Steph Dale
Western Thunderer
Tipp-ex is a very effective solder mask too, it even works when soldering with a flame...
Steph
7mm Dikitriki's Dark side: A WD 2-8-0
- Thread starter Dikitriki
- Start date
Tipp-ex is a very effective solder mask too, it even works when soldering with a flame...
Steph
S
Simon Dunkley
Guest
Maybe it's just me, but Tippex isn't something I would want near any form of heat, and definitely not a flame.
Steph Dale
Western Thunderer
Okay - tell me; why not? I'm not suggesting applying a flame while it's still wet so solvent evaporation/burning aren't a problem. And it does work well.
Steph
S
Simon Dunkley
Guest
You didn't make that bit clear...
Steph Dale
Western Thunderer
S
Simon Dunkley
Guest
Yes, it is. Until someone follows the idea and sets fire to something or inhales the fumes and blames you/WT...
You can't stop idiots being stupid, but you can protect yourself as much as possible from being sued because of their stupidity!
You can't stop idiots being stupid, but you can protect yourself as much as possible from being sued because of their stupidity!
Steph Dale
Western Thunderer
Yes, it is. Until someone follows the idea and sets fire to something or inhales the fumes and blames you/WT...
You can't stop idiots being stupid, but you can protect yourself as much as possible from being sued because of their stupidity!
Hehe - fair point, thanks for the thought. Still worth considering that just because you make something fool-proof won't stop some idiot elevating a male chicken...
Steph
Dog Star
Western Thunderer
Richard,
I have read and re-read your superb treatise on making return cranks and I applaud your ingenuity in getting the nuts to reside "inside" the crank. Sorry to say that I have a few questions.
[1] if the crank pin bushes have 12BA clearance, how can you tap the bush at 12BA?
[2] how much of the bush is projecting to the rear of the return crank?
[3] what stops the connecting rod from bearing on the inside face of the return crank?
[4] how do you set the position of the return crank relative to the crank pin?
regards, Graham
I have read and re-read your superb treatise on making return cranks and I applaud your ingenuity in getting the nuts to reside "inside" the crank. Sorry to say that I have a few questions.
[1] if the crank pin bushes have 12BA clearance, how can you tap the bush at 12BA?
[2] how much of the bush is projecting to the rear of the return crank?
[3] what stops the connecting rod from bearing on the inside face of the return crank?
[4] how do you set the position of the return crank relative to the crank pin?
regards, Graham
Dikitriki
Flying Squad
Hi Graham
[1] The bush I used on the return crank is not a Slater's crank pin bush. It is a miniature top hat bearing that is perfect for tapping 12BA. You see them from time to time at shows, but my stock came from Ron Chaplin which is no help.
[2] Not much at all! 0.3mm.
[3] A washer that goes either over the bearing through the connecting rod (probable), or on top of the bearing through the connecting rod (possible). I've not yet looked at this.
[4] The return crank is tightened against the bearing through the coupling and connecting rods. This bearing is filed back bit by bit by trial and error until the return crank is tight in exactly the right place relative to the crank pin. The only thing you need to watch is that that part of the 12BA crankpin extending beyond the main crank pin bearing is wholly contained within the miniature top hat bearing on the return crank ie tightening it wont force the outer shim layer off.
Yours
Richard
[1] The bush I used on the return crank is not a Slater's crank pin bush. It is a miniature top hat bearing that is perfect for tapping 12BA. You see them from time to time at shows, but my stock came from Ron Chaplin which is no help.
[2] Not much at all! 0.3mm.
[3] A washer that goes either over the bearing through the connecting rod (probable), or on top of the bearing through the connecting rod (possible). I've not yet looked at this.
[4] The return crank is tightened against the bearing through the coupling and connecting rods. This bearing is filed back bit by bit by trial and error until the return crank is tight in exactly the right place relative to the crank pin. The only thing you need to watch is that that part of the 12BA crankpin extending beyond the main crank pin bearing is wholly contained within the miniature top hat bearing on the return crank ie tightening it wont force the outer shim layer off.
Yours
Richard
Dog Star
Western Thunderer
Um, Richard, Alcazar is probably correct judging by photos of SNG on the I'net... which rather begs the question "How is the return crank fitted on A3 engines?".
regards, Graham
adrian
Flying Squad
I presume with a pinchbolt like this
http://www.stationroadsteam.co.uk/stock pages/3010/pages/3010-d.htm
or
http://modeleng.proboards.com/index.cgi?action=display&board=general&thread=3948&page=1#38479
google images isn't that forthcoming with decent images but you should get the idea.
Dog Star
Western Thunderer
Er... the question was sort of rhetorical in that Richard has (a) built an A3 and (b) indicated that he does not know what a pinch bolt / square drive looks like. Come to think of it, neither did I when writing that I would pinch Richard's ideas on making a four bolt return crank 
.
.
Dikitriki
Flying Squad
Hi
It's my ignorance showing through, not knowing the correct terminology. However, I now understand what you mean, and Graham, you may rest assured that DJ does not have a 4 bolt fixing....
I just used the MF components and soldered them to a threaded cap. When I come to do my A4s I will have to see if I can do better. I can see I need to do better on the coupling rod articulation as well....
Still, you learn something every day.
Richard
It's my ignorance showing through, not knowing the correct terminology. However, I now understand what you mean, and Graham, you may rest assured that DJ does not have a 4 bolt fixing....
I just used the MF components and soldered them to a threaded cap. When I come to do my A4s I will have to see if I can do better. I can see I need to do better on the coupling rod articulation as well....
Still, you learn something every day.
Richard
Dan Randall
Western Thunderer
That's a very tidy piece of work! 
Regards
Dan
Regards
Dan
Dog Star
Western Thunderer
Thank you - Mick for the A3 photo.
I wonder why there is a taper pin on one side of the "square" on the pin. I would expect there to be some form of fore-and-aft location possibly by either a shoulder on the square or by the pinch bolt running through a hole which is, in part, in the square.
We all need to encourage Richard to start his A4, with the motion first so that we can see how he does the return crank "because he can" .
regards, Graham
I wonder why there is a taper pin on one side of the "square" on the pin. I would expect there to be some form of fore-and-aft location possibly by either a shoulder on the square or by the pinch bolt running through a hole which is, in part, in the square.
We all need to encourage Richard to start his A4, with the motion first so that we can see how he does the return crank "because he can"
.regards, Graham
, still the same goes for his 8f