《工欲善其事》
教印章雕刻時，同學都會問雕刻刀的問題。其中最多人問，是何時更換刀片?

記得以前中文課讀過《庖丁解牛》，一個熟練的庖丁所用的刀可以用上十年，比一般人的一年要換一次，可以講節省了很多錢。刀是一樣，但庖丁用刀時不會和骨頭硬碰，而是找到牛隻的肉位紋理，向軟位下刀。其實跟印章雕刻也很似。以下是我的小小心得:

It depends.

For daily stamp carver like myself, it takes me every two months to change a NT cutter D-400 knife blade, but every three months when it comes to Olfa AK-4. The more experienced you are to carving, the longer your blade can last. The key is, it’s not when to change the blade, but rather, HOW TO USE your blade.

Here are some of my tips on carving knives:

1. Every knife is destined to its most matching eraser board (just like human beings!) If you buy very inexpensive (cheap, to be exact) eraser board and the quality is not so good, do not use the most expensive knife to carve on it. You will just end up shorten the life span of your expensive blade.
2. If possible, prepare another carving knife with the same brand. This second knife with new blade serves as a comparison when you doubt whether your first knife needs a blade change. Simply carve a line or two on the same board using both knives, and judge by yourself.
3. Every knife serves only a single purpose. If you decide to use the knife for eraser stamp carving, do not use it to carve on wood, paper etc.!
4. Always cover your knife blade with the plastic cap and place them horizontally at all times. Do not put them in pen stand.
5. For Japanese knife users like myself, Olfa and NT Cutter are the two most popular knife brands. Olfa’s blade are more endurable than NT Cutter’s, as their prices indicate their differences.

Look at your budget, expectation and volume of your carving, to decide which knife to choose from. Remember:  intention, not activity.

Hope it helps.