I had really hesitated to post the entire narrative as I thought it would consume too much bandwidth. Please bear in mind that virtually every step of the process can be done a different way in order to fit your specific equipment and situation.
I have sent out about twenty copies directly to individuals and have at least that many requests sitting in my mail box. I am hoping the recent direct mail requests will obtain the narrative from this post. If not, send me another direct email and I will send it directly to you.
Many had asked about the celebration party that took place after the babbitt party. The "party" after the "party" produced sufficient Canadian & American shim stock material such that I may have a temporary corner on the market!
Here it is:
Subject: Pouring Bearings on old “Hit & Miss” Engines
Situation: On September 18-19, 1998 a group of old engine enthusiasts met at our home in Northern Vermont in order to learn the process and also repair bearing damage on a total of six engines. Most of the collectors, who were from both Canada and the U.S., were relatively new to the hobby and none had ever poured bearings in the past. Our instructor was an eighty plus year old Canadian gentleman who had operated a small foundry in years past. His handshake was like putting your hand in a steel vise and his limited English was interpreted by our bilingual Canadian friends for the non French speaking collectors. We all understood when he would say “you
kill yourself doing that!”
Disclaimer: After giving consideration to the litigious nature of the human race it was decided to provide the following disclaimer concerning this narrative: Virtually every procedure and material mentioned in this narrative will cause immediate death, dismemberment, disability, or loss of consortium such that massive doses of “Viagra” will provide little remedy. By even reading this material you are agreeing to having been forewarned of these possible consequences!
The General Process: From information gained from the Internet Stationary engine list and from extensive explanation by our instructor it had been determined that there were many variations of the basic process. The variations were based on available equipment, materials, the specific bearing application, and the machinery being repaired. It appears that the bottom line is that “if it works” you did it the correct way. When possible, I will mention the alternative methods in this narrative.
The Cautions: It appears that the two primary means of sustaining injury in the process are as follows:
1. “Splatter” of the molten metal when transporting or pouring the bearing.
2. Moisture within the mold coming into contact with the molten metal and causing steam and resultant pressure. This steam generated pressure can cause the molten metal to be forced out of the inlet orifice or “pouring hole” or cause a minor explosion of the metal as it breaches the confines of the mold. Any contact between the molten metal and moisture will cause a “splatter” similar to water contacting bacon frying in a hot pan. Most hazards can be avoided by insuring that all primary and adjacent work surfaces are completely free of moisture and that the movement of the molten metal is well planned.
Protective Clothing: Rule one is to cover as much bare skin as possible. Try to use leather boots and that your pants legs are outside the boots as opposed to being tucked into the boots. Open boot tops provide a nice opening for molten metal to reside! We used an old welding mask with clear glass substituted for tinted glass. Safety goggles would be minimum eye protection. Welder’s gloves or at least heavy gloves with the openings taped shut around the shirt sleeve at the wrist are a must. Use a welders bib if you have one. I used an old “Nomex” (fire-retardant) suit that had been getting moldy in the closet since my hydroplane racing days are long since past. While these precautions may seem “overkill” to some…it worked for us as everyone in the group went away without pain or injury. Besides, we didn’t know what the hell we were doing!
The Task At Hand: All of the six engines ranged in size from 1 HP to 4 HP and required the replacement of “split” bearings for the crankshaft or piston rod. The old bearings were either smashed, missing, or severely worn. Two engines had the flywheels still attached to the crankshaft as removal of the flywheels presented a high probability of damage to the components (boy! were they frozen on!).
The Equipment and Materials: The following is a list of materials and equipment that we used. This list may well vary depending on available resources.
Babbitt Material: The babbitt alloy material was provided by our volunteer instructor in the form of five pound “slugs” in the shape of a bagel. The material is available from a number of sources to include “Hit & Miss Enterprises” in Ohio. We also used fragments of old bearings that had been saved when the engines were dismantled.
Dam Material: The dam material used for containing the molten metal was also provided by our volunteer instructor and was in the form of a ½ inch square light brown and waxy material that was formed into a coil. This pliable material had the general appearance of “oakum” used between the planks on wooden boats. It is suspected that the specific material we used may well have been decades old. The modern equivalent is called “Babbitrite” and is evidently available from the Mc Master Carr company in the U.S. Stationary engine list members indicated that they have used everything from modeling clay to children’s “Play Dough” with successful results!
Crucible: We used an electric crucible similar to the type used to melt lead used in casting bullets. I would suspect that almost any suitable container using a controllable heat source would do the job.
Ladle: The ladle we used was a short handled cast iron ladle with a wooden handle for heat insulation. The ladle should be of sufficient size to enable the individual pour in one movement.
