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Member postings for julian atkins

Here is a list of all the postings julian atkins has made in our forums. Click on a thread name to jump to the thread.

Thread: Macc Models
16/05/2012 11:45:30

i must wrote in defence of joe and Macc models as i think Deltic007's comments are very unfair. ive been in this game long enough to know of long delays in ordering stuff with Reeves at Marston Green etc for items they have listed in their catalogue but which werent in stock. i have used Macc models a number of times and have always had a reply to my emails and joe has been very helpful in cutting stuff up for me and the postage and packing has always been superb. it takes along time to build a loco, and its not difficult to order well in advance, which is what i always do. i would happily use Macc models again and again. the quality of his materials is excellent and very competitive prices.

i remember visiting the trade counters of some of the more well known suppliers with lists of my requirements and often i would end up with only half the items on my list! expecting same day type service is in my opinion unrealistic unless you are prepared to pay a hefty premium for such a service.

cheers,

julian

Thread: 5" Gauge Boilermaking - Heat Required For Silver Soldering
09/05/2012 02:33:02

hi ian

i have built a few boilers. i dont think you will have any problems using propane for your MANOR boiler.

plenty of thermolite blocks or vermiculite. main problem isnt how you get enough heat but how you produce your tapered barrel. check with your club boiler inspector what type of joint is acceptable on the barrel. the dovetailed castlelated joint requires a high degree of precision even if this type of joint is acceptable these days. a plain castlelated joint may not be acceptable either. how you plan to silver solder the stays is also a concern.... if silver soldering the stays (which i would recommend) you will need to leave the inner firebox door plate off IMHO.

a 4942 burner will be adequate. things get pretty hot and take about 10-15mins to get to temp. then a few seconds of silver solder disappearing very quickly! i havent had any problems with silverflo 55 either, in fact i prefer it for boiler work. main problem with lots of proper firebricks as a furnace is the very intense heat throwback when trying to do the silver soldering. the extra services of another club member with their own propane torch and bottle for the final bits of the foundation ring and the backhead can be recommended.

i do all my siver soldering in doors where i can judge and see the temperature better, and the gas bottle keeps warm! (yes, i leave the door open!)

cheers, and good luck!

julian

Thread: Any "Beginners" building 5" gauge Boxhill?
08/04/2012 13:14:00

hi bob,

i have sent you a PM

cheers,

julian

08/04/2012 13:06:52

hi bob,

they are 13/16" x 1 7/8" each, 5/16" thick. thats 13/16", not 1  3/16"!

hope that helps!

cheers,

julian

Edited By julian atkins on 08/04/2012 13:10:54

Thread: filing cat iron
24/03/2012 23:27:47

Answer.... an old one! an old warding file should do. it will remove a skin, and if there isnt a skin it wont suddenly remove a large amount of cast iron, as cast iron is surprisingly easy to file. i file all the spokes on loco wheel castings, so am aware of the problem

Thread: How to tune clock bells
14/03/2012 10:50:40

hi glenn,

tuning of bells is as complicated as you have established, as there are lots of important factors to determine the correct 'sound' such as the shape and material of the bell, its diameter, and what harmonics you want. the striking mechanism can also make a difference to tone.

a secondhand set of small handbells might be a possibility (try an advert in the 'Ringing World' magazine). however good sets are expensive and probably wont fit in a normal sized clock case anyway. i have repaired/restored sets of handbells, as well as helping out on restoration projects to restore rings of church bells, but casting and tuning a set (of whatever size) is something for the few experts who do this professionally. you can have a go, but you might be very disappointed at the result and have wasted a lot of time and effort. you might get the right strike notes, but getting the right harmonics is quite another matter. i wouldnt want a longcase clock chiming that annoyed me every time it chimed because of some disonance or clashing harmonics!

as you will note from Claude Reeves, he used dome shaped bells to get them to fit into the clock case, and even someone as skilled and knowledgeable as him bought them from Whitechapel Bellfoundry rather than make them himself!

i commend you for making a quarter chime longcase clock. if you contact your local church bellringing guild or local library there are lots of detailed books on the subject though all out of print. trevor jennings' book can be recommended and will lead you on a fascinating path of discovery!

have a look at the following site for a brief analysis of bell tuning

http://www.hibberts.co.uk/tuning.htm

good luck!

cheers,

julian

Thread: How to repair a banjo
06/03/2012 12:29:33

hi neil,

good luck!

looks like you have quite a bit of careful silversoldering to do to the tensioning ring and tailpiece. the brass probably isnt good stuff so go easy! good quality banjos have bellmetal/gunmetal tensioning rings etc. i would then get all the parts of your banjo properly replated. any cracks in the wooden hoop?

