Search found 872 matches

by Julian Roberts
Sun Jan 12, 2014 5:08 pm
Forum: Chassis and Suspensions
Topic: Gibson LMS Compound
Replies: 66
Views: 9222

Re: Gone Retro: compensation for a Gibson LMS Compound

I had realised that compensating the bogie was not entirely straightforward (!!), in that upward movement of the bogie was restricted by the very small gap between bogie sideframe and loco frames, and there was no easy way round that which would allow the bogie as much swivel as I intended unless th...
by Julian Roberts
Sun Jan 12, 2014 4:19 pm
Forum: Chassis and Suspensions
Topic: Gibson LMS Compound
Replies: 66
Views: 9222

Re: Gone Retro: compensation for a Gibson LMS Compound

The compensation beam was installed with the fulcrum pretty well invisible below the centre slidebar representation, fixed to the chassis just ahead of the motion plate. This was rather nearer the driving wheels than I had intended though still less than half way from the bogie centre. The fulcrum c...
by Julian Roberts
Sun Jan 12, 2014 2:22 pm
Forum: Chassis and Suspensions
Topic: Gibson LMS Compound
Replies: 66
Views: 9222

Gibson LMS Compound

This may be the equivalent of a discussion of the sun's orbit around the earth. But here, from an era perhaps a very long time ago, before CSB, is a description of my LMS Compound compensated suspension. The model has progressed to the point where it definitely runs reliably, though much work remain...
by Julian Roberts
Sat Jan 04, 2014 2:01 pm
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

"Ealing": - thanks, certainly won't make a bogie like that again. LMS Compound bogie will follow sometime soonish...
by Julian Roberts
Sat Jan 04, 2014 1:44 pm
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

8) Hornblocks Because it came with inaccurately spaced holes, my Q1 chassis I originally made in a convention defying way. It didn’t work for long. I had to retrospectively fit hornblocks, which themselves are quite convention defying, but only in manner of construction. The essential thing is to ke...
by Julian Roberts
Sat Jan 04, 2014 1:37 pm
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

I have spent some long rail journeys just around Christmas 2013 skimming through quite a lot of the Forum for the first time. It seems that CSB suspension is seen as the way to go. I find it interesting that fairly early on in Will L's masterly exposition of the whole subject he says that there will...
by Julian Roberts
Sat Jan 04, 2014 1:18 pm
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

7) A recent lesson My Ex-CR Class 782 chassis was made in an unusual way. The details aren’t important, but I made the rods (Gibson “universal” rods) fit the chassis, not the other way round. The normal advice is to treat each 4-coupled section independently. I have found I can have a loco where eac...
by Julian Roberts
Sat Jan 04, 2014 12:59 pm
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

5) Lessons in back to back and wheel fitting One of the reasons I moved to P4 was that I didn’t think the effort involved was much greater than what I was putting into my 00 gauge attempts. For me the chief difference in difficulty of construction is the much finer tolerance of getting the correct b...
by Julian Roberts
Sat Jan 04, 2014 12:35 pm
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

In fact my very first chassis for the Terrier had been a rigid unpowered one, using Romford wheels. Even for this I had carefully set the axle bearings with the rods using jig axles. When it came to fixing on the ready quartered wheels and rods, the very first few revolutions had a slight tight spot...
by Julian Roberts
Sat Jan 04, 2014 12:14 pm
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

4) Lessons in smoothly revolving coupled wheels. I knew fine well the importance of the coupling rods being exactly the same length as the distance between the wheels, from Iain Rice’s books and others. However there is more to it than that. Between my Terrier and my Class 439 I made a 4mm scale 009...
by Julian Roberts
Sat Jan 04, 2014 12:04 pm
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

3) Lesson in bogie pick up The Ex-CR Class 439 loco ran well when eventually complete, with pick ups on the driving wheels. For experiment's sake I tried adding pick ups to the bogie. Try as I might, I couldn't arrange them to pick up without adding such drag that the loco's haulage power was dramat...
by Julian Roberts
Sat Jan 04, 2014 11:50 am
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

2) Lesson in 0-4-4 bogie guidance I learnt something here by accident. The Class 439 being my first P4 chassis, I made up the Gibson milled frames with his P4 spacers. I arranged the inner driving wheels to have sideplay with just the thinnest Romford .005" washers, (the outer ones being washer...
by Julian Roberts
Sat Jan 04, 2014 11:43 am
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

