Search found 132 matches

by Daddyman
Sun Oct 25, 2020 6:44 pm
Forum: David B
Topic: Lost Property
Replies: 26
Views: 10540

Re: Lost Property

Thanks for the tip, David. I've just bought one of the flat ones, but didn't bother with a round one as I couldn't see anything they could do that broaches can't - or am I missing something?

EDIT: OK, I see it!
by Daddyman
Sat Oct 24, 2020 6:54 am
Forum: Chassis and Suspensions
Topic: Bearings in MJT Torsion Bar CCUs
Replies: 6
Views: 292

Re: Bearings in MJT Torsion Bar CCUs

I can't help any more with this, sorry, other than to agree with what you say...
by Daddyman
Fri Oct 23, 2020 7:07 pm
Forum: Chassis and Suspensions
Topic: Bearings in MJT Torsion Bar CCUs
Replies: 6
Views: 292

Re: Bearings in MJT Torsion Bar CCUs

Seems to be in order to allow the builder to check whether the bearings need any washers or not to get the axles held between the side frames without any slop: 8) Place the axle bearings and the wheel sets in position in the correct bearing holes (Blu-tack will hold the bearings in place temporarily...
by Daddyman
Wed Oct 21, 2020 9:59 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

davebradwell wrote: I feel you're getting there but slowly.

Well, thanks to your - and everyone else's - help. Couldn't have done it alone...
by Daddyman
Tue Oct 20, 2020 3:18 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

I have a rake of the clerestory coaches on the D&S complicated compensated bogies, and I think they ride at the right height. At the very least the footboard on coach and bogie line up. Could you not resolve this by further reducing the height of the bogie mounting plate? As a mater of interest...
by Daddyman
Tue Oct 20, 2020 11:15 am
Forum: Starting in P4
Topic: Rt models hudson vee tipper compensation ?
Replies: 14
Views: 465

Re: Rt models hudson vee tipper compensation ?

I spring for 4 reasons:

1. Sprung vehicles look better in motion.
2. They're quieter (since that nice Mr Bradwell alerted me to the row made by unsprung vehicles I haven't been able to go back)
3. Job satisfaction.
4. It's P4 - it's meant to be done right.
by Daddyman
Tue Oct 20, 2020 10:11 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

Just as a matter of interest, you replaced the supplied D&S bogies with some rather complicated fully sprung ones. Did you ever assemble the D&S bogies and, if not, would it be worthwhile building one to see if it gives you the correct ride height? DT That's a very good idea, David, thank y...
by Daddyman
Mon Oct 19, 2020 11:08 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

Just reflecting on this setting issue: as you're trying to get the body the right height as well as the bogie frame you'll need to be very lucky if you can find a combination of wire gauges that will do the trick. Surely a bit of wire bending is almost inevitable unless you do an alternative such a...
by Daddyman
Sun Oct 18, 2020 6:00 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

davebradwell wrote:......but aren't the lengths of primaries and secondaries different? Back to the sums!

DaveB

Rats! 15mm between anchor points for the secondaries, and 17.3 for the primaries. So secondaries stiffer than primaries if the same gauge wire used for both...
by Daddyman
Sun Oct 18, 2020 4:58 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

I only meant you to use an approximation - the ratio between the numbers for 7 thou and 8 thou' is about 5/8 so before you buy your wire you can see it will give 8/5 ths of the deflection - quite promising, but will it be enough? Going to 6 thou' will give 3 times the deflection of the 8 and so com...
by Daddyman
Sun Oct 18, 2020 4:28 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

davebradwell wrote: A fine day with some distant sun, strands of mist, autumn colours and a nice drive with no camper vans.


Sounds nice. I've mostly been cussing bogies...

