7mm Hornblocks & Alignment Jigs and Methods of Springing

These hornblocks are precision components and care must be taken in their application and use. They will then provide reliable and consistent performance. The cast hornblock design has been carefully developed to provide an accurate component which can be fitted with the minimum of preparation but will provide a very accurate fit the bearing block. In turn the bearing is designed to give large wearing surfaces for long term reliability.

The hornblocks are signed to fit the standard chassis cutout provide in most etched or milled chassis kits. The hornblock is fitted from the INSIDE of the frame, with the flat face against the frame and the right-angle bearing guides towards the centre line of the chassis. The square section bearings are machined to accept 3/16 inch axles without reaming. A small lug above the bearing guides is provided. This can be drilled and tapped for a 14BA screw for springing and ride height adjustment.

The alignment jigs are machined from aluminium, and can be lightly oiled to prevent corrosion. They are designed to fit 3/16 inch bearings and the tapered ends will accept coupling rods with the "standard" diameter hole or smaller.

The correct alignment of the hornblocks and bearings is determined by using the locomotive coupling rods together with the alignment jigs. Fit the bearings into the hornblock and roughly locate the hornblocks into the chassis on the inside of the frames, holding them in place with FTM soldering claims. Fit an alignment jig through each pair of bearings and then fit the coupling rods to the tapered ends of the jigs. Check the hornblocks for correct vertical alignment and height, and solder in place.

7mm hornblock sets are available as follows:-

- In pairs, i.e. for one axle.
- In fours, i.e. for two axles.

7mm hornblock alignment jigs are packed in threes.

 

HORNBLOCKS   METHODS OF SPRINGING

Wire/Leaf sprung
Solder a length of sprung wire so that it bears on the top of the bearing. End stops can be made in the same way as for the top sprung version.

Under Sprung
Solder a small nut (a) to each side of the hornblock and screw a retaining plate to them. Either drill and tap the underside of the bearing and fit a screw into the tapped hole or solder a brass screw to it to act as the keeper for the spring.

Top sprung
Drill and tap a hole in the small lug (b) at the top of the hornblock. The screw fitted into this will act as a keeper for the spring and also as a top stop. If required a bottom stop can be made by soldering a small piece of brass or nickel silver across the bottom of the hornblock.