Mini cranks

[David Prime]

Dear all,
I've heard many times the mention of Mini Cranks for outside frame conversion. My understanding was these mini cranks solved the conversion of an N gauge locomotive to outside frame. Does anybody have any pictures of these and how they were used? Any help, pictures etc to explain the principle would be very welcomed.

Thanks Dave P

[B.Meldon]

Minicranks were a product produced by Brian Clark under the Merlin Locomotive Works and Saltford Models product range in the mid 1980

[JulienW]

Minicranks were something produced by Saltford Models some years (30+?) ago, and as Saltford Models have not afaik traded for some time they are a little hard to find.

In essence they composed of two turned brass discs joined with a bar at the centre - a H shape in cross section. One side was fixed to the face of the n-gauge wheel whilst the other was cut to the shape of the crank and the dummy frames slipped over the bar.

An alternative approach is to use something like a broad headed nail (felt nails) stuck to the face of the wheel and then use the shaft of the nail as the stub axle to which the outside crank is attached - Ted Polet has done this for a number of his loco's.

A tip here about making the cranks is to make a stack of sheets(solder them together), drill a hole for the 'axle' and a second one for the crank pin making sure both holes are parallel and perpendicular to the flat of the crank, then cut / file them to shape before separating the stack.

Essentially all that the Minicranks or nails do is to extend the axle on the chassis. As an alternative approach one could strip the chassis down to replace the axles with longer material of the same diameter, if the construction of the chassis allows for this (you can't do this on the older 'white box' Bachmann chassis for example as there isn't an axle to be replaces).

Hope that helps.

Edit: I thought I had taken some photos - thanks for finding them Brian!

[B.Meldon]

Were Minicranks two turned disks with a bar joining them, i.e made in three parts, or were they one solid disk with a slot machined in it?

Brian Meldon

[JulienW]

They were probably machined in one piece (certainly the ones I have are) but they look like two discs linked by a round bar. It's one of those things that are hard to describe in words but very obvious when you see a picture!

[David Prime]

Well thanks all. I think I follow the idea and am now investigating whether I can have the same made again.
I'll see how this goes !
Does anyone mind me copying the details posted above ?

[JulienW]

Well thanks all. I think I follow the idea and am now investigating whether I can have the same made again.
I'll see how this goes !
Does anyone mind me copying the details posted above ?

Good luck with the first bit.  My suspicion is that Brian Clark turned them himself on a small lathe.  It would not be too difficult to do if one has the tools, as the minicrank is essentially two parts (discs) than have not been fully 'parted off', but I wonder if getting them done commercially would mean having to have several hundred (or thousand)...

Not quite sure what you mean by 'copying the details'. Speaking for myself as long as things are credited (and not for commercial gain) then I don't have a problem, though I can't speak for Brian Meldon (who has also posted material) or Brian Clarke who made the things in the first place.

[MickT]

Didn't Meridian once do sets of the same sort of thing for 2 types of Bachmann chassis, more recently than the orginal Brian Clarke ones? I think this might have been for the 2-6-2 and 2-8-0 but can't remember.

Mick

[rod335]

I believe you are right Mick, I'm pretty sure Meridian did them as well. I would have thought it would be quite hard to copyright the principle of these things, there is in reality little alternative to the problem short of fitting longer axles. However, for what it is worth I offer AN alternative, perhaps not quite as elegant. Fit a disc to the wheel centre, plasticard will suffice, thick enough to reach the outside of the outside frames. Fit a flycrank to the front of this disc and drill for a crankpin. This hole can go right through to the original wheel centre for rigidity. Make your outside frames with a slot with a semi-circular top to just clear the disc on the wheel face. If the flycrank is painted, say, red and the disc and frames the same dark colour, the illusion of outside cranks will be almost complete. Especially in the murk below the average narrow gauge loco footplate.

[JulienW]

Didn't Meridian once do sets of the same sort of thing for 2 types of Bachmann chassis, more recently than the orginal Brian Clarke ones? I think this might have been for the 2-6-2 and 2-8-0 but can't remember.

Mick

From memory the Meridian items were a single disc with a stub axle that replaced the plastic centers on the Bachmann wheels.  As the Bachmann chassis at the time (the "white box" type) were split frame their wheels were metal discs in any case this was the only way to extend the axles as, in effect, there wasn't any metal axle to extend between the wheels, just a plastic geared muff (hopefully not split!). As to the ourside cranks that was left to the modeller, though Meridian have sold cast brass cranks in a couple of different styles in the past.

And the 2 types you have in mind Mick were the 0-4-0 and 0-6-0 / 2-6-2.

As an alternative for this type of Bachmann chassis one can use Paul Windle's method, which is to fix a short length of tube to the stub found in the center of the Bachmann wheels once the plastic has been removed (which you need to cut off to fit the Meridian parts) which creates a socket into which more rod can be fixed to extend the axle.  I've done this myself on one of the big 4-8-4 locos which languishes in the 'projects' box...

[JulienW]

I believe you are right Mick, I'm pretty sure Meridian did them as well. I would have thought it would be quite hard to copyright the principle of these things, there is in reality little alternative to the problem short of fitting longer axles. However, for what it is worth I offer AN alternative, perhaps not quite as elegant. Fit a disc to the wheel centre, plasticard will suffice, thick enough to reach the outside of the outside frames. Fit a flycrank to the front of this disc and drill for a crankpin. This hole can go right through to the original wheel centre for rigidity. Make your outside frames with a slot with a semi-circular top to just clear the disc on the wheel face. If the flycrank is painted, say, red and the disc and frames the same dark colour, the illusion of outside cranks will be almost complete. Especially in the murk below the average narrow gauge loco footplate.

That is quite a neat idea Rod.

As a variation on that I have seen some rather nice Vale of Rheidol locos by Dean Whiston (a West Mids. member) where dummy frames have been made with cut outs that closely follow the line of the crank pins. Even without any additions to the wheel face it often takes a second (or even third!) look to notice the subterfuge.

[B.Meldon]

Technomodell do the same thing i.e. cut outs in the outer frames on their RTR 1K 0-6-0 loco:



It is a bit off topic but I think Meridian had planned to release a complete outside frame kit using wheel inserts and resin frames for the Bachmann 0-6-0 and 0-4-0, I can recall seeing the pre-production examples at Pete's many years ago now. But Bachmann stopped selling the chassis and I think there were problems with the strength of the resin parts as well.

Brian Meldon

[David Prime]

These ideas are really interesting. I hope to have a " bash " soon on some ideas
This is the real stumbling block with 009 and it would be ideal to find a nice easy method. I rather like your idea Rod and this is captured well in the photograph above .
Keep the ideas coming. Would be nice to have an article in the 009 news I think?

[David Prime]

Dear Brian
The Technomodel you posted here- is this HOe and if so do you know where to buy? I tried searching the name but didn't find anything like the picture you posted.
Many thanks,

[tebee]

....... I would have thought it would be quite hard to copyright the principle of these things,........

Indeed you can't - copyright does not apply to mechanical or practical things, only to artistic creation.

Tom