Chassis for a J50

Lindsay G
Posts: 113
Joined: Thu Aug 07, 2008 2:16 am

Re: Chassis for a J50

Postby Lindsay G » Thu Jan 18, 2018 12:52 am

Flymo got in before me regarding the use of the three holes on the HL CSB etch tags to alter the ride height. The 3 holes are there primarily for flexibility in positioning the fulcrum holes in the chassis per the indispensable HL CSB jig (there's a guide to its usage on their website if all of this is passing you by!), so if the upper, middle, or lower hole on the tag isn't used per the fulcrum position, strictly speaking, it is a bodge as Flymo has said.

However, I'd rather see this offering more flexibility for fine tuning between different gauges of wire and different levels of holes from the original plan if it really has to come to that, and normally it won't. Now, using different tag holes along the length of a chassis side would definitely be getting into bodge territory, but if the worse comes to the worse - and by no means am I suggesting it should come to this with CSB's - it's a last gasp option for the bodger before checking on the likes of drilled holes being significantly out.

Fine tuning ride height via different gauges of wire or tag holes involves extracting 2 wires and reinserting them or different ones through the same or different holes. Very straightforward, done in minutes. How easy is it to adjust ride height on a compensated chassis?

Lindsay

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Flymo748
Posts: 2112
Joined: Sun Jul 20, 2008 6:00 pm

Re: Chassis for a J50

Postby Flymo748 » Thu Jan 18, 2018 8:41 am

Lindsay G wrote:
Fine tuning ride height via different gauges of wire or tag holes involves extracting 2 wires and reinserting them or different ones through the same or different holes. Very straightforward, done in minutes. How easy is it to adjust ride height on a compensated chassis?


Actually, to leap to the defence of those that build compensated chassis (and that includes me, if it is easier* than my preference for CSBs I would still use compensation) then it can be straightforward. On one locomotive where the beam was fixed through a spacer by soldering, I just melted the solder, moved the beam slightly whilst loose (with pliers to hold it!) and let the solder cool again to hold it in place.

And depending on the material of the beams, and the ease of access to them, it can also be the work of a few seconds. Apply thumb and forefinger, and tweak a bend into it to make the appropriate adjustment. I recall doing this on the very first P4 locomotive I built - an M&L 1076 GWR Buffalo saddle tank. It had, and still has, a single central compensating beam made of a length of nickel silver bullhead rail...

If you have something like a twin-beam set up, either side of the chassis, which is awkward to get at, and/or the beams are etched in brass or nickel with a high resistance to bending in the vertical plane, then the task is more difficult. But the comparison of ease is not quite so clear-cut.

Cheers
Flymo

* An example would be my GER Coffeepot. I initially thought about CSBing it, but then seeing the miniscule size of the model, and the complexity packed into the chassis, I decided that discretion was the better part of valour, and built it as per the instructions with compensation. Yes, I know that someone in CLAG# (Ted?) has sprung one of these tiny High Level models, yet I decided it was not for me.

# But we know that they are all mad anyway... ;-)
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

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Will L
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Joined: Sun Jul 20, 2008 3:54 pm

Re: Chassis for a J50

Postby Will L » Thu Jan 18, 2018 8:06 pm

Not sure the problem is significantly different when adjusting the body height on a compensated chassis either. While you may well want to adjust any failure to sit level by tweaking a beam, adjusting the overall height of the model that already sits level is much more of a problem. If you have a fixed axle then you're right back to adjusting the fit betwixt body and chassis. If you have an all axle compensated chassis then you have more than one beam (potentially 3 or more) to worry about and they will all need tweaking to match. It’s probably easier to adjust the fit between body and chassis.

Of course, a (properly designed*) CSB chassis sits level by design. If you have a CSB loco that doesn't, then the diagnostic choice is between the body/chassis fit or that the Centre of Gravity is significantly out of place. It shouldn't be too hard to locate the CofG which will tell which one you are dealing with.

*If you’re a bodge-myster and have been guessing/adjusting fulcrum placements by instinct, then I'm afraid you’re on your own.

I have come up with this 10 point summary of how you get a CSB fitted loco sitting level with the right buffer heights, which, to ease of future reference I've given a thread of its own.

Julian Roberts
Posts: 584
Joined: Sat Jan 09, 2010 11:33 pm

Re: Chassis for a J50

Postby Julian Roberts » Fri Jan 19, 2018 6:20 pm

Very many thanks for all the replies, and your definitive instructions Will. It'll be some time till I can start this but there's plenty here to mull over in the meantime.


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