Firebox Repairs on a Case 65

engine had failed its recent biannual state boiler inspection and
would require very extensive repairs to its firebox before it would
be allowed to be fired in public again. This article will tell how
these repairs were made.

In Illinois our hobby boilers are subject to a very rigorous
inspection process that includes hydrostatic, ultrasonic and visual
testing. It was during the hydrostatic test phase that the problem
with Charlie’s boiler was discovered. Water began to leak in
one rear corner of the mudring in the lower ogee curve area. Closer
investigation revealed severe wasting to the entire mudring area
and the state boiler inspector made the decision to fail the
boiler. He did not however rule out the possibility of repairing it
at this time, and Charlie was left with some hope that his engine
would be operable again at some future date. It was at this time
which we became involved. Paul Andermann, Larry Marek and I have
been involved in the repair of several traction engine boilers in
the past, and we became interested in the possibility of repairing
Charlie’s boiler. Over the next several weeks following the
show various plans were discussed with our state inspector, and the
decision was made to move the engine to Wheatland Machine Shop in
Naperville, Illinois. This business is operated by Paul Andermann,
a steam engine man himself, and is the meeting place of many of us
with like interest.

Before a more complete analysis of the condition of the firebox
was possible, it was necessary to remove all of the accumulated
soot and scale which coated the inside of the firebox. This was
done with a needle sealer and it was during this process that it
became apparent just how badly wasted the lower mudring area was,
as we actually broke through the boiler plate in several areas.
These areas were later removed with a torch and a more complete
inspection revealed that the entire lower mudring area was wasted
below allowable limits and would have to be replaced. Our inspector
wanted us to remove all the metal from the second row of staybolts
down. This required removing all 78 rivets and 64 staybolts from
the lower firebox area. The rivets were removed by burning both
heads off and blowing a hole through the center of the rivet almost
to the edge; the rivet was then punched out with a drift. The
staybolts were cut around the edges in the firebox sheets and then
burned back so that the sheets would clear when they were dropped
down. After the lower firebox sheets were removed, the remainder of
the staybolts were cut flush with the inside of the wrapper sheet.
The heads of the staybolts were then burned off on the outside, a
hole was then blown through the center and most of the material was
burned out just to the threads. The remainder was removed with a
sharp chisel.

With the lower firebox sheets removed it was possible to take a
closer look at the inside of the wrapper sheet, throat sheet and
back head. This inspection showed some wasting around the hand hole
openings, at the point where the ogee curve met the outer sheets
and also at the point where the staybolts met the outer sheets. We
were pleased, however, that the outer sheets did not appear to be
as bad as the firebox sheets. At this time our boiler inspector
took another look at the boiler and approved the repair of these
areas with pad welding. Each of these steps were followed by
another inspection and the approval to go to the next phase. I
should add that one of these inspections also found a section of
the crown sheet adjacent to the fusible plug to be thin, so this
too would need to be repaired. After much discussion with the state
inspector regarding the different possibilities for fabricating the
necessary replacement parts, we learned that no modification to the
original design would be allowed. We would have to flange and rivet
the replacement mudring sheets exactly like the original. We had
done several jobs in the past involving flanging replacement boiler
sheets, but this was to be by far the most extensive yet. We were
still fairly innocent at this time and not scared off by hard work,
so we pressed forward.

The first step in this process was to design and fabricate
special dies over which to flange the boiler plate. We found that
the amount of offset in the front and rear ogee curve was
different, so it was determined that two dies (made out of cast
iron) would be required. The patterns for these dies were made out
of wood and with allowance for shrinkage were shaped to provide the
proper radius and offset to bend all four corners of the lower
firebox sheets. Special steel is used in the construction of
boilers and boiler replacement sheets and is tightly regulated by
A.S.M.E. Code. Several sheets of this plate was purchased from
Joliet Boiler & Welding with all necessary documentation in
⁵/₁₆‘, ³/₈‘ and
‘ thicknesses. All these plates were stamped with a number that
could be traced should there be any question regarding their
acceptability for this purpose. The dies were mounted on a heavy
steel fixture table with a sturdy hydraulic clamping device to hold
the plates during the actual flanging process. It must be
remembered that the dies were only to be used for flanging the
corners of the ogee curve area; the other areas of this curve could
be formed on a heavy press brake. After this was done, it was time
to start on the corners. Before it is possible to work this heavy
plate by hand, however, it is necessary to heat it to a bright
orange color. This was done in a large coal forge owned by Larry
Marek. As the plate to be flanged was being heated, we preheated
the die with a rosebud tip. We did not want this four hundred pound
piece of cast iron drawing all the heat out of the sheet. After the
sheet was brought up to the proper heat, it was quickly moved to
the die and clamped into place. The actual flanging then was
accomplished by bending the plate over the die with sledgehammer
blows with several people at once swinging before the heat left the
piece. This process was repeated about seven times before the sheet
conformed to the required shape. This flanging required very heavy
labor and many Saturdays before it was complete.

