Search found 390 matches

by davebradwell
Fri Feb 26, 2021 10:30 am
Forum: Chassis and Suspensions
Topic: Alan Gibson Loco axles
Replies: 33
Views: 1817

Re: Alan Gibson Loco axles

Mr Enigma prompted me to dig out an old Gibson axle and it was plus a couple of tenths (of a thou') with a ground finish. I'm sure I've had some that are below nominal, too. Never mind, we like his wheels. Your reamer is clearly bang on spec, too, whereas my cheapie measures about half a thou' over ...
by davebradwell
Wed Feb 24, 2021 4:15 pm
Forum: Chassis and Suspensions
Topic: Alan Gibson Loco axles
Replies: 33
Views: 1817

Re: Alan Gibson Loco axles

I've never heard of an 1/8" clear reamer, the size should be printed on the shaft. Reamers were bought to odd sizes for special jobs so you can have one oversize at a price. I recall a good reamed hole should be between nominal size and 3 tenths of a thou' up, certainly that's what we expected ...
by davebradwell
Wed Feb 24, 2021 11:35 am
Forum: Chassis and Suspensions
Topic: Alan Gibson Loco axles
Replies: 33
Views: 1817

Re: Alan Gibson Loco axles

You all need to read up on your "limits and fits". There's a whole load of different grades of fit covered by this standard but essentially a reamer doesn't cut undersize and steel stock sold for shafts is always ground slightly undersize so they will always fit together. Silver steel is n...
by davebradwell
Fri Feb 19, 2021 2:39 pm
Forum: Signals and Control Systems
Topic: Signal box diagram for Rospeath Lane
Replies: 44
Views: 1687

Re: Signal box diagram for Rospeath Lane

Wouldn't the new 17 be better as 7 to save the signalman a hike after pulling 5? The wiggling dead end sidings through the bridge trouble me a bit - how would driver know when he was about to demolish the buffers? Would they be better straight - I don't know? You might just allow yourself modellers'...
by davebradwell
Sun Feb 14, 2021 12:20 pm
Forum: Serjt-Dave
Topic: LMS D1735 Brake Third
Replies: 18
Views: 1074

Re: LMS D1735 Brake Third

It doesn't seem you'll ever achieve scale width because even axleguards at 23.5 spacing for a std brg is just wider than prototype's 5ft 9in. I'm just re-doing the 9ft bogie etch and it seems printing a channel solebar with springs and axleboxes would be your best bet although bolster detail gets co...
by davebradwell
Sun Feb 07, 2021 9:32 am
Forum: On My Workbench
Topic: Gibson Crankpin slop
Replies: 4
Views: 407

Re: Gibson Crankpin slop

The real issue here is that you're chasing a different problem every time yu put the thing together. If the bush moves to the side then it's a quartering error, outwards and you're after a mysterious crank-throw difference. Get rid of them asap and get some more from Colin. A very long time ago I ha...
by davebradwell
Thu Feb 04, 2021 12:32 pm
Forum: On My Workbench
Topic: Simons workbench industrials. More mineral wagons
Replies: 77
Views: 6621

Re: Simons workbench industrials. RSH high level kit

Like an earlier post I'm struggling with a number of concepts here - I'd just poke an old brush through the spokes to paint the frames. You're going to splodge rust and much all over it later so no point in a first class finish - frames had texture. It's very sound advice to plan to fit wheels only ...
by davebradwell
Sun Jan 31, 2021 9:24 am
Forum: Steam Locomotives
Topic: Hornby Crosti 9F
Replies: 9
Views: 922

Re: Hornby Crosti 9F

Eddie Ford's 9Fs use my chassis.

DaveB
by davebradwell
Sat Jan 30, 2021 10:03 pm
Forum: PeteT
Topic: Stanier 3P - Judith Edge Kit
Replies: 90
Views: 11871

Re: Stanier 3P - Judith Edge Kit

Just to tidy up your queries - I've never used an axlebox on a carrying axle and just file a slot for the axle to rise and fall in as fore and aft forces are small. To take the weight I have just rested the spring wire on the axle (as original B1) but it's a bit nicer if there's a brass pad soldered...
by davebradwell
Sat Jan 30, 2021 2:48 pm
Forum: PeteT
Topic: Stanier 3P - Judith Edge Kit
Replies: 90
Views: 11871

Re: Stanier 3P - Judith Edge Kit

You can work hard to improve it if you wish but I'll avoid the struggle and stick with the safer solution. I can't see any benefits from springing the stretcher, there's a bit more space to fit the springs but there's a potential downside so why bother - there doesn't appear to be much of a trade-of...
by davebradwell
Sat Jan 30, 2021 9:57 am
Forum: PeteT
Topic: Stanier 3P - Judith Edge Kit
Replies: 90
Views: 11871

Re: Stanier 3P - Judith Edge Kit

Thinking more about your sprung stretcher, Pete, mostly to understand if my discomfort with it is rational or not, I realised that lifting a wheel involves the slide moving - there's a sideways component to this basic action. The further away the spring the greater this component. Does that sink it?...
by davebradwell
Fri Jan 29, 2021 10:24 am
Forum: PeteT
Topic: Stanier 3P - Judith Edge Kit
Replies: 90
Views: 11871

Re: Stanier 3P - Judith Edge Kit

PeteT, at least your scheme allows some adjustment of weight on pony. There'd be no point for a bogie as these are so easy to spring. Must admit I've never seen the point of extending csbs to cover carrying wheels except to prove it can be done. I always fiddle with weight distribution when testing ...
by davebradwell
Fri Jan 29, 2021 9:48 am
Forum: Chassis and Suspensions
Topic: Tender CSBs and motor torque
Replies: 27
Views: 1363

