Category: Other projects

Egg cup

Builder: Klaus Zenkert

Creation time of the model: approx. 1.5 hours

A green, boiled egg in a silver egg cup on a wooden surface.

The project

An egg cup was turned from a piece of VA steel (1.4301) on the PM5000 lathe.

Material / tool used

VA steel (1.4301)
Lathe PM5000
Right-hand turning tool
Drill chuck
Centre drill (3 mm)
Drill bit (12 mm)
Drill bit (20 mm)
Drill rod (8 mm)
Cut-off steel (3 mm)
Turning steel for chamfering

Step 1

Make a sketch

A sketch was first created for the desired dimensions of the egg cup.

Technical drawing of an egg cup on chequered paper. Dimensions and angles are noted. Lines are continuous and dashed.

Step 2

Machining VA steel

The VA steel (outer diameter = 48 mm & length = 100 mm) was then machined by facing with a right-hand turning tool.

A lathe with a cylindrical workpiece clamped in a chuck. A turning tool is positioned nearby. Metal chips are visible.

Step 3

Set the centring

In order to be able to drill a hole, a centring was first placed in the workpiece using the centring drill (3 mm).

Close-up of a lathe with a cylindrical workpiece in a chuck being machined by a drill. Metal chips are visible.

Step 4

Drill the hole

In the next steps, a hole 33 mm deep was pre-drilled into the workpiece using a drill with a diameter of 12 mm. The hole was then enlarged to a depth of 30 mm using a larger drill (20 mm diameter).

A lathe with a cylindrical piece of metal in the chuck. A drill bores into the end of the cylinder while a blue coolant nozzle supplies coolant.

Lathe drills a cylindrical workpiece, coolant is supplied. Metal chips are lying around.

Step 5

Turn out the inner taper

To be able to unscrew the inner taper, the top slide was first turned clockwise to 30°. The inner taper was then turned out to the outer diameter of 41 mm using a boring bar (8 mm). The last chip was then turned out with an infeed of approx. 0.3 mm and a slow, even feed rate so that the surface of the inner taper was nice and clean.

A lathe with workpiece in the spindle. The top slide is adjusted by about 30 degrees. Coolant supply is also visible.

Metal tube with internal taper in lathe. Metal chips lying around tool. Mechanical engineering environment with silver surfaces.

Step 6

Grooving

After setting the top slide to 0°, a grooving tool (3 mm) was used to groove a length of 38 mm and the diameter of the workpiece was reduced to 23.5 mm. The groove was then widened to a width of 4 mm.

Metal workpiece is being machined in a lathe, chips are flying. The workpiece is cylindrical and has concentric rings. Tool holder in the foreground.

Step 7

Bring the workpiece to the correct outer diameter

The workpiece was then turned to the outside diameter of 47 mm.

A lathe is machining a cylindrical workpiece. Metal chips are lying around and a coolant nozzle is directed at the workpiece.

Step 8

Turn the outer taper

For the outer cone, the top slide was set to 30° in a clockwise direction. The outer taper was then turned to a diameter of 23 mm using a right-hand turning tool. To make the surface of the outer taper nice and clean and even, the last chip was turned with an infeed of approx. 0.3 mm and a slow, even feed.

Metal part being machined in a lathe. Chips are lying around, red handle of an adjusting device is visible. The focus is on the machining process.

Step 9

Machining the outer diameter of the base

The outer diameter of the egg cup base was turned to 40 mm.

A lathe machines a cylindrical piece of metal. Metal chips lie around the workpiece and the machine.

Step 10

Chamfering

The front edge of the egg cup was chamfered with a turning tool (1 mm x 45°). The 45° bevel for the base of the egg cup was then pre-turned.

Metalworking: A metal, funnel-shaped object is machined in a lathe. Metal chips are lying around the machine.

Step 11

Turn the outer cone for the egg cup base

For the outer cone of the egg cup base, the top slide was set anti-clockwise to 45°. Next, the outer cone was turned with a right-hand turning tool. To ensure that the surface of the outer cone was nice and clean, the last chip was turned with an infeed of approx. 0.3 mm and a slow, even feed rate.

For a better surface finish, the surfaces were then polished to a high lustre with fine emery cloth.

Close-up of a lathe with tool turret, slide and chips on surfaces. Measuring scale recognisable.

A lathe is machining a metal workpiece in the shape of a cone for an egg cup base, chips are lying around.

Step 12

Cutting the egg cup

Once the piercing edge has been deburred, the egg cup is cut to the desired length using a parting tool (3 mm).

Metalworking with a lathe in which an egg cup is moulded. Oil is dripped onto the workpiece. Chips are visible.

Step 13

Finished egg cup

Finally, the cut-off slug was removed and the base surface sanded with emery cloth if necessary. If desired, the egg cup base can be covered with a felt underlay.