You can obtain a large wood spool from almost any electric shop that does motor repairing; or perhaps the wire you purchase for the magnet will be on a suitable spool.

您可以从几乎任何电动汽车修理店，没有一家大型木材阀芯，或者电线您购买的磁铁将在合适的线轴。

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Mount the coil in a vertical position, on a hollow wood base so that a core can be moved up and down through the hole in the spool.

芒在一个垂直的位置上一空心线圈木材基地，使核心可移动通过在阀芯孔向上和向下。

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