Athos 626 vice swivel base

My Athos 626 vice swivel base has 2 mounting ears broke off. Cant find any used swivel bases for this vice, so thinking about building up the ears with braze and machine the mounting holes. Wanted to check here if anyone knows a source for old vice parts before fixing it myself. Thanks. Andy

you can try, but if there is a lot of force exerted, it may fail again.
I have had the best luck on stuff like this using TIG, and nickel rod.

I repaired the base casting on a Rock Island machinist vise a few years ago. Ears were broken off the casting due to United Parcel Smashers. I used Nickel Rod, known as "Ni Rod" with stick welding. What I did was to layout the bolt holes for the vise mounting on a piece of steel plate. I then bolted the base casting and busted-off ears to the plate. This jigged things together for welding. I then unbolted the pieces and vee'd out the fractured surfaces for welding.

Once I had things vee'd out (I vee'd from the bottom and top surfaces, leaving only a little "land" in the middle where the fractured surfaces mated together), I re-bolted the base and the ears to the plate. I pre heated the whole works with a "rosebud" (oxyacetylene torch heating tip) to "cook" the cast iron and drive out any moisture or oil. I am guessing I got things to somewhere near 400 degrees F (my spit sizzled and beaded up and danced on the hot iron). I then began tack welding using the Ni Rod. As I tack welded, I peened the welds using an air needle scaler. I worked my way around the vise base, not welding too long in any one location. When I had a root pass in, I unbolted the base from the plate and "back ground" the welds from the bottom side. I then repeated the process of putting in the root pass on the bottom side, putting the weld in using small 'stitches', and peening with the needle scaler as I went along.

After that, it was a matter of alternating which side of the base I was welding on, top or bottom, and peening the welds as I laid them in. I kept reheating with the torch during the welding.

When I had the base and its ears welded back together, I reheated it in the firebox of my home heating boiler (coal fired). When I had a good dull red heat on the vise base, I pulled it from the fire and buried it in a bucket of coal ash. I let the vise base slow cool overnight. The next day, I ground the welds flush, wire wheeled and inspected for cracking. No cracks found. I then went a step further: not wanting to rely solely on the welds to hold the vise mounting ears, I took some A-36 steel flat bar and "strapped" the ears to the base. If I recall correctly, I used 3/8" thick steel flatbar, heated it to a red forging heat, and formed it around the ears and vise base. I secured the steel strapping to the base using some socket head screws in counterbored holes. It was a matter of getting one end of the steel secured with a socket head screw, heating and hammering and clamping the steel to the vise base, and when cool, drilling, tapping and getting the next socket head screw in. When I had the strapping solidly on the vise base, I then stitch welded it to the vise base, using short stitches and skipping a bit of distance between them.
Lastly, I cleaned the welds up with my angle grinder and then set the vise base up on my Bridgeport. I skim cut the top surface and bottom to insure flatness.


I have had some experience with repair welding and brazing of cast iron. Either process works and each has its applications. When I am dealing with a cast iron part that has to transmit some load or may see shock loading, I like to make what I call a "mechanical repair". That is, I try to add some steel and bolting to span the welded repair and transmit any loads rather than relying solely on the welded repair. Sometimes, this is not possible, and a good brazing or welding job has to do the trick. I often go with oxyacetylene brazing and have had good success with it. However, if you start a repair with brazing and decide it is not working for you, or you decide you'd rather weld, the problem then is the fact that iron which has seen bronze brazing metal will not "take weld". You will need to grind or chip off all the brazing and get down to virgin iron. I believe brazing works well on cast iron as it has some "give" to it. On cooling, the bronze brazing is ductile enough to absorb the cooling stresses rather than transmitting them into the iron (as tensile stresses with resulting cracking in some cases). My objective in peening welding or brazing on cast iron is to help relieve some of this cooling stress. Some welders will peen using the pointed end of a slag pick, and other will use a light chipping gun with a chisel steel ground to a slight radius rather than a cutting edge. I prefer to use my needle scaler.

