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Inaugurate the blackboard…..
Then: I just finished building a robust workbench in the garage. Wanting and having, sooner or later, liberate the tavern from the drum 200 liter I use now, I was considering the possibility of using a part of the table room for installing a rotating floor (by hand, at the moment…..).
Is there anyone who has built something or saw on the net an accomplishment like that?
In terms of space, there would be a plan mirrors max 400mm. At most you move the trunk in the garage, ma, dovendolo pull over to the wall, me there remains the problem of the rotating floor.
assumptions c: spinning machine……radically change my workbench and install it under an electric motor that drives the plan…….I think that Mirco has built a rotating top, which still uses, I would also curious to know how he did it.
hello Henry, a few years ago he came to build me a ball machine with which at least be able to hew mirror, so far as I can show and suggest it comes from my experience. The machine that I built is a like Mirror o Matic, with an eccentric which moves to the right and left arm, above to a rotary table. I attach some photos I took the car, describing a thousand words the solutions I adopted. Of course you can take a cue from the following to achieve only the turntable.
Please, pay no attention to the aesthetic aspect, I have not taken care of and a lot more wear and having worked on have made it definitely dirtier and less "attractive":
If you're going to build you such machinery, I enclose also the Excel spreadsheet that I made with which I simulate the track that describes the tool center on the turntable by varying several parameters, so you can choose the best solution already in the planning stage ...
https://www.grattavetro.it/wp-content/uploads/2014/10/TRACC-UTENS-Macchina-Mirco2.xlsxTips:
Powering it all is a three-phase motor (0.25 HP) converted to single-phase thanks to the use of an appropriate condenser, which it has a sufficient power for the purpose, even if an engine a little bit bigger perhaps would be better.The 3 wheels placed under the rotary table can put them the most externally, do as I did, that I put too much towards the center and when you are working on the edge of the mirror, the table tends to leverage and get up ...
Do not use the types of tires that I used, which are formed by steel balls, as these tend more than anything else to crawl against the plate attached under the rotary table. Put rather of rubber wheels that in most undoubtedly generate less noise.
If you decide to just build yourself a rotating table, in my opinion, not attack the table directly on leaving the motor, but connect it to another tree that receive the motion from the gearbox via a pair of pulleys and belt. I recommend this so you can, changing the pulleys, also change the speed of the table, something that otherwise you could not do.
All the solutions I've taken were taken on my own, since then I had not yet discovered the various sites where the various types of machines are displayed, this to tell you that if you look good in Internet'll find other solutions, maybe (indeed almost surely) better than mine ...
Mirco Congratulations for your work!
The simple rotary table is very comfortable and in the past had made us a thought too.
The rotating floor of Gordon Waite is motorized with a 350watt 4 poli (1760 giri a 60 periods) provided by a three-phase inverter with motor 1:30 which in his case, produces variable speed to zero 60 rpm.Certainly an asynchronous motor from a washing machine would be silent and at no cost, and he would have two poles for two different speeds, one of which is low it can be easily used by recycling the original pulley of the drum of the washing machine. But those usually engines are less powerful 350watt.
(I should go re-read my electrical engineering books to refresh your memory on the torque supplied by a three phase with starting capacitor, I think I remember is a function of its capabilities, which, however, capacity must be excluded in operation, with a consequent reduction of the actual power supplied).@Giulio: is in fact the necessary addition of the capacitor to bring the single-phase AC motor means that the power is reduced to a 60-75 % of the nominal value and the starting torque to approximately 35-45 %in depending on the capacitance of the capacitor. The available torque to the shaft of the rotary table, however, is greater than that of the engine by a factor equal to the reduction ratio.
In fact the power is equal to:
P = Mt * w
where :
P = Power [W]
Mt = torque [Nm]
w = angular velocity [rad/s]
Since the reducer and pulleys decrease the number of revolutions and therefore the angular velocity, the torque must increase…
The impression I got is that the machine using the power of my engine is barely enough, then an engine with a higher power would be preferable (the 350 W of the engine used by Gordon equivalent to an engine from 0.5 Hp).
The engine that I've used is a common induction motor coupled with a reducer which output 59 g / min, which can be further reduced by playing with the size of the pulleys. The use of an inverter is definitely a finesse and a higher quality level, Having regard to the possibility to vary smoothly and continuously the number of revolutions.Good job, Mirco, thank you!
