When building Tich you might be forgiven for thinking that the snifting valve was a bit of an afterthought and you would be right. On the original drawings all you get is a picture of a cut off pipe and a cryptive “to the concealed snifting valve”. So well concealed is it that LBSC didn’t even bother to draw it! In the later revised words and music you have a drawing of the valve and a suggested position. The position is ok but I would make the part of the valve that passes through the smoke box a bit longer. The biggest problem is the pipe which comes from the wet header, if you drill it as drawn, the pipe comes out of the wet header straight into the path of the exhaust blast, which will do nothing for performance! To overcome this what I did was to re drill the hole for the pipe into the side of the wet header and tap the original hole in the front of the header M5 for a short blanking screw. A longer screw here blocks the regulator output which is handy when you come to test the boiler fittings as you will never get LBSC’s disk in a tube regulator to seal. Dont forget to change back after the test otherwise you will be all steamed up with nowhere to go!
Rules are for the protection of fools and the guidance of wise men.
Post by Shawki Shlemon on Jun 18, 2009 9:23:33 GMT
I built a lot of engines , there are no plans without errors , its difficult to remember them . Some errors are trivial and cause no great problems but some are significant like the one on Duke Dog where the offset on eccentric for valve gear is not enough to give sufficient valve travel . I didn't work it out ,relied on the plans until too late , I had to trim the size of the valves , reducing overlap to ensure the valves open both ways . I know a friend who is building the engine and I warned him about it , I also mentioned it on this forum in general chats. Memory not good anymore , what did I have for lunch
Natal - I think there was a problem with the wheelsets. I'm going from memory, but I think Martin Evans drew them out with something non-standard about either the flanges or back- to-back measurement, compared to the SMEE standard.
I recall a comment that he expected Natal to be used on elevated track and didn't think it would be required to go through pointwork. This was in the editorial in a copy of ME, probably late 1980's, but that's all I can remember.
Oh, there might have been an issue with the safety valves too, but I can't be certain.
Natal - the eccentric rods are too long by about 3/32" on the drawing. As drawn, it's impossible to get the timing correct so notching back more than 50% or so is impossible.
This would not affect most builders as I imagine they would leave that till last anyway and measure it 'on the job'.
Slightly more alarming is the top rear corner of the expansion links will foul the lifting arm pivots on the backward stroke. This locks the expansion link + eccenctric rod + return crank and forces the return crank out of position on the crank pin (or bends something if the return crank is pinned). The expansion link could be trimmed on that corner, it just needs about 1/8" less metal there to clear it.
If you are making a slip eccentric Tich dont make the ash pan until you have mounted the boiler. Problem is that the eccentrics hit the ash pan if you go by the drawing. I think this may be because LBSC never made a slip eccentric Tich (I had problems with the brake balancing arm hitting the eccentrics too). You can file a bit of the tops of the eccentric straps to gain more clearance and a slimer pan will be required, a real shame as the pan I am going to now scrap was stainless steel, C'est La vie.
Rules are for the protection of fools and the guidance of wise men.
