# replacing worn axles etc...



## Phippsburg Eric (Jan 10, 2008)

I have run my scratch built forney quite a bit and have found axles and other parts quite worn to the point were valve motion is adversely effected. all bearings were either brass or broze and shafts/pins stainless steel (from K&S)









this is the front driver axle. it is obviously quite worn, it seems the brass bearing is not so worn. it still is a pretty good fit on the axle which was not worn at all.








this is the main crank pin and it is also stainless and shows a lot of wear where the connecting rod was. the main rod had a bronze bearing which was wider and seems to have worn the pin less.

It is obvious to me that I am using the wrong metals. I think I should probably switch to tool steel (drill rod) for my axles and stick to bronze bushings. It seems to me that the Stainless wore out as much as or more than the "softer" brass and bronze which surprised me.

I was looking at On Line Metals to see what they had. there seems to be several choices. It looks like O1 might be the best if I can work with it. My experience with choosing tool steels is limited does anyone have any suggestions?


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## seadawg (Jan 2, 2008)

I've heard that dirt and dust will enbed into the softer brass and wear the stainless. I've had the same issue with a couple of my higher run time engines that I run on my ground level track (Frank S and C-16). The Accucraft C-16 has worn the stainless valve eccentrics in the same manner!


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## cocobear1313 (Apr 27, 2012)

Eric, for sure switch to drill rod. It will wear much better than stainless. I have run it in both bronze and brass in IC engines and have not worn one out to date dispate many many hours of usage. If forever is a goal in a axle, consider music wire. 

Dave


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## BigRedOne (Dec 13, 2012)

I experienced the same issue Dave reported on radio control helicopters: metal balls for control points wear faster than the plastic links attached to them. 

Does it make sense to use ball bearings? The radio control car or helicopter bearings offer a number of options which seem to be sized appropriately for the model steamers. 

It looks like a lot of work to replace the axles and rod crankpins?


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## Reg Stocking (Sep 29, 2010)

Some years ago a retired friend decided to make weight-driven timepiece movements to an 1802 patent. He used stainless rather than drillrod for arbors, didn't finish the pivots to a fine polish, and had nothing but trouble. A clocksmith friend subsequently put a fine polish on mine, and it has run well ever since. Stainless is tricky stuff in this kind of application. With careful polishing it might hold up very well, but drillrod is a safer bet. In any case do your best to keep things clean. Grit embeds itself in the brass surfaces and acts as cutting tools on the steel.


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## Phippsburg Eric (Jan 10, 2008)

Thanks for the help! 

I will order some drill rod and let you know how things work out.


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## placitassteam (Jan 2, 2008)

I have the same problem with my Accucraft C16. It is my workhorse for shows and steam-ups. This winter I plan to replace as many of the bearings as possible with ball bearings.


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## Phippsburg Eric (Jan 10, 2008)

I got my shipment of drill rod today by OOPS and have cut new axles and stripped the wheels off the old worn out ones.


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## Taperpin (Jan 6, 2008)

Eric , 
I wonder if there is space to fit Orings as seals each side of the axlebox, would keep out grit and oil in..which would avoid the "lapping" problem 

Gordon.


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## seadawg (Jan 2, 2008)

Posted By placitassteam on 25 Apr 2013 04:27 PM 
I have the same problem with my Accucraft C16. It is my workhorse for shows and steam-ups. This winter I plan to replace as many of the bearings as possible with ball bearings. 

Winn, when you do get around to this project, don't forget to photographically document the steps and post your procedure here please!


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## xo18thfa (Jan 2, 2008)

I recommend getting bar stock from a source like McMaster Carr, or Speedy Metals for scratch building. You know the exactly alloy of the material. Type 303 stainless running in 360 brass or 932 bronze would not wear like this in a Gauge 1 loco. The material from K&S is unknown. Probably one step above pot metal for all we know.


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## placitassteam (Jan 2, 2008)

Dave, I will definately do that.


