyes:

BTW, the Thai seller has more Marcels on offer though at a much higher price than we paid for ours.

[simonl]

Hi Bob & Stuart,

wrt the Marcel, do you plan on making a prism system and making it a dedicated centering scope? Sounds like a bit of fiddling around. That's why I was hoping for an easy way out with a microscope with an angled eyepiece. The Enco for just over $200 also is tempting.

I was also doing some maths regarding tram errors. My calculations are this: If you tram your mill using the method where you sweep a DI over say 150mm radius over the table and you get a height difference of 0.05mm (over 180 degrees), then you will get the positional error in the X direction of that amount (0.05mm) for every 300mm travel in the Z*. I assume 300mm travel is a bit on the high side, Lets assume you have to adjust the Z by 100mm when using the centering scope, that would mean an X positional error of 2/3 x 0.05mm or about 0.03mm. It still defeats the purpose of a centering scope capable of less than 0.001" positional accuracy.

*According to my maths, the angles work out the same (0.05mm becomes 0.05mm in X for the same distance), I did use trig but my maths could be wrong, I'll have another look as I'm not convinced that my diagram I draw is correct.I'm looking at a series of similar triangles that represent different Z adjustments. In any case it's very much a consideration as has Stuart pointed out.

Simon

[eskimo]

Ha. take that!

Well I'm home now and so much easier to type on a computer than the phone! Stuart, the whole issue of Z focusing distance and tram errors is a real consideration and one that I have not considered. Not much point having the potential to centre to within a 0.001" if it's off by a couple by the time you wind the head back down..

I just made an account with Enco. They will charge $14 tax and $7 delivery to my Nevada Shipto address. That's not a bad deal really. Also I couldn't help myself, I put in a silly bid of $US100 on those 3 hand microscopes. :doh: Dunno why.

Simon

every couple of weeks Enco have free shipping and 20% usually off everything...some times it a bit less but wait till the sales
Usually includes free shipping within the states

and whats this tax bit?...are they in one of the taxable states?

[simonl]

every couple of weeks Enco have free shipping and 20% usually off everything...some times it a bit less but wait till the sales
Usually includes free shipping within the states

and whats this tax bit?...are they in one of the taxable states?

Thanks Eskimo, a 20% off sale and free U.S. shipping could put me over the edge! :U The tax thing may only be because I said I was in the U.S. There was an option to tell them that the item was ultimately being shipped outside of U.S. (although not through them) but it gave me issues so I told them nothing! I went to have another try but their website was unavailable.

Been thinking more about optics. Looking at eyepieces that have a magnification of (say) 10X, it got me wondering. Now it's actually the combination of the two focal lengths of the objective and the eyepiece that gives the overall magnification. So if you use an eyepiece from one optical system (or another brand) in another system, it may not necessarily be 10X eyepiece anymore. Is this correct?

Simon

[Stustoys]

* guess who that is !! :rolleyes:
No idea to whom you are referring :D.



BTW, the Thai seller has more Marcels on offer though at a much higher price than we paid for ours.
Wow 54% off to. Though the other two are new he says.





wrt the Marcel, do you plan on making a prism system and making it a dedicated centering scope? Sounds like a bit of fiddling around. That's why I was hoping for an easy way out with a microscope with an angled eyepiece.

Yes, but if you had a Z issue the fiddling maybe worth it. It was going to be 90deg...angled costs Z.. unless you want one of those fancy "90-then angle" ones.
And it has an adjustable retical.




I was also doing some maths regarding tram errors. My calculations are this: If you tram your mill using the method where you sweep a DI over say 150mm radius over the table and you get a height difference of 0.05mm (over 180 degrees), then you will get the positional error in the X direction of that amount (0.05mm) for every 300mm travel in the Z*. I assume 300mm travel is a bit on the high side, Lets assume you have to adjust the Z by 100mm when using the centering scope, that would mean an X positional error of 2/3 x 0.05mm or about 0.03mm. It still defeats the purpose of a centering scope capable of less than 0.001" positional accuracy.

My maths says its 1/3. so 0.016mm




Been thinking more about optics. Looking at eyepieces that have a magnification of (say) 10X, it got me wondering. Now it's actually the combination of the two focal lengths of the objective and the eyepiece that gives the overall magnification. So if you use an eyepiece from one optical system (or another brand) in another system, it may not necessarily be 10X eyepiece anymore. Is this correct?