1. Spokes on front wheels shown on wrong side of tee ring, as drawn this suits only some of the production of Wm Fosters, the majority were on the other side, i.e. opposite to drawing. 2. No detail for the rivet holes on the front tyres & rear strakes, use 60* centre drill for countersink, prototype practice. 3. Rear wheel strake riveting (4 per strake), alternate strakes should have a centre rivet left out alternating left & right of centre. These holes not countersunk as used for spud bolts. 4. Steering chain anchorages on spud pan are incorrect shape & should be bolted with countersunk bolts(plough bolts), not riveted; also there are more holes to allow the movement of the anchorage to tension the chains beyond the range of the eyebolts. 5. Tank logo on smokebox door too thick, fouls the front drawbar pin when removing pin. 6. Band around top of chimney shown as ‘half round’ this should be ‘quarter round’ as what is shown is too heavy looking. 7. Perch bracket drawn as casting, this should be a steel fabrication that is open front & rear. 8. No details of how to get oil into the swivel pin in the perch bracket. 9. Because of No7 the front drawbar jaw is wrong shape, as it should be fitted to the underside of the smokebox above the perch bracket. 10. Peg for retaining the drive pins on rear wheels could be a pin or a 2-bolt retained plate in a groove in the drive pin. 11. Rear hubcap retaining screws incorrect positioning. 12. Drive pin for right hand wheel not shown correct length, this should go into a drilling in differential centre (detail not drawn) for locking. Right hand pin not required in normal use. Only used when the differential needs locking. 13. Brake disc should be bolted through the inner flange of the RH hub with nuts between the hub flanges. 14. No details on drawings for bolting tender to hornplates or any reinforcing. 15. Top plate / front plate for water tank shown as one piece, this is incorrect & difficult to do, make front plate separate with flange outwards, top plate separate with side & rear flanges upwards. 16. No details of blower nozzle & pipework. 17. No details of blastpipe & exhaust pipework(believe corrected on later drawing issue). 18. Exhaust bore drillings in the cylinder should be larger, 9/16” or 5/8” diameter as the as drawn size is restrictive on the exhaust. 19. Front & rear cylinder cover studs PCD too large, nuts hang over edge of covers & holes run into corner radius of cover casting. Also no extractor bolt tapped holes shown for breaking the joint when removing the covers. 20. Bore diameter used for cylinder cover register, cylinder liner should have a larger bore at ends so cylinder can be re-bored without loosing the register diameter. 21. Valve chest cover stud centres too small, as drawn the threaded holes break into the cylinder block cast valve chest cavity. Again no extractor bolt tapped holes. 22. Governor spindle gland made as drawn will put end load on spindle; this will cause poor operation of governor. Make gland dummy with ‘O’ ring seal on spindle to seal spindle inside cylinder block bore, or alternatively make with labyrinth grooves to seal, this will remove end load & make for freer operation. 23. The correct design of governor was a vertically fitted balanced poppet valve operated by a lever on the inner end of the spindle that exits the front face of the block casting. The slider on the governor unit should also be spring-loaded closed(spring hidden inside slider) with a thicker than drawn vertical spindle. 24. No details of how steam whistle fitted to cylinder block, original fitment was fitted on pipe from manifold by stop valve lever. 25. No details of cylinder lubricator drive. 26. Crosshead bronze slippers, no means of adjustment to compensate for wear as drawn. Full size practice is a box crosshead with slippers retained by countersunk screws thro bearing surface, with shims to adjust clearance. 27. Crosshead should be separate from piston rod, joint being a taper fit retained by a flat taper cotter with draw. 28. Gudgeon pin has nothing to prevent rotation in use, key in head side bore would do. 29. Connecting rod drawn parallel should be slightly fish bellied, diameter should be 5/8”dia at big end tapering to 43/64”dia at middle 3” length to 35/64”dia at little end. Or depending on prototype engine be tapered 5/8” at little end tapering up to big end palm width. 30. Eccentric sheaves should have a slight (1/16”lg) boss on the outside face of each sheave. 31. Eccentric rods drawn much too small in diameter & parallel, should be larger in diameter. 25/64” diameter in the middle & tapering at fork ends to 5/16”diameter over a 2” length. The rest of the rod is parallel but some do have a taper at the eccentric end but not to such a small diameter as the fork end. The fork ends should be made 5/8” square rather than ¾” wide x ½” deep. 32. Weighshaft bracket cutout for lifting arm needs to be deeper to allow full gear availability. Stud next to lifting arm needs moving closer to boiler centre line to clear expansion link, as drawn stud only allows 50% travel before striking by link (no good for starting). 