又稱切字機，是進行排版工作時，需要使用邊欄或花欄時用來裁切成適當長度與相接的45度邊角，或當遇到有罕見的文字時，而在採購不及或是鑄字廠也無此罕見字，即依此字的部首筆劃，另取不同的各自部位，以此機來作裁字工作。當然以此方式所造出的字，無法像一般鑄造出來的單字那麼美觀。

以「鐫」字比喻，此字無銅模字母，需要組字。先找出有金字邊的字，譬如「鑄」字切下左提旁的「金」字，找出右提旁「雋」字，闢如「儁」字，再將兩個偏旁組再一起變成「鐫」字。 

日星鑄字行有一台手工切鉛字機，在沒有電腦造字程式的時代，若有異體字、新創字或極罕用字需要鉛字，都需要這一部手工切鉛字機，如上所述把需要的鉛字部首或筆劃切出來重組。

The sidebar-trimming machine is known as a types-cutting machine. When we do typesetting then we use this machine to trimming types for appropriate length also the 45-degree corner to match sidebar and fence. Or when we need to use the rare character but we are not able to purchase in time or we don't have this rare character of types in the foundry. According to the stroke of this rare character and cut what we need with this machine. Of course, the types created in this way cannot be as beautiful as the ordinary casted types.

For example, we need "鐫" which has no matrix, and we can find another type which has the "金" part with it then we got "鑄" moreover we need "雋" from "儁" after we cut those part we need, and we make up what we need.

Under the signboard of Ri-Xing, there has a manual sidebar-trimming machine below the typeset shelf. At that time, without any computer program for character formation, we have used this manual sidebar- trimming machine to create any rare character of types as above description.