Yes, but I believe the numbers are more of a ball park than an exact figure. So for the most part its likely to be close. Yeah your 10X might turn out to be 12X but I doubt thats going to worry you.


Stuart

[Michael G]

I was also doing some maths regarding tram errors....
...Lets assume you have to adjust the Z by 100mm when using the centering scope, that would mean an X positional error of 2/3 x 0.05mm or about 0.03mm. It still defeats the purpose of a centering scope capable of less than 0.001" positional accuracy.


Two things here - first of all you won't just use the scope for centering. While that may be your prime purpose, you may also use it to look at things like threads or tool tips. Microscopes are useful in a number of ways so there is no need to say that it won't be any good just because of positional errors.

Next, there is measurement to consider. Typically on a measuring device ideally you want an order of magnitude better on the device than you are trying to measure. 0.03mm is roughly a thou, so a microscope that measures to tenth's is ideal. My 10x does that easily. That assumes you are measuring though - positioning something on cross hairs can be a lot more accurate. If you had a DRO so the scope was purely used for position you would probably find that you could position to the accuracy of the scale without too many dramas.

Then there are your calculations. The two underlying assumptions are that the rest of the machine is spot on accurate and the only error present comes from the scope and the tramming - can you really say that your mill is that accurate? There is bound to be something somewhere that makes that number "in theory". As an aside, you should be able to tram to better than 2 thou over 300mm - see if you can find a Starrett 196 indicator. It makes tramming easy and with practice you should be able to improve on that. I find that I can get less than a thou over that distance - in fact, I'd say I get more deflection from the mill head when feeding than the tram error as the cutter patterns look different left to right versus right to left.

Lastly, there is need. Are you really saying that what you are making needs positioning to better than a thou? A typical drill will probably have run out greater than that in use, so really that sort of positioning accuracy is superfluous. It does help to have everything as accurate as possible but I've been on forums where members claim that they can machine everything to 1/10th tolerances and while some may, I would suggest that for the most part they are wasting their time chasing accuracy that is not necessary (even if I would love to be one of those people able to do that). A tenth is 2.5 micron. Is your shed temperature controlled like Phil's is going to be? 'cause if not - :doh:

(Maybe one of the reasons I have trouble with accuracy is not being able to count...)

Michael

[simonl]

Hi Michael,

Thanks for your input. Yes I think I do have a Starrett 196 somewhere….. Actually I can tram to better than the figure I quoted and yes it's a dream with the Starrett :cool: That was a ball park (conservative) figure. Also yes I realise that my Chinese mill will have many sources of error that were not mentioned but it was really just done to get a handle on some figures related directly to the issue that Stuart brought up.

Too right the scope will be used for other uses! I have a 10X magnifier, one of these:
http://www.jaycar.com.au/productView.asp?ID=QM3539

which gets a lot of use, including as you mentioned, threads, hss lathe tools etc. sometimes just a little more magnification (say 20X) would be nice, if for anything other than for interest.

As for positioning accuracy with twist drills, yes I agree, but when using the positioning for boring then I would have thought the required accuracy may not necessarily go astray even if not needed for 99% of projects?

Stuart, yes it should have been 1/3. Is that the only part I got wrong? I'm doing OK then! :q

Cheers,

Simon

[Michael G]

When using the positioning for boring then I would have thought the required accuracy may not necessarily go astray even if not needed for 99% of projects?

You should have said you had a jig borer! (Maaate!)

More accurate is usually better. The point of my post (sorry if it seemed like a rant) was that even if not 100% suitable, those microscopes would probably be fine for 99% of what you do.

Michael

[morrisman]

This may be of interest

Rex Swensen's Web CNC Mill (http://members.optusnet.com.au/swensenr/Optical.html)

[simonl]

sorry if it seemed like a rant


What's the weather like up there on your high horse? :q

I understand the point you were making.

Simon

[Stustoys]

Hi Michael,

I have a couple of head scratches for me here.