Ni Rod is pricey stuff, and you have to be sure to buy a Ni Rod alloy which is machineable. Some less expensive Ni Rods are non-machineable, made for dirty cast irons on jobs like repairing stove grates. What I've wanted to try is the oxyacetylene welding of cast iron. Years ago, cast iron rods having a square cross section were sold in welding supply houses along with a flux for O/A welding of cast iron. In the right hands, oxyacetylene welding of cast iron produced a very sound weld which was homogeneous or nearly-so with the cast iron part being welded. Plenty of engine blocks and large machinery castings were repaired by this process.

Kent at tinmantech sells cast iron rod and flux for oxy-fuel welding cast iron.
Cast Iron Filler Metals for Gas or TIG welding

Me, I yanked the swivel base off my big vise 25 years ago, and bolted the vise down to a 6" square tube that is, in turn, bolted to the floor. Swivel bases always break, eventually. I often straighten things with my vise, using a 24" crescent wrench and a 4 foot cheater bar. Swivel bases cant survive that.

Are you sure it's not an ATHOL vice? Granted another base will be extremely hard to find in any case but correcting the name may help.

Tom B.

Thanks for the link. I just may mount the vice to the bench, or perhaps a floor pedestal (like you did).

Riderusty said:

Are you sure it's not an ATHOL vice? Granted another base will be extremely hard to find in any case but correcting the name may help.

Tom B.

Click to expand...

Yeah, correct spelling would probably help. LOL!

Athol may have poured their vise castings out of a "semi steel"- cast iron with a portion of scrap steel being added to the melt. From my own experience, Athol built a fairly heavy classic machinist vise.

Here is another idea for a repair if you are not inclined to do a welded or brazed replacement of the broken mounting ears: Get a piece of steel plate, perhaps 5/8" or 3/4" thick, a bit bigger then the "footprint" of the swivel base casting. Drill new mounting bolt holes in the plate to tie it to your bench or vise stand.

Secure the swivel base to the steel plate using socket head capscrews in counterbored holes in the plate. This idea will work if there is enough "meat" on the swivel base casting to let you drill and tap some holes up into it. About the smallest diameter capscrew I'd use would be 1/2-13. I would also drill and line ream for some hardened steel dowel pins to tie the plate solidly to the base casting. If the bottom of the base casting is not machined flat, skim cut it before mounting to the plate. If you are not equipped to skim cut the base casting and the plate to flatness, an old trick is to make a shim out of soft copper. Some copper sheet as is used for roofing flashing (available in building supply and lumber yards, usually sold by the pound off a roll) will work fine for this shim. The soft copper will deform to take up for any irregularities in the two surfaces being clamped together.

The plate will give you better bearing contact with your workbench top. A downside to this repair is that it may not be as strong as the original ears (depending on how many and what size of capscrews and dowels are used to fasten the plate to the vise base). For a machinist vise used for normal bench work (filing, tapping, hand reaming, drilling with a hand-held drill, threading, hacksawing, light work with a hammer such as chipping or driving pins, etc) , this repair should be more than adequate. If you plan to use the vise for heavier work such as threading pipe or beating on steel to bend it, or driving out old bearings, this repair is not something I would want to rely upon. Plainly: machinist vises are for bench work done in a machine shop or mechanic's shop. Leg vises are for work done in a blacksmith shop and are made to take the pounding and loading put on a vise when doing bending, twisting, splitting, and similar smithing work. Two very different vises, two different classes of work.

Although written to be "puff pieces" fhttp://www.locknstitch.com/cast-iron-welding.htmlor Lock-N-Stitch, there is some damn good advice on welding cast iron here: Cast Iron Welding - Turlock, CA - LOCK-N-STITCH Inc.

