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hello Giulio
To answer your question about the past chordal made with the machine in imitation of the past manual can tell you that it is absolutely doable naturally with the obvious differences.
If you go to review the following movie https://youtu.be/9jsZ8Nw2jCM and blocks 50 seconds from the beginning so that you see the oscillating arm practically in its entirety will be able to note the following details:
1) The arm by loosening a few screws you can lengthen or shorten
2) The pin which acts on the tool or on the mirror can in turn be moved and set at any point of the swinging arm, and this allows to fix the pin so that the mirror and tool are perfectly superposable getting past CoC or misaligned freely until obtain a past where the center of the mirror wanting arrives almost at the tool periphery and is made to oscillate them as in the chordal carried out in manual. Of course you need to adjust the eccentric which makes it oscillate so that the center of the mirror never exceeds the tool edge.
3) Finally on the top rod left you will notice that a cockerel done manually turn while the whole is in function allows variations of a few centimeters of the oscillating rod length. I thought that this may be useful in the process of polishing or parabolizzazione imitating at least in part the presence of a second eccentric as in Zeiss.
The substantial difference with respect to a manual processing consists in the fact the past is slightly arcuate and that the tool and the mirror are always in mutual rotation, as well herringbone Also on the site you mentioned. I can guarantee that any difference and other such as in past chordal does those 1/3 CoC changes a little bit but if you adjust well to rotation speed (very low) and oscillation, You are obtained very similar movements to those manuals, in any case it is very useful POLSIM. For very low revolutions (I can get to make one full circle of the plate 4 or also 5 seconds) you're right in saying that it is absolutely necessary mechanical reduction otherwise the couple would be too low and the rotation would crash all the time or even would not leave even. As for abrasives I use them already dissolved in the water ready to use like a very thick cream and spray them on the piece of vials provided with spout acted vigorously before use. It 'something that I find very convenient.
As for the trouble you limit yourself to get to the 800 before polishing. I like to push myself more in the often exaggerate ruining everything with some bad lines. Imagine that have arrived to also use the cerium oxide or aluminum for the sake of seeing the final result on the surface.
When the polishing step usually get a fairly reflective surface to allow a control with Ronchi already after about twenty minutes. For the complete polishing instead pass dozens of hours. In this regard I can also tell you that the aluminum oxide works very well giving a very glossy surface, I could not tell you whether better or worse than a polished made with much more expensive cerium oxide.
Usually port at a good point polishing with aluminum oxide and then finish with the cerium oxide.
Hello everybody.
Ciao
From modest experience that I was able to acquire in the design and construction of machines for processing of mirrors as well as in their use I can only confirm what has already been said in the past, namely that it is useful machines in the roughing stage, where greatly relieve the work and shorten the processing time. At this stage, I have used various configurations but the best it seemed that with the mirror above the tool of equal diameter below with past similar to the "chordal", which is carried out in manual. You dig very quickly, but with a poor ball. Reached a fair degree of depth usually alternating aggiustavo the ball past 1/3 CoC mirror under tool above and vice versa using the biggest abrasive and checking the result with the spherometer. So always with the past 1/3 I arrived fairly quickly (1 hour or so for grain with the mirror 200mm) until the grain 1000 or even to 1200 where they usually came scratches the problems that forced me many times to return to the larger grains. Then I have understood that with finer grains must absolutely avoid letting too dry the two surfaces. So I passed to polishing with pitch patina and aluminum oxide or cerium until reaching the ball. In this phase it has been very useful program POLSIM. In this regard I would suggest to Julius temporarily disable the antivirus program and download the possibly saving on memory stick. The parabolizzazione is the only stage where using the single rotation (very slow) of the plan are manually intervened.
As you can see the settings I used in my work are very different from those suggested by Gordon Waite. By this I mean that I think these change depending on what you have available. I have tried to create a machine that could at least roughly reproduce the handwork, with the possibility to vary the amplitude and the type of passed. Time ago, I was also reminded of the idea to change these parameters with stepper motors controlled Arduino just as suggested by one of you. Then I decided to let it go. With my type machines systematic errors are very limited by the backlash that inevitably are created with buildings like this DIY. So unless the machine is not allowed to work for hours and hours without any setup changes I see difficult they occur.
As I have already said some time ago when I described the construction of that car, I love DIY, I love challenges and I love to learn from my mistakes. It's taken me a few month or so of time but in the end I managed well and now I am happy to have it available. Having said that I want to tell you that the building is not trivial, and for those who begins processing a mirror would advise him to devote himself to that and forget the car. Indeed for those before construction even a miss Pharaonic projects and to start with a 200mm, or at most a 300mm Newton configuration.
