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Discussion Starter · #1 ·
I have a question for those that have built a Aster kit. How tight is too tight on the running gear? The loco I just got was a kit that was together, but it had to be completely rebuilt and I am working on the running gear and valve gear now. The chassis will not roll without me putting the lightest of finger weight on he frame, is that normal for new running gear?
 

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Posted By NHSTEAMER on 10/19/2008 9:30 PM


I have a question for those that have built a Aster kit. How tight is too tight on the running gear? The loco I just got was a kit that was together, but it had to be completely rebuilt and I am working on the running gear and valve gear now. The chassis will not roll without me putting the lightest of finger weight on he frame, is that normal for new running gear?



I have assembled two of them, but I have to admit I didn't test the chassis that much to see how well they would roll by themselves. Yes, I spun the drivers and rolled it on the table and I would say they rolled easily, but my hand was on them them and I didn't test them for free rolling.

I think you should be sure to oil the bearings well, both the axle bearing interface and the bearing chassis interface. the bearings need to be able to move up and down in the chassis horns without binding.


Is one axle binding more than the others?


Is the chassis "racked"? I mean, the sides may be parallel, but are the cross members at 90-deg. to the sides such that the horns are directly across from each other.

Are the axles parallel? Is one bearing on one (or more) axle not directly across from the other?

Is a bearing on one (or more) axle(s) cocked in the horns? (Both caster and camber... is the axle hole at 90-deg vertical and horizontal?)

Is each bearing in-line vertically with the opposite of the pair? All wheels firmly in contact with the rail and the chassis level in both axis?


EDIT: One more thing... is one or more bearing not seated against the sides of the chassis horns and thus rubbing on the inside of the wheel hub?
 

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Bill,

When Dan built the Berk and S2 I remember how smooth the chassis would roll on the table by just tapping it back and fourth. I assume that the Mike shoudl be just the same. Maybe tear it down to the drivers and start from scratch as ya never know how it was built.
 

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Bill - it should (or must if you want to operate at top performance) roll freely. Some initial binding can be associated with the water pump. Sounds to me like you have a bigger issue than that.

Try taking one of the main drive rods off, and see if the engine rolls freely. Check that the piston moves in and out on the crosshead while you do that. Repeat for the other side. Do not take the cylinders off unless you have to. First find the bind.

I had to spend some considerable time filing the crosshead on one side to make sure the piston moved without any binding. I also had to file the inside of the driver journal boxes, and the frame to ensure that the drivers would move up and down in the frame easily. I had to file the front end of the main drive rod to make sure it fit without binding in the crosshead. (be carefull with that, only a little tiny bit at a time) Any of those issues could cause the binding you describe.
 

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Another little tidbit, just thinking out-loud... if the side and main rods are on, but the chassis is not fully weighted with the boiler, etc. the wheels/axles will not be in the normal/correct position relative to the cylinders/cross-head guides (they will be too low in the horns, or the chassis too high, thus holding the cylinders and cross-head guide above being centered on the axles) that can sometimes cause a slight bind.

You might also have to "break the edges" of the bearing pillow blocks where they contact the chassis horns... a slight burr will keep them from freely moving up and down and can cause them to not seat square with the chassis.

A small file (I used the file on my Swiss Army knife for all file work... like stated above, just a light swipe or two is all it usually takes. All you want to do is make things slide over each other easily, not make for a sloppy fit.

Also, the chassis paint sometimes leaves a blob near the bottom inside edges of the horns that needs to be removed for a smooth fit.
 

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The chassis should roll freely without the connecting rods and there should be quite a bit of free up and down movement in the driver journal box bearings as well as lateral side to side of the rear most fourth driver. Make sure everything is lubed with a good light weight machine oil. Note too that there was an issue with the axle pump eccentric fitting on some of the pumps. Make sure that everything is lined up and turns smoothly in-line on every rotation.
 

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Discussion Starter · #7 ·
I should clarify my first post a little better, I did disassemble the loco down to bare frame and have started reassembly everything rolled smooth as a Babes $$$ until i added cylinders and valve gear. If I grab the engine at the pilot and just pull or push it the drivers will not turn, but if i put just a little finger weight on the reverser cross link it rolls free with no real binding. Should i be concerned with that, or just run it on air for awhile see if it loosens up and/or look for any heavy wear marks on the gear?

Edit: Water pump not yet installed.
 

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if it only takes one finger to put enough weight on the drivers to get them to roll smoothly with no binding you are fine. Did the pistons move freely in the crosshead guide? Is there any binding whatsoever in the connecting rods to the drivers? (there should not be - check this with the main drive rod off) Put the pump on and repeat. You know it is right when the motion is smooth with no binding. You should be able to run the engine alone (no boiler or any other parts) on very low air pressure. I think I was able to get it to run on 5 psi. Took about 10 to start, but 5 to run. Use plenty of oil. Dont run the engine on air without reoiling every few minutes (at most). Oil is cheap. Asters are not. Don't forget that.
 

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Sounds like you should be able to air test it right now and with the valve covers on, connecting rods and and valve gear connected the locomotive shouldn't really roll freely without a bit of help to move the pistons etc. It should run like a sewing machine in both directions with machine oil spewing out of the blast tube under air pressure.
 

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Discussion Starter · #10 ·
All,
Thank you for all the information! I took some more time on the running gear and found that one crosshead guide was in need of filing. After that it rolled and air tested perfect. Today I ran it for the first time on steam and it ran great, but I do have some questions. What do most of you use as packing compound? I know that the smokebox is not air tight, it steams well but not very well. Also it will steam up on the fan but when I turn on the blower I loose steam I am assuming that the blower pipe is not aimed right and is blowing back to the firebox. (that makes sense right?)
Thank you all for your help, I will take video next time I run it.
 

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Glad you found the problem... there are many places where a minor bit of excess metal or foreign material can cause problems.

Packing compound on the Aster Mikado are rubber ("Viton"??) "O"-rings around the piston rod and valve stem squeezed in place with the gland nuts.

Sealant around the smoke box is supposed to be a layer of the ceramic cloth cemented in place around the inside using the bathtub caulk (that should have come with the kit). The seal at the bottom where the steam pipes go through is a combination of the thin metal plate and the ceramic cloth.

The seal around the barrel of the boiler and the boiler outer (false) shell is supposed to be 2 or 3 of layers of strips of the ceramic cloth glued in place with the bathtub caulk. I glued 2 layers to the boiler and another 2 layers to the inside of the shell such that they would overlap some and fit edgewise against each other also. Then I put the false shell on the boiler. If you fit those parts in place and then wait a few minutes until the caulk-skins over and then place the smokebox in place it won't get glued in (so it can be removed later if necessary) and yet forms a good seal against air leakage between the false shell, the boiler and the smokebox.

I placed a sheet of the ceramic cloth in the cavity of the smokebox door as insulation... the front seals pretty well in and against the smokebox shell without any special treatment.

The auxiliary blower pipe should be right next to the main blower pipe from the cylinders. You can't get both of them aimed up the exact center of the chimney. The Main blower is designed to be in the center and the auxiliary blower right next to it, as close as possible, but be careful that it does not get aimed AT the main blower, which would disturb the flow up the chimney. The tops of each should be at about the same height.
 
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