Perf Rule without matrix or jacket on C&P

if you bring up pressure evenly and gently, using a sharp perf rule, you should be fine on its own. creasing is really only time you would need a matrix. scoring and perfing cut on their own. key here is evenly. do a make ready. if you have no plate on the platen i would tape down a thin piece of steel, preferably something hardened a bit. the perf might tend to cut into platen casting.

I agree with Eric M, you could damage the surface of the platen if you strike cutting rule against it without a jacket.

Depending on the height of your perf rule, you may actually need a jacket as well. If your press is designed to work with, for example, a .918 height form- and the platen gap is set up for a packing thickness of .040”. If you are using .918” height perf rule, you’ll have to put something on there for sure as there’ll be a .040” gap.

But even if you’re using .937” cutting rule, it wouldn’t strike the platen and you’ll actually need a cutting plate- because there will still be a distance of .019” between the naked platen and the perf rule.

b

in addition, with a very thin stock, IE: 60-80lb text, you may see a benefit of a single layer of thin tape on the strike area. this may need to replaced every so many sheets. don’t forget that you may need ejection rubber along side the perf rule. one of the softer grades should work fine (white, grey, red) green and black will be too firm and take up press power.

I’ve always used Perf-a-base, which is a thin metal strip you glue to the topsheet. Simple to use, clean perf; you can buy a roll at NA Graphics. NA also sells the similar Sabertooth backing, less expensive (also a shorter roll), and it is self-adhesive.

never used that stuff Parallel, i have some though. do you hit it with rubber stuck to furniture locked up in the chase then?, with the sheet face down? does it eject okay? it must be a usable product, it has been around forever.

I am talking about metal strip that attaches to the topsheet, sort of a localized cutting jacket. The difference between Perf-a-base and Sabertooth is that Perf-a-Base is attached with a white glue, and Sabertooth has both a self-adhesive and little teeth that dig into the topsheet (that might be helpful on a cylinder press).
Now, Boyd, the company that makes Sabertooth also makes products for offset presses, that’s what you are remembering: Lith-o-perf etc.
I have used low perf rule and Perf-a-Base, perfed and printed in the same pass, without inking the rule.

It should be an axiom to never die cut or perforate directly to the surface of a platen or a cylinder, even with a sheet of tympan paper. Both the Perf-a-base and the Sabertooth are products that can be used on both platens and cylinder for basic perforating. More complex situations, that could include die cutting and scoring are best done with a die jacket, and the standard thickness is .030”. The Sabertooth is my preference—it is easy to use, quick to set up, and does an excellent job.

Combination runs of printing and perforating can be done with these products, and if you don’t want ink on the rule, there is some under .918 perf rule available—I think we have some in stock. I have also seen 2 pt. brass rule glued to the tympan (flat) that serves the same purpose, but you have to back way off on the packing. No ejection rubber is needed. In an absolute pinch, perf direct to the tympan but lay down a strip of masking tape on the tympan in line with the perf to hold the top sheet together, and that’s for short runs. Scoring matrix is not suitable for perfing—some of it has a very thin steel backing, some uses a plastic backing, neither of which is designed for perforating.

Years ago an equipment dealer wanted to sell me a Miehle Vertical. He offered it at a fair price, but I wanted to see the cylinder, which we did and under the tympan was a horror show of primarily door hanger die cuts all over the cylinder surface. He assured me that was “normal” practice, and I told him only a blacksmith would have done such a hack job to a press. He later offered it to me at half the asking price, which was ignored.

There is no such thing as scoring matrix it is creasing matrix. Scoring is when cutting rule is used to kiss cut for stickers or to assist a fold without matrix.
Just ran 20,000 forms 2 numbering heads and 2 perfs .910 8tpi used .021 banding iron as counter for perf on top of tympan I stopped using the flimsy sabre tooth and perf a base long ago.

A piece of perf, score or cutting rule glued to the tympan works as a perf or cutting base.

Mike Conway,
My 1963 Pocket Pal states, ” A score is defined as a crease in the paper or cover stock which facilitates folding without breaking the fold.” ” The most common method of scoring employs a round face scoring rule locked into a form on a press.”
Kiss cutting is not scoring it’s kiss cutting.
Perforating rule ,cutting rule and scoring rule are 3 separate things designed for 3 different jobs. Creasing matrix assists in creasing/mashing the fibers, folding is done by hand or on a machine.
“Dirty perfing” destroys rollers.
best james

James thanks for your source info but take a look at the steel rule with the rounded face and see what is printed on the side of it it. It is creasing rule not scoring rule.
When I make a die for a letterpress shop and they say score I know they mean crease. If I make a die for a folding carton business and they ask for score they mean a cut that does not go all the way through the stock so if diecutting .020 card with .937 rule then the score is .927(approx.) cutting rule
If the client wants a “dirty perf” on the form they get it. Use low perf to keep the roller damage down and it is not expensive to recover.

going to use that,,,,,, “Only a blacksmith….” LOL

Lots of good banter here I hope we answered the question.
https://www.youtube.com/watch?v=nHekN6PsXsw

@Sharecropper Press - That is a perfect idea! Thank you!

Mike Conway, I really don’t care what it says on the side of the rule. I care about what job it will do. I also noticed 3 press’ running and no operators? Scary…/
best james

Thanks James I will get right on it.

We had a simple solution for our Kluge fed C&P. We had pieces of 3/8” steel banding strap that we used as backing to protect the platen. We cut a narrow +- 1/2” notch in the tempan and inserted the strap and help it in place with scotch tape. Worked great and was really easy.