この質問は、掘削機の内部で火花が見られることはよくあることです。
It is not uncommon to see sparks at the interface point between the carbon brush and the commutator as the motor operates.
それでは、掘削機の内部には危険な特定の種類の火花があり、作業をすぐに停止して修正する必要がありますか?また、古い掘削機は新しい掘削機よりも火花が少ないのですか?
I went through a few forum threads where people said sparks inside brushed drill machines are common, but all of them mentioned old drill machines
The amount of sparking will often reduce as the brushes wear in during use of the tool.