Setting gauge pins straight/makeready

Is it possible that a process of elimination may help:-
i.e. is their a variable that is not apparently obvious, - accurately trimmed/cut stock, wear in the fulcrum/axis of the platen proper? allowing minute movement(s) during the actual impression point - hold on the point of impression and with small pinch bar/pry bar attempt to rock the platen (proper) against the bed chase, even a .002” .003” wear in the axis will magnify considerably at the limits of the tympan area.? Is the tympan tight/taught.

Have You mastered the process of setting the impression bolts, and maintaining consistent register, (12th June last,!)

Does the chase clip in positively and maintain the correct orientation from one *pull* to the next ?

All silly suggestions, Apologies, but elimination might prove helpful. - Good Luck.

Amanda:

I’d have to say that I’ve found no better way to set the gauge pins than printing on the tympan and drawing a line at the distance from the printed image which matches the margins you wish to set.

When there is not a straight line at the edge of the form, I draw a center line and measure down from that to set the gauge pin line. One of the advantages of the gauge pins you are using is that they can be positioned and then re-positioned several times as you are positioning the paper on the platen. With these compressible pins, it is often easier to line up the printing stock and then position the pins by sliding them up to the edge of the stock, thus keeping their face aligned parallel to the edges of the stock.

John Henry
Cedar Creek Press

If you add a couple of pieces of brass rule in the lockup at the corner of the plate base where you intent to put your plates, you could print this onto the tympan then remove the rules. From there you will at least know where you base is in relation to the platen.

I don’t do this in normal practice, but do use it as a trick to show new printers the no-go area for standard gauge pins when printing with a Boxcar base.

DGM

I agree with John Henry with one exception as I do it.
I tape a piece of copy paper to the tympan sheet at two corners. Then make an impression. Measure and make the margin marks extending them onto the tympan sheet. Remove the copy paper and read it as your proof.
Join the marks on the tympan paper to make your margin marks.
This saves having to wash and powder the tympan sheet.

Since you are printing with polymer plates, there is a clever trick you can use that is described well on Boxcar Press how-to video #3 (https://www.boxcarpress.com/letterpress-classes-videos/)

I make a computer print of the design, complete with corner marks, and cut it out to paper size. Then using a circle (or two) of scotch tape, tape the plate sticky-side up on your printout so it aligns correctly. Now rest it on your gauge pins, put the press on impression, and turn it over once by hand. The plate will stick to your base — remove the tape from the relief side and you are ready to print! The magic of this technique is that even if your gauge pins are not perfectly square to the base, your plate will still align with the paper.

It is interesting to read the replys sent in. I stàrted letterpress printing in the 1960’s and although primarily printed on cylinder presses, apprentices were given platen tuition. I now fall back on that training with my windmill and Adana, however I have never used a chase base for the polymer plates purchased. I mount polymers either on Aluminum shim and position on honeycombe mount or stick using d/sided tape to high mount and for the Adana this means I can use lead quads for lays which work really well. They give a really firm lay and will give good registration. Here in the UK plate suppliers offer a wood mounting as well in some instances.

Hi Amanda, I’m not sure from your description exactly where in the process you are having issue but I thought I would offer this bit. I had a helper here for awhile and when he set up a job he would spend a great deal of time with the gauge pins. He would see that one side was low and he would adjust that pin but then it didn’t have the effect he thought it would have and he would adjust it again. He did this over and over again and would get frustrated. After I went over the proceedure with him a few times and not seeing any improvement I suggested that he always mark the position of the pin on the tympan before moving it and write out on the tympan which direction he was trying to move the registration. After a while he started to get much better as he could see how moving the pin affected the registration and he stopped forgetting what he had done in the previous step.
I don’t know if that is the kind issue your having but if it is I hope this helps
Bruce