Tim4948's Workbench - Building a LMS buffet car

[tim4948]

The big parts between the girders have now been added, this was the ready of the beams and what seems to be the gear box which is situated under the barrel and immediately behind the front bogies, when I started to install the gear box I realised that I had missed yet another piece off the main girder. If you look at the picture below it shows the gear box installed (made from 1mm plasticard) but the flange that has been highlighted in pencil is where the girder should extend down a bit further, compare it with the picture of the prototype below.

 

 

So now it is time to fix another mistake (obviously I haven't heard of measure twice cut once), the process that was used was similar to the process that I went through to correct the top of the beam. The flange and bottom detailing parts where removed and a new piece of 1mm thick plasticard with both ends tapered was installed, then the bottom flange was reinstalled.

 

 

This was then followed by the detailing parts being added to the girder.

 

 

It was then time to move onto the rear part of the girder, the first step was to cut 3mm off the end of the floor between the 2 girder sides, then install the top flange on the girders. Below is a before and after picture.

 

Before.

 

After

 

It was then time to cut the recess into the bottom of the rear of the girders, followed by the flanges and then the detailing parts. Below is a before and after shot.

 

Before

 

After

 

This now finishes off the big changes that where required to the main girders before the gun can start to be finished off ready for installation. - more to follow on this part either later today or tomorrow, depending on progress being made.

Edited March 8, 2016 by tim4948

[tim4948]

well some progress was made on the gun barrel, the first step was to add another layer of tubing this time having an outside diameter of 12.7mm (the biggest that evergreen do).

 

 

The 2 biggest layers where then filed down to form a taper, filler was then applied to get rid of some of the unevenness that had occurred and filed back once dry. The next step was to add another layer of tubing as the rear of the barrel was still too small, the next layer has an outside dimension of 16.5mm and was the perfect size to slide over the previous layer. A section measuring 23mm was cut off and I decided to file the front edge before fitting this time so that I wouldn't put gouges into the existing barrel (which is what happened with the last lot of filing).

 

 

The next step was to fit it onto the rear of the gun barrel.

 

 

Filler was then applied to this joint and will be finished off once dry

[Londontram]

Just found this thread, what a wonderful job your doing with the model. Looking forward to more updates, Steve

[tim4948]

Hi Steve

 

Glad to hear that your enjoying the build.

[tim4948]

I have had an experiment with doing the rivets with superglue on a scrap piece of plasticard, some of its a bit rough but the bits closest to the camera are looking better than the rest except for a few (these where the last one to be done).

 

 

They may look massive in the picture but actually measure between 0.5-0.75mm in diameter (most are 0.75mm). Please let me know what you think.

Edited March 9, 2016 by tim4948

[KalKat]

Why not use rivet transfers?

 

 

Emma

[tim4948]

Hi Emma

 

As I will probably need quite a few sheets for this model I have decided to experiment with a few cheaper alternatives first to see if they will work.

[tim4948]

Onto the next bit and a milestone has been reached!

 

But first the build up, I have now filed the filler that was applied last night which resulted in the barrel looking like this.

 

 

A close up of the rear section.

 

 

The next step was to make the pivot points which will be fixed onto the girders, this was done by cutting out the below shape from 1mm plasticard, the rounded section on the top was filed to accept a 1.5mm thick piece of 7.9mm diameter tubing.

 

 

Here is a picture of the pivot point fixed onto the girder

 

 

Next up was to set about fixing the pivots to the barrel this was done by placing the barrel on the girder and marking out where the 2 pieces of wooden doweling will be fixed, wood was used as I found that it grips the plastic tubing better than plastic does so will help keep the barrel in the raised position. Once the doweling had been cut to length and the correct profile filed into the end which joins to the barrel they where fixed in position. The barrel was then fitted to the main girder by gently pushing the 2 pivot points apart on the girder and slipping the barrel in so it looked like this. The wooden doweling still needed a bit of trimming which was done after this photo was taken.

 

 

It was then a case of putting the whole lot together to make sure everything fitted. Here are a couple of pictures to show the progress (a oo gauge figure is in from to give a scale of size)

 

 

The next job is to make the mechanism that fits under the barrel.

[tim4948]

I have managed to construct the part which fits under the barrel. First up was to construct the part which the barrel will be resting on, this was made easier as when I purchased the biggest diameter tubing I managed to get a preformed mount for it which meant that I only had to make 2 others, a basic framework was made from 1mm plasticard which ensured that the barrel fitted both snugly and was level.

