Trouble with grippers on 10x15 Heidelberg “windmill”
Hey guys, I’ve been having some issues lately and I thought I’d see if anyone here had any of their brilliant know-how to share. It’s probably a relatively simple fix. As the title says, I’m on a 10x15 black ball Heidelberg windmill.
First, a very basic question. What techniques are taken to minimize the occurrence of two sheets being pulled at once? If you walked into my shop and saw that happening, what specifically would be the process you took to stop it?
Second, and this is the very important one: I’m having issues with my arms. I think that one of them is okay and one of them is bad, but that may just be coincidence and they may both be bad. They either grip the paper at an angle (I’d say about 15-20 degrees off), which ruins the print and can damage the tympan, or they simple throw the paper off altogether, where it either gets torn up in the machinery or thrown to the floor like a stubborn kid throwing a tantrum.
The arms specifically are really interfering with my work, so I’d love to hear any advice on the matter, and whether this is a common problem or not, and fixable or not. Of course, it may well be an operator’s problem as well, as I have had many of those.
I’d also be interested to hear any general tips from owners of similar presses. Oil types and oiling routines, cleaning routines, operating advice, step by step printing process, etc. I’d like to be able to compare what I’m doing with others and see if I’m doing anything wrong/inefficiently.
Thanks so much. I really appreciate all the advice y’all have given in the past.
Daniel
I have a red ball 10x15. I can’t say much about your gripper arm issues as I’ve never had problems with mine. Regarding paper feeding, I’ve found two adjustments tend to work for me. One, keep the pile lower so it doesn’t contact the suckers directly. That allows the air blast to push the paper up to the suckers and less chance of multiple sheets feeding at once. The other is to adjust the tripping spring or the sheet separators. There’s a knob behind the front feed table where you can adjust the tripping spring in and out. If you move it so it protrudes further into the feed table, that should help.
You didn’t mention what kind of stock you were using. Do you have the problem with lighter or heavier stock? Or all types of paper?
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Few extra possibilities, longer thinner separator fingers, left and right of the stock, from either Off the shelf Graphic Suppliers,??
OR
D.I.Y.style fashioned from (old fashioned Alarm clock springs) can be made in the order or 2”-3” long and only 6 point to 9 point wide, with a little practice as gentle or severe as suits the stock,.
OR
Strips of credit card, as separators, again as delicate or severe as required.!!!
OR
Additional rubber suckers, atop the normal suckers, either every one or every other one,
OR
Separators cut from the Whale bone or Plastic insert/strengtheners from Gents dress shirt collars.!!
OR
Slightly increase the weight on the rear pile block, if there is one??
OR
If possible source original Plastic slipper the clips on and spans several suckers,!!! at once, i.e. spreads the amount of *Lift* without bleeding through to the following sheet.???
Hi,
As far as picking up doubles are concerned, agree with the comment about keeping the pile as low as possible and let the blower push the sheet up to suckers, the second suggestion is to have as much tilt as possible. If you are having trouble with the grippers, have you checked to see if the grippers are holding the sheet firmly, it may be that rubber strips in the grippers need replacing. Try picking up a sheet and stopping the press as soon as a sheet is in the gripper and check to see if the sheet is being firmly held all along the sheet if not the rubbers may need to be replaced.
Not sure where you can get replacements from in the US or over here in the UK but it must be possible even to make replacements.
hope this is of some use.
Hey everyone, thanks for the quick and varied suggestions.
jonsel, your comment about the tripping spring is helpful, I hadn’t been utilizing that whatsoever. The air blaster has indeed been a huge help, and I’m embarrassed to admit how recently how I finally realized how to use it properly.
Let’s say I’m printing 300gsm Lettra - cardstock cotton paper. Which sucker configuration would y’all typically use for that? Do you always operate with rubber suckers, or do you ever use them bare?
Mick, lots of different tips there, sounds like the advice of someone with a lot of practical experience. How are you recommending that I apply the various separators to the press?
frank hemmings, when you refer to the rubber strips in the gripper, I’m not sure that’s something I’ve paid much attention to in the past. What it be torn or misshapen? Would I simply replace it? I’ve never seen one for sale but I can think of two places to look first.