I do not know if I would be able to build a similar machine…….But if I could build at least one electric rotating floor, therefore without arm, I could do all the processing phases, from roughing to parabolizzazione?
I say yes.
And I say this because, desiring to build too the rotating floor (…What then I did not do preferring to do a little bit of gymnastics more), I had seen 28 Movies of Gordon,.With the rotary table and the Spinning method (o spin polishing), the work is done with manual action coupled to the rotation of the table only for the excavation of the curve and for the parabolizzazione.
While polishing does not need the help manual, but it is exploited the differential rotation of a neutral tool, diameter proportionately mirror referred to the diameter and equal to 75%, fixed with a bollard (the machine name "Fixed post") so that both of the overflowing 12,5% – 13% . In that way the tool is to work the circumference to 80% of its diameter in the best condition of abrasion, while its center is located at the neutral point that has defined Zambuto “Sweet spot”, where the processing maintains the curve.The rotation of the tool is automatic and differential, and at that point refines the initial roughing in a curve that defines Gordon perfectly spherical.
The working principle of the "Spin polishing at the sweet spot" of the turntable would be already known that, with the tool in a neutral position (sweet spot) It is maintained only by polishing curvature; while in ooze position lower than the sweet spot, It shortens the radius of curvature (digging the center), conversely with external swiveling out the stretches (digging edge).
I had noted that there was a good explanation of the theory and to mirror polishing machines operating principles of looking Principes d'utilization des machines à polir, and I had come across the same document written in English.
…..I searched and found the document in its English translation, which is called “How to use a polishing machine : basic principles”.
Please guys , this is “instigating all'autocostruzione”
, I can not even put me to build the machine ( or maybe yes 
)Exactly Giulio, although as far as the “fixed post” a small tip is to slightly change the ooze tool once in a while, or not put right the fixed arm that holds the tool, but do it anyway to swing right and left of a few centimeters, to prevent the repetition of the action of the “fixed post” kinds of not quite uniform zones, as it has happened to me often encounter.
I happened to observe that after a while it was working with the tool in a fixed position, could be seen on the mirror of different areas so slightly compared to the rest of the surface which usually were roughly in the neighborhood of channels too wide or the tool edge in the part closest to the center of the mirror.
Ah, I jumped into a question the mind: the tool with “fixed post” must have a shaped edge to “stella” o no?I speak as an apprentice (although "scholar"), and as such I think it is a precaution to reduce the edge star all the utensils that are used in the fixes that require their crossing ran the entire surface of the mirror.
For example, in parabolizzazione with subdiametro, are roughly tools used to 35% the diameter of the mirror, and then about the 65%/70% to standardize the figure, performing diametrical centered racing, but aggredirebbero overly the edges of the mirror (which are the two extreme areas forward and backward position of the operating diameter of tools, where the peripheral speed of a rotary table is also an abrasive component more than the manual labor without turntable).
So to get the modest assault on the most delicate area of the suburbs (..better a raised edge to be corrected locally, that a board replied that makes “game over” and refer you to the sphere) It is working in manual mode with a possible rotating floor, I think that definitely indebolirei precaution of the grid in contact with the mirror tool, transforming the edge in star.
But as for the local corrections made with very small diameter tools, which they are usually used with non-interesting tangential ran the entire diameter of the mirror, I think that there would reduce their peripheral contact.
….But you should hear what he thinks Massimo, that with the tools sub diameter there was maneuvered well.
In general I agree with you, However, I believe that a decisive role for the choice of sub-diameter is carried out by the mirror focal ratio, as well as the type of deformation present, that can “mix” cards on the table.
In particular I remember that during the processing of 300 F 3.8 I have been “Convince” by astrotecnico, because I tried ( with bad results ) to standardize the processing of 30% with the tool to 50%, then with a larger. In reality, On the opening of the mirror, I would have to use a tool even smaller ( which I did later ) to eliminate the grooves generated between zones. Even you can get to use tools of a two cm in diameter.
So I think that beyond the general rules, which provide an important reference, the difficulty ( but also the potential ) of the sub-diameter both in having to set each time the most effective machining strategy in relation to the particular state of the form that the mirror presents.
Changing the pitch patina is often necessary for the proper formation of the surface. It is also sometimes necessary in the tools sub diameter, albeit small.
Giulio actual engine power used for your machine is poor. When there is strong friction I think you have trouble.
Hello everybody
, it is a great pleasure to find yourself here ! 
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