 

 

The sides where then made and fixed in place as well as the angle being cut into the front.

 

 

The sides where then extended down using 1mm plasticard and the top detailing added using 1mm x 0.5mm plasticard.

 

 

The rest of the detailing was then added to the bottom portion using 1mm x 0.5mm strips for the flanges which are 90 degrees to the sides and 1mm x 0.25mm strips for the rest.

 

 

The rear end detailing was then done in the same way.

 

 

The side pivot supports where then marked out and then cut from 1mm plasticard.

 

 

A 1mm thick piece of tubing was then added to the top and 16 depressions where made in them with a drill bit to represent the countersunk holes for the bolts.

 

 

The whole lot was then placed together to ensure it fitted correctly.

 

 

Next up will be to finish off the detailing on the front part.

[KalKat]

The pivot arrangement doesn't look to be particularly 'beefy' for holding down such a large gun - is there more to come?

 

Emma

[tim4948]

Hi Emma

 

There is a bit more to be added to the pivot arrangement on the girder but from what I can work out with the drawing and photos that's it.

[tim4948]

The front part of the gun mount has had its detail added to it, The first step was to create the basic framing using 0.5mm x 1mm plasticard.

 

 

The top horizontal piece I had a rounded grove filed into it to allow for the shock absorber to be mounted on the front as in the prototype (where the cross is marked), two holes were also drilled in the top part and the top flanges and had a top edges filed off at an angle.

 

The front plate which fits on top of the lower framing was then cut out of 0.25mm plasticard.

 

 

Once the top plate had been fitted the shock absorber was then fitted using 4mm diameter tubing and the had the end piece fitted made from 0.25mm plasticard.

 

 

The barrel was then fitted to the gun mount along with the side pivots.

 

Next job is to start adding the remaining big parts to the rear of the main girders (the 2 cranes and the track for loading the shells into the back of the gun)

[Dave Holt]

Tim.

I think there should be a strap over the top of the barrel to keep it engaged in the grooves in the gun-slide. From the drawing, it looks like the strap is roughly in line with the trunions.

In large guns like this, the barrel is fixed to a slide forging whose upper surface is machined to match the barrel diameter and which has grooves to match the rings on the barrel. the two are held together with the strap I mentioned (the kick strap). Thus, the barrel and slide move backwards and forwards, on recoil, as a unit. The slide runs in grooves in the elevating cradle and is connected to it by (usually 2) recoil and (usually 1) run-out hydraulic/air cylinders. The trunion pivots are actually on the cradle, not the barrel/slide assembly, of course. Obviously, on a non functional model it's perfectly OK to combine the slide and cradle into a single unit, as you have. However, I think KalKat is probably right that the trunions look a bit skinny, but the main problem is they're too narrow rather than too thin radially, if you follow me.

Enjoying your project.

Dave.

Edited March 14, 2016 by Dave Holt

[tim4948]

Hi Dave

 

Glad to hear you're enjoying the project and thank you for the information on how the barrel and recoil mechanism work I hadn't fully realised/understood what each part did but after your explanation I can now work out how each part moved. The strap that goes over the top of the barrel was on the list to be done but I forgot about it, so it will be done.

 

The one part that I didn't quite understand was the last part, please can you explain what you mean by the trunions look too narrow?

 

Tim

[Dave Holt]

Tim,

If you look at the plan view of the drawing, the part of the cradle which carries the trunions looks to almost fill the gap between the main girders and the barrel. Similarly, the bearing housings on top of the main girders are almost the full width of the top flange, such that the width of the bearings is probably similar to the diameter.

Dave.

[tim4948]

Hi Dave

 

That now makes sense I shall put it on the to do list.

 

Tim

[tim4948]

I have now done the reare parts of the main girder and the silhouette portrait cutter was a life saver as I doubt that I could have achieved the accuracy if cutting the parts out by hand. The first part to be done was the track which is used to guide the trolley with the shell on from the ammunition van into the rear of the gun, the top was cut out with the cutter from 0.25mm plasticard.

 

 

1mm square brass rod was then stuck to the underside of the top piece to reduce the risk of it warping.

 

 

0.25mm x 2mm plasticard was then glued to the sides and the whole assembly was then glued to the supports that I had already glued to the main girders, the end result looks like this.

 

 

It was then time to move onto the cranes, I decided that if possible I would try to make these so that they could move like they did in real life, the parts to make the jib of the crane was cut out of 0.25mm plasticard using the cutter.

