Member postings for julian atkins

hi mike,

for cast iron cylinders and pistons the ideal piston ring material is cast iron piston rings. having said that one of my locos has the above combination with square graphite asbestos packing and is still perfect after 11 years hard work. if you can machine cast iron pistons and cylinders accurately then making cast iron piston rings isnt that difficult and it has been described in ME many many times. i prefer the Prof D. H. Chaddock method rather than Tubal Cain's method. doesnt take long to make a suitable mandrel. if you can get meehanite cast iron then you will make a very fine and easy job of it.

im sure others will have their own views.

cheers,

julian

strongly suggest you have a look at POLLY online catalogue (PDF download) and choose the appropriate gordon smith design. a 3/8" dia seat for a CONWAY as designed seems FAR too big to me! suggest you use gordon smith's 3/16" seat mild pop design. ive just made a safety valve to gordon smith's design (POLLY supply the springs and drawings etc) and has given excellent results on test.

ditch martin evans' design and make a new valve as above - martin evans' design is atrocious!

cheers,

julian

hi tom,

build it properly.

the extra few evenings work is totally insignificant in the overall timescale of building a loco and you will be rewarded with superior performance of the loco.

cheers,

julian

try

**LINK**

v satisfied customer for the cab spectacle glasses for my 5"g STEPNEY loco

cheers,

julian

it is quite an easy casting to file to size using the smokebox material as a gauge. to machine it you will need quite a complicated set up and clamping arrangement IMHO - in the time taken to set it all up and make the clamps you could file it to size. much easier to fabricate out of 6 pieces of brass.

cheers,

julian

hi chris,

that will only happen if you havent backed off the edge of the drill same as you would do when drilling brass.

i have a set of drills and reamers each for brass, steel, and cast iron and i never mix them up!

cheers,

julian

i turn up all my own bolts and studs in stainless and use non magnetic stainless for boiler work. i dont see why a 4.5" boxford cant turn up small stuff unless it's completely knackered! i have on a occasions turned up many 10 BA and 12 BA bolts and studs. never ever use ordinary steel or magnetic steel on boilers, and i wouldnt use bronze compared to stainless due to the lack of shear strength.

cheers,

julian

Edited By julian atkins on 24/10/2013 02:08:55

hi dek,

on locos i machine the facings to fit the frames with a tight fit (with as Jason and KWIL describe a sharp end mill), then rivet to the frames, and use a long end mill to machine the sides for the axleboxes taking very small cuts and setting the frames back to back in the mill. i have a few special long end mills i use only for such jobs. perfect parallel slots are then achieved which of course assists everything else latter on.

cheers,

julian

i use them all the time - they are in effect a superior 'D' bit. no idea why they are as you say 'obsolete' though ive no idea if this is actually the case

cheers,

julian

i have used a shaper - once. when at school i made a pattern for frame stays and cast a load of frame stays in the school foundry. i machined them up - if 'machined' is the right word in a shaper. i realised then at quite an early age ie 16 that there must be an easier way of doing things! i used a vertical slide in the lathe for very many years before acquiring my dore westbury mill 25 years ago. ive never used a shaper since i was 16 and have no intention of ever using one again, and everyone i know who has one proudly shows them off but never uses them!

completely obsolete!

glad the isopon amused a few of you!

cheers,

julian

hi jim,

ive only ever used a hacksaw and file on brass (plus very occasionally a piercing saw). hacksaw blades and files used on brass get painted white in my workshop. i only use brass for tanks and tender - i use steel sheet 1/16" thick for all other platework. beware martin evans' designs where for ease of drawing he shows tank sides and cab and bunker etc all in one piece. a little bit of thought and making the parts in sub assemblies considerably simplifies construction. platework is quite a small part of building a loco in my book (and my least favourite part too) and joining a club with a bandsaw etc or knowing a local engineering form with a proper guillotine saves a lot of time and expense in machinery that wont get used much. all the plate work for my current loco was cut out of steel sheet at home with a hacksaw and filing to size and shape. laborious but very satisfying.

if it's your first boiler, stick to a well proven design with a decent construction series, and a trawl through back copies of ME for how others have done similar sized locos is well worth it too, and join a club and ask other members and the boiler inspector for their advice.

