Setting Roller Height

Use­ful tips to make sure your rollers can ink type properly

Since the gen­er­al pur­pose of a press is to ink a print­ing sur­face and impress paper against it, roller height has a big part to play in qual­ity print­ing. For the smal­lest print­ers there are the “small print­er” approaches of set­ting large cap­it­al let­ters in the chase; ink­ing those let­ters and then inspect­ing to see wheth­er the face is inked, and wheth­er ink has been trans­ferred to the beard of the type. The ideal is to have fully inked the sur­face with a min­im­um of ink being applied to the beard of the type.

The next stage is to use a roller set­ting gauge. These come in vari­ous shapes and sizes. We’ll look here are the basic type that most small com­mer­cial print­ers would have. Flat gauges are typ­ic­ally a block of met­al machined to 0.918” high with a long handle: and have the advant­age that they tend not to tilt and so skew the res­ults. The aim here is to see a thin film of ink over the sur­face. No ink indic­ates rollers are too high; and ink that has been smeared or left on the sides indic­ates rollers are too low.

Cyl­indric­al gauges are more com­mon but can tilt when used. The aim here is to see a thin strip of around ⅛th of an inch of ink on the top of the cylinder.

A fur­ther step to pre­ci­sion was to use a spring-loaded set­ting gauge that included a dial or mark­er to show how low the rollers were on the machine. I am yet to see one in use!

The Neth­er­lands Graph­ic Arts Research Insti­tute worked on estab­lish­ing real­ist­ic tol­er­ances for let­ter­press mater­i­als. They sug­ges­ted that type would still print per­fectly if it was with­in 0.0008” of 0.918”, and so any efforts to be more pre­cise than that would be a waste.

F C Wal­ter, writ­ing in Print in Bri­tain repeated that he had heard a lec­turer stress­ing the need to be with­in an over­all lim­it of 0.0015”, and com­men­ted that it would work “pre­ci­sion and the print­er to death”. He foresaw that a “…print­er, who has toppled, drunk with fas­cin­a­tion into pre­ci­sion-land where everything is beau­ti­ful but use­less.” He pro­posed an over­all lim­it of 0.0030”. The reas­on­ing was that 0.0015” could be so eas­ily dis­rup­ted by stand­ard print­ing pro­cesses (like plan­ing) that it could not be achieved. In con­text 0.0015” is around ¾ of the thick­ness of a cigar­ette paper.