P4 conversion of RTR bogies.

[21C141]

Hi Mark,
Thanks for your email. Not sure how to respond via email as the return address was to webmaster so i post here.

I see what you mean by looking at the photo it does indeed look as though one or more of the wheels are not square on the axel. I've had a look at the bogie and there is a very slight wobble on one of the wheels but nothing like what the photo suugests. I guess this is due to distorsion from using an iPhone camera close-up.

The wobble has been corrected by using the B2B gauge.
One thing i have noticed is that the wheels are not as free running as the original hornby wheels. I thought this might have been due to rubbing on the brakes but they all look clear. The hornby wheels seem to have a bit of end float in the bearings unlike the Gibson wheels which are quite snug, hopefully they will free up a bit with running.

Ray

[Armchair Modeller]

If you squeeze the axleboxes firmly (one axle at a time) with your thumb and forefinger and rotate the axle for a while, it should free things a bit

[21C141]

Following on from the Maunsell simple conversion, I thought i'd have a go at a compensated bogie conversion.

This uses a Hornby LMS Full Brake Van. The pictures are fairly self explanatory so i won't waffle too much.

First the Hornby bogie was removed (just a small screwdriver between the bogie and chassis and it pops out) and a small bush (5.8mm dia, 4mm long)was made to fill the hole (push fit) which was drilled and taped for a M2.5 screw. The edge of the bush was rounded off slightly.

BCU2.JPG

The Brassmasters Bogie Compensation Unit was built as per instructions with one exception. The outermost torsion wire was soldered across the inner brake shoes and not the outer. This allows the curve compensating NEM mechanism to be retained.

BCU1.JPG

The BCU is then bolted to the chassis (you can see the repositioned torsion wire clearer in this picture)

BCU3.JPG

The BCU's have 'ears'to bend up to control wobble, this is done on only one unit which then rub on the NEM mechanism retaining plate. This needs thinning slightly (about 0.5mm) to get the correct ride height.

BCU4.JPG

Cosmetic bits added to suit.

The mounting plate that comes with the BCU is not used.

All in all, a pretty simple conversion which retains the NEM mechanism, and if you want to convert back to OO just pull out the bush (complete with BCU) and pop the original Hornby bogie back in.

I only have a length of P4 track taped to the floor with a 30" radius which it seems to negociate ok, so I'll be taking it to Scale Forum this weekend (Sunday) to try out on the test track.

Ray.