Re: Tender CSBs and motor torque

Re sideplay in tender axles, you'll find that even with none there's enough clearance between wheel and rail to get it round any curve you might encounter - down to 3ft with specified gauge widening of course. In practice there's a bit of running clearance in the bearings which gives a little more m...
by davebradwell
Thu Jan 28, 2021 9:30 am
Forum: Chassis and Suspensions
Topic: Tender CSBs and motor torque
Replies: 27
Views: 1363

Re: Tender CSBs and motor torque

WillL, the reason my tender wobbles is because it has an 1833 motor mounted high up, lead lining the sides, springs close together and it's doing a scale 80. There is no reason why separate springs should be more inclined to wobble than a csb - none of my other models do this. In fact if they are cu...
by davebradwell
Thu Jan 28, 2021 9:24 am
Forum: PeteT
Topic: Stanier 3P - Judith Edge Kit
Replies: 90
Views: 11871

Re: Stanier 3P - Judith Edge Kit

All very sound I'm sure but the prototype put the springs in the pony so I always feel drawn to do the same. Be careful your frame mounted springs aren't compromised by reality - the pony has cosmetic springs on the ends and it's possible for these and constructional details to push the frame spring...
by davebradwell
Wed Jan 27, 2021 3:09 pm
Forum: Chassis and Suspensions
Topic: Tender CSBs and motor torque
Replies: 27
Views: 1363

Re: Tender CSBs and motor torque

Yes, Mike Ainsworth's article was noted but there's an older one, best forgotten now. The Ivatt 4 was Chris Pendlenton's in MRJ 175 - it's still running.

DaveB
by davebradwell
Wed Jan 27, 2021 1:22 pm
Forum: Chassis and Suspensions
Topic: Tender CSBs and motor torque
Replies: 27
Views: 1363

Re: Tender CSBs and motor torque

...and have removed the inaccurate offending bit from my post.

DaveB
by davebradwell
Wed Jan 27, 2021 11:19 am
Forum: Chassis and Suspensions
Topic: Tender CSBs and motor torque
Replies: 27
Views: 1363

Re: Tender CSBs and motor torque

Oops, very sorry, that looks very sound to me. I obviously hadn't checked and was relying on memory so now have the problem of finding what I was remembering. They're not even compensated so I was way off. Didn't intend to cause any upset but there has been a few examples with single u/j creeping ba...
by davebradwell
Wed Jan 27, 2021 9:41 am
Forum: Chassis and Suspensions
Topic: Tender CSBs and motor torque
Replies: 27
Views: 1363

Re: Tender CSBs and motor torque

Sorry, I thought I posted yesterday but clearly failed somehow. All my tender engines have motors in the tender and only one has inside frames - an A1 Pacific. The problem isn't the tender leaning but it wobbles at speed. This is probably a combination of slight out of balance of the motor and varia...
by davebradwell
Sat Jan 23, 2021 1:53 pm
Forum: Steam Locomotives
Topic: Hornby Crosti 9F
Replies: 9
Views: 922

Re: Hornby Crosti 9F

With no play in the axleboxes you'll only need a 6 thou' bump in the track over the length of the wheelbase for one end to be in danger of coming off. I hope you don't want it to go round 2ft curves as well. It would be much less of a problem in EM.

DaveB
by davebradwell
Sat Jan 23, 2021 9:25 am
Forum: Other Workshop Practice
Topic: advice on casting needed
Replies: 16
Views: 1024

Re: advice on casting needed

I've always used Slaters, too and I'll add a few comments to Jeremy's recommendation. As with all castings, large chunks should be avoided as they will sink but 0.3 wire can be cast in sensible lengths and edges can be tapered below this. Sudden changes in section are bad, too. A great advantage of ...
by davebradwell
Fri Jan 22, 2021 2:12 pm
Forum: Other Workshop Practice
Topic: Making a specialised D-bit
Replies: 18
Views: 1505

Re: Making a specialised D-bit

I'll round this off by saying it's better to start with the big drill as it's less likely to wander and in harder materials gives you less chance of breaking the small drill because it's making a shorter hole. Thank Dave Carter for publishing the tube idea in Snooze a long time ago when I was having...
by davebradwell
Fri Jan 22, 2021 11:14 am
Forum: Other Workshop Practice
Topic: Making a specialised D-bit
Replies: 18
Views: 1505

Re: Making a specialised D-bit

Why not drill the 1mm hole then slip in a piece of tube to guide the 0.5 drill? Actually you can use a 0.55 which is just a touch stronger. Certainly in metal the cone of the first drilled hole starts the second concentrically - I've done hundreds of them. Toolmaking at these small sizes would norma...
by davebradwell
Thu Jan 21, 2021 1:12 pm
Forum: On My Workbench
Topic: 16T Weathering Experiments
Replies: 35
Views: 2962

Re: 16T Weathering Experiments

I'm not saying anybody is right or wrong, I'm just taking my time. The paint spec will settle it. Wouldn't the wagons be made from black sheet (hence inside colour of new wagons) which resists rust for a while except where welded but the surface would need removal by abrasion or shot-blasting before...
by davebradwell
Thu Jan 21, 2021 10:36 am
Forum: On My Workbench
Topic: 16T Weathering Experiments
Replies: 35
Views: 2962

Re: 16T Weathering Experiments

Just a minute here, for years we have been happy with the notion that wagons were unpainted inside. I can't see why a couple of photos should change all that - insides may well have been painted for the official photographs in '4A and the pic of the side door uses 2 different shades. The bottom of a...

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