Heavy cardstock on Heidelberg Windmill

Has anyone run 315 lb. cover stock on their Windmill? Is that too heavy?

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I run 40 pt. about 6 tons a year. It’s about 1/8 thick.
Not sure how thick 315 is.. If you try it I’d back off the impression.

I run 60pt stock a few times a month with no problems.


I’m just trying out now this 315# stuff and one thing I’m noticing is when I’m printing with guides the gripper doesnt open enough to let the sheet (more like board) drop down to rest on the guide.

Anybody have a suggestion?

I have never tried this as we dont usually have this problem to solve,rather its the opposite the grippers dont close enough. However you could try tightening the link on the top of the gripper assembly (part T1314) it may hold the gripper open enough that the sheey will not be so tightly held .However it will cause lighter stock to slip in the gripper , if you already have insufficient clearance (when platen closed) with the sheet in the gripper at the point of impression the gripper may be squeezed and damaged against the chase (not crushed in the platen) be careful of this .
Look at that ,as an angle you could consider but I warn that this is not something i have attempted nor considered as i have not had to attempt it .
Good Luck ..
Sorry i am not really a magician!!!!
You may find this may also create the problem of early sheet drop as the grippers release the ssheet for delivery .

Its worth noting that two 315# stocks can have a substantially different thickness, as there is no direct relationship between paper weight and sheet thickness.

I have a micrometer for measuring sheet thickness and adjusting makeready, comes in handy more often than I thought it would when I bought it.

This stock that I am referring to measures at .080” or 80pt.

I struggle to comprehend your weight system , i have always worked in metric measures fo r papers and boards , I know 9oz strawboard from the bindery and 25lb heavy dutch boards , otherwise its GSM or microns .
It is correct as pointed out that boards of a given weight can vary in thickness ignoring coared stocks as they vary dependant on clay coating etc .
I will have a look at the platen over the weekend and try running some paving slabs for the benefit of the exercise , I dont remember running anything as thick with the standard platen set up ,we had different sensor bars that you fitted for different jobs ,the platens performed all manner of work nor alljust printing card or paper ,Ive printed on nylon clothes labels with both platens and cylinders as well as using rubber stereos to print on brass sheet ,perspex ,serviettes, stitched exercise books , leather book cover material ,calico, Buckram ,rexine and anything else that a shortcut to print it quicker than screenprint could was game for the attempt ..

haha, ‘quicker than screenprint could’ depends on the era and the press.
Svecia (now defunct) had some amazingly quick rear-takeoff presses (and even multi-color inline units) that were capable of at least keeping up with the windmill feeding thicker stocks like this, if not run faster than. They had feeders, too, which were able to run thick board and even some that could feed 1/4” wood.

But, all the same my real point is that I admire the ingenuity mentioned here- I would never personally have thought of running brass sheet through a windmill!

I know it’s OT, and that this press is running slow, but here’s an example:


I am familiar with spot uv working butI am not in the practice of it .
Thing are faster now than thirty odd years ago …..
The fastest machine when i was learning offset was running at 12k per hour and you got about 9k of product per hour , Now you are getting in excess of 14k per hour at the same sheet size on the shop floor ,in some of the other fields of print the product on the floor is now ten times what it was in the eighties.
Automation has made a world of difference ,there is room for more of it !

As for the brass sheet ,an old pre war heidelberg spent its lifes retiring years cutting .004 brass to pen shapes for the ruling machine , a heidelberg is a handy piece of kit .