I recently bought a used cross-slide vise on craigslist for $35.

It is a machinist’s vise mounted on two ways at right angles, with leadscrews controlling the vise’s movement along each way. It’s meant to be used on a drill press so holes can be located in the same manner as in a vertical milling machine. The vise is also useful since it allows the piece to be moved under the spindle without loosening and re-clamping it as in a normal machine vise.

The vise was originally bought at Harbor Freight, a store known for affordable but low-quality tools. (I hope that didn’t make me seem entitled… the fact is that while Harbor Freight is great for rarely-used tools, high-quality tools justify their expense in time saved and greater reliability if used frequentlyds.) The previous owner had attached an aluminium soft jaw to the fixed jaw, and the vise was in good condition though the ways were very stiff on account of the machine oil having oxidized and “gummed up”, making it harder to move rather than easier. I took it apart to clean and re-oil it.

How It’s Constructed

The vise is constructed similar to a vertical milling machine. The ways (linear slides) use dovetail slides: a trapezoidal projection on the rail (the “tail”) fits into a trapezoidal cutout on the slide (the “tail socket”). To allow the fit to be adjusted, there is a small shim (“gib”) inserted between the tail and socket that can be pushed inward from the socket by means of two screws. Also, a thumbscrew allows the gib to be pushed in even more to lock up the tail and socket from moving.

There are four main cast-iron pieces. The bottom one bolts to the drill press table and holds the y-axis tail. The middle piece holds the y-axis and x-axis tail sockets. The top piece contains the x-axis tail and the vise body. The fourth piece is the movable vise jaw.

Leadscrews control both axis’ movement and are attached to the top and bottom pieces. Each is inserted through a hole on a steel plate (which kind of acts like a pillow block) and held in place with a graduated set-screw collar. Interestingly, you can vary the backlash in the mounting by sliding the collar in and out, which may be useful for allowing the piece to shift slightly and center itself with the drill (when drilling to a center-punch mark).

Both leadscrew nuts are located on the middle casting; the x-axis nut is cast in, while the y-nut is a press-fit insert.

The vise works like any other machine vise. It has a fixed jaw and a movable jaw. The movable jaw rests on the flat parts of the vise body and also rides along a cylindrical rod. A screw is used to close the movable jaw; one end has a handle and the other goes into a hole in the movable jaw. It is prevented from coming out by a set screw which engages a slot on the vise screw.

Disassembly and Re-Assembly

Unlike many consumer appliances, disassembly was quite straightforward, so I’m not going to record exact instructions. I did take a lot of pictures to remember how to put it back together, though.

After completely disassembly, I scrubbed everything but the fasteners and leadscrew handles in soapy water with a sponge, toothbrush, and pipe brushes. Then they were dried with a cloth and left out for a few minutes. If you do this, be sure not to cut yourself on the sharp dovetails.

Reassembly was just as easy as disassembly, except for adjusting the gibs. After a lot of trial-and-error, I settled on this method:

• To eliminate poor leadscrew alignment as a source of friction, loosen the mounting plate bolts, then move the nut as close to the mounting plate as possible, and then tighten the nuts.
• Oil the dovetails
  • I used motor oil, which is supposed to be an okay substitute for machine oil.
• Tighten the gib screws incrementally until all perceptible play in the ways are eliminated along their entire travel (there may be more play near the ends of travel since less of the dovetails are in contact), but not so much that movement is too difficult. (Exactly how difficult is “too difficult” is for you to judge.) It is usual for the ways to be stiffer near the ends of their travel since those parts accumulate less wear.
  • I tightened the gib screws so the ways slid almost effortlessly in the middle of their travel, but rather stiffly towards the end. My wishful thinking is that this will cause the ends to wear more than the middle if the ways are “exercised” regularly, which will eventually balance things out.
  • If there is paint on the dovetails, scraping it off doesn’t do anything.
• While holding the gib screws in place, tighten the locking nut.

Pictures

Orthographic Views