"How Parallel Is Parallel?"

   The page on  "How Square Is Square" was such a popular topic, I decided to do the same with the other dimension.
   When cutting a panel, we either use a square device to make a cut square to an edge, or we make marks and set a guide rail parallel to the first edge. Fact is that normally we alternate these methods — parallel, then square, then parallel, etc.
   Like square, if the parallel cut is not exactly "on", it is "off." And "off" is as bad as not square.

    We learned in school that you should always make at least 3 marks when measuring for a parallel cut. This way, if we make a mistake we can see and correct it before we cut.

   Following that method, we should also discuss how we make the mark. pencils lose their nice sharp points fast so markings become wide and this allows for a measurement to be a bit off.

   When we are cutting white melamine panels, we minimize that by using an engineer's pencil with .03 lead. In the shop use, the tip breaks quite often.

   Less apt to break is the fine tip markers. You can get those in the .2 and .3mm. They work fine and leave a strong mark that is easier to see with my old eyes.

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   When I am working with solid wood or plywood, I prefer to use razor blades. A couple of taps will place them in the wood and then the rail can be eased up against the ultra thin blade. Of course, you do have to remember to remove the blade before you make the cut. (This photo was from another story where finite accuracy counted.  Click to go there.)

   So far, we have been using the standard tape measure to make these measurements. The tapes are handy and good quality ones will allow for the hook edge.

   In the shop, we prefer to use steel or aluminum rulers. You can hold the tip of the ruler at the panel's edge, and then you can make your mark or position the guide rail.

 

 

 

 

 

 

 

 

 

 

 

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