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Harold Hall

Workshop Processes

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Drawings

I am including a copy of the print out that I used for producing the barrel shaped arm and from this it can be seen that the infeed progressively gets greater along its length, that is from two tenths of a thou to eight thou. Again when viewing this to 8 decimal places the results were identical to those using the CAD route. This was reassuring, as because no formula was needed to be entered in the case of using the CAD program it confirmed that the formula that I had been using both manually and in the spread sheet was in fact correct. I often find this useful to confirm that a formula that I have developed is correct.

 

Just Out of Interest

Having completed and used the calculations I thought that the spread sheet that I had developed had served it purpose but even so kept it on the PC. Later, I had moved into my cabinet making mode to make a dining table and having decided that it should have very slightly curved edges went about fixing a pencil on the length of string with the string anchored at the other end and used it to scribe a curve.

 

I soon learnt that the string needed to be very long, so long that it was too much for our garden. We do live at the end of dead end road where I could use the method but was not keen on the idea. However, I then remembered my spread sheet program and quickly started the PC put in number of increments, half the length of the table and half the difference in the tables width and within a few seconds I had  print out available. Having made a template for one edge from the values I decided that it was too curved and returned to the PC using a smaller difference to the tables width and a second template made. The result can be seen in my Cabinet making pages.

   AMOUNT OF TOOL INFEED  TO

   CREATE THE REQUIRED CURVE  

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              CURVE RADIUS       

           SEE SKETCH NUMBER 5   

                                 

   VERTICAL   HORIZONTAL  CURVE

  DISTANCE   VARIATION    RADIUS        

        1.6250           0.1094            12.13

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     SADDLE FEED  BETWEEN TOOL   

              DEPTH CHANGES      

                        0.0625                  

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        TOOL INFEED              

                                 

POSITION

      SADDLE   TOOL         

          FEED     INFEED        

    0     0             0.0000        

    1     0.0625    0.0002        

    2     0.1250    0.0006        

    3     0.1875    0.0014        

    4     0.2500    0.0026        

    5     0.3125    0.0040        

    6     0.3750    0.0058        

    7     0.4375    0.0079        

    8     0.5000    0.0103        

    9     0.5625    0.0131        

   10    0.6250    0.0161        

   11    0.6875    0.0195        

   12    0.7500    0.0232        

   13    0.8125    0.0273        

   14    0.8750    0.0316        

   15    0.9375    0.0363        

   16    1.0000    0.0413        

   17    1.0625    0.0466        

   18    1.1250    0.0523        

   19    1.1875    0.0583        

   20    1.2500    0.0646        

   21    1.3125    0.0712        

   22    1.3750    0.0782        

   23    1.4375    0.0855        

   24    1.5000    0.0931        

   25    1.5625    0.1011        

   26    1.6250    0.1094        

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     DIMENSIONS ARE IN INCHES