John:

With all due respect to you, Lock-N-Stitch has presented a write-up biased against repair of broken cast iron parts by welding or brazing. They are in business to sell their Lock-N-Stitch services. The reality is for well over 110 years, a hell of a lot of cast iron parts have been repaired by either brazing or welding processes with success. Lock-N-Stitch is correct about the cooling stresses produced by the welding or brazing often resulting in cracking in the cast iron. However, they are partially, if not totally incorrect in their statement that welding with nickel alloy rods will produce a zone of cast iron surrounding the weld "harder than a drill bit". The reality is that nickel-alloy repair electrodes are formulated to prevent this from happening. The nickel and chromium in the electrode are there to prevent the formation of carbides in the weld zone. Admittedly, there are different alloys of "Ni Rod", some are machineable and some are not, as I noted in my post.

As I also noted in my post, the trick is to use a process for repairing brazing or welding of cast iron which has some ductility in the repair weld or braze. This absorbs the stresses set up when the welded or brazed repair cools. This stress is often further mitigated by peening the weld or braze as it is being run.

There are two schools of thought for cast iron welding: keep the heat to a minimum, vs. preheating and postheating to try to get a more uniform expansion and contraction thru the entire repair and surrounding iron. The size and shape of the job determines which approach is used, and this is often a matter of the experience and instincts of the weldor doing the repair.

Another reality is the brazing of cast iron for repairs has been used at least since some time before the first world war. It is a very forgiving process and mechanics in garages and repair shops have been brazing busted castings with a very high success rate. Plenty of old machine tools which were subject of discussion on this 'board have ancient brazed repairs to various castings which have held up for ages of use. Brazing is a process which is almost like a "fall back" or default if the cast iron does not "take weld". Another process which also has been around since some time before the first world war is the oxyacetylene welding of cast irons. This was used with great success to repair cast iron parts on interned ships during WWI damaged by sabotage. It was used by auto repair garages to repair cracked engine water jackets in the pre-glycol antifreeze days. Back then, wood alcohol was added to the water in auto cooling systems as an antifreeze. The alcohol used to evaporate off, and the reduced concentration often went un-noticed or unchecked by the motorists until they woke up to a cracked block. Countless engine blocks were repaired using oxyacetylene welding. Usually, the block casting was preheated in a charcoal fire or with gas burners, and kept covered with firebrick or asbestos. Only the area to be welded was uncovered, just long enough to run the weld. The block was then reheated and allowed to slow cool while fully covered in insulation or the remains of a dying charcoal fire.

I've never kept count of how many cast iron repair welding and brazing jobs I have done over the years. It is a LOT. All have held together. Case in point are the grates in my coal fired boiler which broke while rocking them to dislodge clinker (and a stray rock that had made it into the coal pile). I used Ni Rod, a mild preheat, and peening of the welds with the needle scaler. The repaired grates have held up just fine in service, and it is not gentle, what with rocking the grates to drop ashes and clinker and occasional jamming when a chunk of unburned coal gets between the grates. Another little example is a neighbor's cast iron skillet. The handle was broken off a black iron skillet which my neighbors liked to use. He asked if I could repair it. I vee'd out the break and brazed it with oxyacetylene, then slicked off the brazing so it was nearly flush with the handle and made a neat repair. It is a hefty skillet, and if that repair let go, either food would have landed where it did not need to be, or the skillet might have busted a few toes. It's been in service a few years now.

Another case in point is repair brazing done on steam engine and compressor pistons. Worn cast iron pistons are machined undersize, and built up with brazing. They are then remachined to fit the cylinders (which may have been re-bored) and new ring grooves cut. As a matter of fact, I was invited along for a short cruise on the Hudson River aboard a steam launch just yesterday. The engine in that launch is an old US Navy "K" series compound engine, built in 1900. The cylinders and pistons had become badly worn a couple of years back. My buddy, who is a partner in owning the launch, had the block rebored by a shop down in New Jersey. He then brought the pistons up to my shop. We turned them under by about 0.050" per side using a sharp pointed tool and coarse feed. This left a coarse surface finish. We then used a paste-type of flux and built up the pistons with oxyacetylene brazing. The coarse finish was my idea, knowing that brazing is not a welding process, and hoping for more of a mechanical interlock between the bronze and the iron. After the first pass, I took a cut on the brazing to be sure we had a good bond with the iron or semi-steel pistons. No porosities, nice solid bronze, so we laid on a few more passes. We let the pistons slow cool and then turned them to final diameter and cut the new ring grooves. Yesterday, we were out on the Hudson River in a stiff breeze with a bit of swells, and those pistons were doing their job in that engine.