The objectives look to be 1x, so with a 10x eyepiece, 10x magnification. (there is a 15x eyepiece so 15x magnification for that one). Based on that, I would expect focal length to be around 70mm or so? (getting close to a WAG)

Wouldn't a 1x objective be a flat piece of glass?
How do you work out focal length from lens power?(not saying 70mm its a good ballpark guess for the sort of scope, or is that what you mean lol)


0.03mm is roughly a thou, so a microscope that measures to tenth's is ideal. My 10x does that easily.
Wait, you're saying you can see 0.003mm with a 10x scope, you sure you're talking about the right scope?
I ask as this is an admittedly bad picture of 0.01mm graduations through a 20x scope
http://www.woodworkforums.com/attachment.php?attachmentid=282183&d=1377243121
And think Phils/Markos scopes for measuring wires to the 1/10th is 60x, mine scope like theirs is only 20X so I had to boost it when I was checking my lathe.
Wouldnt it also mean you you see to the nearest thou without a scope?

I reserve the right to be full of it.

Off to the shed to get my slide.


Stuart

p.s. Simon it seems there are standard lengths for microscope tubes or at least some objective lenses have the tube length they are designed for printed on them.

[simonl]

This may be of interest

Rex Swensen's Web CNC Mill (http://members.optusnet.com.au/swensenr/Optical.html)

Thanks for the link. It's a half decent crack at the design. 2.5X magnification, is that enough?

Simon

[simonl]

Hey I went back to Enco website and filled in the info for purchases where they ship to a US address but the item ultimately will ship outside of the US. This is what I got:





Subtotal
$199.95


Total Tax
TO BE DETERMINED


Shipping
TO BE DETERMINED


Total
TO BE DETERMINED










Because your order is shipping to an address outside of the contiguous United States, your order must be reviewed by an ENCO customer service associate to determine the correct taxes, shipping charges and grand total of your order. An Enco associate will contact you within one business day to provide you with the total cost of your order. If you have questions about this review, please contact us via email at [email protected].

Should be interesting to see what happens. Hey I'm now writing in bold red!

Simon

[Michael G]

Wouldn't a 1x objective be a flat piece of glass?
How do you work out focal length from lens power?(not saying 70mm its a good ballpark guess for the sort of scope, or is that what you mean lol)

The only way I can say that it is not is from personal experience. My straight scope has a 10x eye piece lens on it and originally had a 2.5x objective. Without the objective nothing was in focus. With the objective it was fine. I found a 1x objective and all was clear again.

That scope is here. http://www.woodworkforums.com/162209-getting-objective-shed-post1578893.html#post1578893
It's cold and dark in the shed, so I won't check now but from the sounds of that write up I think with the aid of the micrometer dial on the eyepiece I was able to measure 1/10ths. Have to check, so maybe the easily was not quite correct


What's the weather like up there on your high horse?
Cold, wet - but then it's like that all over Adelaide at the moment so nothing special

Michael

[Anorak Bob]

Simon,

One thing that a centring scope can be used for is hole centre finding, albeit small holes, if the scope has a concentrically ringed graticule. The Isoma scope I have has a 6.6mm field of view and the graticule, 12 rings, making hole alignment pretty simple. Centring can be achieved readily enough by picking up the hole edges with the crosshairs and splitting the distance using the table feeds ( which is what I would need to do on larger holes ) but a ringed graticule makes things easier. Even illumination is also a necessity. Some scopes come complete with their own light source, others are naked and in the dark.

If you buy a dedicated centring microscope consider how you might mount the scope in your mill's spindle. If the scope is provided with a straight arbor you would probably mount it in a collet chuck. Collet chucks invariably have some runout. The graticule must be adjusted to compensate for the runout. Unless you dedicate a chuck to the role of scope mounting, you will more than likely need to realign the graticule each time you install the scope in your mill's spindle. My bitty mill has a 30 taper spindle. I have a bored out and cut down 30 arbor permanently mounted on the Isoma. A daub of blue Artline ink on the 13's spindle nose ensures the same positioning of the scope's arbor each time it's installed. After a lengthy struggle realigning the Isoma's mirror, I have achieved repeatability when installing the scope. A great thing because the guilt I felt due to xxxxing the thing up in the first place was close to unbearable.


321040


BT

[simonl]

Thanks Bob,

That's a nice image looking in your scope. I'm glad it worked out for you! I followed your thread on that. Is that image the result of fitting the LED's?

