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Post by IronMan on Jan 29, 2004 20:04:26 GMT -5
Hi, By reading some information in the Shay, I was able to come up with a roundabout way of getting the right size for 1.5 "scale 7 1/4 Guage. Could someone with the know how tell me if this works out . Take the size in Inches. multiply by 25.4 to make it metric then multiply by .0816 for 7 1/4 or .0844 for 7 1/2. Is there an easier way? not that this is dificult, just thought I would ask the experts.  These factors are based on the truck guage dimensions. ( Kozo's words ) Thanks in advance Jean in the frozen North |
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Post by Jamie Harris on Jan 30, 2004 8:31:17 GMT -5
I don't claim to know the answers but i'd like to know if this works as well.
Jamie
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Post by DavidT on Jan 30, 2004 21:24:25 GMT -5
To convert from Kozo's 3 1/2" gauge at 3/4" scale to 1 1/2"scale at 7 1/4" gauge, use this; the metric diminsions times 2 plus 7.2mm. Look this up in the tables in the back to get inches. This will ONLY be use for the axles, tie bars, upper and lower bolsters. The axles, make the center between shoulders equal to 6.87 inches measured while machining. The ends are X2 the book. The holes in the tie bars will need to be half the width of the frame stock used in from the ends. The lower bolster is x2 plus 7.2 LOA. So X2 plus 3.6 for all the drawing diminsions from center. The upper bolster LOA is X2 plus 7.2mm. The spring holes are X2 plus 3.6 from center. The frame attachment holes are only X2. More problems arise from using the nearest inch stock and where to put the matching holes. 1 1/2" scale at 7 1/2" gauge would be X2 plus 13.5mm. Remember X2 means times the book metric diminsions. Have fun and show us some pictures.
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Post by DavidT on Jan 31, 2004 13:54:37 GMT -5
After reading more in the Shay book, I see that the frames for the 1 1/2" scale size are at 206mm or 8.111" to the outsides of the frames. This is more tham X2 the 3/4" scale, so that the driveshafts will line up. So you need to select your frame material and work bakwards to get the lenght of the numerous pieces that space the frames. Also the upper truck bolsters the holes I mentioned previously are for the bearing blocks so they are also spaced further apart, same extra that goes for the spring holes.
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Post by jimbuchanan on Feb 3, 2004 17:42:57 GMT -5
Here is my thoughts on scaling.
As Kozo scales down from prototype dimensiions some of the parts were a little to small or thin so it is natural to select the next size larger. Now when you scale these dimensions up you now have a part that is larger than what you would have arrived at if you had scaled down directly form the prototype dimension.
Next if you are using inch dimensions and are scaling up a metric design you have to again round up and down to the next standard size.
At this point you find out it is easier to redraw every thing to make sure that all of the dimensions have been adjusted correctly.
Have Fun
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