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## Phippsburg Eric (Jan 10, 2008)

I purchased oil quenchable drill rod from on-line metals www.onlinemetals.com it came in 3 foot lengths at a pretty reasonable price. It seems to machine very well. I parted off the two axles, faced them to length and drilled center holes all with now problem at all using nice sharp lathe tools and drills. Winn, if you need a little for your rebuilding, I have plenty now and can send you out some shortish lengths if you need them. I purchased several sizes 

It IS interesting that the Brass journal bearings removed from the old axles seem to fit nicely on the new axles. I agree that the K&S stainless seems to be poor for this use.


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## Mk (Jan 7, 2013)

Hi Eric 

Do you have a tread with pics building the forney? How did you make the wheels?


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## Phippsburg Eric (Jan 10, 2008)

this is a different set of wheels but the procedure is the same. a disk was sawn from rod. it was rough machined in the lathe. then it was set up in the CNC mill and the sokes, counterweights and cranks milled. then set back into the lathe for finishing operations.

here is a video I made about building Number Nine


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## placitassteam (Jan 2, 2008)

Eric, The axles on the C16 appear to be 6mm (.236") and I would need enough to make 4 axles about 2 1/4 inches long. If you would like to sell me some let me know.


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## Phippsburg Eric (Jan 10, 2008)

I only have english sizes...3/16, 1/4 etc I would be happy to send you either of those but I dont think they would help much. I think I payed $15 or so for more than enough of 1/4" so it is cheap enough even to order from on-line-metals, I am sure other sources have similar prices.


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## placitassteam (Jan 2, 2008)

Thanks Eric, I think I already have some 1/4 inch which I used on my scratch built Mason Bogie. If need be I could ream the drivers to 1/4. I'll have to check the availability fo bearings before making a decission. Thanks again for the offer.


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## HMeinhold (Jan 2, 2008)

Metric drill rod is available from McMaster at very reasonable prices.


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## Phippsburg Eric (Jan 10, 2008)

as an update... 

I have machined a bunch of new parts...now to get her all back together and timed etc for proper running.


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## Phippsburg Eric (Jan 10, 2008)

as an added update...

replacing the axles, main bearings, expansion links, crank pins, and valve gear pins with tool steel seems to have taken most of the play out of the system as hoped. I altered the main journal bearings slightly so they would mate with the equalizing bars better and hold the engine up slightly higher than previously (I had turned down the wheels slightly soon after construction) all seemed good...

But once all back together i had trouble getting good runs out of Number Nine. She seemed to hesitate and even 'lock up" even (or especially?) with full boiler pressure. I had once before had similar issues when the safety valve was misadjusted too high and the O-rings in the cylinders extruded out of the slot. (at least that is what I think happened) Anyhow replacement of the o-rings fixed the problem. The heart of number nine are roundhouse cylinders which use silicone(?) o-rings which limit the working pressure to 40psi. Jason Kovak sent me a rebuild kit for the cylinders and I replaced the cylinder o-rings and o-rings at the top of the valve block. I once more checking the valve motion and reassembled her and she now seems as sweet a performer as ever. she starts easily and smoothly under radio control, in both directions. she runs slowly and fast and seems to pull as much as ever. the log train in the video is quite heavy, I haven't tried my normal freight cars to get a count yet.


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## snowshoe (Jan 2, 2008)

Glad to hear shes up and running again Eric. Little by little I have been trying to improve my Accu Forney. My friend has been working with me on mine. Eventually we will tighten up the links on mine (there is way too much play) It runs good but will lock up when starting up but once its going it runs fine. Our next step is to look at the timing etc.....


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## Phippsburg Eric (Jan 10, 2008)

On my Rubys the valve mechanism consists of a brass rod threaded into the valve it self then it is bent to fit into the rocker arm. I had a lot of wear at that point. both the rocker arm and the rod wore enough to create a lot of slop. Perhaps if you added a bushing in the rocker arm you could reduce some of the wear and associated slop. I think I cheated and relocated where the rocker arm and rod meet so that the rod was working on a new unworn section. a temporary fix at best.


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