JeffP Posted October 4, 2014 Share Posted October 4, 2014 They do look good. Two questions, if I may: do you mean 5/32 for the bogie and tender axles, not 5/16? And did you make your own form tool? If so, how, and how do you keep it sharp? Sorry, that's three really...... Link to post Share on other sites More sharing options...
hobbyhorse Posted October 4, 2014 Author Share Posted October 4, 2014 Well spotted Jeff, it's 5/32 for the bogie and tender axles. The form tool came from Alan Harris some time and was flat on the top surface, I found that adding a bit of top rake and sharpening on the oil stone the cutting improved as did the finish. Simon Link to post Share on other sites More sharing options...
hobbyhorse Posted October 8, 2014 Author Share Posted October 8, 2014 With the wheels nearly finished it's time to complete the crank axle. Earlier on the tread Ozzyo ask about the fixing of the crank webs, after some research on the loctite the 603 grade is the most suitable for this application. Although just to be on the safe side pinning the webs should guarantee the joints don't move, holes are drilled 1mm for some pins are located in with the outer pin holes not used until the final assembly with the wheel. Crank in jig to loctite parts Drilling holes for pins. Pins in. The jig that I use for setting the quartering needed some modification for this crank as the setting angles are different to most 4 cylinder locos. A deep pocket was machined in the centre of the block to allow both cranks to sit at 45 degrees to vertical, the outer faces of the block also set the back-to-back with two bolts holding the wheel tight to the block. This jig has evolved over the years with different blocks for S7 and different cylinder layouts such as 3 cylinder and outside cranks, it might be a bit overkill in size but it works. Hoping to finish machining the wheels today as the weather is good for a workshop day. Simon Link to post Share on other sites More sharing options...
JeffP Posted October 8, 2014 Share Posted October 8, 2014 Did you really drill right through those webs from top to bottom with a 1mm drill? How many did you break? Link to post Share on other sites More sharing options...
hobbyhorse Posted October 9, 2014 Author Share Posted October 9, 2014 The drill only goes in a 3/8" so that it penetrates fully the axle section on each side of the crank. No broken drills as the cranks are made from a leaded steel that drills well, the axles are ground free cutting steel that sometimes can be a bit hard. Simon Link to post Share on other sites More sharing options...
hobbyhorse Posted October 9, 2014 Author Share Posted October 9, 2014 Good progress has been made on the next stage machining the wheels. To allow the machining of the rear of the casting the spigot is removed first, with hack saw holding the spigot in a vice. Soft jaws are fitted to the chuck and machined to the wheel tyre diameters and to the depth of the tyre as the castings are griped by the tyres only. Great care is needed turning off the rear backing plate as the spokes are exposed, only small amounts are removed with each pass at a moderate speed around 600-700 RPM. Driving wheel The rear is also recessed, the insulated wheels are countersunk for the tufnal insulation with the others having a central boss. On the bogie wheels only a small recess could be put in. A good afternoons work with this stage completed. Also turned the insulating bushes which are fitted next. Simon Link to post Share on other sites More sharing options...
Pete Harvey Posted October 9, 2014 Share Posted October 9, 2014 Simon Have you had the Wheels Nickle plated or is it the colour of your light shining on the wheels? Top class machining work very profesional. Pete Link to post Share on other sites More sharing options...
hobbyhorse Posted October 9, 2014 Author Share Posted October 9, 2014 Thanks Pete, just the workshop lighting shining off them. Simon Link to post Share on other sites More sharing options...
