Member postings for julian atkins

i am sorry nathan but i dont agree at all! what error can possibly be caused by rubbing a finger over the work?! i regularly do exactly that as the finger dulls the work and allows me to see how accurate my next few strokes of the file are!

bunkam!!

cheers,

julian

you shouldnt use loctite for a safety valve plug!

i use clear plastic washers for such plugs. never had a drip yet! as for 'steam pipe headers' i presume this is the wet header from the regulator pipe... it should be perfectly water and steam tight and capable of still sealing with smokebox temperatures.

chhers,

julian

i had the same problem with the split brasses/bronze bushes for the big ends on my 5"g terrier.

i machined the bearing oversize inside and out then split with a junior hacksaw. i then soft soldered together ala LBSC with eccentric straps.

i then bored them to the journal diameter setting reasonably to true in the 4-jaw.

i then loctited them to some bar of the journal diameter, shoved same in the 3-jaw, and turned the outer diameter. in my case i also turned a groove to locate around the bearing straps with a parting tool.

i then heated up when the loctite disentigrated and the soft solder melted!

all fitted now ok!

cheers,

julian

hi clive,

there is no reference whatsoever in the ME articles to Don suggesting you could 'mix and match', and bearing in mind the valve gears are quite different this could be a recipe for disaster. apart from what Don said personally to me not to open the bores up above the No. 2 diameter and to fit the No. 1 boiler, i am not aware of Don stating anywhere else to 'mix' the 2 designs. i knew Don very well before his untimely death.

Digby, yours is obviously No.2. i would recommend getting the construction series from MEs 1968/9. if you have difficulties i can photocopy you copies. TEE (EIM) can supply the back issues/construction series at a very reasonable price.

it is a super loco (there are actually 4 variations, 1 in 7.25g" and 3 in 5" g (including the LSWR C14 published in Don's magazine LLAS). my own example got 'narrow gauge-ified' with lengthened frames and enlarged superstructure, and was a lovely loco and my kiddies still remind me how i ought to buy it back after i sold it as they were very fond of it and named it 'Molly'! it was painted in genuine LT maroon with stroudley type lining out in vermillion etc.

the throw of the crankpin on No. 2 is too great (i cant comment on No.1) so the die block on mine never reached the end of the expansion link slot by quite a margin to avoid over-running of the valvegear. apart from my previous comment about fitting a separate water gauge top fitting i cant praise this design enough!

cheers,

julian

Edited By julian atkins on 19/06/2012 23:45:13

hi digby,

i replied to your previous post

all the info you need is inder the previous thread that you posted on

http://www.model-engineer.co.uk/forums/postings.asp?th=69058

cheers,

julian

this sounds like a smokebox/boiler ring, and Reeves/ Blackgates etc will have a gunmetal casting in stock to suit. though a slice off some cored bar from a non ferrous metal stockists will save a lot of machining and time and probably be cheaper. my local stockist has been very helpful with such odd requests ive made! also far cheaper via this route for dome bush material etc than buying castings from the ME suppliers

cheers,

julian

Phil H,

comsol caulked threaded and nutted stays are perfectly acceptable under the current boiler regs.

cheers,

julian

i think your milling vice is 'out'. not an uncommon problem, and even with a dodgy vice not difficult to sort out and deal with once the problem is know. often the error only occurs once the jaws are tightened.... everything appearing level till then, the raised sliding section lifting. if your parallels are parallel then it cant be them!

whilst i agree with KWIL that a fully siver soldered boiler (including stays) is superior (and ive done it this way), i wouldnt advise silver soldered stays for a beginner. without oxy-acetylene (and a lot of experience using it) the inner firebox door plate has to be left off if using propane, and this makes things very complicated for a first attempt at boiler construction. unless the boiler is quite a bit above 80psi working pressure, threaded stays caulked with comsol are perfectly ok. let's not put anyone off making their own boiler by making things too complicated!

i would not advise the use of brazing with brass wire on boilers, and i dont know a single boiler inspector who would pass a boiler made with brass wire brazed joints! this is simply due to the decompisition of the brass caused by de-zincification in joints exposed to the water space. ok for steel fabrications such as frame stretchers and drag boxes, but NOT in a boiler please!

No. 2 has angle iron horncheeks, plain coupling and conn rods, and a valve gear to different dimensions.

No.1 has cast horncheeks, a valve rod guide, and the equivalent of split brasses and cotter for the conn rod big end

hi david,

you will have to use silverflo 55 for the boiler as easyflo and easyflo No.2 are no longer available. i used silverflo 55 on my last boiler (a 5"g job). suggest you buy at least £150 worth plus a large tub of flux that is suitable for long heat operations such as thessco F. the amount of silver solder used depends on your skill and the accuracy of the fit of the plates etc, but my view has always been better than too much than not enough.

sifbronzing boiler joints seems to have fallen out of favour these days... this is what LBSC used when he referred to 'brazing rod' as opposed to silver solder. alec farmer recommended sifbronzing certain sub assemblies to aid construction, but if this is your first boiler i would stick to silverflo 55 throughout, and use comsol with its special flux for the stays (threaded and nutted).

good luck!