cheers,

julian

03/03/2012 12:07:09

hi neil,

i have repaired ukulele banjos. i dont think John Grey and Co made very valuable banjos...pretty bog standard really. the tensioning ring is vitally important both to solidity of construction and tightning of the vellum and tone, and if cracked can otherwise cause an annoying buzz sound. anything other than silver solder as a repair wont be strong enough. easy to silver solder, you just need to get it replated afterwards.

can you take a pic of the tensioning ring where the crack is please? happy to help if i can.

cheers,

julian

Thread: Boxhill Boiler Construction
03/03/2012 11:51:33

hi bob,

you are quite correct about the boiler drawing, and it is a pity that martin evans' drawings show no detail of the firebox stays which can lead to confusion, though if you can obtain copies of the MEs for the contruction series all may become clearer (martin is a bit vague about staying BOXHILL and the methods to be employed). 2 methods of staying are described in the construction series, and there are various methods of making and fitting stays. they connect between the inner and outer plates and on the drawings are shown as 4BA but no detail provided as to material or how to fix them on the drawings. my stays are 1/8" snaphead copper rivets with the snaphead on the inside of the firebox, silver soldered in place with a slightly smaller stay spacing than martin evans at 5/8" pitch on mine, so more stays. i added a few 5BA threaded stays near the backhead on the sides of the wrapper and foundation ring, these stays being made out of 1/8" hard drawn phosphur bronze rod which is easily obtainable. the threaded stays stop the risk of anything shifting when silversoldering it all up! i left my inner firebox doorplate off when silver soldering up the inner firebox. this can be a bit complicated when fitting the inner firehole door and backhead to everything else, and i made up some 3/16" x 40 tpi special stays to go in the inner firebox doorplate when silver soldering the firehole ring to it. the special stays then had a plain 5/32" dia portion to fit in holes very carefully positioned and drilled in the backhead. all fun and games!

the alternative is to use copper or phosphor bronze threaded rod and fit nuts on the inside of the firebox and 'caulk' the stays with a high melting point soft solder such as 'comsol'. with this method the boiler plates are drilled, threaded, and stayed after all silver soldering has been carried out and the boiler is otherwise complete. martin evans sometimes specified gunmetal rod for stays but 3/16 x 40 tpi threaded phosphor bronze rod is IMHO much better and easier to obtain and make. the threaded stays have a plain unthreaded length on the outside of the wrapper.

there are quite a few good books on the subject (one by martin evans and the other by alec farmer) but if you can obtain the MEs for 1968 Don Young provides what i think is one of the best descriptions of boilermaking for beginners in his RAILMOTOR construction series. far better than martin evan's description for BOXHILL IMHO!

the other point about BOXHILL's boiler is the side extension pieces on the outer firebox wrapper. if you think about it there is no need for one each side if you cut and bend the wrapper accordingly...only one side needs an extension piece which simplifies things, and make it the right hand side of the boiler coz the reverser is on the left hand side. this also avoids the extension piece getting in the way of the foundation ring if you are otherwise making the boiler to martin evans' drawings. the extension piece should IMHO be done with quite a high melting point silver solder such as silverflo 24 and you need the appropriate flux for it too. the rest of the boiler can be done with silverflo 55.

i flanged all my own plates, and Don Young had a better method for the dome bush recommended by alec farmer using only a small register compared to the dome bush outer diameter.

hope this is some help!

cheers,

julian

 

Edited By julian atkins on 03/03/2012 11:54:30

02/03/2012 09:14:25

hi bob,

the BOXHILL boiler is unorthodox. there are no longitudinal stays or crown stay girders that connect with the outer wrapper or crown rod stays. the longitudinal stays are replaced with 'palm' stays - the strip of material on the backhead and smokebox tubeplate to strengthen it. (incidentally the new boiler for DOLGOCH built recently by the SVR for the TR has these type of stays). the lack of proper girder stays between crown of the inner firebox and the outer firebox wrapper was a new departure by martin evans in 1963 using instead a curved inner firebox wrapper crown with girder stays that only fit to the inner wrapper. he reckoned that this design avoided the need for proper girder stays and the 'difficulty' of fitting them to the inner and outer wrapper.

i have never had a problem silver soldering proper girder stays to the inner and outer wrapper, so i dont know why martin evans did this. bearing in mind that the BOXHILL boiler has quite a high working pressure because of the small cylinders, and the inner wrapper is shown to be only 1/16" thick, i think his boiler design can be improved upon. (i dont like the BOXHILL boiler design AT ALL!)

see my post of 21/02/2012

http://www.model-engineer.co.uk/forums/postings.asp?th=56115

it is quite a small boiler so poses no problems being a small round topped boiler.

however as you will note from the above link, i have made my TERRIER boiler to be what i think is both an improvement on martin evans' design, and far more like the prototype boiler.

