In my last several columns, I wrote about selecting the parts of a tool string for a cable-tool or spudder operation. We selected a drill bit, drill stem, perhaps drilling jars, and a then wire-line socket. We chose a drill rig of proper capacity equipped with a drill line, sand line and (hopefully) casing lines — all also of proper capacity. We are ready to go drilling, right? Well, not quite. We still have a few more tools to procure for our cable-tool operation.
The first thing we need is a set of tool wrenches. The tools I mentioned in paragraph one are held together by tool joints. These tapered joints come in assorted sizes, all of which have a shoulder at their major diameter. Generally, manufacturers standardize these joints to dimensions defined by the American Petroleum Institute — hence the name API joints. This ensures tools from one manufacturer work for those of another. At one time, apparently, manufacturers each had their own designs and dimensions for joints. I have known at least one driller (and a good one at that) who used non-standard joints on his smaller-diameter tools. Most drillers, however, use the API standards. For spudders, these sizes vary from a joint with a 1.75-inch major diameter used in 3-inch wells, up to a joint with a 5-inch major diameter for larger holes. That appears to be the largest joint you can buy tools for. I know of two larger API joints, but catalogs do not list tools with these sizes.