9.7.09

3822

Pic's on this post have been re uploaded on 2/8/09. No 'photobucket' link anymore and much more detail - GL


Enough talk - Let's get to it!

A standard (non streamlined) 38 class Pacific DJH white metal and brass kit built for a mate as a 40th gift (his wife paid for the kit, I just built and painted it!) about 8 years ago.
Finished in Bakers Verdant Green enamel, it took three attempts, several phone calls and the inventing of some new words to get the finish right, it is modeled in pristine "straight out of the shop" condition, hence the clean side rods, connecting rods and tyres and lack of dirt. The only weathering was Dulcote and the handling it has had over the years.
The lining is a WAO kit, the valances were lined in sections as the complete decal was too much of a handful. Some of the boiler bands also resulted in some new words being invented as well!
It has a tender full of real coal and a Kerroby crew that never seem to do much.
The headlight is a lens that Lloyd Sawyer used to sell and the name escapes me - as do many things these days.....

This loco has had a rough start to life, one of the owners daughters picked up the box one day with a little too less pressure on the box sides and the whole lot went careering into a tile floor nose first, sorry no pics, several spare parts, some judicious straightening and a lick of paint and all was good again.Originally built to run DC, when the owner was bitten by 'the bug' 3822 arrived back at the LLC&W Workshops with a strange looking component to be fitted, I think it was called a 'dee-coe-da'? Wires like cat hairs, lot's of 'em, and all different pretty colours to boot. Lots of shiny tiny ity-bity tronical stuff stuck to a bit of green plastic ! Conversation went something like this: "What's this do?" "I dunno, can you fit it ?" "Fit it where?" "I dunno. Its for deeceecee layouts" "What ? Have you read the instructions?" "Don't be stupid, that's your job." " Right o, where did I put that soldering iron ?"

After scaling back to the bare four wires required to make the thing move it was off to Ray Pilgrim's place to see if worked. This thing ran like a clock on DC but we were about to enter the dark world of "the extra C".

Quite a few DJH kits use a pick up system called 'half live'. There are no actual pickups on the loco, it uses the the wheels (non insulated) on one side of the loco and the same set up on the tender but on the opposite side or rail. So motor connections are fairly simple, one terminal to the loco chassis and the other to the tender. Its in the latter part that the trouble starts as far as DCC is concerned.

Apart from the fact that a white metal and brass locomotive is a giant, rolling short circuit looking for somewhere to strike, the path that the DCC signal takes from the rail to the decoder, via the tender, in standard form, is fraught with danger. From the rail to the live wheel, to the pin point end of the axle, to the bearing cup (usually glued in), to the bogie side frame, to the bogie spreader, to the bogie screw/nut/spring, to the tender body, to the tender coupler pin, to the loco draw bar, to the decoder 'pickup' wire washer/tab, where the first actual soldered connection is encountered !!

That's 11 non soldered electrical connections for the signal to travel through, if done in standard 'off the instructions' form. I should add that DJH/ARKits make no claim that the instructions are 'DCC friendly' as they were mostly written well before DCC came into fashion.

The fix for this is to fabricate some 'axle wiper' type pickups from 0.5 mm phospher bronze wire. These are soldered to the bogie pivot washer and lightly bear on all 4 tender axles, a wire, approx the same gauge as for the motor, is soldered to the other side of the washer and connected directly to the appropriate decoder wire. If the decoder was being fitted in the tender the actual decoder wire could be used. This has cut out 10 of the 11 non soldered joints ! This does not increase the number of pickups but makes them a whole lot more reliable. Should you wish to take things to the next level I have heard that PC board can be used to make pivoting pick up mounting plates, fitted to each bogie with pickups on each wheel. This would double the amount of tender pickups! Good luck! The pickups described here and shown in the pics, were made and fitted by Ray Pilgrim.

The other annoying problem with this kit, and others, is the tendancy for the front (and rear in this case) bogie retaing nut/screw to come loose and fall off during running. The obvious solution here would be glue, but this makes tuning and repairs a bit painful.

In the case of the front bogie a better fix is to remove the screw and file a small 'flat', about 2 or 3 threads wide, on one side on the end of the screw. Then drill a 0.4 or 0.5 mm hole in the middle of the filed flat. Form up a clip out of 0.4 mm brass wire with some round nosed pliers and use this like a 'split pin' to hold the bogie on the screw. If the bogie is adjusted to the right height using the nut, mark this point, file the flat and drill the hole at the appropriate point and the nut can be discarded and the bogie can be held in place with the pin and a washer without any problems. If you need to raise the bogie slightly then add extra washers as required. This tip courtesy of Ian Dunn.

The rear bogie on the 38 is a bit different. A screw passes through the body then the bogie pivot, then into a threaded spacer in the chassis. If this screw is tightened too much the bogie wont move in any direction, not enough and the screw and the bogie will fall out. The fix is similar to the front bogie. Remove the brake rigging plate from the underside of the chassis and fit an M2 screw through the threaded spacer from above so it is pointing down. Refit the plate and bogie and trim the screw so there is just enough protruding to file the flat and drill the hole. Note: If this screw is left too long it will foul on points.

Should you wish to improve front bogie articulation even more then fit a brass tube 'sleeve' to the bogie screw. Carefully file out the slot in the bogie to a loose fit, but not too loose, over the sleeve. Good side to side movement is required but not excessive 'fore and aft' movement. This prevents the bogie from becoming 'hung up' on the thread of the the bogie screw.

Enjoy!

3 comments:

  1. Gary, I'm extremely impressed by the workmanship on this model of the 38! I love your description of the white metal kit as a giant rolling short circuit!

    Oh, and Congrats on becoming a fellow blogger!
    --blair

    ReplyDelete
  2. Thanks Blair. Your comments are much appreciated.

    Is it good enough to prompt a bit of steam working on Narrabri ???

    I have just re done the pic's on this post and added a couple of links. The detail on the pic's is much larger now.

    Cheers
    GL

    ReplyDelete
  3. Gary,
    Whilst I probably won't be investing in any steam power anytime soon (a 59 Class may prove too much of a temptation, eventually!), I won't turn away any visitors from overseas bringing teakettles large or small with them to operate! Consider that an invite!

    ReplyDelete