In fact my first loco in P4 was the DJH kit of an 0-4-4T Caledonian Railway Class 439. This I arranged in an adaptation of the normal Flexichas chassis. The outer driving wheel is fixed as usual, but the bogie supports all the weight of the rear of the loco, the inner driving wheel being sprung by t...
by Julian Roberts
Sat Jan 04, 2014 11:31 am
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

Re: In search of smooth running: my lessons in loco construc

In the 0-8-0T LNER Q1 that I made in about 2009 the suspension is as for a compensated 0-4-0 with a rocking front axle on centre beam. The springing of the top wiper pick ups is all that holds the two centre pairs of wheels down. Maybe the adhesion of the loco suffers compared with what it could ach...
by Julian Roberts
Sat Jan 04, 2014 11:29 am
Forum: Chassis and Suspensions
Topic: In search of smooth running: my lessons in loco construction
Replies: 13
Views: 6187

In search of smooth running: my lessons in loco construction

I was looking on the Forum for ideas for an LMS Compound. Not finding much, I went ahead anyway. Now that the model is a working proposition, I thought I'd post up what I'd done in case it helps anyone else. But as some of my ideas don't make sense without explaining them more fully, first I'm posti...
by Julian Roberts
Wed Jan 01, 2014 3:31 pm
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

David - "782 for Barnton" is covering pretty well exactly the same ground just now, regarding forming the boiler plus bits and fitting, all a similar CR loco. Lindsay makes it all sound pretty easy You have the firebox of course (conveniently hidden on the 782), but that can be tweaked to ...
by Julian Roberts
Mon Dec 30, 2013 6:36 pm
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

David I'm glad those pix helped. 'Fraid others will have to answer the question of the power of the soldering iron at your voltage. Best of luck getting it all put together nicely, look forward to progress reports. Jim has always been very helpful when I needed this and that so I ought to have thoug...
by Julian Roberts
Fri Dec 27, 2013 9:39 am
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

Some photos of 812 body underneath. Apologies everyone if this is taking an inordinate amount of space on the forum for rather unsightly photos!
by Julian Roberts
Fri Dec 27, 2013 9:13 am
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

Dave Unfortunately work takes me away soon until New Year's Day. Just a few thoughts for now, this is written in haste. I found the instructions left ambiguities all the way along for a novice like me at that time, and there was a fair amount of work to do to make some parts fit. I am now making ano...
by Julian Roberts
Tue Dec 24, 2013 12:44 pm
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

Please excuse my brief sentences. On delayed trains in storm battered UK and struggling with mobile phone to write. You have welcomed my (via private messaging!) idea of offering thoughts on how I found the next stage of joining the boiler and footplate. (Being on my first brass kit at the time). Wh...
by Julian Roberts
Tue Dec 24, 2013 11:26 am
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

Nice door improvements! I arranged half a mm sideplay each way i.e.1mm total movement on middle drivers. But none on front. For 4ft minimum curve. Possibly not all that is needed. Frames have to be built that bit narrower to allow that. Sure others will offer better qualified advice re front wheel s...
by Julian Roberts
Tue Dec 24, 2013 10:22 am
Forum: Steam Locomotives
Topic: A Class 782 for Barnton
Replies: 46
Views: 17288

Re: A Class 782 for Barnton

Looks and sounds delicious. How satisfying. The area of metal on chassis that you wonder whether is superfluous I used to mount copperclad for top wiper pickups, my Gibson chassis having a similar outline at that point. But I imagine you have planned already for them...?!
by Julian Roberts
Fri Dec 20, 2013 9:25 pm
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

Dave: It's a year ago you were doing the cab, sorry I've only just alighted on this thread. For what it's worth for anyone else, Jim at Caley Coaches sent me (free) an amended part for P4 for the floor etc, that included the boxes that cover the wheels, which made it a whole lot easier. Nice roof, t...
by Julian Roberts
Fri Dec 20, 2013 5:59 pm
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

Thanks! So far I've never built a loco where the guard irons were right, but maybe that's still my fault (I'm on my 9th now in 15 years!) Yeah, here's 2 pics - the counterweight is worth putting on, but I like to highlight details with the weathering (Allan Goodwillie has done some proper weathering...
by Julian Roberts
Fri Dec 20, 2013 8:03 am
Forum: Steam Locomotives
Topic: The Great 3F build off
Replies: 197
Views: 75206

Re: The Great 3F build off

Jim at Caley Coaches kindly provided me with an etch for the reversing gear counterweight etc, for £5 or less, I forget. Fraid I didn't take pix during construction of that phase, but this shows it, loco on the way to completion two or three years ago.

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