QUOTE (0-6-0ST @ 9 Oct 2008, 00:10)
<{POST_SNAPBACK}>The next stage involves removing the brass parts from the fret. These are 4 x corners & 2 x buffer spring protection plates. They all needed rivets tapping out. I don't have much experience but I use a modified pin punch and tap them out on a plate of aluminium. I find this has just the right amount of resistance to produce a small rounded rivet. These were all then glued in place on the plastic frame.
Next the 4 x 'W' irons & 4 pairs of cast brass brackets. The quality of the lost wax castings is excellent. The instructions recommend soldering the brackets to the irons whilst still on the fret which I did and then dressed nibs and any signs of excess solder as they were removed.
I tried the horn blocks in place and they needed no attention but I found the bearings too tight to risk pushing into the blocks. I know I should use broaches to ream out fine fit parts but if at all possible I use a fine square file. The square removes material evenly from the hole and unlike round files they do not bind having contact only at the four corners, the bearings fitted neatly. Now to assemble Axle boxes and blocks c/w bearings to the 'W' irons, this I found most difficult avoiding glue on moving surfaces but eventually success.
I thought I would try various methods to remove the Axle boxes from the spru.
I used my Dremel'ish with a rotary saw blade and cut up the main ribs into many smaller parts. I believe this material is harder than the frame plastic perhaps ABS or something, so heating in a water dish didn't appear to help as a lot of pressure was needed with the craft knife. I have not yet seen a sprue cutter that I like so I returned to my home made razor saw, for now but a sprue cutter is a must for the future.
I would appreciate advice on which is the correct shape for the top of the Axle boxes. The red Oval in my picture indicates my 1st. thought and the red spot position my 2nd. this 2nd. point allows the spring in the Axle box to be seen
but may not be right.
Fitting the 4 x 'W' iron c/w Axle boxes etc was a little awkward but all went together quite well.
One good lesson I must remember for the future is to check that the locating pips on the plastic parts fit into their respective holes in the brass parts. This would be easy before assembly and both are free. Having discovered a large difference late on I had to open the holes in the brass carefully and tried the brass part frequently, as these pips & holes are to ensure accuracy in assembly it is easier to ream out the brass holes to fit the pips rather than the other way round and loose positioning. This was pretty tricky to do when fitting the irons to the already assembled frame
I marked the picture to show the locating Pips * and you can see it was a pain to do this for the 'W' irons with the assembled frame, I must do better.
I may modify this tank wagon to a slightly different design which I know is not strictly correct but I will give it a try.
3rd stage The mechanical braking system. Trying to identify the parts e.g.. safety hangers, upper hanger bracket etc. my knowledge here was sadly lacking. I found a visit to Paul Bartlett's web site 'BR wagon photographs' of great assistance. Wagons pictured from a number of angles helped me to figure out how the equipment operated and was mounted on the frame.
The upper hangers c/w brake blocks cleaned up. Then the safety hangers removed from the brass fret and folded up into a 'U' The instruction says these should be located in a slot in the upper hanger, I must admit I had difficulty in positioning these as the slot is only a very faint couple of marks and getting the angle right was not easy. Next this small assembly is fitted to the under frame ribs with the blocks aligned with the wheels. This in fact is key to the whole arrangement and shows how the rest of the system fits together. The 4 'V' hangers removed from the fret and the outside pair are folded to allow them to fix into the outside face of the solebar. A piece of plastic rod is provided to enable the accurate alignment of the brake assembly. I substituted this for a piece of brass wire which gave more ridged control across the wagon. I passed this wire through the outside 'V' hanger, the inside hanger, the brake gear then across the frame through the other side components before then gluing all four 'V' hangers to the solebars. The brass wire is cut leaving 4mm of excess wire protruding passed the outside 'V' hangers. I also threaded a small piece of wire sleeve onto the brass wire between the inner and outer 'V' hanger to act as a spacer as on the prototype wagons.
Next the brake lever racks were removed from the fret , bent and glued to packing blocks on the solebar. I left one or two small components of at this point to move onto the truss rod. After removing the rods from the fret you need to form 4 rivets on each, this rod is 1.4mm wide and I did not make a good job of these.
Another lesson, I must practice with a variety of suitable "punches" for placing rivets in narrow strip.
The instructions also request the rods are soldered to the base of the 'W' irons. I am not sure this would be a good idea at this stage in the assembly. The plastic axle boxes are approx 1.5 - 2.0 mm above this point and there would be no way of shielding them from the heat so I glued these in place. Once these are fixed the small strap from the base of the lever racks is bent to contact the truss rod and glued. The brake lever is placed just to check positioning.
I think a book on how prototype vehicles actually go to gether, braking, wheels suspension / compensation etc. might be a good idea perhaps on PO trafic, if some one can recomend a suitable book this may be a good Christmas gift
