# Scratch outside frame 2-8-2 HELP ? number one



## Ted Nordin (Feb 27, 2008)

Gentlemen, long story short. Before B'mann Connie or K27, I wanted an outside frame mikado I could afford. Accucraft and Berlyn were far above any budget. Route I went was an Aristo Mikado, driver size scaled close.

Obviously, many complications would occur, especially for one with very little building/modeling experience and no metal working ability or tools. Any knowledge I possess has come from Large scale sites. I did not want to replace any axle with longer ones + the aristo problem with loose drivers had to be considered.

Solution I arrived at is a self-contained frame and counter-weight assembly requiring only one connection to aristo drivers. Counter weights will revolve via connection from counter weight axle to crankpin on one of the powered aristo drivers. 

QUESTION: How can I make this connection where crankpin end must rotate and axle connection must be fixed. Distance center to center is 9mm so gears seem impractical even if available. My counter weights at this time are fashioned from plastic B'mann drivers so as to have an accurate spacing on all four and has a 1/4 inch axle which protrudes thru frame towards but not touching aristo drivers. My solution at this point is a sleeve over the counterweight axle with 2 diametrically opposed holes. A stiff enough wire (rod) with an eye at crankpin connection would protrude the sleeve far enough that it wouldn't slip out of sleeve. Sleeve would be hard fixed to axle .

Theory is almost backwards from reality. Here the drivers turn, connection then turns the counterweight axle, which via siderods turns the remaining 3 counterweights and then back up the chain to the valve gear. Will it work, sure hope so but not betting any pink slips 

I am stopping production at this time until you experts speak. Thanks in advance. Ted "Zippo 6" 

PS: I would love to answer any other questions as to process so far. I will ultimately take photos before final assembly


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## Pete Thornton (Jan 2, 2008)

How can I make this connection 
Ted. 
What a complicated but ingenious way to make an outside frame! 

Question for you - I assume you are keeping the siderods on the Aristo chassis? I guess with their multiple gearboxes you don't need to . . . 

Your wire and sleeve are OK. I'd be inclined to favour a 'crank' - a brass piece that fits the axle and the other end fits over the crankpin of the Aristo wheel. 

If you can dispense with the siderods on the Aristo wheels, then you have an easier job. I think the wheels are held on by screws? Find some spares, then put one in a vice and drill a hole in the head with a vertical drill. That will give you a place to mount an axle 'extension' [glued or soldered in the hole] to drive the dummy axle outboard. Or just solder a pin across the screw head with a right angle protruding outwards to angage the pin on your dummy axle.


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## Ted Nordin (Feb 27, 2008)

Pete, Thank you for your response. 

I hope to avoid the aristo siderods. One reason I went with aristo was to have the independently driven wheels to allow for more "sloppy (imprecise) measurements" outside the frame. I have run engine without aristo siderods fine but cannot guarantee the drivers will remain quartered. I might just run a wire between crank pins to keep drivers properly oriented. What do you think? Thanks for addressing this aspect as I was going to bring it up next. Better to solve both issues together 

If I understand you correctly, one suggestion is to provide revolutions to the "new" axle by extending the aristo axle. I wonder though about the lateral movement of the drivers. OMG, I will have this problem no matter what. I assume solution would be to have corresponding lateral movement for the counter weight assy thru the outside frame. 

How would your crank idea work? I like it but my inexperience doesn't visualize the hard connection on the axle. Is it a pressure fit? Would axle be reshaped with flat surfaces? 

Off to church. later and thanks Ted


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## DKRickman (Mar 25, 2008)

I just thought of something.. 

As I understand it, you want to make a stub axle and counterweight assembly which fits in the dummy outside frame and is driven off of one of the Aristo crank pins. If so, it won't work! You'll need some way of keeping the side rods on the counterweights in line, and that means quartering and a second side rod, or some other mechanical coupling. Four axles with only one rod coupling them will not stay in line, and will pretty quickly bind and break something. 

