Bar & Pin - Colin E. Chopper Large Head Coupling

Bar & Pin - Colin E. Chopper Large Head Coupling

 

PDF of technical drawings head over to our Technical tab.

 

Chopper couplings are common around the world especially on narrow gauge railways but they have not been widely adopted in the miniature railway hobby as they are not cross compatible with other coupling types without complex adaptors. These couplings designed by Colin Edmondson look like chopper couplings and hence complete the appearance of a narrow gauge train but will function just as conventional Bar & Pin couplings. 

 

The chopper is able to flex around corners to cope with most back garden curve radiuses with the aid of rubber bushes, a common feature of many of Colin’s designs. Available as either an assembled ready to use product or as a laser cut kit of parts, the product is an ideal solution for many narrow gauge modelers in the miniature railway hobby.

 

Colin Edmondson Chopper Coupling large head assembly/kit of parts

 

For all technical details please consult the drawings on the Technical Page of this website

 

The couplings are best suited to 7 ¼ narrow gauge rolling stock although the items can be used with 10 ¼ , 7 ¼ , 5 - Consideration should be given to the expected load on the coupling. 

 

Welded and assembled coupling (Single)

 

SKU: Chop-Assem(SING)

 

Weight: 0.86kg

 

Welded and assembled coupling (Pair)

 

SKU: Chop-Assem(PAIR) 

 

Weight: 1.72kg

 

This is completely ready to use and install on your rolling stock. The product comes unpainted so you can match the color to that of your rolling stock/engine. The parts will have been welded and dressed flat to ensure they have an appropriate finish, but will benefit from some careful paint prep to ensure a good finish. 

 

Kit of parts (pair)

 

SKU: Chop-KIT(PAIR)

 

Weight: 1.6kg

 

Only sold as a pair this is the kit of parts  with associated sundries of rubber bushings and bolts. This is a simple kit to assemble and comes complete with a set of easy to understand instructions developed by Colin.

 

Further details of the design

 

The product is of mild steel construction, it should be painted for protection against corrosion by the installer. Fasteners are zinc-plated steel with bushings made of high shore rubber.

 

These are a unique design of chopper coupling developed by Colin. The true simplicity of a Bar/Pin coupling means that almost any combination of rolling stock can be made provided the couplings are of similar heights. We encourage you to take a look at Colin’s recent blog post on the subject of bar/pin couplings if you are yet to do so.

 

https://www.miniaturerailwayworkshop.com/post/link-and-pin-couplings-in-miniature-railway-use

 

Recommended to be used with a 10mm plain pin and Heavy duty 11 MM Hole Mild Steel Coupling Bars with a length of 140mm+

 

It is the operator’s responsibility to ensure the day-to-day safety of the railway. For more information about this, please consult the HS2020 guidelines from the Passenger Carrying Miniature Railway Safety Group (PCMRSG). Ensure that you consult their website yourself, so for the latest version go to:- www.pcmrsg.org.uk

 

Making a Purchase

 

This listing is for one or two couplings, select the number of couplings you require from the drop down menu. Please note there is approximately a 1 week lead time on this product from payment until dispatch unless otherwise noted - larger orders may incur longer lead times as these products are only kept in small quantities. You may also contact us for large orders and specific requirements or modifications required for your locomotive.

 

Defective items will be repaired/replaced within one year from the date of sale, damage caused through improper use is not covered by this guarantee. Please be aware that in order to achieve the functionality desired by this product, the prongs are thin at the end of their taper. Extra care must be taken when handling and transporting the product to avoid bending of the prongs and no liability can be accepted by MRW for damage to these components.

 

Monitoring your chopper coupling

 

The product is generally regarded as maintenance free/very low maintenance, however care must be taken to ensure the coupling is in safe operational condition. The rubber can deteriorate with prolonged direct sun exposure and the meatal work could in very rare scenarios develop stress fractures, especially in the event of derailments. Should the operator/installer choose not to take measures to protect the couplings sufficiently from corrosion and continue to do so through their working life, they operate the product at their own risk. The operator should check the product for corrosion, rubber deterioration and excessive play at joints and bolting points before use to ensure it is safe to pull locos and rolling stock.

 

We do not provide information about the tensile strength of these coupling bars, they are cut from Mild Steel grade S275. It is your decision as the end user what is an appropriate load for the bar as many factors could come into play which may affect their strength. For heavy trains you may wish to use a thicker bar, we are looking to provide more coupling bars of various thickness and sizes please contact us for more information.

 

Transportation

 

When transporting your loco or rolling stock, we do not recommend that the chopper coupling is used as a tie down point as the long length of the coupling may lead to it flexing or damaging the buffer beam. Instead we recommend the coupling is removed with the single nut on the inside and then a simple pin is placed through the remaining form. If you are unsure on the best way to transport your locomotive or rolling stock please do discuss with us further before making a purchase. The product should be stored in a dry environment as excessive moisture has the ability to cause corrosion.