I was first introduced to brazed repairs to cast iron by a garage mechanic who was a buddy of my father. Mom had broken a gas range burner grate, and a neighbor had busted some cast iron part of an old push type reel lawn mower. I was maybe 10 when I went with my father to have the parts repaired. My father's buddy had me get the "Boraxo" from the shop wash sink, put a pair of goggles on me, and told me to watch. He showed me how to light a torch and adjust the flame, and showed me brazing, making a point of showing me how the braze metal had to "wet" the cast iron. It was a quick job, and both parts went back into service. We never had any pots dropping onto the range burner with that repaired grate, and as far as I know, the neighbor cut her grass with the repaired part in her push mower.

Truth to tell, no one gave a second thought to brazing of cast iron being a process more prone to failure than not, as Lock-N-Stitch would have us believe.

Plainly, some instincts for welding and brazing are required to make a good repair on cast iron. It is not a total black art, nor is there any real mystery or secret to it. Plenty of people have been welding and brazing cast iron for ages.

Joe Michaels said:

What I've wanted to try is the oxyacetylene welding of cast iron. Years ago, cast iron rods having a square cross section were sold in welding supply houses along with a flux for O/A welding of cast iron. In the right hands, oxyacetylene welding of cast iron produced a very sound weld which was homogeneous or nearly-so with the cast iron part being welded. Plenty of engine blocks and large machinery castings were repaired by this process.

Click to expand...

It’s hot as hell! For structural welds like that base after welding you’d need to put in a furnace running at 1600°F, let it soak to oven color & shut the furnace down. So it’s an overnight affair.

Manifolds, tranny cases, (eroded) pump impellers you can get away just real slow cool down from weld. Fixing a flowerpot below with some Kastweld 111.


Good luck,
Matt

Matt:

Thanks for posting the youtube of your O/A cast iron welding. You are correct, in your "hot as hell" note. As I posted, the oldtimers would preheat an engine block or similar in a charcoal fire or with large gas burners, get it to somewhere near a dull red heat, and cover with firebrick or asbestos insulation before welding. Only the immediate area to be welded was uncovered. Once welding was completed, the job was re-heated to that same dull red color, then left to slow cool covered in insulating material.

When I did the vise base repair, it was for another fellow. In rethinking that job, which was a few years back, the fellow was out in Iowa and the vise may have been a Prentiss (not that it matters). I guess I am getting older and having a "senior moment" as the time was I could recall every job or engineering job I ever did, and where every tool or chunk of scrap I had around the shop came from.

It was cold weather, so I had the advantage of having my coal fired home heating boiler firing. When this boiler is on the line, it has a nice deep bed of burning anthracite coal. Once the house is up to heat, the forced draft blower usually does not run, and the boiler simmers along on natural draft. This gives an ideal bed of burning coal to stress relieve or anneal work in. The firedoor is surprising large (I wing a smaller coal shovel into it when firing coal. I did the repair welding on the vise base outdoors, maintaining some kind of preheat and interpass heat with the rosebud. I was also peening each section of weld as I went along, using the air needle scaler. While Ni Rod is ductile, I've had enough experience with it to know that post-weld cracking is quite possible. Peening stretches the actual weld metal to counter the contraction from cooling of the weld and will somewhat neutralize the tension set up in the weld zone. As soon as I was done welding, I rushed the job down the basement and put it into the coal bed in the firebox. I hoed some of the burning coal over it so no colder draft would get to it. I kept peeking in the firedoor and moving the coal off the job with a poker just enough to check its color. When it reached a dull red, I kept an eye on the job and the time, as the boiler firebox can get work hot enough to burn it or melt it. After about 20-30 minutes of soaking in the firebox, I pulled the ashes from the ashpan of the boiler, so those were nice and hot. I dumped the ashes in the ash barrel, then put the job into the hot ashes (which has a few glowing coals in amongst them), and covered it with more ashes and put a steel plate over the top of the ash barrel. I left the job cool in the ashes overnight.