cheers,

julian

dave,

for any form of expansive working slide valves and piston valves need lap, otherwise the steam continues to enter the cylinder right up to the exhaust/release point

cheers,

julian

i am not familiar with this design, but surely with stephensons gear with launch type links and nil lead in full gear, the amount of advance on the eccentrics = lap on the valves, measured by axial distance as opposed to in degrees. its then quite a simple matter to work out the angle of advance. if the eccentrics were at 90 degrees to the cranks that would be quite wrong if there was lap on the valves... which i am sure there is! if the design is with cams and poppet valves the same principle applies?

cheers,

julian

Edited By julian atkins on 07/06/2012 12:46:42

hi stephen,

its not a problem oiling the big ends or eccentrics at all. all you need is an oil can with a long bit of 3/32" copper pipe attached to the end. i have 2 other locos with inside stephensons gear, though i do recommend large oil reservoirs in top of the big ends and small ends. the eccentrics actually dont need much oil; i find a squirt when steaming up on the steaming bays is more than adequate for a day's running. its the small ends and slide rods that need more oil and regular top ups whilst in steam. they are easy to get at on BOXHILL. hardened pins and slide bars can be recommended, and close tolerances on all the working parts. i recently took to bits one of my locos, and the chassis required no attention at all after 15 years hard use public running.

it isnt easy at first to see the eccentrics and big ends for oiling till you know where to look on an inside cylinder stephensons valvegear loco, but once you get the hang of it and where to look and move the loco into the right position its easy! so dont worry about 'oiling up'!

cheers,

julian

have a look at

http://www.bluebell-railway.co.uk/~uhaa009/bb/pics/terriers.html

which is where the above pic came from.

as might be expected the Terriers underwent numerous detailed changes over the years, as crosshead pumps were replaced by injectors, and vacuum brake ejectors fitted in addition to the westinghouse air pumps, but essentially Stroudley's original arrangement and design was retained. Boxhill has been faithfully restored to original condition in the NRM. note also in the above link of pics how the martin evans reverser is nothing like fullsize, and note the rectangular firehole with 'Webb' type door, and the large radius to the backhead. the curved cover over the backhead actually acts as a saddle and has the tanks bolted to it, taking their weight, which is why there are no brackets to speak of underneath the running boards. note also the 'quadrant' type water valve handles in each corner half way up the front spectacle plate... these originally controlled water from the tanks to the pumps, and were re-used when injectors were fitted.

cheers,

julian

hi bob,

yes the steam chest drain cock would go on the undersideat the rear and connected up to the same linkeage for the cylinder drain cocks.

the manifold/turret martin evans designed for BOXHILL is pretty awful! it wouldnt be difficult to arrange for a second steam valve for a second injector. note however that the fullsize Terriers didnt have a manifold/turret. injector steam valves (when later fitted) were on the boiler barrel either in front of the dome or just behind, and would only be correct with the A1X rebuilds with the Marsh boiler. however, either side of the water gauges were 2 backhead valves, and these could be used as injector steam valves with pipes inside extending forward and up, if you didnt want to fit a manifold/turret. it is well worth having a look at a fullsize Terrier backhead to see how beautifully everything is arranged and proportioned! then you will realise what a mess martin evans made of BOXHILL's backhead! (he did the same with FIREFLY around the same time too!)

cheers,

julian

hi bob!

drain cocks 3/16 x 40 tpi. the positioning of the cylinder cover bolt holes can be improved upon from the drawings, and if you havent machined the cylinders to drawing you will need to offset the drain cocks as done by norman barber in his excellent construction series (there isnt enough metal on the bottom of the cylinders to fit them where they should be). in fullsize the draincock linkeage is sort off attached to the front guard iron by an extra bracket and then goes up, then along, to the rear L-H cab box underneath the L-H running board. well worth fitting 5 cylinder drain cocks... 4 for each end of the cylinder and one for the rear of the steam chest. if you want to make them yourself LBSC's 'Live Steam' book/'Shop Shed and Road' tells you how with drawings. unfortunately martin evans glossed over cylinder drain valves on BOXHILL.

the smallest commercially available injector is 12 oz per min which should be suitable (try Polly or Blackgates, usual disclaimer, and you may have to order well in advance). ive got to make up a batch for STEPNEY when i get round to it, and 2 will be fitted to mine as i cant stand axlepumps or crosshead pumps!

cheers,

julian

apologies my mis-reading... though i still think 13" is too long for a 5"dia barrel (instead of my mis-reading 22"!). 1 /2" dia flue tubes at say 11" long should be ok. recess the front tube plate 2".

only 6 x 3/4" dia tubes is daft, and what about superheater flues?

foundation ring thickness should be 5/16", not 1/4" for this size boiler.

see jim ewins' research in the SMEE journals and at the end of martin evans' 'model locomotive boilers' book

the springs are also a bit light. i fitted 'Greenly' type springs within a spring. dont be allarmed if the loco is quite lively on a track. i also did away with the 4 element super heaters (No.1 boiler) and fitted my standard 2 element 1/4" dia type. if i had known that 20 years later i would be working from Rhymney depot on the Rhymney line i might have taken a bit more care with prototype details! if your friend has a No. 1 RAILMOTOR, don's drawing of the hudswell clarke chimney cap is wrong!

cheers,

julian