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Step 2: Cambiar la correa del variador (changing drive belt)

La que usé originalmente, luego de fracasar mis intentos de fabricar yo mismo una correa, fue como expliqué en su momento la de un electrodoméstico, comprada. Funcionó bien, pero era plana, lo cual le restaba rango a la variación de velocidad. Para entender por qué era eso, imagine que la correa tiene el ancho de los conos: en ese caso la variación sería cero. Luego de algunas averiguaciones y de tener la suerte de dar con una persona entendida en el tema, compré unos trozos de banda de nitrilo, de sección circular de 7 mm, especialmente indicado para lo que yo necesitaba. Corté un trozo de longitud adecuada, con los extremos en un ángulo bastante agudo, a efectos de aumentar la superficie de unión. Calenté un trozo de chapa en la llama de gas, lo aseguré vertical con la pinza y una bandita de goma para tener ambas manos libres, y apoyando los extremos del trozo de nitrilo esperé dos o tres segundos hasta que se fundieron. Luego, rápidamente los uní, y esperé un rato a que se enfriara.


The one I used originally, after failing my attempts to make myself a belt, was –as I explained at the time– of an appliance purchased. It worked well, but it was flat, which limits the variation range of speed. To understand why that was, imagine that the belt is the width of the cones: in this case the variation would be zero. After some research and be lucky to find a knowledgeable person on the subject, I bought a few pieces of nitrile band of 7 mm circular section, especially suitable for what I needed. I cut a piece of suitable length, ends on a fairly sharp angle, in order to increase the bonding surface. Heat a piece of metal in the flame of gas, I assured it vertical clamp and a rubber band to have both hands free, and supporting the ends of the piece of nitrile, waited two or three seconds until melted. Then, quickly joined and waited a while for it to cool.

<p>Tu variador es un buen idea. Tabien tengo un lathe y necessito que hacer un variador. Voya usar un motor variable de un treadmill viejo. Necessito que hacer calculaciones para convertir MPH a RPM. </p><p>Si puedes, haces un video para puedemos ver al operacion del variador.</p>
<p>Hola, CementTruck, gracias por tu comentario. Lamentablemente no puedo hacer el video, porque aunque el variador funcionaba bastante bien, no era eficiente para transmitir fuerza, dado que pese a la cera adherente la correa patinaba con frecuencia. Hace unos meses lo reemplac&eacute; por un juego de poleas, que tienen un canal semicircular y entonces proveen un mejor agarre, con 4 velocidades.</p><p>Respecto a los variadores el&eacute;ctricos, tienen el mismo problema que el variador de doble cono: no transmiten potencia, al menos los baratos. </p><p>Convertir MPH a RPM es sencillo, pero hay unos tac&oacute;metros &oacute;pticos baratos que funcionan bien. Yo compr&eacute; uno en <a href="http://www.aliexpress.com/item/Holiday-Sale-Digital-Laser-Photo-Tachometer-Non-Contact-Tach-205/1214884096.html?s=p" rel="nofollow">Aliexpres</a> que parece ser bastante exacto.</p><p>---------------------------------------</p><p>Hello, CementTruck. Thanks for your comment. Unfortunately I can not make the video, because although the drive worked pretty well, it was not efficient to transmit force, as despite the sticky wax the belt often slided. A few months ago I replaced it by a set of pulleys, having a semicircular canal and then provide a better grip, with 4 speeds. <br><br>For electric drives, they have the same problem as the double cone drive: no transmit power. Cheaps, at least. <br><br>Convert MPH to RPM is simple, but there are some cheap optical tachometers that work well. I bought one in <a href="http://www.aliexpress.com/item/Holiday-Sale-Digital-Laser-Photo-Tachometer-Non-Contact-Tach-205/1214884096.html?s=p" rel="nofollow">Aliexpres</a>, it seems to be pretty accurate.</p>
This is very cool! Great instructable!
Thanks, SlickSqueegie.
Lastly (after the instructable) I did some grooves in the lower cone, that improved a lot the transmitted force.
Excellente Instructable. <br>Yo uso estos carretes tambien, los que yo compro son para puertas de la ducha, o para otras puertas correderas. <br> <br>Excellent Instructable. <br>I use these reels too, the ones I buy are for shower doors, or sliding doors.
Gracias, Bill, siempre eres tan amable!
beautifull job and judging by the shavings you must use this alot
Thanks for your comment, Bobby. Really I don't use a lot the lathe, only some hours weekly. Turning is a very pleasant task, but I must do many other things.
Que hace este macina?
Woodturning. Thanks for asking.
Your welcome.
homemade wood lathe.
Yes, it is! Thanks.
Muy buen trabajo, que bueno que lo sigues perfeccionando.
Gracias! Realmente mejor&oacute; en forma notable. Ya no rompo los vidrios de la galer&iacute;a con trozos voladores de madera. (Thanks! Really it improved markedly. I do anymore not break the glasses of the gallery with flying pieces of wood).
Nice job on this! Thanks for sharing.
Thanks for your comment!
Yes, Phil. The lathe won a lot of usefulness with these improvements. Thanks for comment.
It is always good when you can refine a tool until it is just the way you want it.

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