The Aristo mechanism itself should work fine without rods, since each axle is independently driven. You don't need to worry about quartering, either - the wheels could just as easily be simple disks, and it will work fine. But the dummy outside frame, axles, and rods will either have to be rigidly connected to at least two axles (in which case quartering is important on those two axles), or connected internally. If there's room, you might manage a small chain and sprocket system, or gears, to connect the 4 stub axles on each side.


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## Tom Leaton (Apr 26, 2008)

Ted. 

I assume you are discussing the electric version of the Aristo Mike. Once the drivers are held on with an external screw, you might consider sending off for a few replacement driver screws. You want to have a longer axle on one of the axles to drive the outside rods. So, braze/silver solder a stub extension to the screw head that is drilled and tapped to accept your crank bolt. This extension could, possibly, consist of a shoulder screw with its head cut off and the ends filed flat. Since this soldering will cover up the screw head, you will want to file flat spots on the side of the extension so you can screw it in place and then tighten it up. Then add your outside frame and rods. I have never attempted this; it is just an idea. 

Tom Leaton


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## Ted Nordin (Feb 27, 2008)

Ken and Tom, thanks. 

I do hope it works and Tom, hopefully will not need to go the axle extension route. If so, I'll be back at you fast, as in real fast.

Ken, I think your concern is valid and maybe my solution will work. The 4 stub axles you so accurately described have very little movement in the fixed frame, 7/16 axle in a 1/4 inch hole. Took a long time to get accurate spacing even with a digital caliper.
By hand I have been able to get circular movement on a practice frame. The spacing is such that only way stub axles will all insert is if all are quartered (with connecting rod attached to all). I sure do hope you are wrong. That is reason my first iteration uses b'mann drivers as base for counter weights so that crank pins on the counter weights are uniform distance from stub axle center. As of now, my test side rod connecting counter weights has the same exact spacing (25.55mm) with minimal movement at the crank pins.

Searching bins at Ace today, I am at this point. Got a roller pin (not sure if real name but has the gap running entire long axis) Press fitted it to stub axle. Then took a elec connector for circular terminals and ran the aristo crank pin through it and attached it to driver. Took a machine screw and tightened into connector where wires normally would be crimped. Took a dremel and widened gap for screw shank and then ran the bolt head into the pin. Head prevents screw from pulling out. This will allow screw to move with the 3 mm lateral distance of the driver. A plug at end will retain the screw inside the pin. I then inserted axle through frame and re-pressed the counter weight onto it. 

Ready to put engine on rollers and see if a single counter weight will spin. One problem, AFRAID IT MIGHT NOT WORK. So to allow a decent sleep I will wait until tomorrow for satisfaction or dejection. Certainly one spinning weight does not equal four. If it works, great. Then must do a second side. If not, then gents we will have to attempt other solutions.

FYI, but only if interested, are some other details. Cab is a B'mann Connie Cab (that one rec'd a big hauler one in a downsize) and steam and sand domes are also B hauler. Steam piping and air tanks etc will stay in aristo configuration at first. Headlight moved up top to NG practice. Have ordered a generator and trailing truck from B'mann K27 parts. Didn't want to take the time to do a David Fletcher complete build. Had a heck of a time with outside frames, couldn't find a stiff enough foam board and styrene sheets available were too short to do a one piece frame. Needed something firm yet easily cut using band, scroll, hack or razor saw. Another Ace search yielded the bottom strip from a garage door. Is working great and thickness provides enough stability to stub axles. Tender has scratch doghouse added, coal boards, and hump from water chute was squared and is base for the back up light. Bought a b'mann chassis to get the complex valve gear. $50 but maybe some spare parts for me or others in need.

Will provide news tomorrow unless spouse has a LIST and must be out of town tomorrow aft til midnight. Again thanks, finders crossed and not rods. Ted


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## Pete Thornton (Jan 2, 2008)

a stub axle and counterweight assembly which fits in the dummy outside frame and is driven off of one of the Aristo crank pins. If so, it won't work! You'll need some way of keeping the side rods on the counterweights in line, 
Kenneth, 
You are correct given what Ted described. However, I believe the reason for the counterweights is that there are outside connecting rods as well. As long as the opposite sides are at 90 degrees, there shouldn't be a problem with just one connection. 

