High Level Jinty Chassis and Twin Beam Compensation

[Guest WM183]

Hi all.

So I have been working on collecting the parts and tools to build a EM (or more likely now, P4) Jinty for what feels like 1824 years. I have finally acquired the Brassmasters detailing etch, a High Level chassis kit and gearbox, a Mashima 1020 motor, and a set of Gibson P4 wheels. I have jig axles ready to go... now on to my question.

The chassis is designed for twin beam compensation on the front two axles. However, I have read somewhere - I think - that with twin beams, the rear axle must also be able to pivot? Is this true? Is compensating both front axles any better than simply springing the center axle, a la Bachmann's locos? I suppose it ensures the loco's weight is distributed across all wheels better?

I got P4 wheels, so I guess a P4 build it is. Though I could simply turn the axles down to EM width, and use the wheels (with smaller flanges, yes) in an EM build... hmm. 

Anyway. The compensation question! 

Thanks folks,

Amanda, the confused.

[DCB]

If the rear axle is fixed the loco will move with the rear wheels.  High level gearbox and Mashima sounds like you are stuck with fixed rear axle, that's a big lump of motor to have wobbling around.  

I have never understood why we compensate steam locos where its really difficult because of coupling roods and you don't notice the compensation working but don't compensate diesels where the beams are right in your face. and their movement is very noticeable.

[Miss Prism]

If you make the twin beams springy, you won't need to worry about the rear axle.

 

[Grovenor]

And if the beams are not springy, then itwill be equivalent to a rigid 0-4-0.

 

Edit

Should have pulled out my half built kit and looked, sorry for just adding to the confusion.

Edited March 12, 2022 by Grovenor

[Guest WM183]

So springing is better than a flex-chas sort of arrangement? 

 

[davknigh]

The HighLevel chassis is set up with a rocking front axle and twin beam compensation for the remaining wheels. Chris’s kits are very well designed and if you follow the instructions to the letter it is difficult to go astray. Read the instructions a couple of times and carefully examine the excellent drawings as well to get the best start.
There is some useful information on the CLAG website should you wish to go full suspension :http://www.clag.org.uk/pannier-csb.html  It is for the pannier but the chassis is very similar to the Jinty.

Cheers,

 

David

[jbg]

I’d echo David’s comments. 
 

High Level chassis are well designed and generally follow the same formula - one rocking axle and the others with beam compensation. Gearbox is tailored to fit. 
 

I’ve built 3 Panniers and a 14XX in P4. All work well as designed with no need to modify the compensation arrangements and there is no reason to think the Jinty will be any different. 
 

If this is a first attempt at a P4/EM chassis I’d suggest simply following the instructions and not getting side-tracked by CSBs or other modifications. These can be made to work well but it’s better to build up confidence by building one as designed first. 
 

Good luck. I’m sure there’ll be plenty of support here and the Scalefour Society Forum may also be useful source of information and advice. 
 

Jeremy

[Guest WM183]

OH! I missed that one axle rocks and the other two are compensated.  I have read the instructions a couple of times, but I am not the sharpest blade on the mower. 

I shall read them again!

Amanda

[Guest WM183]

Seems that this kit has the rear axle fixed, and twin beam compensation on the front 2 axles. I will just follow the instructions and be careful!

 

[Nile]

Looking at the instructions I can see that the 'twin beams' are soldered together to form a single central beam that the front axles can rock on. This should work ok with a fixed rear axle.

[davknigh]

I just checked the instructions, I was wrong. The rear axle is fixed if built as supplied. Apologies for any confusion. 

There is also a helpful article by Tim Shackleton in MRJ 160 on using the chassis and super detailing the Bachmann Jinty with the High Level chassis and a Brassmasters detail fret.

 

Cheers,

 

David

[Miss Prism]

11 hours ago, Nile said:

Looking at the instructions I can see that the 'twin beams' are soldered together to form a single central beam that the front axles can rock on. This should work ok with a fixed rear axle.

 

So they're not 'twin beams' after all.

[Guest WM183]

Ah, so it is a single beam! I thought it was two that rode on the hornblocks. I am so, so sorry. I was confused by the instructions and a picture, but it does later say to "layer them up" and to "fit the compensation beam". I am not the sharpest blade, I am so sorry.

 

 

Edited March 11, 2022 by WM183

[harry lamb]

I like the weight of the model to be transfered to the rails via proper bearings so I use a triple beam system where the beams themselves have no contact with the axles. This system also works with 6 coupled steam locomotive chassis with HL gearboxes. Regards. HL