Alex Jackson Couplings

On returning to 2mm Finescale modelling, my original intention had been to adopt the commonly used DG Couplings. After all, I had experienced them on Kingswear and because they're widely used, essentially the 2mm Finescale coupling of choice, they do allow different owners rolling stock to couple together if required.

Alex Jackson first demonstrated his now famous coupling at a meeting of the Manchester Model Railway Society in 1949, but it wasn't revealed to the world until an article by John Langan and Norman Whitnall in the January 1960 edition of the Model Railway News. Their use in 2mm Finescale was first recorded in X by X.

The main advantages for me, especially compared to the DG, are the designs unobtrusive appearance, it's almost invisible at typical viewing distances. Also, the couplings at each end of the vehicle are identical, so vehicles can be operated either way round without effecting performance; typically DGs are set up with a hook on one end and a loop on the other to ensure reliability.

Standards

5mm above rail height?

Tail... 0.15-0.2mm in front of the buffer face? Too little impedes the coupling and uncoupling, too great is unslightly, can cause fouling on opposite wagon and can contribute to uncoupled wagons being recoupled on reverse curves.

The Hook

0.008" Phosphor Bronze Wire

Bending The Hook

"Adams Pattern Pliers"

Jigs

Mounting block "depth gauge", compare underside of wagon with a.r.l.

Coil Jig

6mm Brass Angle
1.5 Brass Rod

Hook Setting Gauge

+magnet

Flexibility / Coil Spring

Mounting

The tradional method of mounting the coupling at the opposite end of wagons can often result in the vehicles twisting when heavy loads are pulled. Later the hinged shank and counterweight method was invested but this requires a lot more effort to install and probably wouldn't scale very will to 2mm Finescale.

Droppers

Forward Pulling Post - Chris Pendleton Winning With The Jackson MRJ 223. Moves the pulling position forward from the far end of the chassis to a point forward of the centre, avoiding lozenging forces and at the same time solves the otting issues raised by tricky chassis situations. The pullingpost is set on the centreline about 3.5 mm behind the leading axle and the coupler shank is cranked around it 90 degrees horizontally to the same side as the coupler tail and again for another 3.5-4mm to make a 'Z' bend in the shank. From here it makes its way back to the fixing point 65mm back from the head, by whatever convenient route offers, straight or otherwise, being relieved by the pulling post of any need to be straight and level and taking traction forces. It may even double back to a single paxolin fixing point.

1) Glue on mounting blocks to chassis to correct positions and ceiling heights (5mm a.r.l. TBC, 1/2 of Chris Pendlenton) for the pulling post mount and that or higher for the fixing point.

2) Cut approximately 50mm (TBC, 1/2 of Chris Pendlenton) of 0.008” (TBC, as used by Jim Watt) and "grind off end burs".

3) Form coupler head in home-made orignal Jackson tubular jig, checking angles agains't templates.

4) Measure from buffer face to post mouting block centre, set "Turner shank bending jig" to this and make a tailside right angle bend in the shank.

5) Make a return bend in the same plane, re-aligning shank to the longitudinal and 3.5-4mm (TBC) offset to avoid wheels and brakes but also guve enough flex, and then back to the fixing point, making any other bends and weaves underfloor fittings may dictate.

6) Positon and solder dropper clip to shank if using Pin and Clip type.

7) Looking side on, pre-bend the shank to be level between head and post over the axle position, then dipped or straight as necessary to meet the fixing point, imparting a very slight upward bow to the finished shape to instil some slight upward tension.

8) Mount Turner Mounting Jig to wagon buffer shanks, inser coupler and check the shank aligns with the fixing point mouting block.

9) Solder shank tail to mounting block, remove jig.

10) Drill 0.5mm in first corner of shank for post and fit.

11) Tweak shank to achieve alignment and tensions against post and its mounting block ceiling, checking head against height and centre gauge.

12) Fit dropper pin and, if using "clipped U type", tweak clips to ensure retention without interference of vertical hang.

13) Darken with metal black, not paint, followed by nutralising rinse and washing.

14) Bench test tensions.

15) Road tests.

DCC

Books


Magazines
	Model Railway Journal 55 Jackson Couplings David Booth, John Langan, Norman Whitnall
	Model Railway Journal 56 Jackson Couplings, Part 2 – Modern Developments David Booth, John Langan, Norman Whitnall
	Model Railway Journal 79 Jackson Couplings in 2mm Jim Watt
	Model Railway Journal 94 Rubber Mounted Jackson Couplings George Mitcheson
	Model Railway Journal 123 Altered Alex Jacksons Vincent de Bode
	Model Railway Journal 131 Jackson's for Sprung Bogies John Darch
	Model Railway Journal 223 Winning With The Jackson Chris Pendleton