I use this method for post-weld stress relieving on Ni Rod repair welds on anything halfway thick or heavy, if it will fit through the firedoor of the boiler.
Not scientific or precise, but it does work.

At the powerplant, we had a large and complex cast iron housing/hydraulic oil reservoir from a Woodward Governor. It had developed a crack and oil was seeping out through that crack. The casting was unobtainium for all practical purposes. One of the mechanics who was a very experienced welder with a lot of insight for the work volunteered to try repairing it. He stop drilled the crack, and vee'd it out with a die grinder and carbide burrs. As crazy as it sounds, he beat the flux off some Ni Rod we had in the weld shop, cleaned the rod further on a wire wheel, and used it as TIG rod. His idea was to put as little heat as possible into the casting, since it was a very large and thick casting. It made sense, since the surrounding iron would be almost an infinite heat sink and would pull heat frm the weld zone and cause cracking if things got too hot. The weld was run a little at a time, with peening, and stopping to let the work cool. At no point did the heat from the weld ever get too far into the surrounding casting. We used "Tempilsticks" and our hands to check temperature on the casting. As I recall, the welder worked a little each day on that job, never working too long to avoid getting too much heat built up locally in the casting. The result was a sound repair. Dye penetrant showed no cracking. An air test showed no leakage. The part went back into service on one of the Woodward governors on the big hydro turbines.

That repair is the other extreme in the thinking for cast iron repair welding. Either you get the job so hot that it expands and contracts uniformly (as you were doing in the flower pot repair and as I did in the vise base repair), or you minimize the heat put into the work (as the repair to the governor casting was done). I call it "having a sense for the work", or "Getting inside the metal and finding out what it wants to do".

Personally I have little experience compared to many of you welding cast iron. The little I have done has worked out but I don't like doing it out of fear based on all the horror stories of cast welds cracking. The only thing I can say that I found is the quality of the casting makes a world of difference. One locomotive I worked on which ran up into the early 1990s had been ordered from Montreal Locomotive Works using cast iron where ever possible instead of cast steel. Someone has the original paper work on the order. Even though this was built in 1912 I think. Down to most of the smaller castings were cast iron. By this time most locomotive castings were cast steel from my memories working on other locos anyway. This loco I mention had the worse possible quality castings ever. She is a 50 ton 4-6-0. When we had her drivers off we sandblasted the wheels looking for cracks before sending them to be machined and have new tires put on. We found numerous small surface crack in the spokes and a larger deep crack in main driver hub. I v'd out the spokes and hub before welding. The comments about "heat sink" is understood by me. While I did weld up the spoke cracks I think they were nothing more than surface cracks and not structural defects. But I was not leading that parade and did what I was instructed to do. Back to casting quality. Would be laying in a bead and hit a sand pocket and poof the world went wonky. That happened all the time when building up or repairing castings on this engine. Other repairs it is almost like welding steel. I repaired a couple of handles on a camel back drill press with E6013 was what I had handy. Was shocked but it worked and like the locomotive it was almost pig iron. Another part on same drill press did not weld up good and needed to have brazed. If I knew how to braze I would of gone that route. Those poor castings on the locomotive welded up good. We tested with dye penetrate and the company that did the wheel work checked them too and said job was good. 16 years later this engine sits in pcs do to not so funny comedy of errors. I will leave cast repairs to you guys. Have done it and can do it, but I am ready to drink heavily by the time I am done. I really stress about it, foolishly. Side note on Canadian 4-6-0. She was built for switching coal mines and collieries in Manitoba moving cars to be switched onto the mains serving these mines. Never had been rebuilt and was so worn out it is beyond belief. But it ran and ran and ran good for many years on a tourist RR. It only went a mile or two per trip during its mining career. It was broke in well. Running 4 miles one way pulling two or three passenger cars was really stepping out for this old gal.

