MJT W Irons & Compensation Units

[gwrrob]

Can anyone confirm that the width of this product is 23mm throughout the range as I'm looking to fit some to an old kitbuilt wagon from K's I have.The product I have in mind is MJT 2299.

[Miss Prism]

MJT outside rocking irons are about 24.5mm over outside faces. 25mm clear between solebar recesses should be fine for the fixed unit, but I usually allow up to 25.4mm clearance for the rocking unit.

[gwrrob]

Could I use these on a Parkside kit and keep their W irons, axleboxes and springs assuming I'd got the clearance.

[Miss Prism]

No.

[gwrrob]

What are my options then or could I recess the solebars where they sit.I've just found Mikkel's excellent SDJR roadvan build from a Slater's kit.

 

http://www.rmweb.co.uk/community/index.php?/blog/75/entry-15378-sdjr-road-van/?st=30#comment_55533

[Miss Prism]

 
For wagons with wooden solebars (like Mikkel's box van), the recess needed might only be very small, but for Parksides with metal solebars, the recess needs to be quite pronounced if one is attempting to retain the correct solebar-outside-face position.  For MJTs, the length of the recess is approx 14mm.
 
Chop off all the 'W' from the kit, file the rear until no trace of the W exists, and attach the spring and box to the W-iron. I tend to leave the shackles on the solebar, and chop between the spring and shackle. Alternatively, leave the spring attached to the shackle (example, although for a sprung application), and chop between the box and the spring, but this is a bit tricky to get working properly with rocking W-irons:

[gwrrob]

Thanks for updating your post Miss P.Using these etched brass W irons complements these nice tiebars available from Cambrian.

 

http://www.rmweb.co.uk/community/index.php?/topic/118398-brass-strip-for-4mm-wagon-tie-bars/&do=findComment&comment=2557483

 

Mikkel has also suggested just using the w irons as they are and not having a rocking unit on one.

[Miss Prism]

Mikkel has also suggested just using the w irons as they are and not having a rocking unit on one.

 

I could never manage 'the plate glass trick', but there is a constructional advantage in the all-rigid method, namely of headroom. With 12.5mm diameter wheels, MJTs with rockers require 10mm clear (9.8 mm absolute minimum) above the axle centreline to the top of the rocking unit - this takes us to just over 16mm headroom requirement, which is above the critical 15.75mm underfloor height most model kits require (assuming buffers are to be set at their nominal 13.8mm height.)

 

For MJTs without the rocking unit, only 15mm clearance above railheight is required with 12.5mm diameter wheels. Most kits can cope with that, after slicing off the silly underframing.

 

I use packing pieces (10 thou or 20 thou plastic) between the top of the units and the underfloor when assessing buffer height, and then glue the packers to the top of the W-iron. If the floor is wonky (we've all done it), the packers can be varied in thickness from side to side. All that is then required in the final fitting is therefore a quick splash of solvent.

 

MJTs are 15 thou, and are strong.

 

 

[Fat Controller]

Where I've used the rocking units, I've cut away part of the floor to create a 'well' for the unit to sit in- otherwise, the vehicle, especially if it's a short-wheelbase one, looks (and is) too high.