Firebox Repairs on a Case 65

| September/October 1997

Forming die

Forming die and clamping assembly used to flange corners.

525 West Van Buren Avenue Naperville, Illinois 60540

The 1993 annual show of the Northern Illinois Steam Power Club of Sycamore, Illinois, opened with one engine conspicuously absent. Longtime participant Charlie Fruit of Kirkland, Illinois, and his 65 HP Case engine, Number 35072 were not found in their usual spot under the oak tree. We learned from Charlie later that day that his 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.