 

 

The 2 triangular pieces then had 0.5mm holes drilled through them.

 

 

The jib was then assembled with a 1mm square piece of plasticard glued inside the far end to give it strength.

 

 

The mast was then cut from 2mm square plasticard rod and a 0.6mm hole was drilled through the top and a piece of 0.5mm diameter brass wire was glued inside the hole.

 

 

The jib was then connected to the mast and the base of the mast had a 0.6mm hole drilled in the bottom, a piece of brass wire was then glued in the hole.

 

 

Once both of the cranes had been made up I made sure that the arms moved independently from the masts.

 

 

Their positions were then marked out ready for the holes to be drilled through the top surface of the main girder for the brass wire to pass through. 2 layers of 1 mm plasticard was the stuck to the underside of the main girder where the brass wire was to pass through, the holes where then drilled through and the brass wire was passed through, cut to length and a scrap piece of plasticard was then glued to the brass to stop the cranes from falling out when the model is turned upside down. Here is the end result.

 

 

The next step will be to add the detail to the rear of the gun barrel.

[tim4948]

I have been experimenting further with the rivets and have got the below result with superglue, the dimensions of the piece of plasticard used is the same width as what I have used for the top flange on the main girders, below is a picture of my attempt followed by a picture of the real on for comparison

 

 

Let me have your thoughts.

[tim4948]

The rear of the gun barrel has now been done, this was done by sticking on a piece of 1mm thick plasticard which was then filed to the correct shape. Here's a before and after shot.

 

 

It was then time to add the detail to the rear of the barrel, this was done by using various diameter pieces of round plasticard for the hinges and lever to open the rear of the barrel for it to be loaded, off cuts from the plastic tubing that was used for the barrel was then added for the piece which fits to the rear of the barrel and bridges the gap to the track for loading the shells.

 

 

I have also started to add some of the detail which goes at the front between the main girders, this is the progress so far and has been done by using various diameters of round rod and small pieces of plasticard for the square pieces. This has been a bit of a pain as there are very few photographs to go from and the diagram that I am working from does not really help much, also because of the size of some of the pieces it has been very fiddly and time consuming but I think the end result is looking beginning to look good.

 

At the start before any of the detailing has been added.

 

And here is how far I've got so far, there is still plenty to be added.

 

Next up is to continue with the detailing.

[tim4948]

More detailing has now been done with the front of the main girders receiving the attention first, the platforms where made from 1mm plasticard and the frame work was made from various square and rectangular pieces of plasticard strip with round rod being used for the front section, still to be added is the diagonal bracing which goes on the top but this will be added when the gears that go between the 2 platforms have been added.

 

 

I then continued with the detailing between the girders, the piping was finished off up to the big tank and the various parts that would have raised and lowered the gun where then fitted to the girders underneath.

 

 

A view of what is visible when the gun is mounted and raised up to its maximum angle.

 

 

The piping was then added to the parts under the barrel.

 

[tim4948]

I have come up with a different method for doing the rivets, I have used superglue gel and a toothpick with a fine tip and dabbed it in the glue and then the plastic, the strip of plasticard in the picture is 1mm wide. Let me know what you think.

 

[ikcdab]

This is first rate. Well done. Excellent modelling!

Rivets look great.

[tim4948]

It's been a while since the last update (work & holidays), but some progress has been made since the last post.

 

The gearing that goes between platforms at the front of the main girders has been made up and fitted.

 

 

The top diagonal bracing was then added to the framework.

 

[Dave Holt]

Tim,

Welcome back. I was beginning to worry about the lack of recent posts and wondered if you had given up on us.

When you consider the shear massiveness of the main girders and gun cradle, that extension at the end looks amazingly flimsy! It's a wonder that it could survive the rigours of use and shock from firing.

Looking forward to further updates,

Dave.

[tim4948]

As boche-buster is beginning to look like the finished product I decided it was time for it to go on an outing, so here it is posing on Northwick.

 

 

And here is a better side on view of the train which is loosely based on the formation which is shown in the YouTube link below.

 

 

 

At the moment there is:

 

A GWR Mink F standing in for the LNER ammunition van - still trying to locate a drawing of this

A BR Class 08 standing in for the LMS class D3/7

A LNER 4 wheeled pigeon van standing in for the as yet unidentified LNER van

A SECR 8 ton van standing in for the van at the rear.

 

There would have been a picture of boche-buster with its barrel raised but I forgot to take a picture.