How would your crank idea work? 
Which one ;-) 

This is where a picture is worth a thousand words. But I don't have a picture handy. . . So let's try this. 

Ted - the connection between your Aristo wheel/axle and the new outside frame stub axle needs to be physically short but also tolerant of slight misalignment, etc. A universal joint would do the job, but would be too long. 

A simple universal joint consists of a crank (two 90 degree bends making the handle parallel to the shaft, like a car crank handle, or a winch handle) 
http://www.rvworkshop.com/sc_images/products/638_thumbnail_image.jpg 
If there is a peg sticking out of the shaft that is supposed to be driven, the crank will push it in roughly the same motion as is driving the crank. 

I thought your original idea of using the crankpin in the wheel was a valid version of this - your stub axle just needs a pin to be pushed by the wheel's crankpin.


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## DKRickman (Mar 25, 2008)

Posted By Ted Nordin on 21 Apr 2013 07:42 PM
Ken, I think your concern is valid and maybe my solution will work. The 4 stub axles you so accurately described have very little movement in the fixed frame, 7/16 axle in a 1/4 inch hole. Took a long time to get accurate spacing even with a digital caliper. By hand I have been able to get circular movement on a practice frame. The spacing is such that only way stub axles will all insert is if all are quartered (with connecting rod attached to all). I sure do hope you are wrong. 

I'm still concerned about it. Four axles in a rigid frame with VERY well fitting bearings and rods will be more reliable, but I don;t think they'll be reliable enough. Any slop at all will allow the rod to bind, particularly at the ends of the stroke. Assuming that you intend to run the model, all the parts will wear and increase the chance that something unpleasant can happen.

Picture the rod at the end of the stroke - level with the axles. If you rotate one axle, ANY slop in the rod or axle bearings will allow another axle to begin to rotate in the opposite direction, and quickly bind.

As I think about the problem, I suspect that driving one of the middle axles might tend to reduce the problem. I'm not sure about it, but my gut tells me it might be the case.


Kenneth, 
You are correct given what Ted described. However, I believe the reason for the counterweights is that there are outside connecting rods as well. As long as the opposite sides are at 90 degrees, there shouldn't be a problem with just one connection. 
If there is no quartered rod on the other side of the stub axles, it won't matter how the driven axle is actually driven. If all the stub axles are driven, then quartering will also not matter since the Aristo drivers are all powered. Since the only real problem is (as mentioned above) that there is a possibility of one axle trying to rotate backwards, mechanically driving all the axles will entirely prevent the problem. Of course, you could then run into other issues, related with trying to drive a rigid axle from a more movable one (as you noted).

In the end, I think the idea of extending the Aristo axles in some way is the most mechanically reliable method. As much as I like the out of the box concept and creative concept, I think it needs to be done with good mechanical practices in mind as well.


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## Ted Nordin (Feb 27, 2008)

Ken thanks for your continued ideas and input. I decided to halt at this point as I'm certain you are correct that one will inevitably go south when all else is north. Tomorrow I am going to try your double anchor idea running off of 2 and 3. Your hypothesis about end of stroke has occurred on my hand powered practice assemblies. 

Pete, your description is invaluable. I have fashioned a crank idea I hope works. A thick nylon washer around the crank pin drilled with a 1/16 shank screw protruding towards the stub axle. A roller pin (with gap) pressed onto stub axle and head of screw rests inside this pin. The gap allows the screw to move in and out to accommodate the axle movement. I think one connection on each 2 & 3 might address the problems you gentlemen highlighted. 2 & 3 will need a rod to keep them quartered. 

Thank gosh for these forums - lifesavers to be sure. More tomorrow (out of town today) Thanks again, Ted 

If these ideas don't work back to drawing board. Don't want to do Plan Z small HO or N scale motors inside the large cylinders providing force. This won't work either once the MLS experts get going.


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