hobbyhorse Posted October 11, 2014 Author Share Posted October 11, 2014 Next is to fit the insulation to half of the wheels. The Tufnal is turned to fit the wheels with an allowance for the glue to penetrate. A slow setting Araldite extra strong adhesive is used to fix the Tufnal bushes into the wheels, to cure and harden the glue the wheels are placed into a preheated oven at 100c fan for 1 hour- no jokes please about basting them! Once the insulated wheels are cool the the final machining is done, this includes turning the Tufnal insulation down parallel with the rear of the tyres and drilling and reaming the axle holes. The two sizes of axles are from precision ground mild steel which Alan supplied, other suppliers can supply this material, or you can use silver steel. It’s worth checking the size of the steel as the fits required need to be precise, the steel that I’ve got differed in size by 1 thou which might not sound a lot but it’s the difference between it fitting, splitting the castings or falling through. The reamer sizes used are 3.95 for the 5/32 and 4.75 for 3/16. Two types of axles are used and require a high degree of precision to make them, to me this is the hardest part in making the wheels with some scraping of axle parts to achieve the final set of axles. The bogie and tender wheels use a screwed type, the female part is made first by drilling the 6BA tapping size first and then reaming the first 1/8" of the hole 5/32 and complete by tapping the bottom of the hole. The male part is next made by turning firstly a few thou over the 5/32 size then the thread is cut on the stepped section, I use some emery sticks to dress the over size section on the male part down to fit the bore. The driving wheel axles don't have the threaded section as taper pins are used to hold the axle together, but are made in the same way as the tender axles. To describe the fit between the two parts of the driving axles is a cheesy fit ( ie-the feel you get when cutting hard cheese with a knife) The male parts of the axles are pressed in first with the axle held in the collet chuck and a brass bush bored with the axle size mounted in the tail stock used to press the wheel on, the bush ensures that the wheel is parallel to the axle. Next the other part of the axle is screwed or slid on to the male section and the same procedure used with the insulated wheel. The Bogie and Tender wheels are also gauged at the same time. Gauging the Bogie wheels. All the wheels mounted on axles, ready to fit the drivers with crank pins. Simon Link to post Share on other sites More sharing options...
Horsetan Posted October 11, 2014 Share Posted October 11, 2014 .....to cure and harden the glue the wheels are placed into a preheated oven at 100c fan for 1 hour- no jokes please about basting them!.... I fry mine in lard. Link to post Share on other sites More sharing options...
hobbyhorse Posted October 12, 2014 Author Share Posted October 12, 2014 The wife still finds it strange the need to cook the wheels. Simon Link to post Share on other sites More sharing options...
Horsetan Posted October 12, 2014 Share Posted October 12, 2014 The wife still finds it strange the need to cook the wheels. A thought did occur to me as to whether cooking them would cause uniform expansion of the entire wheelset, and then uniform contraction when cooling.... Link to post Share on other sites More sharing options...
hobbyhorse Posted October 12, 2014 Author Share Posted October 12, 2014 Good point, I've not had any problems so far using this method from eight foot drivers down to small bogie wheels. I wouldn't want the oven any hotter. Simon Link to post Share on other sites More sharing options...
Horsetan Posted October 12, 2014 Share Posted October 12, 2014 Good point, I've not had any problems so far using this method from eight foot drivers down to small bogie wheels..... That's good. Would be funny if you ended up with beautifully-turned and finished wheels of slightly differing diameters, though...! Link to post Share on other sites More sharing options...
JeffP Posted October 12, 2014 Share Posted October 12, 2014 Not funny for the wheel owner...not at the price of AGH wheels even then... Do you turn any sort of internal groove inside the wheel to key the adhesive? OR saw a slight slot? And why are the axles so long? Link to post Share on other sites More sharing options...
hobbyhorse Posted October 12, 2014 Author Share Posted October 12, 2014 The bushes are just a few thou smaller than the hole, with the Araldite cooked it bonds really well to the bush and casting. So strongly bonded in fact a few years ago the araldite ran from the wheel onto the runner used on the tray to keep the wheels clear of the base, it wasn't easy parting the two bits. As an experiment I did tap some cooked glue 6BA once and was impressed with the results. The over long axles allow them to be held in the collets on the lathe when pressing on the wheels. Simon Link to post Share on other sites More sharing options...
hobbyhorse Posted October 14, 2014 Author Share Posted October 14, 2014 With all the wheels mounted on the axles, next the chucking material is removed and the centres of the wheel countersunk and the crank pins fitted to the drivers. Using this jig the wheel is held in the correct position to drill the crank pin holes. Two sizes of holes are needed, a larger size for in insulated pins and a smaller size for the non insulated ones. For the insulated side Tufnal is used with the pin mounted in the Tufnal and then machined to fit the wheel, the non insulated side the pins are a push fit. The last job is to set the back to back on the 2 non crank drivers and the quartering. Using the same jig that is used for the crank but this time for the tapered pins. I use 1/16th pins and a matching reamer, firstly drilling a 1.10mm hole through the axle followed by the reamer which is feed into the hole under power( very carefully at around 150 rpm). The final assembly of the crank went without any problems, once the parts are set into the jig a final check was made to ensure that the orientation of the crank was OK. Next the jig was put onto its side so that a small amount to loctite could be placed onto the joint between the driving wheel stub and the crank. I made the distance over the outer sections of the crank 10 thou less than the back to size, this allows space for the loctite between the rear of the wheel and the 3/16 axle when the crank is removed from the jig. The crank was then left over night before the last of the fixing pins are fitted, and cleaned up. With the wheels completed, it's always encouraging when the wheels are tested in the chassis with the rods on and rotate without binding. Back to some metal bending with the boiler, cab and firebox. Simon Link to post Share on other sites More sharing options...
