The
+ slide ways of machine tools are very sensitive components and should
+always be clean and free from any debris. The machines for industrial
+production are carefully designed today with protective elements, not
+only to keep the slide, slide ways and sensors clean but also avoid any
+pollution of the environment. However, in the enthusiasts' workshops
+this is not the standard. Most lathes and milling machines the author
+has seen have no or at best very rudimentary devices for the protection
+of the slide ways or lead screws. Clearly any protective cover needs
+some space and reduces the usable travelling distances of the carriages,
+ slides or work heads. As long, as the machines are operated manually
+the operator may be responsible for removing the swarf. For CNC
+controlled machines another solution is necessary. For grinding
+equipment an effective slide protection is a must because the dust of
+abrasives together with the lubricant of the slides is a very efficient
+lapping paste.
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There
+ are different solutions to protect the sensitive components of a lathe,
+ milling or grinding machine. One very simple answer are bellows and
+this short article will show, how they can be made. In Photo 1
+ is my Sherline milling machine, converted into a CNC machine. The slide
+ and lead screw of X-axis are protected from swarf in the design of the
+machine but not the respective components for the Y-axis. Therefore, two
+ bellows were installed. One end is mounted to the cross slide, the
+other ends are held by two flanges, fixed to the base plate by a spring
+loaded ball detent. So the bellows can be easily lifted for cleaning and
+ lubricating the slide ways, no tool is necessary. In Photo 2 the bellows for a Stent tool grinder is seen.
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Figure 1
+ shows the folding scheme for bellows. It is a simple matter to make
+this from a sheet of paper. But with other materials, e.g. leather or
+fabrics this would be difficult or even impossible. Paper has the
+necessary stiffness and if folded becomes flexible at the edges.
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The bellows in Photo 3
+ were commercially manufactured. To make these from different materials,
+ even from sheet metal, very special jigs are used. I would not go into
+the details. But please notice, the folding scheme is different from
+Figure 1.
+ This has the property that the side parts of stretched bellows move
+together, opposite to the behaviour of the bellows of Figure 1. In the experience of the author these features are not really essential.
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Clearly
+ bellows from paper wouldn't be suitable for the purpose regarded here.
+But a combination of paper, more precisely, polyester paper, and a
+ protective layer could be the solution. By accident the author received
+ a somewhat worn out protective cover for an ironing board. This is a
+compound of a thin foam layer and a fabric which has a metalized
+surface. The foam was easily scraped off. he metalized fabric together
+with the polyester paper has proved to be the perfect material for
+bellows for milling and grinding machines.
Manufacturing Details
First
+ it is necessary to make the design, a drawing with the folding lines.
+In the compressed state the folding angles are zero, for the maximum
+length a folding angle of 45 Deg. is recommended, however not more than
+60 Deg. To avoid errors the lines should show the folding direction by
+different line pattern or colours. An example is seen in Figure 2.
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The materials for the bellows can be seen in Photo 4. The drawing for the folding lines is now transferred to a sheet of polyester paper as seen in Photo 4a. Recommended grade is 120 to 180 g/mm2,
+ equivalent to 0,1 to 0,15 mm thickness. In this case the drawing was
+made with an inkjet printer. However, to dry the drawing takes several
+hours if not a day. A laser printer cannot be used, because the
+polyester paper becomes warped by the heat. But as seen in Photo 4b
+ the polyester paper is available with a millimetre grid and then a
+manual drawing of the folding lines is really a simple matter. In Photo 4 c the metalized fabric is shown from the rear side.
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Now
+ the polyester paper is folded in several steps. Here the bookbinder's
+traditional tool, the folding leg, comes into its own; two examples are
+shown in Photo 5. The folded paper bellows are seen in Photo 6.
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Then the fabric and paper bellows are put together with white PVAC glue as seen in Photo 7. The completed bellows are shown in Photo 8.
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Joerg + Hugel is a Member of the Society of Model & Experimental Engineers +and this article first appeared in the SMEE Journal in February 2014.
+