ModelWorks Foden Builder's Diary Please read disclaimer
Mounting Boiler in Chassis

Wednesday 19th November 2008: I have been putting off final assembly of the Foden for several years and today I finally fitted the boiler into the chassis.  I found it easy to mount the boiler but as it has the potential to be a swine of a job I have written a detailed account.  

Since February 2008 the boiler has lived on a trolley but it is now VERY HEAVY


Slowly rocking the boiler up to the correct height
 

Ever since the boiler was delivered it has lived on a 4 wheel trolley.  This made it easy to move around the garage and it has done it job well.  With the addition of cylinder, hornplates and motion it has become far to heavy to consider lifting.

When I built my Burrell I intended to buy an engine hoist to assist with assembly but fortunately after a chance remark to Steve he explained how to use bottle jacks.   This was so successful that I decided to employ a similar technique for the Foden. 

Yesterday I assembled the back axle and fitted the rear tyres.  I had planned to place the chassis on blocks but as I found it so easy to wheel around I decided to wheel the chassis into the boiler.    I calculated that with the boiler foundation ring approximately 250mm above ground level the chassis would be in alignment.  

Unfortunately the boiler was a bit low on the trolley and in order to avoid lifting it I rocked it up using a bottle jack.  Heres how:- I first jacked up the front pivoting on the foundation ring's back edge.   This enabled me to change the front foundation ring support for a beam supported by blocks on the garage floor.  I set the height of these so that the foundation ring was just touching.  I then slowly lower the jack and since the centre of gravity of the assembled boiler is in froward of the foundation ring the boiler comes to rest on the front foundation ring support and the jack/front smoke box support.  I then added more packing to the rear foundation ring support.  Additional packing was also added to the front so that the boiler would not have far to fall should the jack fail.  I then repeated this until the boiler was at 250mm on the front foundation ring support.  It is harder to describe than do! It should be noted that the main weight of the boiler at all times is on the blocks and daylight at the jack end is kept to a minimum.

The main boiler support was provided by a beam under the foundation ring with stabilizing support at the front

The chassis was surprisingly easy to move around on the rear wheels

First bolts loosely fitted between chassis and saddle

Next I rolled the chassis into position and tested the alignment of the chassis to saddle bolts.   The alignment on one side was perfect but it required a slight sideways movement to bring the other side in line.  The encouraging thing was that I had the boiler at the right height and I was able to loosely insert 3 of the bolts on each side.

I then loosely fitted the 4 hornplate chassis mounting brackets to the chassis and it looked as if my luck was running out.  The mounting holes in the bracket did not align with those in the hornplates. Since I have previously fitted the boiler to the chassis  I knew that all the holes would align provided I had the boiler in just the right position.  The back of the boiler was slightly too low and by using jacks under the beam supporting the foundation ring I was able to adjust the packing to bring the rear of the boiler into perfect alignment with the chassis mounting brackets.  I now had the boiler supported in exactly the right position and it was just a matter of fitting and tightening all the mounting bolts.

Boiler mounted in chassis ready for the front axle

The next task was to remove the trolley and prepare for the fitting of the front axle.  Using a version of my rocking technique I adjusted the support packing so that all the weight was taken by the beam supporting the foundation ring and the rear wheels.  Since there was now no weight on the trolley it was simply pushed out of the way.  I then temporally rebuilt the packing under the boiler saddle (on the garage floor) and by jacking the rear of the chassis was able to remove the weight from the beam under the foundation ring.  This enabled me to rebuild the packing directly under the foundation ring ready to mount the front axle.

While this account may appear long winded it only took half a day and I personally never lifted the boiler.

Testing the ability of the front axle to rock

Thursday:  I got on and fitted the front axle today supplied in kit 2.  Since the tie bar from the axle back to the boiler are an essential part of the axles support I decided to fit these next.  This should have been a simple job but I caused myself a lot of grief, see kit 17.

I was concerned that the tie bars would prevent the axle rocking so I decided to check this out.  With the aid of my bottle jack I simulated one wheel falling into an extreme pothole.The axle passed with flying colours.

Fitting of front brakes from Mini

Friday: Having got over yesterdays blunder I fitted the front brakes and assembled the steering.  I am now waiting for the loctite to set before fitting the front wheels.

Saturday: Fitting the brake drum took a little longer that it should due to an oversize hub.  See kit 5.

At last my Foden is on wheels

Weekending Friday 28 November: I took things at a leisurely  pace this week.  I have now fitted most of my stock of painted parts and will soon have to start opening boxes containing untouched kits.  I have dug out kit 12 and plan to trial fit the brake accessories.

Brake shoes removed from left hub
Rub is at bottom left on backplate.

Monday: I spent today curing an annoying metal on metal rub withing the left front wheel.  At first I put this down to the brake shoes but when striped the hub down, removed the brake shoes and reassembled it the rub was still present. In the end I tracked the problem to the rim of the brake drum rubbing on the backing plate (in the outer grove).   The bake baking plate appeared warped at the point at which it rubbed the drum.   I tried to deepen the grove in the backplate using a cutting in my mini drill without success.  I then removed the backplate and tried to flatten the backplate again without success.  In the end I resorted to mounting the backplate in my lathe and remachining the grove so that it was true with the backplate's fixing. I then reassembled the hub, without the brakeshoes and was rewarded with a wheel that would turn without any hint of rubbing.   It is clear that a lot of fetling is required when assembling the front hubs but the alternative is to put up withgrinding noises whilst driving.

Re-tapping the saddle bolts to M6 to provide extra strength

Tuesday:  Today I have been working on front mud guards supplied in kit 12 which led me to ponder the strength of the saddles fixing bolts.  I have been uneasy as to the strength of the 6 M5 bolts which Modelworks use to attach the boiler saddle to the chassis.  When tightening these I have had to hold back on the applied torque as I am very conscious how easy it is to sheer a bolt.   The Rex drawings show these as 1/4" BSF and M6 would make a better substitute.   The data tables show that the effective cross section of a M6 thread is 14.2 mm² as opposed to 8.8 mm² for M5.    This is backed up by my tests which demonstrated that M6 bolts are nearly twice a strong as M5.  It turned out relatively easy to drill out, retap, and replat each bolt in turn with an much stronger M6.  Fitting of the mud guards is described here.

continues