Automatic machines, because all are made so?

[Giulio TiberinI]

Joseph was confident in the fact that you would intervene, since you've experienced positively and with great practical result is the construction that the use of a car.

Question: Past imitating the chordal done manually, you were able to apply it in your car?

Ok for the adjustment of poor quality produced by the ball past chordal, using racing 1 / 3D c.o.c. This would say that is an ever present technical requirement.
(Only in the case of manual labor with a tool disk glass, You can be done in less than spherometer because you are sure to have produced good ball to the disappearance of the always present in the damp air bubble between glasses that have different radius of curvature).

On the use of very fine abrasive carborundum, always uncomfortable for laborious kneading that could cause dangerous seizures, I must say that since the first difficult experience, that occurs only in the already shedding (Also from the "salt shaker" it is always too down and concentrated into small piles), that motion due to strong friction, I wanted to try to stop the grama 800, passing immediately to the pitch and cerium oxide (or zirconium).

The experience was positive because after only 45 minutes of manual polishing work, the mirror 250mm already had a glossy band 5 or 6 centimeters in width of the horse 70% diameter, which faithfully reflected the plot for the purpose of squares neon ceiling above me.
Obviously the degree of gloss is just starting, but it is significant efficiency of the oxide of cerium or of zirconium tested, and the advantage of not use abrasive glass of fine grains of glass, But paying the penalty of an only slightly increased polishing time.

With machines, that thanks to their speed (40 or 50 At the minute) get equally good efficiency, I see that is not used carborundum but it is preferred the white corundum very diluted in water to look very milky, with the use of a spray.

I will follow your suggestion regarding the installation POLSIM always interesting.

I saw her on a movie that ven Gordon explains how to do the hand parabolizzazione on the rotating floor that runs very slowly.

Thanks Giuseppe for your authoritative intervention.

[Giulio TiberinI]

I forgot that (I'm losing it!!) also EnricoR, He had built an interesting rotating floor with inverter (as I like it), described here with images

Hi everyone

[GiM]

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.

[Giulio TiberinI]

With the information Giuseppe.

And, I see that the aluminum oxide polishing precious stones (and glass) It costs a third cerium oxide (10 against euro 30 for half kg).

The aluminum oxide is widely used for the machining which starts from puddling and continues with the polishing, It is industrially available in grit sizes from 24 to the 1500.
But alas it is sold in bags of several kilograms, and it seems to me that it difficlissimo to be found in low amounts useful to grattavetro, except for the finer grain polishing, which it is easily.

The hardness of corundum is 7 compared to 9 del Rats (done 10 that of diamond). But for its less aggressive it is preferable (and also recommended in the processing hand). This, however, will significantly extend the work by hand, but not appreciably higher than that in the machine.

[Fabrizio Dringoli]

You are all really smart and prepared,I'm pleased to be joined this forum,I think that will give me a big hand.
My cmq was just an idea,but I think that I will follow the advice of GiM,leave it alone for now the car and dedicate myself to building a nice Dobson but alas now I ordered a couple of slides 310…..I can not start from the bottom….

[Giulio TiberinI]

A 300 It is not a departure “from below”, but let's say that it is at the edge of a “Safety height”.

Is’ challenging yet, if you have no ambition to invent new ways risky, to reach the goal described in detail in the tutorial and texts even to this blog, It requires no new explorations, and good result is only a matter of time, to correct the optics in the best way. And time for an amateur is not money.

But perhaps the time not even surpass 250 direct labor hours, But not counting the wait to make the twenty Foucault tests that require one day each.. (scratch tonight and tomorrow night I do the test, and scratch my correzione..e away so, until the perfect parabolizzazione).

good job…and we are here on purpose to help the classic routes and now notes.

[Giulio TiberinI]

Who possibly can affect, I inserted the following link an article with short video tutorials, POLSIM on the use of software to simulate the excavation of the initial spherical curve of a mirror with a simple rotary table and tool in a decentralized position fixing.

Simulator (not only) polishing parabolic mirrors (POLSIM Software)

[Author]

Posts