A few years ago was helping on a locomotive where we installed a new axle on main drivers by interference fit. Unrelated to cast welding but to over come the heat sink factor we took the two wheels with the tires on and put them in a heat treating oven and heated them up to maybe 250 degrees but after being in the ovens over night they were evenly heated. With the axles in liquid nitrogen the went together like butter. They are not coming a part anytime soon. But I mention this as it would of been an approach to heating up the hub on that other locomotive mentioned. That would of required a bigger oven as that wheel set was whole but could of been heated evenly the same way and allowed to cool slowly in a much easier to control environment.

Regards, John.

Personally I have little experience compared to many of you welding cast iron. The little I have done has worked out but I don't like doing it out of fear based on all the horror stories of cast welds cracking. The only thing I can say that I found is the quality of the casting makes a world of difference. One locomotive I worked on which ran up into the early 1990s had been ordered from Montreal Locomotive Works using cast iron where ever possible instead of cast steel. Someone has the original paper work on the order. Even though this was built in 1912 I think. Down to most of the smaller castings were cast iron. By this time most locomotive castings were cast steel from my memories working on other locos anyway. This loco I mention had the worse possible quality castings ever. She is a 50 ton 4-6-0. When we had her drivers off we sandblasted the wheels looking for cracks before sending them to be machined and have new tires put on. We found numerous small surface crack in the spokes and a larger deep crack in main driver hub. I v'd out the spokes and hub before welding. The comments about "heat sink" is understood by me. While I did weld up the spoke cracks I think they were nothing more than surface cracks and not structural defects. But I was not leading that parade and did what I was instructed to do. Back to casting quality. Would be laying in a bead and hit a sand pocket and poof the world went wonky. That happened all the time when building up or repairing castings on this engine. Other repairs it is almost like welding steel. I repaired a couple of handles on a camel back drill press with E6013 was what I had handy. Was shocked but it worked and like the locomotive it was almost pig iron. Another part on same drill press did not weld up good and needed to have brazed. If I knew how to braze I would of gone that route. Those poor castings on the locomotive welded up good. We tested with dye penetrate and the company that did the wheel work checked them too and said job was good. 16 years later this engine sits in pcs do to not so funny comedy of errors. I will leave cast repairs to you guys. Have done it and can do it, but I am ready to drink heavily by the time I am done. I really stress about it, foolishly. Side note on Canadian 4-6-0. She was built for switching coal mines and collieries in Manitoba moving cars to be switched onto the mains serving these mines. Never had been rebuilt and was so worn out it is beyond belief. But it ran and ran and ran good for many years on a tourist RR. It only went a mile or two per trip during its mining career. It was broke in well. Running 4 miles one way pulling two or three passenger cars was really stepping out for this old gal.

A few years ago was helping on a locomotive where we installed a new axle on main drivers by interference fit. Unrelated to cast welding but to over come the heat sink factor we took the two wheels with the tires on and put them in a heat treating oven and heated them up to maybe 250 degrees but after being in the ovens over night they were evenly heated. With the axles in liquid nitrogen the went together like butter. They are not coming a part anytime soon. But I mention this as it would of been an approach to heating up the hub on that other locomotive mentioned. That would of required a bigger oven as that wheel set was whole but could of been heated evenly the same way and allowed to cool slowly in a much easier to control environment.

Regards, John.

I, too have done quite a bit of cast iron welding over the years.

Exhaust manifolds and grate bars IME are the worst to weld. Manifolds tend to be thin and large, and both often act barely metallic. I guess that oxygen penetrates along the graphite flakes of hot cast iron, and a casting with enough "thermal history" is as much iron oxide as iron. The only way I have managed to weld some of these has been oxyacetylene, with flux, where there is no limit to how much you can "puddle".

