Search found 365 matches

by davebradwell
Sun Nov 08, 2020 9:06 am
Forum: Steam Locomotives
Topic: Frame Spacing
Replies: 26
Views: 2139

Re: Frame Spacing

You might slot out the hole in a couple of 2mm washers so they can be clipped onto the worm shaft to reduce the end-float without any risk to the running, Julian. Top tab is my favourite method of restraint but that will probably interfere with your ballast weight. As you say, if axle can rise, fall...
by davebradwell
Fri Nov 06, 2020 4:02 pm
Forum: Steam Locomotives
Topic: Frame Spacing
Replies: 26
Views: 2139

Re: Frame Spacing

It's possible, Julian, that some of the noise may be related to how you contain the endthrust of the worm which isn't visible in the gearbox photo. The bearings supporting the worm shaft should have their flanges towards the worm to give the greatest area and then pack between worm and bearing face ...
by davebradwell
Fri Nov 06, 2020 9:53 am
Forum: On My Workbench
Topic: Ralph's workbench
Replies: 53
Views: 7455

Re: Ralph's workbench

DougN, I can come up with an A4 drg of stations on the Pickering and Seamer Branch - try Wykeham, Forge Valley, etc. Looks similar but might not survive close study. There'll be something in the 3 vols of NER Architecture but it will take some finding.

DaveB
by davebradwell
Thu Nov 05, 2020 5:11 pm
Forum: Steam Locomotives
Topic: Frame Spacing
Replies: 26
Views: 2139

Re: Frame Spacing

Sorry, Julian, I missed your motor photo. Indeed the drive shaft is a very sound arrangement and it could never work with a single u/j although there are ways it can be done with the right kind of coupling. Can't see the gearbox restraint so will always be suspicious. Is it on a rubber pad to reduce...
by davebradwell
Thu Nov 05, 2020 5:02 pm
Forum: Steam Locomotives
Topic: Frame Spacing
Replies: 26
Views: 2139

Re: Frame Spacing

A thought, WillL. With 4-4-0 or 0-4-4 and fixed pivot on bogie might it be better to have a little sideplay on both coupled axles so they traverse in opposite directions on a curve so sharing the required offset between them? Certainly allowing play on the axle furthest from the bogie will reduce th...
by davebradwell
Thu Nov 05, 2020 4:06 pm
Forum: Steam Locomotives
Topic: Frame Spacing
Replies: 26
Views: 2139

Re: Frame Spacing

My current project has Gibson 6ft - 2in wheels. Front and rear needed a 0.3 washer each side and centre did without to give some sideplay, although this is rather excessive and I hope won't give trouble shorting on the rather complicated brakes. No wheels were harmed in the making of this model whic...
by davebradwell
Wed Nov 04, 2020 8:03 am
Forum: Steam Locomotives
Topic: Frame Spacing
Replies: 26
Views: 2139

Re: Frame Spacing

I believe a large gap between wheel and frame looks ugly and toy-like so have always considered the boss on the back of a wheel to be adjustable and irrelevent to frame width. It's easily filed. Have been using 16.2 over for years with axlebox flanges outside this. Most wheels need washers and every...
by davebradwell
Tue Nov 03, 2020 9:35 am
Forum: Guest Book
Topic: 0-6-0 CSB with one fixed axle
Replies: 10
Views: 2249

Re: 0-6-0 CSB with one fixed axle

if you want to assess the benefits of springing then you have to spring all the axles. If you have a fixed axle then the game's over and whether you spring or compensate the others it won't behave like the real deal, although, as has been said, the pick-up will probably be improved. The solution is ...
by davebradwell
Sun Nov 01, 2020 9:53 am
Forum: Track and Turnouts
Topic: Masokits etched chairs turnout construction for Kyle of Lochalsh
Replies: 63
Views: 7538

Re: Masokits etched chairs turnout construction

Yes Martin, I add on the gauge widening when choosing my drills to get the right check gauge. It's perhaps an odd way to do it but I go over the whole thing with vernier and drills after construction to see what I've ended up with. Thanks for confirming the check figure is constant.