33. No lubrication details for weighshaft. 34. Little end brasses as drawn difficult to assemble/adjust, replace with plain bush for ease of repair. Taper key type should have no heads and is locked by set bolt from flat top surface of connecting rod little end. 35. Front spectacle plate too tall. 36. Cylinder block not tall enough, should be 6.666” from top of mounting saddle flange to top surface, combined with No35 causes fouling of regulator rod on front spectacle plate so requiring crank in rod. 37. Crankshaft too short by at least ¾” on flywheel side as drawn, head of flywheel key projects beyond shaft end unless flywheel is fitted back to front. Casting might allow up to ¾”longer than drawn, 3.333” length from outside face of bearing brass. 38. Crankshaft bearing brasses should be vertically split & on some engines 3 pieces. 39. Flywheel rim drawn parallel, it should be ‘crowned’ (24” rad) to retain drive belt. 40. Crankshaft/2nd shaft bearing housing should not be split as drawn; prototype is a 1 piece casting. 41. R/H crankshaft/2nd shaft housing should have larger 1.25” bore in 2nd shaft bearing, with no bottom bearing adjuster bolt on RH crank housing. 42. 2nd shaft should have a cross-pinned slip fit collar 7/16” thick on left hand end outside of bearing bracket requiring a slightly longer end to 2nd shaft. 43. 2nd shaft should have no collar on RH side as drawn, but be the collar diameter 1.25” thro the bearing housing. Removal of shaft by removing pinned collar & withdrawing of shaft thro bearing housing and hi/lo gears. 44. 3rd shaft should not have machined collars inboard of bearing housings, but a cross pinned slip fit 7/16” thick collar on the left hand end outboard of the bearing housing requiring a slightly longer left end to 3rd shaft. 45. No details for drain cock linkage. 46. No lubrication details for right hand 3rd shaft bearing & rear axle boxes. 47. Front fixing bolt hole for gear change bracket requires tapped hole in hornplate as cast bearing bracket ribs & boss on outside of hornplate precludes use of thro bolt. 48. Bottom water gauge fitting much too low on backhead, requiring cutouts in axle box flanges to clear blow down cocks and drain pipes. 49. Water gauges are incorrect pattern as prototype had screw in units into ‘stand pipes’. 50. No details of wire rope anchorage to winch drum. 51. No details of injector piping / water valve etc. 52. No details of pressure gauge piping & shut off valve. 53. No details of drain cock pipework. 54. No valve timing/eccentric setting details. 55. As drawn the threaded fitting on the water lifter fouls the winch rope when using the winch. Extend the elbow fitting under the lifter to clear the rope as per full size, as the supplied casting is incorrect pattern, not long enough on the vertical leg. 56. No details of the storage brackets for the water lifter hose. 57. The as supplied hand wheel for brake & steering are the wrong pattern, use 4½” Burrell items (LSM) to be closer to prototype. 58. Eccentric throw should be 7/16” not .328” as this does not give full port opening. 59. Reverser quadrants have slots marked to far from centre for expansion link length, cut to suit from in situ marking out. 60. Dog on reversing lever too thick with corresponding too large slots in reverser quadrants. 61. Safety valves as drawn leak, very bad design, 1* angle on valve seating and point contact from cross bar(pivoted not brazed) contacting below seating surface to valves will improve sealing matters & be to prototype. 62. Increase safety valve size to ½” bore. 63. Additional ½” hole in bottom of cylinder block with larger holes from annular cavity to steam dome. 64. No details for front wheel rubbing/protector plates on boiler barrel. 65. Diameter between hi & lo pinions on crank should not be as drawn but 2.083” Dia and crowned for governor belt on hi pinion, 1.625” Dia but parallel on lo pinion. 66. Hi & lo pinions on crankshaft should be wider to give a tooth width of 3/4” on Hi & Lo, spacing between 1.625”. If replicating cast gears lo should be 13/16” with 1/16” thick shroud added 67. Hi & lo gears on second shaft should be wider to give a tooth width of 13/16”(cast) or ¾” = 1/16” gap(cut) on Hi & ¾” on Lo, 1.5625” width dimension over outside of gears. Greater travel will be required on speed change mechanism. 68. No details of oil hole in gear change fork. 69. Secondary drawbar pins need to be longer as retaining pins foul on winch roller lower bracket bolts. 70. Front wheels should have camber of approx 1.5* not upright as drawn. 71. Regulator rod should be 5/16” diameter & straight(see No 35). 72. Winch drum should be a lot closer to hornplate, centre of drum groove should line up better with fairlead roller centre line. 73. Corner radius on the end of the hub caps drawn too small, make x 2. 74. Hub caps should be retained by studs and nuts, not bolts.