Projects Cassegrain type or similar or machining diameters greater than 300mm are difficult and often those doing them without any prior experience leaves half the battle because of the difficulties that sooner or later you have.
My advice is: started with small projects and bring them to term if he stays there the desire you can always indulge in something bigger and challenging.
As for the machines are not indispensable, you can work quietly the hand mirrors, but if you really costruitene there one that is within your reach and then you learn to use it in the best way.
The user guide in these cases is not supplied and easier than you have to write it.
Julius the site you indicated is very attractive and in fact I read about it a lot when I decided to make my car as you noticed that it looks a lot like the Elgin Waineo represented them. The only substantial difference lies in the fact that the point at which it is hinged the rod that connects the swinging arm with the eccentric I have connected with the pin that moves the tool or the mirror depending on the circumstances, so as to limit stress of the motor. As you probably guessed by observing the last of the represented machines, placing a second motor with an eccentric at the point where it is hinged to the rocker arm could transform the machine into a Zeiss considered by many the best in this field at least at amateur level. In fact, if the two eccentrics and the rotary table are driven by three different engines is practically impossible that they remain perfectly synchronous providing that randomness which prevents the generation of periodic motions dreaded, but frankly so far I have not felt the need.
Hello everybody This is the road that I've used.
The network of Ronchi is the fastest way to appreciate if the direction taken is the right.
Then I think when you get parable that produces interference patterns identical or very similar to those ottenure via software to various focal lengths, best switch to Foucault.
With the latter surely it is best appreciated the kindness of the parable or her mistakes.
I follow with great interest your job because even with my 300 mm for various reasons are firm for months now.
Great! The central zone is spherical.
Continue until you get to extend it to the edge.
Good job
You patterns, usali!
With Ronchi you can more easily understand that with Foucault if you're near or far from the ball.
Using the position lattices intrafocale extrafocal or if you have a ball perfectly straight lines appear.
If they are not their distortion will tell you how far you are and what points you have to touch up.
When you've got the ball you can always use Ronchi you closer to the parable. To qualitatively assess the quality of the work done you will be able to refer to the ideal figures given to you by Ronchi program for windows 2.0 downloaded from this same site.
Its use is quite simple.
At that point you should use simultaneously also the method of Foucault that you also provide the numerical values on the quality of the parable I forgot to tell you that when printing is best to set the printer to make them draw lines horizontally rather than vertically. This improves print quality.
There is no need to export the file to PDF. You simply send in print by clicking on the icon on the top left of the screen. If you do not have a printer put the program files to a USB stick and take it behind launching it on a PC with an attached printer.
CiaoHello everyone
I intervene again in this discussion to tell you that a grid can be printed by using the PrintaRonchi program easily available in the network:
http://www.mirrorgrindingmachine.com/
With it's easy to determine the spacing of the lines and the print size. As written previously I will also assure that the print quality is already more than acceptable with a good quality inkjet not to mention the quality that you get with an ordinary laser.
Hello everybody Ciao
I think the simplest solution, faster and cheaper to have the reticle is still printing with a laser asking the favor of someone who owns it. Alternatively, you could print it with an inkjet capable of printing high resolution photos, inferior quality gratings are obtained but still usable for the purpose. I was able to print them both ways, then placing a rectangle of appropriate size on a slide holder, the results obtained are however satisfactory in both cases. It is clear that the less precise the print, the less clear the lines that appear on the Ronchi image will appear, causing the observer to doubt that the mirror has a rough surface, but said possible roughness is better evaluated with Foucault's blade. Having said that, I think you should at least give it a try and evaluate the result.
One last recommendation, transparencies for printing with lasers and those for inkjet printers are different and incompatible with each other. Those for inkjets have one of the two surfaces slightly rough in order to allow the absorption of the ink. These sheets used on lasers tend to melt and stick to the platen roller (big trouble).
Those for lasers have perfectly smooth surfaces and if they are used on inkjets they do not absorb the ink that would spread and ruin the print, so eventually at the stationery you will have to ask for the appropriate transparencies. To obtain the drawing of the lines you can use a special program (whose name escapes me now) downloadable from the net and that allows you to print the number of lines per millimeter you prefer. My warmest congratulations.
A really nice tool to look at and I'm sure functional for the purpose Hi Stefano.
What you get with a chordal passed like the one that appears from the video can deepen very quickly the center. Unfortunately, that kind of past does not provide some good ball. If you own one spherometer measuring the radius of curvature at the center and near the edges. You will notice immediately that the center of the measured radius is shorter than the edges. Moving from the periphery toward the center gradually you reach the desired arrow would allow him to have a more regular ball immediately. In my opinion anyway to bring everything back in the right track just continue to "scrape" with the canonical past 1/3 CoC remembering to often exchange the tool position and the mirror so as not to exceed the desired arrow. Sconsigliatissimo, always in my way of seeing, switch to finer grits before the spherometer indicating a good evenness of the surface, allungheresti only the processing times. This should also allow you to eliminate irregularities at the edges.
