Harold Hall
Workshop Processes
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