This list is a live document that can be updated at any time, drawings supplied by Bill Newcombe. Compiler P Hancock Date, 14-apr-2005 Updated, 03-sept-2005 Updated, 04-nov-2005 Updated, 21-aug-2006 Updated, 05-sept-2006 Updated, 06-sept-2006 Updated, 19-sept-2006 Updated, 22-sept-2007 Updated, 29-sept-2007 Updated, 09-sept-2008 Updated, 05-oct-2008 Updated, 01-Nov-2008 Updated, 16-Nov-2008 Updated, 11-April-2009 Updated, 06-July-2009
4" Foster agricultural traction engine running and a 4" scale Foster 7NHP double crank compound showmans road loco under construction with a 5" Gauge Alco WDLR 2-6-2(Mountaineer) under construction as a gap filler.
Hi all does anyone know of any problems with the drawings for Don Youngs black 5 Thank you
Yup! They're too complicated for my little brain with his mix and match of metric and imperial - I'm really grunting with mine!
I have found out only eight were built with that chassis and boiler combination so limiting your Number sorry I have not found out which they were yet, but I will change the boiler to the one for the number I want.
Don's modified valve gear is an improvement on the original LBSC but still does not give particularly good valve events.
The problem with the LBSC design is the poor suspension of the expansion links (from the bottom) and also the 180 degree rocker which reverses the valve timing with respect to the crank position. This is ok with inside admission valves but not outside admission slide valves if using locomotive style links.
Don does improve the situation by altering the suspension of the links to the centre but still leaves the 180 degree rocker. It would probably be better to dispense with the rocker altogether and drive the valve directly via a solid link (as in the GWR locos). Don's design would then give much better results, especially if the suspension point for the link is moved forward by 0.11".
It is possible to get very good events in the simulator with the 180 rocker but the suspension point needs to be much further forward (0.195") and the lifting arms increased to 1.5"in length. Maybe the amount of die slip introduced to correct the defects in the design would be excessive?
Simulator results for the original LBSC:
You can see that one end of the cylinder is doing all the work and the other doing virtually nothing.
Don Young design:
Much better but still nowhere equal cut offs
Nearly perfect but needs some one to try it. I accept no responsibility if it doesn't work ;D
Like Paul, when I built mine it is slip eccentric, large boiler. I completed it back in the '90s.
1) stop collars - difference between "words and music" and the drawings in the book. I have the step marked as 5/32 off of the centreline on the drawings (pg 31) to match the words and music. On mine, I had to soft solder a bit of shim to get the forward/reverse valve events working ok so obviously I made a mistake...
2) ash pan - as Paul noted, as drawn, it hits the valve eccentrics. I made a flat "u" shaped bit that works - open at front and back; front has an extension that goes over the axle pump.
3) snifting valve - I did not fit one. When living in Wellington, NZ, it was pointed out to me that some of the still-working contractors locos survived 100 odd years without them! My little tich is ok and has run many kilometres without one.
4) superheater/regulator - superheater got plugged at first steaming. I'd not bother fitting one, and let the superheater flue actually act as a heat-transfer tube. My regulator is a screw regulator, much like a stop valve. It does not leak. IIRC, the screw thread is 1/4, coarse thread, end of spindle is about a 45 degree taper.
5) steaming - it took a while to learn how to fire. It still takes concentration, but is a heck of a lot of fun. I start with charcoal soaked in kerosene; fill the firebox as full as you can. When the charcoal starts glowing, I add in welsh steam coal with a teaspoon. When running, it takes lots of little bits of coal often; the fire must burn brightly, so blower must be used to keep the fire bright.
I have also used petroleum coke; note that when the tubes and fire gets blocked with ash, Tich dies. Do not expect a long time running, but expect to fly a couple of times around the track! It is BY FAR the most fun that I have had with scale steam locomotives - but to each their own.
Alan, I suspect that this topic moves rather slowly and contributions are sparse, but its value is high if the reader figure is anything to go by - 5596 is a high score. In my humble opinion please don't remove the thread. It needs to be current constantly to deliver its value. Don
Hi there The older Highlander drawings (I don’t know if it has been changed) have an error which means that when the driving wheel axle boxes are in the running position in the horns, the front bogie axle boxes are at the top of their horn slots. The effect of this is to make the engine light footed as any track irregularities which lift the front bogie wheels takes a lot of the weight off the driving wheels. I’m not certain but from memory the design of the superheater headers means that the superheater can not be removed through the front ring of the smokebox. This might not seem like a big problem but when you only want to remove the superheater it creates a lot of extra work. Paul