![]() Locks are intended to be stacked or laminated to a depth of 80% of the thickness of the material being repaired with a hammer. Lock can be installed to add strength across cracks. Because these pins seal on the threads, it is possible to install them at steep angles to the surface. All LOCK-N-STITCH ® pins are designed to be installed up to the shoulder so the head can twist off while leaving a small amount above the surface to grind or machine off. The steel pins are made of a soft machinable steel that has the same expansion rate as cast iron with about the same hardness and corrosion resistance. Our L Series pins consist of three different diameters, several different thread length, and are made of either steel or aluminum. Remember, L Series pins create spreading pressure. If the casting doesn't have enough structural strength to contain the spreading pressure, extension of the crack can occur. This results in spreading pressure on the crack. The most important thing to remember about the L Series pins that when tightened into the casting they seal on the threads because the pin is bigger than the tapped hole. Special designed Full - Torque ® thread inserts can be used to repair a stripped or cracked bolt hole permanently. Special designed pins create a drawing force pulling the cracked parent metal contrary to the spreading force created by conventional thread.Īdditionally, high tensile strength locks are used where additional structural strength is needed.īy installing pins and locks, the repaired part can be stronger than original and perfect sealing is also guaranteed. Metal Stitching is a technology to repair damaged or cracked metals using special designed pins and locks without welding. Hardening will also make machining, drilling and tapping difficult if not impossible. In cast iron, hardening results in brittleness and the loss of good properties such as vibration dampening and ductility. Rapid cooling of high carbon iron and steels will cause hardening. However, it is responsible for the lack of difference between yield and tensile strengths.Īnd hardening is caused by the weld or Heat Affected Zone cooling too fast. The high carbon content gives cast iron many of its desirable characteristics like free machinability, uniform heat transfer, excellent wear surface and high quality casting capability. This often requires re-machining of critical surfaces. This is why cast iron must be preheated over 482ЃЋ in order to relieve stress.Īt 649ЃЋ cast iron can stretch to relieve stress under strict oven welding procedures.Īll welds properly performed on cast iron result in some distortion. ![]() Peen each 1 inch weld with this method too.INTRODUCTION/ Renovation for crack repair: LOCK-N-STITCH ®īecause yield and tensile point of cast iron are the same, it cannot bend or stretch to absorb stress caused by thermal expansion and contraction. Never allow the metal to get so hot that you can't place your hand on it. ![]() Once a good weld deposit is made, the two sides of the crack can be welded together. Using the methods discussed above, weld the studs in place and cover the entire surface of the break with weld deposit. This type of pin can actually hold a crack together rather than just fill it, and may be used to repair cracks that cant be fixed with ordinary tapered or straight pins. "Castmaster" pins (manufactured by Lock-N-Stitch) have a unique "spiral hook" or "reverse pitch" thread pattern that grips both sides of a crack when the top shoulder of the pin bottoms against the metal. Screw steel studs into the threaded holes, leaving 3/16 to ¼ of the stud above the surface. ![]() After welding allow the block to cool slowly be insulating it.Īnother choice is to not preheat it at all.ĭrill and tap holes over the surfaces that have been beveled to receive the repair weld metal. V- groove the crack and Weld in 1 inch long segments and peen the weld after each bead. Aim for 1200 degrees.īut never, I repeat never over 1400 degrees since its effects the characteristics of cast iron at that temp. Hard to preheat a block being its so damn big and acts like a heatsink constantly sucking the heat away from the effected area.Įither preheat between.500-1200 degrees. Never heard of using stainless on cast iron although I'm not saying its not a choice.
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