Starting at the beginning with Mirror Screws

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Re: Starting at the beginning with Mirror Screws

Postby Harry Dalek » Tue Sep 15, 2020 9:55 pm

Steve Anderson wrote:
Panrock wrote:...However it would be fiendishly hard to align the slats on such a device. Steve O

Is it possible to CNC a screw out of a single lump of aluminium? I'm not sure if it would be possible to get the mirror finish required from these machines, and polishing it manually would be seemingly impossible. It would also be expensive. One little error in calculations or programming and you end up with an expensive, useless lump of metal...but is a thought...

Steve A.


I recall i think in Germany in the 30's they were going to made them out of bakelite ,you can get a good finish on that ,i can only think they chrome plated it some how looking into it ... for plastic
s-l640.jpg
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https://www.ebay.com.au/i/111323993602? ... 4wQAvD_BwE

I had some chrome paint for some time but was not impressed with what i got ,it was not that good a mirror finish as shown in the photo of the hat .the kit is a bit to pricey for me look more it to the paint side if there's a cheaper way like just a spray can !
I can only think if that's possible a plastic mirror screw must be possible just a matter of finding a strip of plastic or similar to cut to size ...i don't have a drill press or CNC at the moment so drilling accurately is a problem ..
Any case very inspiring Steve O and how you have kept at it want to improve it really showed how to do it right, if i live long enough seeing how the years fly by quicker as you get older i want to make one of these buggers !
Last edited by Harry Dalek on Tue Sep 15, 2020 11:12 pm, edited 1 time in total.
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Re: Starting at the beginning with Mirror Screws

Postby Panrock » Tue Sep 15, 2020 10:40 pm

Harry Dalek wrote:Any case very inspiring Steve O and how you have kept at it want to improve it really showed how to do it right, if i live long enough seeing how the years fly by quicker as you get older i want to make one of these buggers !


Then go for it Harry! You know you want to. I'll give any help I can. :D

I've heard there is one (industrial) 'spray on chrome' process that actually gets good results. Unfortunately I don't have details immediately to hand, but a friend with a '49 Buick is using it for his overriders.

Steve O
Last edited by Panrock on Wed Sep 16, 2020 3:52 am, edited 1 time in total.
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Re: Starting at the beginning with Mirror Screws

Postby Harry Dalek » Tue Sep 15, 2020 11:42 pm

Its on my mind to look into it Steve but factors like having to drill all those plates correctly i would need at least a drill press no matter what material i used .
And you have to do these things cheaply as its more than likely a one off experiment .
But as i said its on my bucket list to do : 0 ) .
Couldn't look around for any thing at the moment even if i wanted to lock down in Melbourne can't go 5km from the house even then only for a good reason .
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Re: Starting at the beginning with Mirror Screws

Postby Harry Dalek » Wed Sep 16, 2020 11:20 am

Iooking on line our hardware shop Bunnings sells 3mm thick aluminium flat bar 1m lengths under 7 bucks various widths and lengths also ...3mm thick .
line wise for a 120 line screw what was yours ? for a 32 line screw still seems a bit thick to me but i suppose it depends on how big the screw is to match it ...good to have some advice Steve O on the Quirks of this rotating beast . :?
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Re: Starting at the beginning with Mirror Screws

Postby Steve Anderson » Wed Sep 16, 2020 2:39 pm

Panrock wrote:To quote from that paper: "It’s been said that there are two types of researchers - those who have blown a laser diode and those who will." Steve O

From the aviation industry..."There are two types of pilots, those that have landed gear-up (undercarriage-up), and those that will." Thankfully I'm still in the second category.

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Re: Starting at the beginning with Mirror Screws

Postby Panrock » Wed Sep 16, 2020 7:40 pm

Harry Dalek wrote:Iooking on line our hardware shop Bunnings sells 3mm thick aluminium flat bar 1m lengths under 7 bucks various widths and lengths also ...3mm thick .
line wise for a 120 line screw what was yours ? for a 32 line screw still seems a bit thick to me but i suppose it depends on how big the screw is to match it ...good to have some advice Steve O on the Quirks of this rotating beast . :?

I used stainless steel slats, not aluminium, which would have dulled quickly. The thickness was 1.5mm. This gave a picture 180mm high at 120-lines, though the indexing holes were designed so (as an alternative) the slats could be locked together in pairs, giving double-width (3mm thick) for 60-lines. My screw started life as a 60-line screw and later changed to 120-lines.

