The only thing handier than being a machinist that knows how to weld, is being a machinist that knows how to weld and has a few welding tricks up his sleeve. Here are a few tricks that I have come across over the years:

1) Filling holes - Many times when we are welding, we will have to fill holes or lay down hot iron on a part where there ain't no iron (thin air). This situation can be due to poor fit up, worn out parts or an error in processing. Lets say someone drilled a 3/4" diameter hole in a piece of 1/8" thick hot rolled steel. A closer look at the drawing reveals that the hole actually should have been 3/8" diameter or maybe in a different location. Here is the simplest fix that I know of. Clamp a piece of aluminum beneath or behind the hole to be filled. The alumunium should be substantially larger in diamter than the hole. The aluminum serves two purposes: as a back up strip and it will act as a heat sink. Once you have the alumunium clamped in place, simply begin welding on the steel and lay a weld bead down on the aluminum and fill the hole. Unclamp the aluminum back up strip, let it cool for a minute, then knock the aluminum strip off with a hammer. You may notice minute pieces of aluminum imbedded on the opposite side of the weld bead. Simply grind the back side of the bead smooth and weld on top of it if needed. This welding trick can be done with a MIG welder(wire feed) or a stick welder. It can be done in a flat position or horizontal (down).

As a side note, many years ago I worked machine maintenance in a large foundry. We had a shaker table that sheared a 1" key on the input side of its eccentric shaft and in the process destroyed the keyway. The repair was not going to be easy. The shaft needed to be removed and a new keyway cut in the shaft. The machine weighed 20,000 lbs and needed to be just about totally disassembled. I used this welding helpful hint to repair the shaft without taking the machine apart. I found a piece of 1" thick aluminum and clamped it into the remnants of the keyway and filled the rounded off portions of the keyway with a stick welder. I waited for the aluminum to cool and then knocked it out of the keyway. A little touch up work with an angle grinder and a mill file and we were back in business in less than two hours.

2) Broken Bolts - the next time you break the head off of a bolt and you can't remove the remainder of the bolt from the part, try this little trick. If the shank or grip of the bolt is above the top of the part it is stuck in, place a hex nut over the broke bolt. Begin welding on top of the broken bolt filling up the inside diameter of the nut, making sure that you get good penetration on the top of the bolt shank. Let the bolt cool completely before removing it. The heating and cooling of the welding process should help loosen the bolt making its removal much easier. Joe Polaski who bought a Mini-Tram at Cabin Fever Expo in January gave me this helpful hint. Many thanks - Joe.

By the way, I just received my Home Shop Machinist magazine for March/April 2004 and they have an excellent indepth article on this procedure. Awesome Fixture Table

When it comes to fab work, nothing is nicer than a store bought welding fixture table. Some look like they were made in blacksmith shops, others look like they were made in aero space machine shops, none are cheap. However, here is one that you can build on a budget and works better than most. My good friend, Mike Butcher, at MPB Alumafab came up with this idea and it works great. Take a look at the pictures below. The first picture shows the top of the table which is 1/2" hot rolled steel plate with a grid pattern of 5/8" diameter holes drilled thru. The second photo shows an 11SP Vise Grip that has had the lower jaw cut off and both halves are welded to a 5/8" diameter x 12" long grade 8 bolt. The third photo shows these tools in action. To use this fixture system, the lower jaw (without the clamping lever) is hammered down onto fixture rails and are kept there until the job is done. The upper jaw with the clamping lever is used for clamping and unclamping parts in the fixture. These upper jaws are easy to unclamp and pivot out of the way. To remove the lower jaws (fixture clamps), simply smack them on the bottom of the bolt from the underside of the table. This is a great fixture table that is cheap and easy to build.