A Trip to the Socket Factory

The new SK plant in Sycamore, Illinois is only a couple of years old. The 100,000 square foot building has a showroom and offices in front and a factory in back—where ratchets are assembled, and sockets, extensions, and adapters are manufactured.

The machines in this photo turn steel into sockets, not by machining or drilling, but by pressing the metal with a series of dies that form it to the shape of a socket. It takes a tremendous amount of force to do this.

The material for sockets arrives at the plant as coiled steel. Here it is being fed into a machine that will straighten it and then cut it into short slugs or billets.

Steel billets are fed into a machine that through a series of punching operations will turn them into sockets. Click here to see video of the machine in action.

This is the machine from the previous photo with the door open so you can see more of the mechanism. Billets feed in from above and are held in fixtures while dies push in from the right. After each pressing operation the spring-loaded jaws on the left grab the pieces and move them down to the fixture below for the next operation. At the end of this process the roughly formed sockets fall onto a conveyor below.

This is what 12 point sockets look like at various stages of forming. It’s important to note that no metal is removed during these particular processes; the change in shape (and length) is due entirely to the displacement of metal. From left to right the pieces are: billet as it enters the machine, after pressing from both ends, after the openings for nuts and bolts have been formed, after the socket is punched deeper, and after the square hole for the ratchet drive has been formed at the opposite end. The shiny piece on the right has been punched and then lightly machined, so it contains slightly less material than the pieces to the left of it.

These sockets have been formed to shape and their exteriors lightly machined. If you look closely you’ll see that openings don’t go all the way through. The center will be drilled out in a later operation.

Sockets are being fed into a computer-controlled machine that will smooth sharp edges and slightly chamfer the openings. The chamfer makes it easier to fit the stem of the ratchet into the socket and the end of the socket over a bolt.

The file-like rod on the right is a broaching tool. It fits inside of a machine that pushes it through the center of the socket to size and finish (smooth) the square hole for the ratchet drive.

These 6 point sockets are at an intermediate point of processing. When the machining is complete they will be sent out for hardening and plating, and then returned to the plant for packaging and shipping.

To distinguish them from standard sockets, impact sockets receive a rust resistant coating but are not chrome plated. They have thicker walls and are made from a more ductile material to prevent them from shattering when subject to the action of an impact wrench.

Unfinished parts are stored in surplus army ammo boxes. These boxes came from the old SK plant in Chicago and were brought to the new plant in Sycamore. I’ve seen ammo boxes used in more than one factory—probably because they are cheap, durable, and easy to get.

The retention bearing on the stem of this drive adapter has been placed over a spring in a hole. A press fitting tool will be used to push the bearing into the piece and deform the edges of the hole so it won’t fall out. The spring-loaded bearing will then be used to hold sockets in place on the adapter.

Ratchets are assembled at the Sycamore plant with parts produced in other factories. Click here for a video of ratchets going together.

Finished pieces are stored in bins until they are needed—to be packaged separately or in blow-molded kit cases with ratchets and additional sockets and accessories.

This is the shipping area. I wish I’d been able to shoot video of it in operation because the mechanism is kind of cool. It works like the clothes storage rack at a dry cleaner: When the operator needs a particular item he calls it up on a terminal, the rack rotates, and that item moves to the front where it’s easy to get at. The operator can then package the item and ship it out.

When SK built the new factory it left room for expansion; this area is empty now but will likely someday be filled with machines. The plant currently contains a mix of old (from the Chicago factory) and new equipment (purchased after the move to Sycamore).

A Big Tool—the wrench, not the guy in the photo. This oversize wrench bears the SK label but was likely produced by sister-company Western Forge, at its plant in Colorado. Wrenches and sockets this size and larger are typically used in the oils and gas industry at wells, pipelines, refineries, and the like.

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