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Replacement valve gear


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I have a Hornby MN loco that has badly damaged valve gear, neither Hornby or Peters Spares have replacement units, does any one make an etch that I can use to replace the existing. I tried to repair the existing but the crosshead casting casting broke and the pins in the drop links bent when I had repaired one side. The original problem was that the connecting rod joint with the crosshead had sheared off on both sides.

As the crosshead and valve gear is unique to this loco in the Hornby range and I doubt if I could make it from scratch, I think I remember  that someone made an etched kit that maybe I could use the valve gear to repair my loco.

 

thanks in anticipation of an answer 

 

mike

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Most model valve gear's are a poor DSC_7370.JPG.80fcbb006dd78babb9c795318f78b45b.JPG

Most model valve gear's are a poor representation of the real thing. Comet do kits for various locomotives that could possibly adapted to your use. These are what I adapted for a Hornby B1.DSC_7369.JPG.15d1ce1d15f80a460c72dc8a20c9c7a1.JPG

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1 hour ago, jf2682 said:

Nicely made!  Can the gear be modelled in different cut-offs?

 

 

Maybe one day we'll have decoder operated radius rods in sync with direction of travel - just a silly thought.

 

 

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3 hours ago, Right Away said:

Maybe one day we'll have decoder operated radius rods in sync with direction of travel - just a silly thought.

 

 

Should be possible to create something mechanical to make the gear run forward in forward gear and back in back gear but actually making the die block etc work might be a step too far.

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Already done in O Gauge. Although it's not fully automatic, you can use a servo remove the  gear from forward to reverse using a playable function button.

Baz

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14 hours ago, Right Away said:

Maybe one day we'll have decoder operated radius rods in sync with direction of travel - just a silly thought.

 

 

Yes you can make it up with different cutoffs and should be possible to have servo operation of the reversing gear, but it would be fiddly in 4mm and is it really worth the extra complexity. Most people would never notice it. This is the completed B1.

DSC_7448mod.jpg.7225c49672b8764bde06ea3a478496cf.jpg

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On 18/03/2019 at 18:48, Right Away said:

Maybe one day we'll have decoder operated radius rods in sync with direction of travel - just a silly thought.

 

 

 

It was done in S scale many years ago. IIRC a small motor drove a screw to reverse the gear on changing direction.

 

Most 4mm models are set in mid-gear though Hornby Dublo set theirs in forward gear (apart from the 4MT 2-6-4T which is in reverse). Many models have the return crank wrongly set which makes the whole exercise pointless.

 

Proper locomotives have the gear between the frames, so it's not a problem. (Ducks for cover....)

Edited by Il Grifone
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