Heidelberg Windmill: how many pressure?

I was wondering how you can say what’s the pressure limit of the press for a specific kind of paper (or better cardboard) using photopolymer plates.


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Hey Fabio, Got that monster up and running I see.
Bring the pressure setting out to 0 on the handle. Pack the platen as described in the manual using the gauge on the delivery side guide. Adjust the handle slowly until you get a good print without debossing. If the print is heavier at the top of the platen, remove a piece of packing and increase the handle pressure slightly and try again. If the pressure is heavier at the bottom of the platen, back off on the handle pressure and add a piece of packing. Usually I advise .003” at a time for the packing adjustments.

Hi mate :)
Still not, but I’m very near to it :)

With heavier you mean with more pressure respect the bottom part?

Another question, I’ve seen some prints like this:

How can I understand how much is the limit of the Windmill, withouth damaging the safety collar?


(i’m referring to the pressure limit)


I suggest you read page 49 of the manual.

The attached is a copy of the relevant part.

image: HAP_1.jpg


You are right Bern. I absolutely got it bas akwards, and I’ve been doing this for years!!! Time to retire before I start hiding my own Easter Eggs.

If you look closely at the pictures in the link you posted, you will see that the stock that is shown is a very soft, or blotter type of paper. Kind of like a coaster under a beer glass. De-bossing used to be a flaw in letterpress and was the equivalent of today’s back -of -the sheet offsetting in lithography.
However, de-bossing has become the rage in today’s market. People like it for several reasons: one is that it looks very upscale compared to a standard flat print or thermographed business card. Another is that a de-bossed card tends to stand out in a pack of business cards, making it easy to find.
But that was not your question. You can safely deboss on your Windmill without causing damage. It actually requires no more pressure, or maybe even less, than embossing with a die and counter die. Make sure that you have the correct packing (Not like I described above - what a pillock - but the way Bern described) and build the pressure with the handle bit-by-bit until you get the result you want.
I don’t know how well this works with poly plates, someone here will be able to answer that, but I have seen copper and zinc plates that de-boss beautifully.
Also, when you de-boss, you have to watch your ink density and tack. Otherwise, if the ink is too “thin” you will halo your type and lose the effect you were looking for. Debossing needs to be very clean to be effective.
It takes quite a bit to damage the safety collar. The machine will let you know you are abusing it before you get to that point.

linegauge, i’ve owned a windmill since the early 1970’s and i still have to check that page bern posted every once in a while. Dick G.

Hello guys,
thank you all and thank you linegauge.

Linegauge: what do you mean with “The machine will let you know you are abusing it before you get to that point”?

In which way the Windmill will notify it to me?!


Remember, these are well built machines. Referring to the link in your earlier post, you could probably punch the type straight through the cards shown and not have damaged the machine. It is built to take a lot more pressure than you are going to give it by de-bossing. I have locked windmills up in the past to the point that the clutch either started slipping or the belt on the motor spun off the flywheel and the safety collar remained intact. Usually this was due to several heavy sheets feeding at one time. Unless you plan to die cut plywood, don’t be too concerned about the shear collar. Always use just the pressure needed to give the best results and you will be in good shape.

Again I forgot to answer your question: As you reach a point where you have too much impression, the machine is going to bog down somewhat or the clutch will slip. Long before you reach that point, you will have probably noticed that you have lost the de-bossing effect and gone to a true die cut right through the card.

you’re really a treasure for the windimill owners!

Just another thing, when you speak about the clutch, what do you mean? I know what’s the clutch is but where is on the windmill?


Attached to the big handle on the left side of the press. The one that makes it go.

Thanks linegauge!