Jump to content
 
  • entries
    192
  • comments
    1,001
  • views
    174,326

Bristol Barrow Road - Roundhouse Roof Trusses

barrowroad

Entry posted by barrowroad

1,754 views

 Share

The roundhouse kit of parts provided by York Modelmaking contained 13 roof trusses that were cut from 2mm mdf, but having made the decision to replace the two main girders with metal versions I decided to go the whole hog and replace the roof girders. Now I know some will think this to be foolish but I have concluded that the mdf versions are not robust enough to facilitate removal of sections of the roof for display purposes.

 

blogentry-6970-0-38299000-1340650372_thumb.jpg

the mdf version of girders and trusses

 

This decision has not been taken lightly as it will involve fabricating 39 seperate trusses - 3 bays each of 13 - and then joining each set with longitudinal roof bracing.

I carried out the necessary research - always an enjoyable task - and produced a drawing of one roof truss. Here are a couple of photos of the interior of the roundhouse showing the best close ups of the roof truss structure I could find.

 

blogentry-6970-0-23660000-1340651101_thumb.jpg

 

blogentry-6970-0-07455300-1340651142_thumb.jpg

 

I produced the following drawing and used it to calculate the quantity of nickel silver and brass I required to make the structure. Rectangular section brass,T section brass, brass tube and nickel silver wire formed the shopping list.

 

blogentry-6970-0-58333900-1340651402_thumb.jpg

 

The best way to produce a consistent product is to use a jig so I constructed one on a scrap piece of melamine board using pieces of track ply and made a trial truss.

 

blogentry-6970-0-65160100-1340651567_thumb.jpg

 

Some while later I now have three completed trusses.

 

blogentry-6970-0-02218800-1340651794_thumb.jpg

 

Each truss is held together as per the prototype using tie bars and clamps which are formed on the model using 1.5mm tube and 0.8mm wire. These dimensions were upgraded from my original choice - used on the trial truss - of 1.2mm and 0.7mm wire. Why you may ask? The 1.2mm tube has a bore of 0.6mm and required enlarging using a 0.7mm drill. I subsequently found a supply of the 1.5mm tube which makes life easier and speeds up assembly and cuts down on the number of broken drills.

 

Only another 36 to go......................................

  • Like 7
 Share

3 Comments

Recommended Comments

Killybegs

Robin, you really are a glutton for punishment! However, I do agree that it's going to be a lot stronger and it's going to look so much better. I'm really looking forward to seeing the final result. Coincidentally, I have just been drawing up the roof trusses for Killybegs train shed which will also comprise metal tubing (rectangular) and wire, but I only need thirteen!

 

John

Link to comment
JeffP

I look at this for inspiration.

When I start Falcon, I'll have some very repetetive bits to make: EIGHT brake cylinders, and EIGHT sets of leaf springs, for example.

 

That pales beside 36 trusses, however........

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...