there is no reason whatsoever why you shouldnt fit proper girder stays and longitudinal stays to martin evans' boiler as designed.

cheers,

julian

Thread: Any "Beginners" building 5" gauge Boxhill?
24/02/2012 13:41:28

Peter,

that's a great pic of what appears to be a very well made loco. you could always put the front axle between centres when dismantled for painting and turn the section between the axle boxes down to 1/2" dia.

cheers,

julian

23/02/2012 13:26:56

if you make the tanks as a self contained unit anyone starting from new can make the running boards out of steel plate anyway which saves on brass!

peter,

did you find there is much clearance between the top of the front axle and the bottom of the crosshead on your TERRIER? the axle dia is supposed to be 5/8" all along and i would be interested to know if yours is relieved locally to clear the crossheads.

cheers,

julian

22/02/2012 10:35:08

hi peter,

it wasnt my intention to put anyone off building BOXHILL, merely to list some of the design faults for the unwary.

i have never liked martin evans' habit of using the running plate as the bottom of the water tanks as this makes assembly and painting difficult, and the saving in brass is minimal and not worth the extra hassle... so i would recommend anyone to make the tanks as self contained units.

also be very careful with the castings as there is hardly any machining allowance on them.

good luck with completing your own TERRIER and the radial tank!

 

cheers,

julian

Edited By julian atkins on 22/02/2012 10:35:39

21/02/2012 23:43:50

dennis,

thanks for your post! i had found your youtube clip sometime ago and it's great! you have built a cracking loco!

as mentioned in a few other posts on this subject here and elsewhere the drawing errors seem to be as follows:-

the axlebox and horncheeck drawings are awful.

the boiler is nothing like a fullsize TERRIER and neither are the cab controls (which is such a shame as Stroudley was an artist down to the very last detail). so far as the boiler is concerned, it goes for overkill with the grate area and ends up with quite a low free gas ratio through the tubes. it doesnt have the sort of rectangular firehole that the fullsize has nor the large radius on the backhead flange, and it is extended and slopes down over the rear axle. this is quite unnecessary IMHO, and mine has a full depth firebox sitting within the rear horns as per fullsize. the 1/16" inner wrapper i think is suspect as is the lack of proper girder stays. i dont think the palm stays are up to modern standards either. the lower water gauge bush is too low (there should be 2 water gauges anyway as per prototype). my boiler design has a 5/16" foundation ring all round and a 3/32" inner wrapper and a flat topped inner firebox with girder stays. dont forget the boiler is working pressure 90 psi. my own boiler is 4" dia which fits easily between the frames and the front of the rear horns losing only 1" on the grate area of martin evans' boiler design despite the wider foundation ring, and thicker inner wrapper. i have had to use some quite thin boiler insulation material to just about keep to the correct outside diameter. the dome is moved forward to be in line with the driving wheel centre line for the later Marsh boiler.

although the side elevation is pretty accurate in martin evans' drawing, the front elevation is NOT! for some inexplicable reason he widened the buffer beams and side tanks and cab. the GA side elevation is correct for the shape of the cab roof but as you have noted on sheet 8 the detail of the cab roof is not and is wrong.

depending on how particular you want to be, there are lots of differences from the prototype that add nothing to the miniature ie tank extending into the cab on the r-h side, cab windows too large and in the wrong place, tanks slightly too low etc..

for an original A class TERRIER the smokebox should NOT be circular, and in any event martin evans shows the diameter of the smokebox and smokebox door too small by quite a lot.

unfortunately martin evans also completely cocked up the valvegear which has far too large a throw on the eccentrics. this can be accomodated but only with a longer length expansion link to correct this fault. no suspension offset is shown whereas there should be one for good valve events.

apparently the balance pipe requires additional holes in the frame not shown, though personally i dont see a problem with making the balance pipe as per prototype. i dont like the well tank idea, so mine will have a wagon to go behind for extra water and coal.

i have heard horror stories of the press fit valve spindle glands coming adrift so best to silver solder these in place.

the balance weights on the wheels shouldnt be proud of the wheel tread and should be slightly less. the works diameter of the wheels is 4', so martin evans' 4 3/16" is slightly less than fullsize.

shame about the lack of room for 4 lifting links to the expansion links and the cut away required on the slidebars as this precludes the use of channel section slidebars as per prototype. my TERRIER has the cylinder block moved forward by 1/4" to give a longer conn rod length nearer to prototype. if i hadnt already machined the cylinders and crankaxle to drawing i would make the outer crank webs 1/4" thick and gain a bit more space for the port passages and a larger exhaust passage. i would also make the cylinders as long as the castings would allow to get a bit more piston width as there is ample room at the front for longer cylinders.

the front frame cut out should be the same height as the rear freame cut out and it doesnt take much to fabricate a crosshead pump body to fit the larger cut out. the crosshead pumps are in line with the motion centre line on fullsize, and again it doesnt require much to achieve this in miniature.