One concern raised during the flanging process was of the
possibility of thinning out or fracturing the sheets in the most
heavily worked areas. This fear, however, proved to be false, as
subsequent inspection showed that thinning was marginal. We were
careful to work the plates in such a way that pushed the excess
material to the edges. Care was also taken not to work the plates
after the heat had left them or to scar the plates with the
hammers, always striking the plate with the face of the tool and
not the edge. Some areas were driven into place with specially
built fullers and flatters struck by a sledgehammer. With careful
smith work under the direction of Larry Marek a very professional
job was done. This part of the project proved to be by far the most
difficult and time consuming, many weeks, many hundreds of pounds
of coal and much energy expended in the process. In retrospect
however, it is this phase of the job of which we are most proud;
brute force applied with skill produced the shapes that we would
need to bring this engine back to life.

Riveting mudring; note coal forge in background. Larry Marek
placing heated rivet into hole, Paul Andermann (not shown) in
firebox forming heads, and Charlie Fruit shown about to use rivet
hammer for bucking.

After the flanging phase was complete it was time to trim and
fit the plates to replace the sheets removed from the firebox. As
seen in the photo, six separate sheets were fabricated to
accomplish this goal. The actual fit-up and installation of these
sheets also presented quite a challenge. Lifting this heavy plate
in and out to check fit was tiring work. Much adjustment and
fitting were necessary before we felt the seams could be drawn
close enough to make them steam tight. Where the sheets overlapped
scarfing was needed to taper the edges down to eliminate the gap
left by the plate thickness. This was done by heating the corner in
the forge and drawing the edge out on the anvil. Finally, after all
the sheets began to look like they may fill up the gaping hole in
the bottom of Charlie’s boiler, we began to transfer the rivet
and staybolt holes. First, the rivet holes in the vertical seams
were drilled, bolts were then used to hold the entire assembly
together for final fit-up as the mudring rivet holes were
transferred. I might add that these holes were all drilled
undersize so final reaming could be done prior to driving rivets,
so perfect hole alignment would be assured. Lastly, the staybolt
holes were transferred by using a staybolt tap with a hole through
the center to guide a transfer punch. These too were drilled
undersize so that a staybolt tap could be used after final assembly
to tap both holes in perfect alignment. Paul made all of the
staybolts on his lathe by chasing the threads with a sharp
‘V’ tool bit, quite a job when you remember that there were
64 stay-bolts to be replaced! I should add that documentation also
had to be provided to the state inspector on the material used to
manufacture these staybolts. After the last of the holes were
drilled and the final fit-up had been checked, we sent the
replacement sheets out to be annealed to relieve all stress that
had been put into the sheets due to the heating and bending. The
vertical seams were riveted prior to installing the entire assembly
into the firebox for welding into place. Final approval was given
by our inspector on line-up and we were given the okay to weld the
entire replacement assembly into place. With the entire replacement
assembly in place for the last time, the project then turned over
to Joliet Boiler & Welding. The welding process was left to the
professionals as per the requirements of the A.S.M.E. Code. With
our inspector there to witness the root pass, the okay was given to
weld the entire assembly to the remaining firebox sheets. This was
the day we had been working towards for a long time! The actual
welding process was fairly straightforward, but the guys from
Joliet Boiler took the better part of two afternoons to complete
the job. A horizontal weld around the entire firebox joined the new
and old sheets together. Two vertical welds were needed to join the
two halves of the replacement sheets at front and back. And last,
the patch in the crown sheet was welded into place. It can be seen
from the photographs that all of the staybolts adjacent to weld
seam areas were welded. This was done for two reasons: first, to
eliminate leakage due to the heat of welding. Second, to build up
the wasted area adjacent to the staybolt head, a condition often
found around staybolts’ heads subject to the heat of the
firebox.