Hello everybodyVery well. I will create the mold in such a way as to have the full disk in the lower part closest to the fire so as to allow the bubbles to flow towards the back….
I think I also see the helical plastic focuser in the foreground. It is one of those fittings to be placed on the outlet hole that is practiced on polyethylene tanks. It is one of those fittings to be placed on the outlet hole that is practiced on polyethylene tanks. It is one of those fittings to be placed on the outlet hole that is practiced on polyethylene tanks. It is one of those fittings to be placed on the outlet hole that is practiced on polyethylene tanks. The latter, to make it more precise and smoother, I coated it with Teflon tape.
The latter, to make it more precise and smoother, I coated it with Teflon tape, The latter, to make it more precise and smoother, I coated it with Teflon tape: The latter, to make it more precise and smoother, I coated it with Teflon tape.
The latter, to make it more precise and smoother, I coated it with Teflon tape. The latter, to make it more precise and smoother, I coated it with Teflon tape. The latter, to make it more precise and smoother, I coated it with Teflon tape, The latter, to make it more precise and smoother, I coated it with Teflon tape, The latter, to make it more precise and smoother, I coated it with Teflon tape, The latter, to make it more precise and smoother, I coated it with Teflon tape. For example, I tried several times to print the Eiffel Tower and despite having succeeded the degree of finish did not satisfy me. For example, I tried several times to print the Eiffel Tower and despite having succeeded the degree of finish did not satisfy me. For example, I tried several times to print the Eiffel Tower and despite having succeeded the degree of finish did not satisfy me. For example, I tried several times to print the Eiffel Tower and despite having succeeded the degree of finish did not satisfy me.
For example, I tried several times to print the Eiffel Tower and despite having succeeded the degree of finish did not satisfy me 1 For example, I tried several times to print the Eiffel Tower and despite having succeeded the degree of finish did not satisfy me 25 e 30 euro, For example, I tried several times to print the Eiffel Tower and despite having succeeded the degree of finish did not satisfy me 1 For example, I tried several times to print the Eiffel Tower and despite having succeeded the degree of finish did not satisfy me, just be patient because some prints via assure can take even tens of hours and this is probably why the prices requested for printing are high even if frankly I don't even know what figures we are talking about.Sorry Stefano I have a question to ask.
In your last speech I read that you lack even the excavation 1mm par reach the desired arrow, so I suppose you're using carborundum grit 60 or at the 120.
Now what I do not understand is that in the picture you've posted, unless I do not have hallucinations, you can clearly see the reflection of the ruler that you place on the glass in the works, as well as the depth of the excavation. Now I saw that I came to use the grain 1200 that gave me a fine satin finish but without even the shadow of a reflection, explain to me how you did it? What escapes me?
Go ahead calmly with your project that will grow together and hand in hand with your experience.
Go ahead calmly with your project that will grow together and hand in hand with your experience, Go ahead calmly with your project that will grow together and hand in hand with your experience. Go ahead calmly with your project that will grow together and hand in hand with your experience. Go ahead calmly with your project that will grow together and hand in hand with your experience, Go ahead calmly with your project that will grow together and hand in hand with your experience . If everything were easy, we probably wouldn't even consider such an undertaking because it would bore us. If everything were easy, we probably wouldn't even consider such an undertaking because it would bore us.
If everything were easy, we probably wouldn't even consider such an undertaking because it would bore us, If everything were easy, we probably wouldn't even consider such an undertaking because it would bore us.
If everything were easy, we probably wouldn't even consider such an undertaking because it would bore us, If everything were easy, we probably wouldn't even consider such an undertaking because it would bore us. 
https://s1.postimg.cc/t0k4rys3z/20170729_210519.jpg
https://s1.postimg.cc/xzvjnqctr/20170729_210513.jpgIf everything were easy, we probably wouldn't even consider such an undertaking because it would bore us. That piece like many others of the telescope structure I drew with a CAD and then printed with the 3D printer that can be seen in the background. That piece like many others of the telescope structure I drew with a CAD and then printed with the 3D printer that can be seen in the background. That piece like many others of the telescope structure I drew with a CAD and then printed with the 3D printer that can be seen in the background. That piece like many others of the telescope structure I drew with a CAD and then printed with the 3D printer that can be seen in the background. That piece like many others of the telescope structure I drew with a CAD and then printed with the 3D printer that can be seen in the background.
