Love your work. When I was building my 'Melly' I considered replacing the bushes with bearings. Now I'm thinking about it again and then using your timing method, I can see the logic in it and how it gives better results if used with care. I too have not pinned the cranks on my loco. Thanks for sharing.
Good explanation and straight forward method for valve adjustments on Roundhouse locos'. I like your method of measuring the distance from the slide valve connection to the front of the valve chest. Thanks for posting.
Setting the 90 degree relationship between return crank and main crank is much more easily accomplished by fabricating a pair of brass strips, one to place the main crank at either 3:00 or 9:00 position, and the other to place the return crank at 12:00 position. This is the same principle as a quartering jig. To get the right dimensions, you must measure your driver diameter, your motion diameter (nominally .125"), your main crank throw, and your return crank length. Lay these out in CAD to get the size of your two spacing strips. Rotate your driver so the crank pin touches the top of the main crank strip. This puts it at either 3:00 or 9:00. Now rotate the return crank so that it drops on top of the return crank strip. If the strips were accurately cut, you should be dead on 90 degrees.As far as the return rod length goes, this, too can be determined first by CAD layout. To test it, I use a method similar to yours, except I open the steam chest and observe the valve movement front-to-back to determine if the travel is equal in both directions, and measure the distance from the "D" valve to the front or back wall of the steam chest. The theoretical length of the return rod does not always give best results!I scratchbuild American prototypes from Roundhouse components and as such have different spacing of components than Roundhouse standard. My locomotives are all inside frame, so my frames are scratchbuilt, too. Closer spacing from driving wheel to cylinder dictates different return rod geometry. Not always a lot of fun!I have built a 2-8-0 Consolidation, a pair of 2-4-4-2 Mallets, and a Climax geared locomotive using these methods, and they all run well.BTW, nice touch adding ball bearings. My axle bushings wear out too fast!
I built 2 locos based on Romulus. They were fitted with Walschearts valve gear designed by late valve gear wizard Don Ashton.
Love your work. When I was building my 'Melly' I considered replacing the bushes with bearings. Now I'm thinking about it again and then using your timing method, I can see the logic in it and how it gives better results if used with care. I too have not pinned the cranks on my loco. Thanks for sharing.
Good explanation and straight forward method for valve adjustments on Roundhouse locos'. I like your method of measuring the distance from the slide valve connection to the front of the valve chest. Thanks for posting.
Thank you for the great guide. I will now be able to spend some time setting it up correctly. Your Billy runs so well! Thanks for sharing. :-)
What did you use for the drain cocks?
Setting the 90 degree relationship between return crank and main crank is much more easily accomplished by fabricating a pair of brass strips, one to place the main crank at either 3:00 or 9:00 position, and the other to place the return crank at 12:00 position. This is the same principle as a quartering jig. To get the right dimensions, you must measure your driver diameter, your motion diameter (nominally .125"), your main crank throw, and your return crank length. Lay these out in CAD to get the size of your two spacing strips. Rotate your driver so the crank pin touches the top of the main crank strip. This puts it at either 3:00 or 9:00. Now rotate the return crank so that it drops on top of the return crank strip. If the strips were accurately cut, you should be dead on 90 degrees.As far as the return rod length goes, this, too can be determined first by CAD layout. To test it, I use a method similar to yours, except I open the steam chest and observe the valve movement front-to-back to determine if the travel is equal in both directions, and measure the distance from the "D" valve to the front or back wall of the steam chest. The theoretical length of the return rod does not always give best results!I scratchbuild American prototypes from Roundhouse components and as such have different spacing of components than Roundhouse standard. My locomotives are all inside frame, so my frames are scratchbuilt, too. Closer spacing from driving wheel to cylinder dictates different return rod geometry. Not always a lot of fun!I have built a 2-8-0 Consolidation, a pair of 2-4-4-2 Mallets, and a Climax geared locomotive using these methods, and they all run well.BTW, nice touch adding ball bearings. My axle bushings wear out too fast!
cracking video. WIll spend forever now working on mine!!
Great advice - thanks for sharing that Terry!
Cheers
Chris