Windmill uneven pressure top to bottom

Although this video is referring to printing, the principles are the same with die cutting. It helps if you understand the how the Tiegel works in terms of impression adjustment. There are also clues in the manual. Hope you are using a die cutting jacket.

http://www.youtube.com/watch?v=4Ja49Zs11Sk

Mike,
How tall is the die and how thick is the jacket?

Basic clamshell platen practice, if impression is to heavy at the bottom reduce your tympan packing and increase the impression, the reverse if it is too heavy at the top

What height is your rule and what thickness plate have you got in the press because generally your problem indicates being over packed .
Overpacked (in cutting and creasing terms using a cutting plate to protect the platen surface) can be caused by rule height too high or plate too thick .
Also the stock you are using if extremely thick can throw you a bit because the crease needs to be lower than normal in relation to your cutting rule height .

With respect to all concerned, when a new name/handle appears for the first time, surely it would make sense, be politically correct, courteous and initially more constructive to look up the (New) User profile and proceed accordingly;- I.E. work on the basis that as the new kid on the block, desparately wrestling with all the intricasies of the newly acquired technology, needing a few basic building blocks rather than advanced principles. Starting perhaps with little breakdown on parallel approach, progress to the limitations of clamshell and THEN! the methods to achieve the end result. Apologies if I dont see this as a natural progression!!

Hi everyone, I appreciate all the responses. To some concerned I am using .937 hight die cutting rules in all four corners just to see how the impression looks (bottom two are fine there is no top impression at all), I am using a die cutting jacket with NO packing at all. If I put packing at he top still no impression. Didn’t know if there is a internal adjustment to the bed to square it up (like a C & P)?
At out shop we have been in business since 1955 we run 14 engraving presses, 1-C & P, 1-Foil Kluge and 2-verticals along with 2-Thompson die-cutters. I just purchased this windmill and just needed a little help.

Hi Mike,

Sorry if you took my comment as derogatory. It was certainly not meant to be.

I was hoping to point you at some online resources so you could learn more about the platen adjustment concepts for this press. You will also find a manual for download at letterpresscommons.com

I was in a hurry when I read your post and see now that you have no packing, are using .937 rule as well as a cutting jacket.

Not absolutely sure if it is universal for all Heidelberg Tiegels/Windmills, but the manual says to use .918 cutting rule. We always use .918 rule for die cutting on our 10 x 15 and have no issues. There are no platen adjustment screws like on some platens, just the impression adjustment on the impression throw-off lever at the center-base of the press between the feed and delivery tables.

Peter and Anonymouse were headed in the right direction it seems.

Hi Mike,

The 10x15 presses I am familiar with are typically setup for .918 rule and .030 die jacket with .010 hard packing to startup and check.

At “0” on the impression handle, the platen should be parallel to the bed. More impression will tip the top toward the bed and the reverse is also true. Fine adjustments are made by changing packing thickness and impression.

Manuals are available for download, along with parts book and “Tips for the Pressman”. (Found here, Letterpress Commons and Boxcar Press.)

Regards,
AnonyMouse

The mouse has it about right ,we use type high cutting rule and a thirty or fourty thou plate depending on the task , thirty thou is a good option as it allows for pressmans adjustments .
The rule you state in the explanation of your current predicament is much too high therefore the lower portion of the platen is contacting too early . If your rule was too low then the top would be cutting whilst the bottom would not , this phenomenon we refer to as toeing and healing in the uk , it is overcome by correcting the forme height and impression to bring a levelled approach for the last few thou of the platens action at the point of full impression .
When you turn the impression collars on the lever in and the visible numbers are increasing you are moving the top of the platen toward the forme ,when you add packing you are in effect moving the bottom of the platen toward the forme , if you reverse these actions the effect is also reversed ,wind impression collar out toward zero moves the top of the platen away from the form ,removing packing will in effect move the lower portion of the platen away from the form ,it is the balance of these actions you need to learn ,however you need to have the correct rule to start out or you will never get it .

Just came across this post. I wasn’t sure if you corrected your problem or not. As mentioned, .918 rule is best suited to the Windmill. When we have spots on the length of rule that don’t perforate we add a bit of paper UNDER the rule (behind the chase) in that particular spot. I use anything from onion skin up through 110 index held in place by a small piece of scotch tape. This is an old timers trick I learned from my dad back in the 1970s.