Center Finding Level & Punch

A center-finding level and punch lets you hold round stock o the drill-press table, find the exact top of the stock, and center punch it so you can drill a hole through the exact centerline of the shaft.

What you'll need:

  • Keystock, 1” x 1” x 3” long*

  • Adjustable angle plate (#37-005) or good vise

  • Transfer punch, 5/16”

  • Drillbits: 1/16”, 19/64”, 23/64” (#71-010)

  • Reamers: 5/16”, 3/8”

  • Dial indicator (#19-006)

  • Stanley plastic level replacement vial**

  • Ball end mill, 1/2”

  • Small, round needle file

  • Two pieces of wood, at least ¾” x 1 ½” x 8”

  • Five-minute epoxy***

  • Talcum powder***

  • Center punch

* Regular square stock will work also. To use it, square the stock first on the mill or lathe (see Machine Tool Technology, pp 316-317). In the lathe, mount the stock in a four-jaw chuck and face one end with a turning tool. Then turn the stockand do the other end.

** Available at a good hardware store or lumber yard.

*** You can use JB Weld or metal filler in place of the epoxy and talcum powder.

Step 1: Miling the V-groove. Clamp the keystock on the angle plate or mill vise at a 45° angle (Fig. 1). Mill a V-groove so the right angle is approximately 3/4” from the end. The hypotenuse (open portion) of the groove should be about 7/16” wide. Remove the keystock from the angle plate or vise.


Figure 1.A & Figure 1.B

Step 2: Drilling a hole for the transfer punch. It's common to want a setscrew close to the plate portion of the sprocket or near the body of a pulley, so it is an advantage to offset the transfer punch.If you are right-handed, it's easier to hold the tool in your left hand and the hammer in your right.

Figure 2

With the tool's short end toward you, make a deep center punch in the bottom of the groove 5/16” from the left end of the groove. ( Left-handed machinists – make the punch 5/16”from the right end of the groove.) Put the workpiece in the vise and drill a 1/16” pilot hole all the way through it (Fig. 2). Turn the workpiece over and enlarge the hole to 19/64”. Then ream it to 5/16” for the transfer punch (Fig. 3).


Figure 3

Step 3: Drilling the level vial hole. Mount the workpiece in a four-jaw lathe chuck, align it with a dial indicator (Fig. 4), and drill a hole 1 3/4” deep with a 23/64” drill. Start the hole with a center bit to keep it from drifting off. Ream the hole to 3/8” and remove the workpiece from the chuck. The vial should fir into the 3/8” hole with 1/8” above the top of the vial to protect it from hammer strikes. The hole center should be 5/16” from the top surface.

Figure 4

Step 4: Cutting the sight hole. Put the workpiece back in the vise (Fig. 5). With the 1/2” ball end mill, cut a sight hole 0.325” from the end and 1.35” long using the main leadscrew for the feed.

Use the wood for a mill stop between the carriage and tailstock. Move and lock the tailstock to set the left end of the cut for the sight hole. Cut another piece of wood to go between the carriage and headstock. It should let the carriage move 7/8”.

Figure 5

Cut the sight hole until the opening in the hole for the level is about 1/4” wide. The 3/8” reamer will help clean up the sight hole, but you'll need the needle file to get rid of the sharp edges. Shorten the transfer punch to 2” and chamfer the cut edge with a file or grinder.

If you use the epoxy and talcum powder, combine them until the mixture resembles cream cheese. Plug the hole around the vial with the epoxy mixture, JB Weld, or metal filler and your project is completed (Fig. 6).

Step 5: How to use the transfer punch. Try not to flinch when you use the transfer punch. If you do, the end of the punch won't move as far. Also, don't strike the punch more than once; you may break the small, sharp point if it isn't lined up perfectly with the first mark. When the point is marked, enlarge it with the regular center punch.

Figure 6

There are one more trick. When you put a setscrew into a workpiece with a keyway, put the keystock in the keyway (short on one end) and let it rest on the vise jaws. Then tighten the vise. The vise will hold the work square, and the drillbit will cut the keystock about the right length. Dress the ends on the belt sander, and you have the key. You may encounter one or several problems with this project. First, drill press tables are seldom exactly level. Second, your level may be off slightly. Both problems are easy to correct by checking the drill table with the level punch and noting the error. With the level punch in the same direction, set the level bubble to show the same degree of error.


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