Impression Problems (Thrust Collar Differences)


We are working on a Heidelberg Windmill Platen Press 10x15 (black ball) and are having some impression issues. Over the span of a few weeks, the impression became inconsistent. We did a bunch of trouble shooting, including testing packing levels and impression strength. Now, we have no impression at all.

We changed the shear collar after noticing some hairline fracturing (still using the old thrust collar, on the right in the image) and that didn’t fix the problem.

We have another thrust collar but upon comparing the thrust collars we have in store, we saw a 1 mm difference between the two. The darker thrust collar on the right is the older one we took out. However, when we put the newer one in (on the left in the image) it causes the shear collar to stick out from its slot at the back of the press about 1 mm. Is this normal or is something wrong internally with the impression mechanism? We are hesitant to run the machine with this new thrust collar.

Any help would be greatly appreciated!

image: Thrust Collars, 1mm difference

Thrust Collars, 1mm difference

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Isn’t the part number stamped on the collar? It needs to match the part number in your parts manual.

No, There is nothing stamped on either of these thrust collars (Ive also heard them referred to as spacers).

I checked my spare collars; they both measure .550 thick. They are stamped ‘special material’ and (S) 40/40.

The “collar” on the right is not Heidelberg equipment; the other one is, unless your press is so old that there was a change made, decades ago. A serial number might be helpful. When replacing a thrust collar, the adjoining part, steel thrust collar, T-1053, must be present. This info was gleaned from a parts book for a press of about 1956. There were changes made periodically during the span of construction of this equipment; many of them may be made to fit on existing, more elderly machines; some of them may have been modified. We have three of them — 1954, 1962, 1973, and have had two others, all ’60s presses.

It’s possible there’s a break in the impression throw-off lever. It can be fixed/welded by a competent machinist, I’ve had that done.

We figured it out. There were micro cracks in the old shear collar (we had to use a magnifying glass to see them). So we replaced it and used the thrust collar on the left. The impression works fine. Thank you all!