Pete Harvey Posted October 14, 2014 Share Posted October 14, 2014 Simon Excellent work, one thing that has me puzzled how will you be fitting the bearings to the axles? Pete Link to post Share on other sites More sharing options...
hobbyhorse Posted October 14, 2014 Author Share Posted October 14, 2014 Thanks for the kind words Pete, earlier in the tread I described some split bearings for the crank axle. Simon Link to post Share on other sites More sharing options...
Pete Harvey Posted October 14, 2014 Share Posted October 14, 2014 Simon I remember that posting but what about the pony and bogie tender wheels? Pete Link to post Share on other sites More sharing options...
hobbyhorse Posted October 14, 2014 Author Share Posted October 14, 2014 The pony and bogie wheels have a male 6ba threaded stub that screws into the female axle, one of the photos shows this when pushing the wheel onto the axle. Hope this explains. Simon Link to post Share on other sites More sharing options...
Pete Harvey Posted October 14, 2014 Share Posted October 14, 2014 I understand now Simon thank you as you have said the pictures do show you pushing the wheels on to the stubs but not screwing the stubs together. Pete Link to post Share on other sites More sharing options...
hobbyhorse Posted October 18, 2014 Author Share Posted October 18, 2014 The assembly of the footplate and valance was straight forward and without any problems other than ensuring that the curves on both drop sections matched the valance, the more modern kits use a jig to assemble these parts. The cab like the running plate goes together well. I like to build kits that can be disassembled for painting, the body's of these locos will be in three sections, footplate, cab and boiler/firebox. The photo of the cab bottom shows the fixings to the footplate, generally a strip of brass is soldered to the removable part then both parts assembled and then drilled through both parts tapping size. Then the brass strip is tapped and a clearance hole is drilled in the other. The boiler/ smokebox is checked with the saddle for fit. As the firebox/boiler will be a separate module an extra internal former will be needed at the cab end for fixing to the cab, this is cut from 1mm brass sheet with a tracing for the shape taken from the cab front. Unfortunately the firebox wrapper has been preformed to the wrong shape and also the two etched internal formers will need reshaping as these don’t match the cast front section or the cab front. To keep the firebox square on the bottom face the internal formers are bolted together with some studding, with the spacing checked against the tabs and slots in the footplate. The reshaping of the wrapper is done with a selection of bars fixed in the vice, starting with the crown of the firebox then working down each side carefully ensuring both sides are equally shaped. To get both fireboxes to the correct shape took most of a day’s work, I much prefer a flat etch and do the shaping myself. Test fit with the spacers. Boiler unit test fitted to running plate. Once the boilers had been attached to the fireboxes the smokebox wrappers are formed, but before fitting a mounting plate for the speaker is mounted in the smokebox. The speaker screws to this plate. The smokebox doors will need to be removable for access to the speakers, unlike those with a central dart these have clamps around the edge so a plate will be fixed to the inside of the door which will screw to the speaker plate with access to the screw down the chimney. Basic bodies complete. Simon Link to post Share on other sites More sharing options...
N15class Posted October 18, 2014 Share Posted October 18, 2014 Is one going olive green without smoke deflectors? A very nice build. I have always liked the LN's never had need to acquire one. If I did it would have to be 860 Lord Hawke with the round fire box, Link to post Share on other sites More sharing options...
hobbyhorse Posted October 18, 2014 Author Share Posted October 18, 2014 Yes correct, that"s my one. The other one will be in BR livery for the customer and is Lord Hawke. Simon Link to post Share on other sites More sharing options...
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