REPRINTED FROM TYPE & PRESS / COURTESY OF the APA
By C. Prentice Smith
Type & Press, Spring 1981
These two pressroom helps should improve anyone’s quality of printing. I’ve found them extremely helpful.
BIAS LOCK-UP OF PRESS FORMS
At one time it was possible to purchase bias chases for Gordon presses. However, if none can be had, you can easily enjoy the benefits of such form lock-up by making a set of wedge – shaped furniture for each size of press you use. The chief advantages of bias lock-up are the protection of the rollers from being cut by sharp vertical rules in the form, and better inking of isolated lines of type or rules in forms that cannot be locked with type high bearers, as well as improved register when feeding paper to the “low” corner of the gauge pin pattern.
Take two pieces of hardwood (birch or maple are best) 3/4″xl-1/8″ – long enough for the longest dimension of your chase. Cut each piece into two long wedges, tapering from 1/8″ at one end to approximately 7/8″ at the other (allowing 1/8″ for the saw kerf). Be sure this taper cut is accurate, straight and square with the 1 1/8″ faces. Cut one pair of wedges about 3/4″ shorter than the short dimension. Place the four wedges, as furniture, around the outside of the form, against the inside of the chase, so the form will be tilted downward toward the left side of the press; quoins may be locked against the wedges. Be sure that all four corners inside the wedges are right – angles. To insure this, make all four wedges at the same saw setting; then cut them to length afterward.
Besides these two helps, I use a 10-power Hastings magnifier for inspection of my work, both at makeready and throughout the run, to keep ink and impression at their best.
ROLLER SETTING GAUGE
In order to have proper contact between rollers and the type-high form I use an aluminum bar gauge, made as follows: Take a bar of metal about 3/4″x1-1/4″x3″ longer than the short dimension of the press for your largest press (13″ for a 10″x15″ press, for example). Place it between centers on a machinist’s lathe and turn it down to type-high diameter (.91811), leaving an inch of non-turned handle at one end. Check with micrometer to insure accuracy. [A roller setting gauge can be purchased from NA Graphics.]
With rollers properly inked, no form in the press, and with rollers held firmly at mid-position on the roller bearers (bed tracks), place the gauge flat side against the press bed to avoid getting ink on the gauge. Then, turn the gauge one-quarter turn (be sure rollers do not move and that the gauge does not slip up or down as it is turned). This will leave a band of ink made by each roller on one of the cylindrical faces of the gauge. Withdraw the gauge carefully so as not to smear those bands of ink. Repeat this operation for both sides of the press, then correct the truck diameters with plastic tape or with the cone adjustment (Morgan expansion trucks), until the bands of ink on the gauge are all equal and about 3/16″ to 1/8″ wide. Clean ink from the gauge each time. Note: the accuracy of this method depends upon having the bed tracks type-high and parallel to the press bed.