DaveB
by davebradwell
Sun Nov 01, 2020 9:11 am
Forum: Track and Turnouts
Topic: Masokits etched chairs turnout construction for Kyle of Lochalsh
Replies: 63
Views: 7538

Re: Masokits etched chairs turnout construction

Drill shanks make useful gauges for things like check rails, Julian. A query for the experts - did the check gauge stay the same regardless of curvature or was there a check gauge narrowing to allow the wheeelset to lie at an angle? I can see there may well be sufficient clearance incorporated in th...
by davebradwell
Sat Oct 31, 2020 9:46 am
Forum: Tools and Techniques
Topic: Loctite
Replies: 7
Views: 1197

Re: Loctite

Well, my 20year old bottle won't stick anything and before that it could go off suddenly while the joint was being assembled. Will only buy another bottle when I have an immediate application. Biggest problem with the stuff isn't whether it sticks or not (that's usually pretty obvious) but where any...
by davebradwell
Wed Oct 21, 2020 8:51 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 40
Views: 3357

Re: Carriage ride height and springing

Wrote this last night but it conforms where you're going. It would be such a step backwards to remove the nicely designed sprung bogies with their smooth ride and replace them by compensated just for the sake of working out how to adjust them. After all on the full size they would have had to go rou...
by davebradwell
Mon Oct 19, 2020 7:43 pm
Forum: Starting in P4
Topic: Rt models hudson vee tipper compensation ?
Replies: 14
Views: 932

Re: Rt models hudson vee tipper compensation ?

It's very easy to make stock that won't stay on your track so when you're starting why not go for something that is almost certain to work rather than pick a solution that should be alright if you can make very good track at your first attempt. Yes, you can clip new wheels into a Bachmann mineral wa...
by davebradwell
Mon Oct 19, 2020 8:32 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 40
Views: 3357

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 as...
by davebradwell
Sun Oct 18, 2020 5:16 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 40
Views: 3357

Re: Carriage ride height and springing

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

DaveB
by davebradwell
Sun Oct 18, 2020 4:53 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 40
Views: 3357

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 come...
by davebradwell
Sun Oct 18, 2020 3:29 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 40
Views: 3357

Re: Carriage ride height and springing

Dr. Daddyman then, it would seem. Well, he's floored me by mixing up lettering conventions, but then I'm working from an old textbook that uses pounds and inches and assumes we're on planet Earth. d was always wire diameter with D reserved for diameter of coil springs. Deflection was anything else. ...
by davebradwell
Sun Oct 18, 2020 8:19 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 40
Views: 3357

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 the...
by davebradwell
Sun Oct 18, 2020 7:47 am
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 40
Views: 3357

Re: Carriage ride height and springing

My springs are longer than yours so a direct comparison isn't possible. Just remember that deflection is inversely proprtional to the 4th power of the spring diameter. You might try phos bronze which is a little more than half as stiff as steel so this will almost double deflection for same gauge. P...
by davebradwell
Thu Oct 15, 2020 8:47 am
Forum: Chassis and Suspensions
Topic: Sand pipes for removeable wheelsets
Replies: 9
Views: 799

Re: Sand pipes for removeable wheelsets

A further advantage of Dave Holt's plate is that the brakes are well secured against drifting or being knocked out of alignment and so causing shorts. Being able to easily dismantle a model is important when getting the chassis to run properly - if it's difficult, this will discourage you from makin...
by davebradwell
Sun Oct 11, 2020 9:14 pm
Forum: Starting in P4
Topic: Carriage ride height and springing
Replies: 40
Views: 3357

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 c...
by davebradwell
Sat Oct 10, 2020 4:06 pm
Forum: Chassis and Suspensions
Topic: CSB for a Single Driver
Replies: 50
Views: 5292

Re: CSB for a Single Driver

I wasn't thinking of anything non-linear, WillL just fiddling with the rate of the springs. In your csb all springs are deflected the same amount (-ish as axlebox may not co-incide with point of greatest deflection) so you can only increase the load by shortening the span of a spring which also incr...
by davebradwell
Thu Oct 08, 2020 5:29 pm
Forum: Steam Locomotives
Topic: Drive for an N2
Replies: 6
Views: 1115

Re: Drive for an N2

I have a set of rods but no other spares, I'm afraid. If the builder followed the instructions with the hornblocks, these rods should be an exact match for the wheelbase, give or take a thou' or 2.

DaveB
by davebradwell
Wed Oct 07, 2020 8:12 pm
Forum: Steam Locomotives
Topic: Brassmasters Rebuilt Royal Scot, 46109
Replies: 127
Views: 15723

Re: Brassmasters Rebuilt Royal Scot, 46109

I did wonder if I was jumping into a trap with the wheels, Dave but couldn't really see any difference in the crank position. B1s could have odd sets of wheels but at least it's the same moulding, just different balance weights. I'm sure you'll sort it out but slight differences in throw are a disti...
by davebradwell
Wed Oct 07, 2020 3:40 pm
Forum: Chassis and Suspensions
Topic: CSB for a Single Driver
Replies: 50
Views: 5292

Re: CSB for a Single Driver

What you need here, WillL, is to modify your csb algorithm to enable the support points to be moved vertically. In this way you could have stiffer springs with low deflection for the carrying wheels and low rate but greater deflection on the drivers. This would address concerns about pitching as the...

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