Brazing, or "braze-welding" as it is sometimes called to distinguish it from capillary brazing of well-fitted parts also works well, and if done well will make a joint stronger than the parent iron. In my experience, a fresh break in cast iron cannot be brazed, and I suppose this is because CI usually breaks through the graphite flakes, thus the fracture surface is largely non-metallic. I vee the break out, as if for fusion welding, before brazing. If the iron properly "tins" or is wetted by the bronze, I see no need for mechanical interlock. The actual interface between the braze and the iron is a diffusion zone, and as strong as the metal. Nor do I use embedded pins or studs within a CI braze or weld job. IMO, all these do is reduce the loadbearing cross-section.

Usually these days I prefer to use E-NiFE55 SMAW (stick electrode) rod, DCRP. On good quality iron it is the quickest method and gives very good results. I weld 1/2" - 2" or so, depending on the weight , complexity, and temperature of the job, and peen vigorously while the bead is still hot, and skip around, as Joe M. describes.. Cheaper than 99% Ni, and I do not see how composition of the welding rod can affect hardness/machinability of the HAZ of the parent iron. Only slow cooling can do that.

I always use pre-heat, maintained through the process, and very slow cool.. Several reasons. First it removes moisture and oil. Second it minimizes thermal gradients, thus thermal stress, and cracking. Third, it anneals everything (if hot enough), which provides all the ductility the materials are capable of. Fourth, it slows the cooling, minimizing "quench" and formation of hard martensite and cementite, which reduces brittleness, reduces cracking tendency, and promotes machinability.

A manifold or cylinder-head I will pre-heat and weld in a furnace---which may be merely a charcoal or wood fire enclosed with random sheet metal. Yes, one gets pretty well cooked, reaching in through the smallest possible holes in the furnace, to weld and turn the casting. Often I clamp the prepared casting to appropriate steel "strongbacks", whether angle irons or plates, to maintain alignment as I weld and turn the workpiece over to weld from all sides. Everything heats and cools together.

A small, simple part not likely to suffer from thermal stress I will preheat only locally with a torch, to prevent quenching.

I welded water-jacket cracks on a Cummins 855 engine, in the truck, a few years ago, so of course I could not preheat into the red, but I used a big soft propane flame to get the whole side of the engine up to 300-400 deg F. Even such preheat, well below transformation temperature, acts as an austemper for the HAZ and provides significantly increased ductility.

A customer misused the 3-point hitch on a small John Deere and pulled the lugs right out of the rear-axle housing. Again, only mild local pre-heat was practical, some of the nicest cast iron I have ever welded.

Repaired a backhoe outrigger once, presumably Austempered Ductile Iron, that twisted through 45 degrees before it cracked most of the way through its U-section. After veeing-out the cracks, I clamped one end to my large I-beam workbench, supported the other end on a jack-stand and and clamped a 6-foot lever with anvil hanging on the end. to the other. Built sheet-metal and glass-blanket furnace around it. Lots of propane. As it heated, over several hours the twist sagged out of it. I removed the anvil when it was straight, and welded it up. Who says "creep" is always a bad thing?

I once made the mistake of offerring to repair a cracked cast-iron sectional domestic heating boiler. IIRC four of the sections were cracked, not one as I had thought. I chased cracks for hours, and even after getting them all, I had to fill it with salt water overnight to rust the pinholes shut...but it went back into service successfully.

Joe M.'s suggestion of steel reinforcement is a good one. Oliver crawler final drive (bull gear) housing split when a roller went AWOL from roller bearing and passed through gear mesh. After welding it back together, I made a hoop of 1/4" x 1 1/2 flat iron. a little too small to go around the rim of the housing, heated it up to a forging heat and drove it over the housing. Housing will never again see tensile stress.

Yes, cast iron can be welded as good as new...But if it broke in the first place, sometimes that means it was not strong enough when it was new.