Close up to show part of locomotive footplate



These components are strong and accurately-etched gearboxes in 0.7mm (0.028") nickel-silver which use ballraces instead of the brass bushings commonly found. They typically include fixings for Canon 1833, Mashima 18xx, 16xx or 14xx motors. More information including Application Notes, Planning Sheets and Instructions are available towards the bottom of this page.

Branchlines/Ultrascale Based Gearboxes

Available in only 13:1 ratio, to suit motor-mounted ('Power') or non-motor-mounted ('Remote') variants.  These were originally developed for diesel locomotive bogies. In either version the gears require a 2mm worm shaft and fit 3/16" diameter axles. The kit includes the fret, gears, bearings and instructions.    

Markits Based Gearboxes  

These are a variation on the classic Markits ‘7H’ gearboxes, available in 13:1, 20:1, 26:1 and 40:1 ratios. The 40:1 is also available in a 2-stage variant; the 40L. They are each produced with motor fixing screws centres of either 12mm (Mashima 18xx series) or 15mm (Canon 1833). The single-stage gearboxes are additionally available with 10mm motor fixings for Mashima 14xx and 16xx series. Please order by gear ratio and motor/fixing screw centres (Mkits 13:1, 20:1, 26:1, 40:1 / 10mm, 12mm, 15mm). The pack includes the fret, gears, bearings and instructions.

Romford Based Gearboxes

Most useful for older or smaller prototypes, these gearboxes are available in 30:1, 40:1 and 54:1 ratios. The fret comes with two motor mounting plates which cover 10mm (Mashima 14xx and 16xx series), 12mm (Mashima 18xx series) and 15mm (Canon 1833) motor fixing screw centres. All gear sets take a 2mm motor shaft and a 3/16" axle. Please order by gear ratio (Rford 30:1, 40:1 or 50:1). The kit includes the fret, gears, bearings and instructions.   Assembled gearbox

SDMP Components

Hornguides.  Known as ‘47961’, these are designed for use with Slater’s 7961 ‘Insulated Square Bearings’ and provide an easy to adjust, insulated, sprung hornblock system which is particularly useful for split axle or ‘American’ pick up approaches. These are a simple assembly in 28thou” (0.7mm) etched brass. To complete you will need a set of springs (such as Slater’s 7164) and the 7961 bearings. Axle cut out required is 7.5mm above axle centre line and 11mm wide.

Ballraces.   Good quality steel bearings, as used in the gearboxes.  
      FR156zz; 3/16" id, 5/16" od, flanged, shielded  
      MF62zz; 2mm id, 6mm od, flanged, shielded  
      New MF52zz; 2mm id, 5mm od, flanged, shielded.
Other ballraces are available to order, please email us with your requirements, including quantity, and we will be happy to quote .

Constant velocity joints.   A low-cost solution using a ball bearing and a short length of silicone tubing.  For 2mm shafts: 1 ball bearing, 2cm tube  Extra ball bearing Extra cm tubing

       6 Hornblocks


       Branchlines gears power gearbox. 13:1
       Branchlines gears remote gearbox. 13:1
       Markits gears single stage gearbox. 13:1, 20:1, 26:1 or 40:1        (Add '-13' for 13:1, '-20' for 20:1, '-26' for 26:1 or '-40' for 40:1)
       Markits gears two stage gearbox. 40:1
       Romford gears single stage gearbox.  30:1, 40:1 or 50:1        (Add '-30' for 30:1, '-40' for 40:1, or '-54' for 54:1)

Canon 18/33 motors are available from us as part of our motorising packs for Finney7 kits, POA

Downloads For SDMP

Planning Template for Branchlines Gears Power and Remote Gearboxes (PDF)
Instructions for Power Gearboxes (PDF)
Instructions for Remote Gearboxes (PDF)
Planning Template for Markits Gears Gearboxes (PDF)
Instructions for Markits Single Stage Gearboxes (PDF)
Instructions for Markits Two Stage Gearboxes (PDF)
Planning Template for Romford Gears Gearboxes (PDF)
Instructions for Romford Gears Gearboxes (PDF)
Instructions for '47961' Hornguides (PDF)

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