Driver Journal Box

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From Allen Locos Yahoo Group

  • BB Beard
The pedestals for the set at the main rod connection should be a sliding fit .002 to .005 under the other end of the side rod needs to be able to handle the side rod arc plus the up and down rail changes. ( a little looser) Allan said it is a locomotive not a watch.
  • Bill Shields
If you don’t have ‘side to side play’ then the loco will bind in curves. Whatever numbers are shown should be followed.
All things considered, you don’t really need the ‘ears’ on the inside of the boxes – I never bother putting them on unless you want ‘prototype’ looks.
  • Andy Pullen
I typically set journal boxes up in the 4 jaw and bore them and skim the face first. After that, I will mill the sides using a micrometer with a ball attachment to get them equal. Once the sides are cut, you can mill the bottom of the box to square it with the sides and cut the top for any equalizer parts.
The Chloe box requires a bronze sleeve bearing. So, the size isn't too critical. Make the bushings to fit if need be. I use gauge pins to get the bores identical, but a turned and polished piece of round stock that is parallel will work for a gauge.
The slots on the sides aren't critical, either. Make the width of the box .002"-.005" narrower than the pedestal opening. Hold the thickness of the flange that goes closest to the wheels close to your print's dimensions. The inner flange doesn't need to even be there. You can just mill it away. 1/32" is probably the minimum extra spacing I would machine it to.
I built a Chloe frame for a customer a number of years ago. I purchased a length of turned, ground and polished round steel for the axles. That's nice stuff and saves a bit of time with Allen locomotives. You then have a nice round axle with a nice finish on it already for mating parts.
  • Bruce Mowbray
I always found it easier to do all of the flat milling first, then put the axle hole in last. I bring the outside dimensions and slot dimensions of the box to size, leaving about .005" for the pedestal opening clearance (front to rear) and leave about 1/32 inch side to side for "rock in the box". Taking care to make all of the boxes the same, I would then locate the axle hole, banking on the shoe and wedge faces of the box (the face that rides between the pedestal openings). I use a boring head to bring the final hole size. Before coming to finish size, check the location (centrally between the shoe and wedge face) of the hole on a surface plates using an indicator and a spacer that fits in the pedestal slot. Adjust the setup if necessary. Then go to finish size.

Journal Box Packing

Miniature Journal Box Packing

From The Miniature Locomotive, June-July 1953

The journal boxes may be packed with cotton wicking or yarn according to railroad practice, however a piece of felt will be easier to apply and is more apt to be satisfactory. When string is used there is always a danger of it becoming wrapped around the axle.


References