The slats were laser cut by a local firm. I tried to polish their reflective edges myself but it was extremely hard work and not very successful. Eventually I had to have a polishing firm do it. They obtained a good mirror finish (essential) but in so doing, removed enough metal to disturb the balance. So on the finished screw I had to use a balance weight.

It was a hard project. 32-lines should be easier.


Steve Anderson wrote:From the aviation industry..."There are two types of pilots, those that have landed gear-up (undercarriage-up), and those that will." Thankfully I'm still in the second category.

Funny, I've always associated the name 'Anderson' with flying. In the 1960s there was a boy at my boarding school (Donald Anderson) whose father (Andy?) was a BOAC Flight Captain. Young Donald claimed to have flown an aircraft too.

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Re: Starting at the beginning with Mirror Screws

Postby Harry Dalek » Wed Sep 16, 2020 8:53 pm

Yes finding stainless still is a problem i have only seen it sold as flat plate as in (rulers) may be a bunch or those ..i recall trying to drill and cut the stuff at BHP when i was 19 giving me a hand saw to cut bolts it was not easy ! half the time i broke the blade ....why they didn't have an angle grinder at BHP is beyond me !
But working with this type of steel is hard not a easy thing for those of us with lack of tools.
There are many ways to do the same thing but the end results can be worse as below this one needs some thinking ...
i tried an idea today using the ( i ) plates from a transformer bolted them together and polish them up about 60 plates it sort of works but to thin ,soon as you try and drill them even in the stack they warp a bit ...would of tarnished and rusted in time any way
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Re: Starting at the beginning with Mirror Screws

Postby Panrock » Wed Sep 16, 2020 8:58 pm

You're a born experimenter Harry, and I'm sure you'll succeed in the end.

Transformer lams are a novel approach. Maybe you could make an ultra-light miniature screw...?

Steve O
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Re: Starting at the beginning with Mirror Screws

Postby Viewmaster » Wed Sep 16, 2020 9:25 pm

Panrock wrote:You're a born experimenter Harry, and I'm sure you'll succeed in the end.

Transformer lams are a novel approach. Maybe you could make an ultra-light miniature screw...?

Steve O

Yes Harry, As I made the 'Nipkow Nipper', then you can make the, 'Screwy Nipper!'
“One small step for a man,"......because he has Arthritis.
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Re: Starting at the beginning with Mirror Screws

Postby Harry Dalek » Wed Sep 16, 2020 10:22 pm

Hi Steve and Albert Yes the small screw might be possible again with the old idea of stainless steel razor blades i mentioned many a posting ago the edge is a problem may be? i suppose you could grind it flat or may be angle the screw ....for the light could be a laser line ,the laser i have is one those you can focus it very thin ...but it would look like a giant against a stacked version of these...may be it could project larger to a screen
I do like no drilling needed some thing to think about .... ,there are similar things about the same size i will have a look around for other ideas but so far this is up there .
I do have another project i am looking into but this is on my mind .
another idea is the ruler 15cm but would have to drill that one under 20 bucks for 32 of them
https://www.aliexpress.com/item/3280036 ... LmxOW&mp=1
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Starting at the beginning with Mirror Screws

Postby Harry Dalek » Thu Sep 17, 2020 12:19 pm

I thought i would show you the ( i ) transformer lamination material idea that went bung on me .
I knew the idea might be good for a short time screw and i would think giving the Steel a polish should get similar results .
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The good thing about them is predrilled for polishing just bolt together and sand the coating off and start polishing i only did a quick proof of concept idea on them just to see if it was worth the effort ! i could just start to see a reflection as in photo below .
i thought i would give the drilling side of it a go even with no drill press and that was a no no the plates are very bendable even in the stack putting pressure on them drilling as you see the stack starts to warp ...here to the stack is all out of alignment after i pulled a good percent off and tried again .
The optical side was better when i had them all in alignment after i have been at them with the drill they were way out .
My plan was if this worked out use the i's from a micro wave transformer might be a bit more stronger with size .
I think the idea is sound if drilled correctly ..a drill press and a nice sharp drill would help !
May be chrome plating the exposed edge might stop rusting but thats something i have no experience in

I had a look to see if the alignment and bend could be corrected quickly for some photos and it seems so below ,if you spent some time polishing could be better than my quick experimental results
DSCN7119.JPG

DSCN7120.JPG

DSCN7117.JPG


Below here is the drilling warping mistakes from yesterday

DSCN7092.JPG
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Re: Starting at the beginning with Mirror Screws

Postby Panrock » Thu Sep 17, 2020 7:34 pm

Interesting stuff, Harry.

