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spine tester in PA

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mox1968:
hi guys I have built the spine tester mentioned in the last issue of PA magazine but hit a wall at the last fence making the scale!!I dont really follow the instructions there ,Im a bit lost as to how to mark out the upright marks from the bottom of the scale.I never really used inches as a decimal scale like that so not sure how to work the sizes over to a ruler or  other measuring device??

Lombard:
Measure the horizontal line as specified in the article, then a vertical line at 90 degrees to that. Using the chart giving deflection values, you will need to multiply them by five, as the ratio is five to one on the needle. That is to say, (for the sake of easy math), if you hang the two pound weight on the shaft, and had one inch of deflection, the pointer would, from zero, register five inches of travel on the vertical line. So take those deflection values provided in the chart, multiply by five, then take that result and measure up the vertical line that amount for each of the values that you will be using.

hillbilly61:
mox..Same here. Dave, I still don't understand  :( I guess I'm just a dumb ol hillbilly ;D If all the marks on the scale are the same would'nt it be easy to say, from the bottom mark up 2" and every 1/4" above that, make another mark? Or something of that naturer?

Lombard:
Yeah Mark, if the author had did as you describe, it would no doubt have simplified the scale for most folks. Take for another example, page sixty figure 5a of the June/July 2010 issue of PA, multiply .75 by 5 for a result of 3.75 inches. That 3.75 inches would be measured on the vertical line and a dot placed at that point. Now with an arrow in the supports with a two pound weight hung on the shaft deflecting the pointer to that dot, would indicate an arrow of approximately 30 pounds of spine. Another way to get this scale would be to scan the image and save it a jpg. Open in MS Paint, change the size there and print it out, and there you go. I am not all that computer savvy, so perhaps someone else can guide you through the enlargement of figure 6b on page 61 to workable portions. Otherwise, just do the math, and place the results on the  vertical line, thus making your own scale. 

mox1968:
ok thanks lombard I think I have it now!!But I totally agree with mark would have been a lot easier to me to give me some sizes to mark off from the bottom of the vertical line.I been out of school for a lot of years now and find using a measuring tape comes more naturally now.

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