tread-mill

基本解释

Tread is machined using numerical - control machine. Mill tool is designed.
在数控铣床上加工螺纹，需要设计盘形铣刀。
And this would help him to understand why constructing artificial flowers or performing on a tread-mill is work, while rolling ten-pins or climbing Mont Blanc is only amusement.
这个道理使他明白了为什么做假花和蹬车轮就算是工作，而玩十柱戏和爬勃朗峰就算是娱乐。
The process of producing 3A21 tread plates by two-roller rolling mill was studied. Many good suggestions were offered on hot rolling stocks, roller, lubricant and maintenance of patterned roller, etc.
对两辊轧机生产3A 21 合金花纹板的工艺进行了研究，并对热轧坯料、压花前坯料、轧辊工艺润滑剂、花纹辊的维护提出了良好的建议。

You can refer to a task or a job as a treadmill when you have to keep doing it although it is unpleasant and exhausting.
A treadmill is a piece of equipment, for example, an exercise machine, consisting of a wheel with steps around its edge or a continuous moving belt. The weight of a person or animal walking on it causes the wheel or belt to turn.