It's worth remembering that when we view from the side the stack of slats, bolted together as one block, we are seeing a 'preview' of the appearance of the blank raster that these slats would produce when later made into a mirror screw. So, any 'cloudiness' or 'lineyness' or 'greyness' visible on the block would show just the same on the raster. And under the picture.

For a good mirror screw picture, the block of slats must have a perfect mirror finish with no gaps between the lines. The side of the block must look continuous, as if there were no slats. You should be able to see your face in it!

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Re: Starting at the beginning with Mirror Screws

Postby Harry Dalek » Thu Sep 17, 2020 9:11 pm

Panrock wrote:Interesting stuff, Harry.

It's worth remembering that when we view from the side the stack of slats, bolted together as one block, we are seeing a 'preview' of the appearance of the blank raster that these slats would produce when later made into a mirror screw. So, any 'cloudiness' or 'lineyness' or 'greyness' visible on the block would show just the same on the raster. And under the picture.

For a good mirror screw picture, the block of slats must have a perfect mirror finish with no gaps between the lines. The side of the block must look continuous, as if there were no slats. You should be able to see your face in it!

Steve O


Ho Yes Steve i have reviewed your posts and saw how good your screw looks lined up like these i only spent a few minutes working on the slats with what i had handy which was not much ! i just wanted to see if this sort of crappy steel would shine up if worked on ... Stainless steel is what you want for this but for experimental quick go it might be possible with the right gear to drill and polish .
One thing that comes to mind if you pass a small current though steel it stops it rusting bit of useless information tarnishing ?
Still looking in to this Screwy business :lol:
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Re: Starting at the beginning with Mirror Screws

Postby Panrock » Thu Sep 17, 2020 11:07 pm

Harry Dalek wrote:Ho Yes Steve i have reviewed your posts and saw how good your screw looks lined up like these....

Not so good. The first 60-line pictures, using the slats I polished myself, were decidedly 'milky'. See pic. So I learned this the hard way.

And you're right. It's a screwy business! :lol:

Steve O
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Re: Starting at the beginning with Mirror Screws

Postby Harry Dalek » Fri Sep 18, 2020 9:25 am

Panrock wrote:
Harry Dalek wrote:Ho Yes Steve i have reviewed your posts and saw how good your screw looks lined up like these....

Not so good. The first 60-line pictures, using the slats I polished myself, were decidedly 'milky'. See pic. So I learned this the hard way.

And you're right. It's a screwy business! :lol:

Steve O


Looking back a few years i saw Dom's go on the forum which looked a bit cloudy so i can see its important to go with a high finish but i suppose its how much work you can put into it polishing is very hard with out the right right gear how happy you are with the results any thing is better than nothing .
i was looking into your problem with thin light at a distance from the screw ..distance giving a thin enough line for the screw ? i know your swapping over to lasers PWM yes ?
I have seen the mirror screw projected to screens looking at the vintage ones, instead of direct viewing ...you really would have to do this with lasers
The line laser i have length of the line depends on distance ....easier for a casing for sure and adjusting to size of your screw ,if you pass this laser line laser via those laser printer long flatish lenses the line becomes even finer as i can't adjust the thickness of the laser line seems fixed but that again works good .
The laser line laser lens is different to a focus to a point focus laser even just its lens would be useful must just have a standard laser diode behind it .
Another idea would be to use a laser printer polygon mirror with a standard dot laser to produce the laser line to project to the mirror screw would it give you different line frame rates depending on speed adjustments on both this is the case for 2 mirror drum systems i have played with .That would be interesting first multisystem mirror screw.
BTW this place in the UK sells polished Stainless Steel more than likely pricey and you only want the edges really can a screw edges either side work or just one side ?
http://www.c2stainless.co.uk/strips.html
I made my mind up on the razer blades and 15cm stainless steel rulers they were only 17 cents for 2 got 64 of them and under 10 bucks for 100 double edge razer blades i can have a shave with the left overs :lol: both are on the way from good old virus free China gives me a month to think about drilling and or polishing
This does not took to bad doing it by hand

youtu.be/HPLhtNwcjYQ
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