すじがね

すじがね【筋金】

metal reinforcement.

●筋金を入れる put steel into 《sb's》 backbone [soul, spirit, mind]; give 《sth [sb]》 backbone.

筋金入り

●この腕は筋金入りだ. This arm of mine is as strong as steel.

・筋金入りの保守主義者 a dyed-in-the-wool [an out-and-out, a hard-core] conservative; a conservative to the core.