Project Update - 12 December 2015

The plan for today is to simulate on the training module what we will be doing on 549's boiler in regards to the installation of the tubes.


The day started quite early and the initial events went a bit like this;

• 8.30am at Bunnings to pick up a 30M air hose. The compressor is diesel powered and generates a lot of noise and fumes, we want it as far away as possible from the work area.
• 9am at the museum, move the Sherman Tank (Compressor) from next to S549 to outside of the workshop.
• 9.30am - Dom kindly provided the hose fittings and attachments and also provided the service of fitting them to the hose, compressor and tooling. Thanks Dom.
• 10am - The team assembles on site eager to get into it. The module is located in a workable area and the all the tooling is assembled and laid out.

The first thing that we needed to do was to calculate the amount of tube side wall reduction or crush on the tube we needed to achieve to ensure they do not leak under pressure. The tube in its current state is loose within the tube plate, we need to workout the gap between both, then work out what the tube inside diameter will be if there is no gap, followed by if we were to further crush the tube against the tube plate.


There is a simple calculation formulae that will give us the answer, it goes like this: (I am going to use actual measurements taken for an S class).

Step 1, work out the clearance between the tube and the tube plate,

1. Measure the tube plate hole                                           58.625mm
2. Measure the outer diameter of the tube                         57.150mm
3. The clearance is determined by subtracting 2 from 1      1.475mm

Step 2, what would the inside diameter of the tube be if there was no clearance between the tube and the tube plate.

1. Measure the inside diameter of the tube                       50.840mm
2. Add the clearance determined in step 1                          1.475mm
3. Inside diameter at metal to metal (no compression)     52.315mm

Step 3, the required wall reduction or additional crush needs to be added to the inside diameter, for steel to steel tubes it is 7%.

1. Determine the wall thicknesses of the tube by subtracting the inside diameter from the outside diameter, step 2.1 from step 1.2. (57.150mm - 50.840mm) 6.31mm                                     
2. Calculate 7% of the wall thickness which will determine how much we need to reduce the walls of the tube.                                                               0.4417mm 
3. Add the 7% to the inside diameter at metal to metal from step 2.3, this then will give the expanded tube inner diameter.  52.315mm + 0.4417mm = 52.7567mm

Kirk and Josh calculating the required wall reduction

Now that the arithmetic lesson was over, we needed to get our hands dirty. The first job was to ensure the rolling surfaces of the tubes were clean from rust and scale. This reduces damage and ensures longer life for the expanders.

Josh cleaning the insides of the tubes prior to expanding

We decided to experiment a bit further with the tube projection just to ensure we have got it right, this time we chose the measurements of 5.5, 6, 6.5 and 7mm. We clamped and wedged the tube at the smokebox end of the first tune and ensured the projection at the fire box end was 5.5mm, we then expanded and flared the firebox end. We then progressed through the next three tubes ensuring the projection was correct for each. Following the expansion process, each of the tubes inside diameter were measured to ensure we were achieving the required wall reduction.

Expanded and flared tube - Fire box end



We then went onto the smoke box end and expanded these also, again measuring the inside diameter to ensure we were achieving the required wall reduction.

Signs of a happy team. Josh and Greg expanding the smokebox ends of the tubes

The four tubes were then beaded, demonstrating the process to Josh, Greg and Kirk of how its done, don't worry your turn will come. From this, the ideal projection was found to be 6.5mm.

Greg, Kirk and Josh then took over and expanded and flared another six tubes, the only way you'll learn is to give it a go for yourself. The three amigo's all took turns at the controls, all the tubes were expanded beautifully with Josh taking the gold medal in expanding the perfect tube at 52.7567mm inside diameter, amazing.

And now for what everyone has been waiting for, the beading. Under the watchful eye of the boilermaker, each of the team took turns in expanding a tube each, I must say for first timers they all did exceptionally well (maybe too well, might put me out of work..!!).

Greg giving his first tube a go at beading

Kirk's turn - Kirk is currently doing an apprenticeship as a boilermaker at ANI.
Not too many apprentice boilermakers pick up these skills anymore. 

The team today did extremely well today, eager to learn and as a end result new skills being learnt. Just goes to show, anything is achievable with the right attitude and enthusiasm.

The end result of the training session.
Note: the four tubes that the projection were trialed are the second row up with the
smallest projection (5.5mm) starting from the left, the 6.5mm one is the third from the left. 

Well that's it for this week, we will be commencing on the installation of the tubes on S549 this weekend - stay tuned.

5 December 2015 - Project Update

On Saturday the 5th of December we played around with the training module once again, the plan was to try out the pneumatic tooling, the tube set-up and expanding/beading techniques.

But firstly, following the initial trial on the training module, a number of items were identified to be obtained prior to giving the real test case a go; no use going full steam ahead if we are stuffing around with 1/2 of the required equipment. The list went like this;

• 3/4 drive to Morse adaptor insert; the new tube rolling equipment mandrels are 3/4 drive and you guessed it, we had every size but..! That's where we get local industry involved and have components manufactured to our specifications. Pressform Engineering manufactured two new adaptors and they work a treat.
• Corking gun - Loaned from a former WAGR boilermaker that happened to still have one in his cupboard, its not what you know but who you know.
• Compressor - When we did the first trial, the volume of air that was available from the small compressor was good but for about 30 seconds, to install the tubes on the S would have taken more time than what's available in our lifetime anyway...! The word went out and Boulder Loopline came to the rescue with their compressor, thankyou.

One of the tasks we wanted to confirm today was the amount of tube projection from the firebox tube plate. I was always told that it should be between 3/16 and 1/4 of an inch but I wanted to confirm a length prior to installing all the tubes into the boiler. This is very important because too little projection runs the risk of damage to the tube plate when beading the tube, too much and there is the risk of poor beading due to excess material.

Drawing showing tube projection and flaring

So we set three tubes up, the first at 4.7625mm (3/16"), the next at 5.5mm and the last at 6.35mm (1/4") and with the use of the pneumatic motor and expanders we expanded and flared all three.We expanded and flared the three tubes at the firebox end first ensuring the projection was what we wanted, we then moved to the smoke box end and expanded the tubes at this end also.


Now for the beading. We purchased several beading tools when we ordered the expanders, we however found that they required a fair bit of shaping as initially they wanted to dig into the tube and cause damage, this took several goes to get right.

Typical beading tool

The Three Amigo's, following beading of the ends.
Note: damage to tube plate on the left and centre tubes due to insufficient
tube projection (4.76 and 5.5mm respectively).
The tube on the right was set at 6.35mm stick-out and beaded nicely.

Close up of the right (good) tube.

Drawing of expanded and beaded tube

We persevered with the small compressor for these three tube which added to the difficulty but never the less we achieved a fair bit today.

The plan for next week is to finalise our techniques and to train (give a go) the members of the team so we all know what is expected on the boiler.