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Post by Dan Myers on Jan 7, 2004 14:18:37 GMT -5
I'd like to start a thread for anyone that has found: * errata in Kozo's books, such as specifying something obviously the incorrect size. * mistakes, such as showing an incorrect way to do something, or * changes, such as suggesting a better way to machine a part versus Kozo's method. For my part, the A3 book I received was missing a complete page! After e-mailing Village Press, I received a reply within 24 hours. They're replacing the book at no charge to me. Before, I was very impressed with the quality of the writing and the publishing of the book (with the exception of this small mistake). Now, I'm very impressed with Village Press' customer service! These folks know how to encourage a hobby such as ours. Given that live steam railroading isn't the cheapest activity, it behooves the suppliers to make sure the customers are very happy and satisfied. I have two Kozo books now, and I can definitely say that I'm going to buy two more (and probably the new shay when it comes out!). Good job, Village Press!! All the best, Dan www.cdmrr.com
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Post by DavidT on Jan 11, 2004 18:25:33 GMT -5
I was looking very very closely at the plumbing for the tender and found on page 61 figure 9-12 a #32 drill size hole is shown as (.166) not the correct (.116)
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Post by DavidT on Jan 12, 2004 0:14:24 GMT -5
Sorry! That last note for page 61 is from the A3 book
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Post by DavidT on Jan 31, 2004 21:35:26 GMT -5
The Shay Thinking about dimensions for various gauges for other posts, I decided to draft up the pieces and check out the numbers. For 1 1/2" scale at 7 1/2" gauge I do not get alignment at 30mm offset as specified in the larger scale section. I get approx 26.5mm. Two drawings gave me different answwers. This is making the engine shaft align with the right journals. Using the 30mm offset would put the engine shaft outwards the 3.5mm.
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Post by Dan Myers on Dec 9, 2004 7:09:18 GMT -5
I just wanted to add this to the errata thread some of us were building.
DavidT wrote:
"Wanting a project for my new Excel program, I put in all the skew gear formulas. I found in formula 10 (page 190) that the wrong value of R sub 2 was used. 23.53 is shown in the example, but the correct value from formula 6 is 28.53. That make the results .45mm larger at 35.44mm. This is the outside diameter of the gear, so it is not a earth-shaking problem."
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Post by Dan Myers on Mar 31, 2005 12:06:56 GMT -5
From another thread, re: 1-1/2 scale A3 drivers:
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Post by locodan5416 on Jul 1, 2005 12:58:42 GMT -5
I don't like the whole steam chest assembly in the A3. A 45 degree angle is very difficuly to do on a mill, and I think when I get to the point of building the engine i'm going to change it around to make it easier.
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Post by locodan5416 on Jul 30, 2005 12:22:08 GMT -5
another little mistake is the second locomotive featured in Kozo's A3 book, look at his assembly of the guide bars and link supports, its backwards
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Post by Russells on Jul 31, 2005 16:15:16 GMT -5
Possible interference in the valve linkage !!! After completing all of the components of the valve gear and reversing gear it is possible to test your A-3 engine on compressed air. That is when I discovered an intermittent problem where the lower inside front corner of the combination lever makes contact with the lower crosshead guide. This only happens when the reversing gear is set to allow a full stroke of the valve gear forward, and when the clearance in the linkage allows it to swing inward toward the crosshead guide. I suppose you could mill or file the inside corner off of the combination lever to solve the problem. However; I choose a different path. After machining and assembling all of the parts I compared my valve gear to the close up photo on page 97 of the A-3 book and discovered that the proportional relationship between my combination lever and link bracket and Kozo's were different. My valve gear clearly looked much shorter than that in Kozo's photo. I found a good valve gear calculator program online and recalculated all of the valve gear proportions. I made the following changes: Combination Lever (17-9 page 103) upper hole spacing was 5/32 (.156) is now .171 Combination Lever (17-9 page 103) lower hole spacing was 1 25/32 (1.781) is now 1.931 Link Bracket (17-16 page 104) was 1/2 (.500) is now .650
After remaking the parts to the new proportions, the engine ran flawlessly and appears far closer to the proportions in Kozo's photo on page 97. I had intended to post this a year ago when it happened, but am only now getting around to it. I would like to hear from anyone else that has gotten this far.
