J72 chassis conversion for DCC Part 4

The replacement 3D printed muffs and gears proved to be out of gauge for OO at 14.7 mm rather than 14.4 mm so I revered to the replacement Bachmann set I ordered 3 sets of wheel spacers and 3 intermediate gears for a shade under £10.

The first loco wheel set was finished this morning and the chassis chipped as I type its running in on the rolling road.

Oh bu**er I have just fried the chip! The grey wire gets trapped when the body is fitted and shorted. So a small mod milling a bit more metal away to allow the wires to sit lower clearing where the casting fits inside the tank.

J72 chassis conversion for DCC Part 3

Today I completed the first motor conversion

 Then fitted two brass pins for the chassis pick-up

The replacement 3D printed muffs and gears arrived, not sure if they will do the job still it was worth a go! 

J72 chassis conversion for DCC Part 2

As the weather was quite pleasant the mill table was degreased and the vice set-up. One set of chassis frames now milled

 

 

 An 8mm hole not 5mm as first mentioned drilled where the motor brushes contact the frame. This was necessary to isolate the motor brushes from the frames.

There is now ample room to fit the chip into its new pocket and even room for some packing, and I have just received notification that my replacement 3D printed muffs and gears or on there way via UPS, I’ll post how I get on with these when they are fitted.

Bachmann 32-500 BR Standard 5MT DCC fitting

Due to the numerous detailed fittings careful handing whilst removing the body is essential, starting with the rear left driving wheel remove the small slotted screw holding the speedo drive and gently ease away.

Moving forward to the front of the loco there is a cross headed screw under the bogie assembly that has to be removed

finally at the rear again there is another cross headed screw under the brake rodding. I could not find an easy way of removing all of the rodding so I unclipped the rear actuator trunnion and nudged it a bit to access the screw. 

Short countersunk is the front and long cheese head the rear.

Having removed the body, it is a tight fit you will see the blanking plug just forward of the gearbox, remove this and plug in your decoder I used a Hatton’s standard 8 pin which fits into the plastic cradle supplied.

Before I reassembled the loco I performed a quick check on the programming track to see if I could read the chip.

Reassembly is of course done in reverse order; check the body sits flush against the chassis you can see this from where the screws fit not forgetting to locate plate that sits on the rear screw pillar and the tender draw bar. 

Gently tighten the two mounting screws checking the alignment of the body as you go.Reattach the speedo drive to the rear driving wheel and finally the fiddly bit the rear actuator trunnion. A test run before reprogramming the CV’s that I job done.

J72 chassis conversion for DCC

J72 chassis conversion for DCC

One of the sick J72’s has been stripped and degreased in my ultrasonic bath.

I propose to remove around 2mm of material between the marks on the frames (lower picture) the other side will be milled to the same profile and a 5mm hole drilled where the motor brushes contact the frame. This will allow the chip to sit in the boiler and the holes will allow the motor wires to exit the frames without making contact. Unfortunately the weather has taken a turn so I will not be degreasing the mill this week! As a foot note I have found another source of Replacement gear and muffs for split-frame Bachmann J72 see this link http://shpws.me/FD3X

Bachmann J72

 My two J72's arrived today both externally pristine, looking at the mechanism they are little used. However they are both suffering from the “split axle” on the centre wheel set. I hope my mail to Bachmann can source a new set of axles. 

Apparently this is quite common with split frame locos even when they are stored!