First Surface Mirror?
First Surface Mirror?
Has anyone ever tried old hard drive platters as a first surface mirror? They are incredibly smooth and very reflective. I have several laying around, but I have no need to cut them and no way to test the outcome.
mnmyco
mnmyco
Re: First Surface Mirror?
I found this website about using hard drive platters in laser as mirrors. In case anyone is interested to read it I posted it here. I think I will try cutting some soon.
http://www.imajeenyus.com/optical/20140 ... ndex.shtml
MNMyco
http://www.imajeenyus.com/optical/20140 ... ndex.shtml
MNMyco
Re: First Surface Mirror?
These hard discs have a look as if they might not reflect the whole light spectrum equally so I would check the image quality before spending much time implementing them somewhere.
Re: First Surface Mirror?
Good point. Do you have any suggestions for a good way to test that? Especially if it does not involve cutting the disks?
MNMyco
MNMyco
Re: First Surface Mirror?
Well, I just took one and used it for my fluorescence condenser side lighting unit. The surface looks perfectly silvered to me, I didn't find a hint to uneven spectral reflection.
This was out of my stack of optic DIY material, a 2,5'' disc. It was made from some kind of glass. I tried to cut it with a glazers diamond - not good. Then with a diamond dremel wheel - not much better. In the end I needed two discs to get a suitable but ugly shard!
Another source are Polaroid cameras (be careful - prices mith increase already) or microfiche readers.
Bob
This was out of my stack of optic DIY material, a 2,5'' disc. It was made from some kind of glass. I tried to cut it with a glazers diamond - not good. Then with a diamond dremel wheel - not much better. In the end I needed two discs to get a suitable but ugly shard!
Another source are Polaroid cameras (be careful - prices mith increase already) or microfiche readers.
Bob
Re: First Surface Mirror?
A metallic first mirror for dental and mouth treatments is cheaply sold on eBay and is (I am sure) much easier to cut than a hard disk; I used an ordinary hacksaw, 24-32 TPI grade should be good. No diamond tools were needed.
Hard disks are useful as-are, spinning shiny gadgets. One reason they have been named called "hard" is the difficulty of cutting them, in contrast to floppies which could be cut with simple scissors
Hard disks are useful as-are, spinning shiny gadgets. One reason they have been named called "hard" is the difficulty of cutting them, in contrast to floppies which could be cut with simple scissors
Re: First Surface Mirror?
Hi Doron,
what are the dental mirrors made of? Aluminium?
If precise size is important the hard discs I used are not great. The diamond wheel didn't cut them well (maybe a question of the right wheel) and the mirror got hot which induces cracks. With patience and water cooling it will be possible to cut it well , but this is quite an effort. On the other hand side it can be expected that they stay very flat which would be a big advantage for the observation light path. In my case a roughly oval shard was good enough so it didn't matter. I can imagine that a normal abrasive wheel would have cut this material better. I expected the hard discs to be aluminium based - these were not.
Bob
what are the dental mirrors made of? Aluminium?
If precise size is important the hard discs I used are not great. The diamond wheel didn't cut them well (maybe a question of the right wheel) and the mirror got hot which induces cracks. With patience and water cooling it will be possible to cut it well , but this is quite an effort. On the other hand side it can be expected that they stay very flat which would be a big advantage for the observation light path. In my case a roughly oval shard was good enough so it didn't matter. I can imagine that a normal abrasive wheel would have cut this material better. I expected the hard discs to be aluminium based - these were not.
Bob
Re: First Surface Mirror?
Hi Bob
Dental mirrors are made of steel - some kind of stainless. Thickness about 1.5mm. They are coated, and the coating is fairly strong and does not chip off.
They are flat and optically good.
Dental mirrors are made of steel - some kind of stainless. Thickness about 1.5mm. They are coated, and the coating is fairly strong and does not chip off.
They are flat and optically good.
Re: First Surface Mirror?
There are two types of hard drive disks. Some are made of aluminum and others are made of ceramic. Seems most people that cut them use a jewelers saw and some sort of cutting fluid I believe. Maybe some day I will give making a DIY water jet cutter. I know it has been done.
MNMyco
MNMyco
Last edited by mnmyco on Sat Oct 19, 2019 1:50 am, edited 1 time in total.
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Re: First Surface Mirror?
Could a dental mirror be used for an image-reflecting sirface? I have some old sz7 trinocular add-ons with bad mirrors, and sizing a glass fsm is a pain.
Re: First Surface Mirror?
I cannot testify for the imaging quality (never tried); what are the allowed/wanted dimensions (l/w/t) of the replacement metallic fsm ?Scarodactyl wrote: ↑Fri Oct 18, 2019 11:12 pmCould a dental mirror be used for an image-reflecting sirface? I have some old sz7 trinocular add-ons with bad mirrors, and sizing a glass fsm is a pain.
Re: First Surface Mirror?
What would be a good test for a mirror? Looking into it with a pair of binoculars at a subject with fine detail?
Ordinary sheet metal is not that flat so it is the question whether they ground it flat or not.
Ordinary sheet metal is not that flat so it is the question whether they ground it flat or not.
Re: First Surface Mirror?
Scarodactyl wrote: ↑Fri Oct 18, 2019 11:12 pmCould a dental mirror be used for an image-reflecting sirface? I have some old sz7 trinocular add-ons with bad mirrors, and sizing a glass fsm is a pain.
I still have a leftover piece from the dental mirror. The mirror was large enough to cut out 3 pieces for my microscopes. If some of you folks can conceive a quick simple test of imaging, that can be done with basic means, I might be able to run it and report.MicroBob wrote:What would be a good test for a mirror? Looking into it with a pair of binoculars at a subject with fine detail?
Ordinary sheet metal is not that flat so it is the question whether they ground it flat or not.