With the replacement sheets all firmly welded in place, it was
time to replace all the mudring rivets and staybolts. A crew of
four of us spent the better part of a Saturday driving the new
rivets into place. Larry was the forge man, heating the rivets to a
bright orange heat and with a pair of tongs inserting them into the
open holes. Paul was in the firebox with an air hammer to form the
heads. Charlie was on the outside with an air hammer to buck the
rivets, and I removed the bolts and reamed the holes with a bridge
reamer to insure perfect alignment. Working as a team we worked our
way around the entire mudring, putting in a rivet every several
minutes. We had done quite a bit of rivet work before this job, so
this phase of the project went very well. We must have had a good
job, as only a couple of the rivets had to be taken out and
replaced due to looseness. After the rivets cool we go around with
a small hammer and tap to find loose ones. We have found that loose
rivets cannot be made tight enough to be steam tight. However,
tight rivets that leak or drip during hydrostatic testing can
usually be caulked shut with specially formed caulking tools in a
small air hammer.

The last step of this project was to replace all the staybolts.
As I noted earlier, the holes for the staybolts were put in prior
to installing the sheets in place. With this done it was only
necessary to tap the holes to accept the new stays. Of course I
make it sound easy, but it must be remembered that there are 64
stay-bolts in the mudring area plus the four in the crown sheet
patch. The stays that Paul made were cut to length and screwed into
the mudring sheets, leaving about to ³/₈‘
extending past the sheets. With a large sledgehammer used to buck
the other side, an air hammer with a special rivet set was then
used to form the heads. This work was done cold and in some ways
was much harder than driving the rivets. The staybolt set we used
created a head that matched the one that Case used very closely.
Lastly, we had to caulk the seam at the base of the mudring. This
was done with a round nose tool in a small air hammer. No welding
joined the plates at the bottom so caulking alone was used to
create a steam tight joint.

Finally it was time to fill the boiler with water for the hydro
test. Throughout the project we had much doubt as to whether we
could ever get it sealed up again to be steam tight. We had
essentially used the same construction methods as when the boiler
was built in 1919, much of which we had to learn as we went along.
But as the project came closer to completion it became obvious that
the care we had taken would pay off. With hand hole plates back in
the boiler after two years, we slowly began to fill it with water.
Everyone there was pleasantly surprised that, contrary to
predictions, the water did not flow out the bottom as fast as we
put it in the top. In fact, with the boiler full we only had some
steady drips; these could, we hoped, be sealed up by caulking.

This boiler is allowed 100 P.S.I. in Illinois, so the
hydrostatic test given was 150. As the pressure rose, some of the
drips became sprays, but with careful caulking we were able to slow
them down enough that the pressure test was deemed a success. The
final inspection was done by our inspector several days later. He
found everything to be in order and a certificate was given to
operate the boiler at 100 P.S.I. After all the long hours we had
spent on this job we were all very pleased that it had turned out
so well. After reassembling the engine the big day came when we
could finally steam the boiler up for the first time in several
years. Under pressure we only had a few small leaks and the job was
declared a success.

In closing I would like to say a bit about our antique hobby
boilers. Many of these boilers are now reaching an age when they
will soon require some type of heavy repair to remain safe to
operate. Others, however, are in excellent condition and with
proper care will be safe for many years to come. Each boiler must
be evaluated on its own merits. It simply is not fair or accurate,
as some will do, to declare all antique boilers unsafe due to their
age or supposed engineering flaws. Most of the boilers being
exhibited today represent many, many years of engineering
knowledge. Don’t forget that in the 19th and early 20th
centuries some of the best and brightest engineers dedicated their
entire careers to perfecting the steam boiler. The traction engine
boiler built in 1920 represents 100 years of refinement. Any
machinery that is used, however, is subject to wear and will
require repair to extend its useful life. It is becoming fairly
routine to hear of front tube-sheets, crown sheets and even barrels
or fireboxes being partially or totally replaced. There is an
extensive network of people out there dedicated to preserving our
industrial and agricultural heritage. If this work is done in a
safe and proper manner by qualified workers the life of these
boilers can be extended many years.