Typically on marking out the second pivot is over a spacer

 

Do you mean the fulcrum located 16.5mm forward of the centre axle? It's not easy to alter this dimension by much, but I could have a play with another possible plot to see if anything could be done.

Comparing my part-built High Level Collett chassis with the 57xx one I built recently, the spacers are in pretty much the same positions relative to the axles on both. I can't see how the fulcra would foul a spacer, though they may come very close to one of the footplate supports or brake hangers. For the 57XX, I used the fulcrum positions in the third example on the clag page (the one with 16 and 19.5mm spacing either side of the centre axle). This didn't foul any spacers but does mean you need to shift the vacuum pump a little.

 

Nick

Watching with interest...!

 

Regs

 

Ian

It is the 19.5 from centre line hole which clashes directly with the spacer.  (the gearbox locater one)  19.5 on the HL jig is bang in the middle of it...

Maybe mine is different to yours? It is only part-built but the spacer that supports the gearbox locator is just under 8mm behind the centre axle. The slot in the frame at just over 19mm is for one of the footplate support brackets (part 32). Maybe you could work around that by cutting down the part of the bracket that folds over behind the frame?

 

From Russ' response to CK's question on my 57XX build, there's not really a lot to choose between the different plots. The reason I avoided the first one was the point he made on the clag page about the error potential in short outer spans.

 

Nick

Would be nice if future High Level releases came with half etched holes for the csb mounts

I think Chris Gibbon is considering the idea, but the problem is not so much the choice of the longitudinal plot positions, but the choice of the vertical position. (The latter would constrain a builder to a particular choice of hole in the carrier, and given the different final weights builders might want to adopt, that constraint could be seen as being too inflexible an approach.)

I think Chris Gibbon is considering the idea, but the problem is not so much the choice of the longitudinal plot positions, but the choice of the vertical position...

In theory, yes, as there may be a choice of vertical position with some of his chassis. With the 57XX, though, there is little or no choice because the horizontal parts of the front and rear frame spacers determine where you can put the wire. Only the top position in the carrier was viable, so any adjustment for different weights would need to be by wire size.

 

It will be interesting to see if Rich reaches the same conclusion with this chassis.

 

Nick

On the Pannier chassis, I think it is just possible to use a jig 'B line', but a jig C line is much easier, and does not involve any alteration to the rear spacer. I'm not familiar with the 2251 spacer elevation, and of course the axle datum line is higher than the Pannier, so the situation is slightly different. Chris is probably wise to let the CSB fans determine their own chosen favourite fulcrum line from his standard carrier height settings. Besides which, if Chris really did want to go fully CSB, he'd have to start providing beam apertures in his spacers! (Which will antagonise his non-CSB customers, who in are in the large majority.)

 

What CSBers really want on frame etches is a thin mark to denote the axle datum line - not difficult on a HL etch, but far from easy for frames having a bare 6mm rectangular cutout.

On the Pannier chassis, I think it is just possible to use a jig 'B line', but a jig C line is much easier, and does not involve any alteration to the rear spacer...

Yes, probably. You'd probably need to use one of those straight handrail knobs or a piece of cross-drilled wire for the front as I don't think a normal knobbly knob would sit down close enough to the top of the front spacer. Fitting the vacuum pump would also be more difficult.

...at what point do you solder on the csb brackets?

With my first 57XX, I put them in immediately after the hornguides. That way I could put a piece of wire through them to help work out what needed chopping out of the spacers. With the second one, I put them in much later because I already knew what to do with the spacers.

 

Nick