I think trial and error appeals more than that maths, though.
by Daddyman
Sun Oct 18, 2020 1:20 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

Oops, yes it's the cheap ones which stay coiled up (even when you unwind the ends out of the coil). I tried some as they were half the price - perhaps they're fine for guitars! You also have (in theory!), for a simple wire spring between two knife edge supports... (L)ength vs d is a third power rel...
by Daddyman
Sun Oct 18, 2020 10:25 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

Thanks for that, Ian - and for explaining the fourth power thingy: my PhD is in literature so I need such things explaining in small words... Just one question: you say "a diagnostic is that they stay coiled up when you take them out of the bag" - that is a diagnostic of cheap or good-qual...
by Daddyman
Sun Oct 18, 2020 8:30 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

Unless there's physical limits to how far springs can deflect - will they hit something - then that would be "yes" a few times. Tweaking springs isn't too bad as once you've made one you can just copy it on the others. Drill a 2mm hole in a piece of anything and scribe a line across at th...
by Daddyman
Sun Oct 18, 2020 8:03 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

Thanks, Dave. I was trying to avoid bending the springs, as I would need to get 64 bends consistent across the train (8 bogies, 4 springs per bogie, 2 bends per spring). But anyway, bending only solves the primary problem - there's no way to bend the secondary springs because of how they are held in...
by Daddyman
Sun Oct 18, 2020 7:09 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

I've now fitted the 8-gauge springs and the carriage still sits too high: both the bogie upper edge and the buffer centres are too high, meaning that both primary and secondary springs are too hard. Putting 20g of weight over each bogie does get the springs to compress enough to give me the correct ...
by Daddyman
Mon Oct 12, 2020 7:02 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

Well I submitted a post which seemed to go but it's not there. Are the primary springs too high? You can check against the drawing. You have to set both primary and secondary springs separately and it helps if the primary springs are stiffer than the secondaries. First check the bogie frame is the ...
by Daddyman
Sun Oct 11, 2020 6:26 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

I can’t comment on the springing side of things, but my preference is for a carriage that weighs about 180-190g. That seems to make it possible for the buffers and any sprung gangways to do their proper work without any tendency for forces to push vehicles off the track. I should perhaps explain th...
by Daddyman
Sun Oct 11, 2020 6:00 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Re: Carriage ride height and springing

Given you know full spring compression takes you below the height you want, (i.e. the ride height you want is in the available range) and that the axle ends seem to be below mid travel in the W irons, I think putting in thinner wires is the obvious first choice. Thanks, Will. You're right of course...
by Daddyman
Sun Oct 11, 2020 3:43 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 31
Views: 1324

Carriage ride height and springing

Hello. I'd like some advice on carriage springing and weighting if the membership would be kind enough. I'm building some D&S NER carriages and have replaced the bogies with fully sprung (primary and secondary) ones from Miscellany/Rumney Models. I've followed the instructions, but am having pro...
by Daddyman
Mon Oct 05, 2020 3:42 pm
Forum: Electrics
Topic: Scale Clocks
Replies: 11
Views: 891

Re: Scale Clocks

Ah!
by Daddyman
Thu Oct 01, 2020 10:48 am
Forum: Tools and Techniques
Topic: Glazing - your thoughts please
Replies: 29
Views: 1208

Re: Glazing - your thoughts please

I've tried a number of adhesives, but found Canopy Glue best. It looks just like PVA.... That's because it is just a fairly thick sort of PVA. Ordinary wood glues will do the same job. They don't. I've just run an experiment, gluing some perspex to bare brass. I used a cheap PVA I bought at a model...
by Daddyman
Wed Sep 30, 2020 6:17 pm
Forum: Tools and Techniques
Topic: Glazing - your thoughts please
Replies: 29
Views: 1208

Re: Glazing - your thoughts please

Thanks to both! Useful links if I decide to try glass Re6/6, thank you.
by Daddyman
Wed Sep 30, 2020 11:09 am
Forum: Tools and Techniques
Topic: Glazing - your thoughts please
Replies: 29
Views: 1208

Re: Glazing - your thoughts please

Eileens sell clear styrene PETG sheet which apparently has the same transmission properties as glass. https://www.eileensemporium.com/materials-for-modellers/category/eileens-clear-styrene-petg-sheet Regards Paul Bannerman Thanks! Looks like it might be a bit thick though? - the thinnest is 1mm.

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