We were advised by an experienced cutting engineer, who produces very high quality cuts, that ‘wearing’ in a new diamond stylus before regular use can significantly extend its lifespan. This simple practice has allowed them to achieve a much longer working life from their diamond cutting styli compared to using them immediately for cutting audio.
While this approach may seem unusual at first, it is actually a well-established principle in many other industries that rely on precision cutting tools. In fields such as metalworking, glass cutting, and precision grinding, tools made from ultra-hard materials like diamond, carbide, and ceramics often require a gentle “wearing-in” or “lapping” period before being pushed to their full operational capacity. This is done to remove microscopic surface imperfections, reduce the risk of edge chipping, and stabilize the cutting surface, ensuring consistent performance under load.
When a stylus is subjected immediately to high cutting forces—especially loud music cut with heavy bass and significant excursion—it can lead to imperfections of the stylus tip. This kind of damage can compromise both groove quality and stylus longevity, your cuts may still have a nice quiet noise floor, but stylus life could well be shortened.
The method of ‘wearing in’ is done by allowing the diamond to cut unmodulated grooves across a perfectly flat, stable surface. This can help to:
- Stabilize the cutting edge to reduce the risk of breakage when cutting demanding audio.
- Create a more predictable cutting surface, resulting in more consistent groove quality and reduced stylus wear over time.
- Smooth out any microscopic issues that could be left from manufacturing and handling.
How to Break in a Diamond Cutting Stylus:
Step 1: Make sure that your lathe is fully calibrated, from groove depth, rake angle and stylus travel to centre spindle.
Step 2: Make sure groove depth is 50µm.
Step 3: Use a perfectly flat 12” disc. If there is any flare on the outer edges you could try to tape it down to the platter. Make sure the room and disc is nice and warm, then cut an unmodulated (silent) groove at 33rpm with nice tight pitch allowing for 30 mins per side. Leave stylus heat off for this.
Step 4: Done.
Whilst this is second hand information, it comes from a source we trust, with this now becoming regular place in their workflow. The amount of time you cut for is up to you, you could try 30 mins, or if the disc is lovely and flat then 1 hour wouldn’t hurt.
The crucial thing is cutting at the right depth, on a perfectly flat surface, adding no extra stress to the stylus and allowing it to seat itself nicely into the disc.