the reverser arrangement is nothing like Stroudley's, and can easily be made to be the same in miniature.

as mentioned above Stroudley was an artist when it came to details, and there is no reason whatsoever why the correct arrangement and design of cab controls should not be incorporated in miniature.

one advantage of modelling STEPNEY though is that she hasnt had a westinghouse pump fitted since the 1930's! on mine, the brake cylinder (vacuum on the fullsize STEPNEY) is a steam brake cylinder, and the large reservoir contains a filter and supply from the wagon and acts as a sump to feed the injectors which are rather small but are tried and tested!

martin evans' frame stretchers and motion plate are nothing like the prototype, and in fact the prototype had more frame stretchers that can be with advantage be reproduced in miniature.

Stroudley's design is so beautiful and perfect that it seems such a pity to depart from it in any way! generally, a very successful design in fullsize can be reproduced successfully in miniature without any departure from the original apart from the internals of the boiler, and the salter safety valves etc.

otherwise a lovely design and it is remarkable how so many successful working locos have been built to the BOXHILL drawings!

14/02/2012 09:18:48
i am building a 5"g terrier as a copy of STEPNEY in fullsize too!
there are a few other posts about BOXHILL on here and the model engineering clearing house website that may be of help.
good luck with your own terriers! i am afraid that there are quite a few errors small and large in martin errors' drawings, though lots of people have built locos strictly to the drawings ok.
so far ive done the frames buffer beams crankaxle other axles and the wheels and the completed cylinder block, and also made the chassis for an LBSCR 10 ton wagon to go behind for extra coal and water.
i can also recommend norman barber's excellent write up of his POPLAR on the modelengineeringwebsite referred to above.
i am trying to make my STEPNEY as close as possible to the original as she now is, so am departing quite a bit from the drawings of BOXHILL
trevor-i think you have gone for overkill with the 5mm frame thickness instead of 3mm though as long as you remember to keep the outside frame dimension of 4.5" this wont cause any problems as long as you adjust the stretchers and cylinder block width accordingly etc the boiler as designed is only 3.75" wide so will fit ok between the thicker frame material you are using
good luck!
Thread: Boxhill by Martin Evans
24/06/2011 13:20:41
Dennis is quite correct about the cab roof... sheet 8 of the drawings shows the shape of the cab for the side elevation as the front elevation! a typical martin evan's error, though to be fair to him the general arrangement drawing on sheet 1 does show the correct front elevation curve to the very distinctive Stroudley cab roof.
 
i would be very interested if anyone has the details of a Gordon Smith type safety valve suitable for Boxhill please?
13/06/2011 09:50:53
by the way, martin evans did take liberties with the buffer beam and running board width to accomodate wider side tanks than prototype, and of course the tanks never protruded into the cab as per one side of BOXHILL. anyone building a model of engines post 1905 needs to check if it was one of the locos fitted for motor train working because these had their buffers raised (see pics of Stepney etc..). A class Terriers should not have a round smokebox as described by martin evans, and the boilers of the prototypes were quite different with the rear of the boiler being shorter and not sitting above the rear axle, and with a large radius to the backhead flange and a completely different arrangement of controls and firehole ring and door 9what an awful backhead he designed when compared to Stroudley's artistic design!).
the smokebox diameter and smokebox door diameter should also be larger by 1/4".
there are other detail differences between martin evan's drawings and the fullsize locos...the rear drawbar should extend forward as far as the rear axlebox, and martin evans did comment on the use of 'channel' shaped slidebars in his description. the axleboxes had a high lip on their outside face to prevent grit and dirt getting into the axleboxes from the wheels, and of course the prototype engines all had underhung leaf springs which isnt difficult to do in miniature.
you will gather from the above that martin evan's side elevation is very accurate to prototype at 1 1/16" scale, but the end elevations are not! i have a copy of the original Stroudley general arrangement drawing from Engineer magazine in 1873. don young's 7 1/4" gauge design NEWPORT is far more accurate to prototype.
13/06/2011 09:19:36
Stroudley had his own pet ideas about balancing cranks, and position of crankpins vis-a vis the crank axle... the balance weights were large and crescent shaped and at 180 degrees to the crank axle webs. the crankpins were in the same position and in line with the crank axle webs/connecting rod pins for each side of the engine. martin evans explains this on p. 360 ME 15th sept 1963, and there is no error in his drawings for the wheels, apart from the fact that to be true to prototype the balance weights are flush with the spokes which as already commented upon he corrected in a later article. it would be quite wrong to follow the 'usual' arrangement of balance weights and their position relative to the crankpins and crank axle on a Stroudley engine!
a close examination of photographs of Terriers will confirm this.
hope this helps.
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