Acetylene Torch Set: An acetylene torch set was used to heat components and also provide the mold release agent in the form of carbon black. Stationary Engine list members indicated the use of everything from small propane torches to high heat blower guns used in paint removal. All indicated successful results?
Alignment Tools: In each case we used the piston and piston rod inserted in the engine piston sleeve as a means of achieving proper alignment with respect to the piston rod and the crankshaft. An alternative would be to use a jig of some sort to insure a 90 degree alignment between the crankshaft and the piston rod.
Spacer Jigs: These jigs were used to gain proper spacing between the crankshaft surface and the base such that the bearing would be uniform in dimension. The jigs used varied from engine to engine. When a spacing stud was already in place on the engine base all that was required was a short wire wrap on this stud to provide an “oiling groove” in the finished bearing. If no such stud was present we used an adjustable support platform placed under either the crankshaft itself or under the flywheels if they were still attached to the crankshaft. The support platform was made of wood with the “support” surface shaped to the contour of the shaft or flywheel to ensure stability of the components.
Fake Shims: Temporary shims made of hardwood were used as all two piece bearings were poured as a unit. The hardwood shim was .125 in thickness and had four grooves cut on the surface that set against the crankshaft surface. These grooves allowed the molten metal to flow into the lower bearing space. The temporary wooden shims would be later replaced with metal shims when the engine was reassembled.
Heat Gun: Our instructor did use one piece of modern equipment in his process. A hot air heat gun similar to a women’s hair dryer was used to heat the crank journals and also maintain heat on the metal just prior to the pouring of the bearing. The hot air gun was used as it provided uniform heating that would not alter the qualities of the crank metal by overheating those areas.
The Actual Procedure: A 1 ½ HP Massey Harris base was placed on a perfectly flat concrete surface. All metal surfaces in the immediate vicinity of the bearing surfaces were cleaned of grease and moisture with great care. We used “Acetone” as a cleaner and the hot air gun after the Acetone had completely dispersed. Two short pieces of #10 gauge wire were twisted into an elongated “X” to form the oiling groove in the finished bearing. This “X” was bent to the contour of the bottom of the bearing mold such that it laid perfectly against the surface. It was then removed, covered with carbon black using the acetylene torch, and replaced in the bottom of the mold. The crankshaft had carbon black applied to the journals. It was then placed in a wooden jig that supported the shaft directly over the bottom of the bearing mold (the engine base) at the same spacing indicated by the old fragmented bearings. The wooden jig was situated at the very end of the crank shaft and sat on the concrete floor. The jig had a wide base for stability and was adjusted for height using shims between the jig and the floor. The piston rod, which was attached to the piston located in the sleeve, was then attached to the center journal of the crankshaft. The 90 degree alignment between the crankshaft and the piston rod as well as the desired bearing spacing were triple checked for proper dimensions. The wooden temporary shims were placed into position. A perfectly clean and dry grease cup base was installed in the bearing caps after the threads were coated with carbon black. The interior of the grease cup base and the interior of the bearing cap were treated with carbon black prior to the unit being loosely bolted into place on top of the crank journal and temporary wooden shim. The moldable dam material was placed firmly around both upper and lower openings of the “pour” space. Care was taken not to push the dam material into the desired pour space. The metal surfaces were initially heated with the hot air gun and this process was completed using the acetylene torch. Care was taken not to disturb the dam. The hot air gun was then used again to keep the metal warm until the very moment of the metal pour. To be honest, the metal was more warm than hot, however, no pour voids were encountered. The babbitt metal had been melted such that it was molten and had a blue sheen to the surface. The molten metal was ladled into the grease fitting base and eventually filled both the lower and upper mold areas. The bearings were allowed to gradually cool over a couple of hours and when the caps and temporary shims were removed the excess material was either filed or shaved. The wire forming the oil grooves was removed and the operation was complete. We eventually completed six engines over a two day period.
Alternative Methods: Evidently some people prefer to pour only one half of the bearing at a time. Some people like to pour the complete bearing on a “dummy” journal and then cut the bearing from the dummy surface. I would think that the chosen method is more dictated by the placement and type of bearing than anything else.
Conclusion: Preparation was 95% and bearing pouring was 5% of the operation!
Note: If I have confused you or myself with my descriptions of the bearing pour I will be most happy to clarify any point via direct email. In spite of our success, I tend to believe we gained only a small fraction of the knowledge required to make a living in this profession! Thank you for your interest. We would also appreciate any additional information you might care to add to our knowledge base.
Ken Brown- K1KNM
One Resident Moose
Vermont's Northeast Kingdom
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