cheers,

julian

hi Nobby,

i build miniature steam locos in 3.5" and 5"g, and i cant think of any situation where i want to create a 1" dia shape in steel 4" long. if i had to i would probably use a ball ended end mill, or would mill with a square edge then add isopon filler!

cheers,

julian

i thought that the model engineers size vertical mill such as the dore westbury and all that has gone since has made shapers obsolete? (dore westbury owner here). cant understand why anyone would want a shaper in this day and age!

cheers,

julian

hi gill,

careful miking of all the parts is a start. i would suggest you make the crosshead to be attached to the piston rod - carefully getting the piston rod parallel with the crosshead slides. then fix the slidebars temporarily in position. any mis-allignment will be obviously apparent. then its a case of carefully filing or machining the rear end covers or adding shim to the underneath of the slidebars till all fits snuggly and is parallel. if the piston is a jolly good fit in the cylinders and the rear cover perfectly concentric then any friction with no slop in the hole in the end cover for the piston rod then any mis-allignment will show up with the slidebars and will be readily apparent. one of these jobs easier to do than describe! just takes a bit of time and patience and as with all things loco wise 'fitting' is the key to success and long trouble free running.

cheers,

julian

hi geoff,

a very good question!

oil doesnt disappear in the cylinders - it forms a sort of emulsion which then gets carried via the exhaust. the LP cylinder will have saturated steam with the oil emulsion mix from the HP cylinder so will be perfectly ok.

cheers,

julian

hi mike,

the clarkson pitch of stays is way too big. i would stick with LBSC's pitch of stays.

if you are a 'lone hand' dont expect to finish the boiler then join a club and get a boiler certificate - these days club boiler inspectors will expect to see the internal joints of a new boiler and inspect construction as it progresses. and if at some stage you intend to sell the completed loco if it has no club boiler certificate it is basically a loco without a boiler.

cheers,

julian

i have a bit of a long memory re these things and would add messrs Marchant, Dr J. Bradbury Winter, C.M. Keiller, Jim Ewins, W.A. Carter and Roy Amesbury, all deceased. they all published info on what they built which has been invaluable to model engineers ever since. Cherry Hinds Hill MBE must rank of the very best still alive.

cheers,

julian

Edited By julian atkins on 17/09/2013 21:59:06

building a loco boiler is the most expensive part of building a loco - it always has been if done properly. there is no point starting a loco that you intend eventually to steam and run if you are likely to fall down at the boiler building stage, or cant afford a professionally made boiler. of course you can have many happy years building a working chassis if that's your thing (not mine!) and many do.

very few of us can afford a sudden outlay for a boiler - in my case it is a case of stocking up on silver solder and the copper i need over a few years. in my case i dont build locos that have boilers beyond my capabilities size and pocket wise. ive spent far more over the years on copper and silver solder than i ever have on workshop machinery!

a copper boiler is worth the extra cost compared to steel IMHO for all sorts of reasons not least the fact that the loco's re-sale value is enhanced by a well made copper boiler, if ever that need arises.

i should add that ive only built 3.5"g and 5"g locos. quite big enough for me!

cheers,

julian

hi martin,

if you have a solid fuel stove or open fire leave them in the banked up fire overnight. or use a tungsten carbide tool (not insert) and very slow speed and keep regrinding the tool on a green wheel.

cheers,

julian

Edited By julian atkins on 11/09/2013 23:45:21

dear john,

im not sure what the answer is at all!

im the only member of my club actually building scratch built steam locos as opposed to buying kit built or commercially sold models.

DRO. CNC,CAD etc have no place in my workshop which consists of very basic and antiquated machinery.

i dont want a treatise on how to use carbon steel tools - im not quite that backward. the stuff i hanker after is how alan crossfield produces locos that win IMLEC year after year and the sort of stuff that roy amesbury used to produce and write for ME. ive a 70 year old collection of MEs that tell me anything else i want to know - with the added advantage that forums such as this and model engineering proboards produce replies to queries in a matter of hours.

no easy answer to all this. i havent got a solution im afraid.

what is the going rate for a page in ME/MEW by the way these days?

cheers,

julian