Russells
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Post by IronMan on Aug 2, 2005 9:03:14 GMT -5
Hello Russells, I have not gone that far yet I am still on the tender tank, what I have found in upscaling is that you can not double Kozo's measurement for the bending of materials. I crossed check with Machinerys Hanbook after having some difficulties, and found out that you must use the formula that is appropriate for thickness size, I used that formula and checked Kozo's measurement and they dont match. Could some one that has gone that route, tell us if they had any difficulties with that part of the project? Thanks IronMan
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Post by Russells on Mar 2, 2006 19:52:34 GMT -5
A-3 Boiler Blunder:
In Kozo's book for the A-3 on pages 132 - 134 figure 23-1, the main boiler elevation, look at the front tube sheet length. It is 7/16". In the view above, the front tube sheet is set out from the boiler shell 1\4", leaving 3\16" (.188") to form the silver solder joint. The minimum safe overlap for this joint should be somewhere around (.156"). So far, so good!
Now look at figure 23-7 on page 135. The diameter given for the front tube sheet blank is 4.04". The outside diameter after forming the sheet is 3.57", the sheet thickness is 0.08" and the inside fillet radius is .060". Now lets do the math. The length taken up by the bend is the 0.06 radius + 0.08 sheet thickness = 0.14". The center flat section is 3.57" minus (2 x 0.14) = 3.29". The side stright area is the desired length 7\16 (0.437) minus 0.14" = 0.297. The bend allowance is the inside fillet 0.06" plus 1/2 of the sheet thickness 0.04" = 0.10" times (1\2pi) 1.5708 = 0.157. Follow so far? Good! 3.290 center flat. plus 0.594 (2 x side stright). plus 0.314 (2 x bend allowance). equals 4.198 ***** not 4.04
The side stright will be reduced by 0.08" if you follow the book plan, leaving only 0.10" for joint overlap. Not enough for a good safety margin. The book has an error in the bend radius. I believe all of the formed sheets have this same error, but it is less critical where the sheet overlap is greater. The front tube sheet requires a greater outset in order to align and seal the smokebox, so it would not be advisable to reduce the outset to make up for the short overlap.
Surprising that no one else has posted this before. CHECK EVERYTHING --- TRUST NOTHING !!!
Russells
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Post by atlantic442 on Mar 3, 2006 1:28:06 GMT -5
Steam passage depth in cylinders is not given, Page 86 14.1.3 paragraph 3 Refers to Figure 14-7 for specified depth. No depth is given for passages.
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Post by Russells on Mar 3, 2006 7:41:05 GMT -5
Atlantic442,
The depth of that feature is not at all critical as long as it connects with the holes drilled in the next step and of course, doesn't break thru into the cylinder bore. I believe mine are milled about 1/8" deep. You can start shallow and go back deeper later, after the holes are drilled. You can expect many minor omissions like this the further you go in the book. Kozo carefully feeds you information thru the tender construction and then expects you to fill in some of the blanks on your own as you gain experience.
Russells
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Post by peterl78940 on Mar 7, 2006 1:04:03 GMT -5
here's a change that I made and so far am pretty disappointed with, perhaps someone else has some experience in this...
I saw in another book the piston rod and valve rod seals held in by screw-in packing nuts rather than Ko's slide-in and fix with a set screw method, so I tried it.
But, several problems arose, first, trying to get the hole tapped deep enough - started with a bottoming tap, then proceeded with a ground off bottoming tap to get all the way... and still the nuts don't go all the way in - or if they do then the rods bind and won't move...
Similar problem threading the nut, had to grind the side of a die so that it was a "bottoming" die to get the threads all the way to the shoulder...
I'm still not entirely sure whether it is my tapping that isn't deep enough, or my die(ing?) that isn't deep enough, but the parts don't go all the way together...
And if I put the O-rings in, then it all gets worse as far as binding.
-Pete Lawrence.
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Post by Russells on Mar 7, 2006 9:56:38 GMT -5
Hi Pete:
If you're going that route then here's how you make it work. You need to shorten the overall length (threaded length) of the male threaded packing bolt, say 0.060" - 0.080", or whatever you can't thread properly plus a little. Next, bore the hole in it oversize, enough so it cannot hit the rod if the threads don't run true. Now make a bronze bushing that makes up the length you machined away in the previous step. It should be a good fit to the rod but have ample clearance on the outside diameter, say 0.005" or more to the housing. Don't tap the housing all the way to the bottom where the "O" ring is going to be. The "O" ring won't be able to seal on those threads. So, the male threaded packing bolt pushes against a bronze spacer which compresses the "O" ring. This arrangement allows the rod to self align because of the extra clearance you cut in the bore of the packing bolt and on the outside of the bronze spacer. It also offers a fine adjustment for the amount of sealing pressure used, and you can still use Kozo's set screw to prevent the threads from moving once you have it set. Hope this helps.
Russells
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