I suspect that one of the two arms is worse than the others. When they fail, they pick it up as usual on the farthest end of the arm, but fail to close nearer down; sometimes it tries to make an impression like this, which leads to a crooked print, and sometimes it just throws the paper, either into the ink drum and rollers or off to the side. I’m not sure if I’m just repeating myself here, but I thought I’d make another attempt at explaining my problem.
Re the gripper pads - If you have a copy of the operation manual, have a look at page 110 which tells you how to replace the rubber strips, even giving details of the materials to use. I think there are copies of the manual on the web. If you need help, I can scan the page and post it.
The manual is worth it’s weight in gold and if you don’t have one it’s worth down loading, its available on the Letterpress Commons site and the copy they have look at page 106.
Frank,
Thanks a lot. A friend of mine actually gave me an original manual a few years ago and it’s one of my most treasured press possessions.
I just examined both the manual and my press and, in fact, I don’t think my grippers have any rubber at all, if that’s possible. I don’t know why, but it means they haven’t had any for years. The manual specifically recommends .012” rubber sheet and “double sided plate mounting adhesive.” I definitely want to try that out.
As far as I can tell, it’s just sheer metal on my grippers. I’ll put my macro lens on and take some pictures tomorrow.
.012” is awfully thin. Isn’t that basically tape thickness? What if I taped a thin strip of black electrical tape to it?
The adhesive on electrical tape tends to creep and the vinyl will start to move causing feeding problems. Not all electrical tape is equal, and the really inexpensive stuff should be avoided. I have not found a source for the recommended rubber sheeting, but in my experience, it is an important factor in getting the Heidelberg grippers to work properly for feeding and register.
Hey guys, I think the .012 rubber sheet might be used by dentists and called dental dam material.
Duncapher, thank you for the Nod, unfortunately just general ramblings accrued over a long time, now and again, helpful.!
One more try follows :- nobody has, as yet apparently suggested, the factored in adjustments to the individual grip of the Fingers and Arms, via the left and right hand threaded adjusters, just inboard of the ends of the grippers, well documented.!!! involves individual grip test, per gripper, along the length of each, possibly synonymous with your problems.
+ also been discussed before, the Bosses that carry the gripper arms proper, are *Malleable* and intended to be fine tuned/re-aligned, either through Longevity, or serious pile up on the run, it does happen.
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N.B. Here U.K. this adjustment is normally undertaken By H/berg trained and equipped technicians, and involves a special purpose tool,!! i.e. the grippers are removed and a >>Bending Bar<< upwards of 36” long slots over the Boss(s) to achieve realignment, and then, gripper adjustments proper.
[email protected].
[email protected].
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Re the rubber inserts under the fingers, genuine replacement rubber, initially, but this may have involved Service Exchange units from H/berg service dept, (Possibly Whittenburg U.S.A.) Certainly Senior Graphics, & Ray Cantor, in U.K. might even be worth an E mail for Info.??? ABOVE.?
If all else fails for rubber inserts, (and we have in the past) BUT might not be applicable in The States?? 2 possibilities, (1) acquire a normal Cycle puncture repair kit, with a selection of Vulcanised repair patches, in different sizes and thickness,s make excellent pads even if a little grinding down with a Dremmel style drill and abrasive stone, stuck with D,S.A. or upholsterers, & flooring specialist, Double Sided Tape.! . (2).We have also used the uniform thickness vulcanised rubber strip that covers the heads of the spokes, to protect the inner tube.
Good Luck and Seasons greetings, Mick..
P.S. afterthought,! you should have the means to adjust/change/substitute, the fine seperators that are seen through the front stock pile support, close to air blast nozzles, (are they weak and tired) and hopefully you may have the means to fit extra selection of fingers, left and right of the pile, extra auxiliary stanchion,s.
Thanks for the all the information everyone. It sounds like masking tape is the way to go for a quick fix until I track down some .012” rubber, which, as ted lavin suggests, may be available through a dentist. I’ll report back if I have any success!
Well, ebay has a product available called “Latex Rubber Film” at $33 (+$15 shipping) for a 6” by 5’ roll, and larger sizes available.
I imagine that might work great, although there’s no way I’m going to buy $50 worth of material for two strips of it.