stephensons link problem

[David Bothwell 1Participant @davidbothwell1]

I am working on a two and a half inch 0-6-0 engine with Stephensons link motion. I have had the engine running, but stripped it down to paint it. When re-assembled the valve links are not working properly. I have stripped it down and assembled the engine more than once! One side seems ok, but instead of opposing steam inlets being open sometimes the same side can be open. Hope I have made it reasonably clear. Very frustrating and any help or suggestions gratefully received!

[David Bothwell 1Participant @davidbothwell1]

motion is not working properly

[John BaguleyParticipant @johnbaguley78655]

David,

Just a thought – have you got the eccentric rods connected to the expansion link the right way round. You may have got the forward and reverse rods crossed over on one side.

Out of interest, which loco is it?

John

[WorkshopPeteParticipant @workshoppete]

Hi David

As John says sounds like you have crossed rather than open eccentric rods change end for end on that link and all should be ok . Very very easily done.

Regards

Peter

[David Bothwell 1Participant @davidbothwell1]

Thanks for both replies, The loco is a 2.5 inch Southern Maid (LBSC) The eccentric straps are marked (punched) with pips 1 to 4, When I took a photo before dis- assembly these pips were at the top of the loco (looking down) that is (I think) how I received the loco, but after dis assembly I notice that one of the actual eccentrics on the axle was punched with four pips ( which now meant that pips appeared underneath) after I put it back together!. If I understand "Workshop Pete" I think you are saying undo the two wrong eccentric (straps)and reverse these on the axle?

[WorkshopPeteParticipant @workshoppete]

Hi David

It sounds like it has reassembled wrong after the strip down. It is important that that the eccentric rods on both expansion links are attached the same way. if you rotate the axle the top of both expansion links should move either forward or backwards not one forward and the other backwards. if this the case swop the eccentric rods over. The worst that can happen is that when you put the reversing stand in forward the loco goes backwards in which case both sets of eccentric rods will have to be changed over but at least you will have a starting point to sort out your problem.

Best of luck

Peter

[David Bothwell 1Participant @davidbothwell1]

Hello Peter,

Many thanks for the post, unfortunately I have not solved the problem. I have this morning swapped the numbered straps (4) back to what I thought was their original positions. Which was number 4 on the left of the loco I am still experiencing an opening of the valves at the same end. I may not have explained very well. So here goes again. On the axle (middle of three) where the eccentrics are fixed I have reversed the positions of the straps, the outer two straps (1 and 4) now move forward as the inner (2 and 3) move in the opposite direction (backwards)as the axle is rotated. The only other way I can think of altering anything significantly would be to undo the eccentric connections to the die block and reverse these. But as I did not touch these I cant think it would work. Sorry for the laboured description. Any suggestion most gratefully accepted!

[Author]

Posts