WRT finding holes, for larger holes I use an edge finder, I used to use a DTI but found the edge finder quicker and easier especially now I have a basic DRO installed. For smaller holes, I am yet to find a method suitable. I hope this is where a scope will fill that gap. I had assumed that the parallel shaft will just fit in one of my er collets and away I go. Now you come with the complication of runout from my collets! :doh: Well then there would be spindle bearing runout, especially given they are just regular tapered roller bearings, nothing fancy…. I may as well just line the holes up with a matchstick!:C

I could make a dedicated MT4 arbor for it but I would suspect it may would not be any better in the runout stakes! Isn't that the reason why I read some people rotate about the spindle axis and make adjustments to ever reduce these errors?

It also puts into question all my other practices when using edge finders. When I use an edge finder, it gets placed in a collet too. Admittedly I have a dedicated 1/2" collet that only gets used for the edge finder but it would suffer from the same runout issues yet all my "accurate" work is done using this edge finder. I understand what you are saying but I think I need to "keep it real". I use a DRO that has a resolution of 0.01mm and the following accuracy:

Accuracy +/- .002” per 6" or .025 mm per 150 mm (Note: others on Ebay are advertising an accuracy of .001" per 6". This is simply not true. All of these DRO units are made by Igaging and accuracy outlined the provided literature as .002" per 6". )
Repeatability .001” or .05 mm

I suspect any runout errors would be swamped by the limitations of the above? What do you think?

Simon

[Stustoys]

I found a 1x objective and all was clear again.

Shows how much I know about optics :D

Maybe you have better eyes than me. Even on the best of the three 20x I have tried it on*, the Marcel is best, the picture above is zoomed up so much that it maybe misleading. I can split 0.01mm but thats about it..... but then thats 2/10ths.:rolleyes: Not only 2/10ths of a thou, but 2/10th of



Even illumination is also a necessity.
If the postie would hurry up we'd have this sorted.



I have a bored out and cut down 30 arbor permanently mounted on the Isoma.

Soon to be ripped out and replaced ;)... ok maybe not
Do you have the power and focal length table for the Isoma's handy Bob? I cant seem to find it... or am I making it up and there is no such thing??


Stuart

*this may well be to do with focal length......I guess its only far that something 20x with 300mm focal length is going to be way smalles than something 20x with 80mm focal length....... So maybe 10x with a shorter focal length is enough?

[Stustoys]

I could make a dedicated MT4 arbor for it but I would suspect it may would not be any better in the runout stakes!
runout doesnt matter*.......it just needs to be repeatable. With an MT it might be harder than a BT as you would have to look after the location. with a BT you can only put it in two ways......

*"doesnt matter" in this case depends on how much retical adjustment you have, so maybe 1mm... maybe not.



It also puts into question all my other practices when using edge finders. When I use an edge finder,

It depends on the edge finder you have. if its like a wiggler...again, run out doesnt matter**.

Stuart

** with the ball end........not so with the cylinder/disc end***

***unless you are using the cylinder/disc to edge find on a horizontal diameter(which is what I think its for anyway) in which case runout wont matter unless the runout or the diameter is large.

[Anorak Bob]

Simon,

Stu has pretty well summed it up. Stuart also made a comment a while back that when using a mill, thou accuracy is realistically all you can hope for. Plenty of times when even that is not attainable, blunt cutters, poorly sharpened cutters, flex in the workpiece mounting, table out of whack ( a downside of a universal table ). The list goes on.

The leds I bought are still in the bag, untouched. Leveling the ant eaten kitchen floor has eclipsed everything.:no: The illumination in that photo was via a 20 watt halogen lamp. Not ideal because of the shadows it casts.

Stu,

The Isoma is a 20X model. The dimensions shown don't include the ringlight.

321050321051

BT

[Stustoys]

The Isoma is a 20X model. The dimensions shown don't include the ringlight.
:doh:Well that drawing I can find....... I was sure it was in something you typed.........memory fails me again

Thank you

Did your slide turn up yet? I'm thinking your 20x Isoma with 34mm focal length might be twice as "powerful" as the 20x Marcel with 75ishmm focal length?

Stuart

[Anorak Bob]

:doh:Well that drawing I can find....... I was sure it was in something you typed.........memory fails me again

Thank you

Did your slide turn up yet? I'm thinking your 20x Isoma with 34mm focal length might be twice as "powerful" as the 20x Marcel with 75ishmm focal length?

Stuart

I will check the focus dimension again Stu. 24.5mm rings a bell but from where??

No slide yet.

BT

Checked .... the distance to the focused plane from the ring light is 24.3mm and the ring light is 17mm deep.