impression depth, packing

If you’ve adjusted your packing down to tympan only and the impression is still showing, you have little other choice than to adjust the bolts.

can you lock up “bearer blocks”? one block in each corner? place these off the sheet and image area and away from guides and grippers. i understand that these would seem to pickup ink from the rollers… but what if you made them less than type high, then build up from your platen, some matching contact patches. this might be enough to control the pressure of your press. don’t hit these too hard though. the ones i use for foiling are 1” square. otherwise as stated above, adjuster platen.

This has happened to me and the only option I found was to back off the impression as far as possible till the ink did come in contact with the paper, a kiss impression and, no packing or tympan.

Casey
iLP

Thanks so much for the insight into this, everyone. Eric, I like your bearer block idea and I may explore that.

Was trying to avoid altering the impression bolts but it may be a good opportunity to learn how to control the impression with them (only when needed, of course).

I’m assuming there is a thread on briarpress regarding proper adjustment of these bolts.

Thanks again!

Joshua

Bearer blocks seem like they would really, really hurt the bearings of your press.

Why wouldn’t you adjust your platen to give you a better undercut so that you can control exactly how deep your impression is with packing? If you ever want to do die-cutting or creasing with channel matrix this will be necessary, not to mention being able to correctly print 220# or print any stock without a deep impression.

Bearer blocks are going to force your press to not close fully while it is giving its all to do so; adjusting the platen bolts will allow it to devote its energy to a good looking print, not towards crushing blocks in between the bed and the platen.

modernman, you have over-thought my point on this matter. bearer blocks are not used to back the impression off. the purpose of them is to control impression by either balancing pressure IE: you have a large area on one side of the press then balance pressure with the 2 blocks on the other side. Same for top to bottom. (this is actually Much better for your bearings.) OR if impression seems a bit erratic.impressions than end up deeper then shallower. many older presses have Some sort of “play” in them that can be taken out with careful adjustment of bearer pressure. i have seen where even an oiling cycle can change things. if you are worried about bearings,,, you should be grabbing your oil can more often. an ssortment of shim stock with double sided tape helps with dialing this in. one layer of .003 is better than 3 layers of .001

That is a good technique for evening out pressure, especially when large areas of print fit in a corner of your chase, but this particular person is asking how to back pressure off, not even it out.

Using corner bearers, does it not seem like you are suggesting to them to use bearers in such a way that you use them to decrease the travel of the platen and lessen the impression?

to a point, yes. that is the second part of the equation: to take out or reduce the amount of freeplay in a given press. all old ones have some…i generally build up each corner until i get a decent impression on the pads. if you are noticably flexing the platen…now that is too much. the required pressure is only specific to that given job on that given press. so diff jobs may have diff pressures needed…
just to note…that if this press is to be used for die cutting,,, then i Would spend the time and lower the bolts. this would allow some room for a protective, extra die cutting plate. a seperate plate then, if NOT using a top plate, would then be needed to run regular jobs. if one IS using a top plate then, a seperate plate of same thickness would used underneath as a filler plate.
on another note. if this is a clamshell press the bearer process probably won’t do the trick. i am assuming that this is an old CP style press.

jjdewitt,
What press are you printing this on? If you need a thicker paper than 220# lettra then perhaps you should duplex your stock….then you won’t have to worry about your impression showing through on the unwanted side.
You really should learn how to adjust your platen http://www.apa-letterpress.com/T%20&%20P%20ARTICLES/Press%20&%20Presswor...

if your image is just “showing” and kinda shinning up the back of the sheet, try laying down and hitting against some 1500 grit wet/dry sandpaper. (the dark grey kind) you might still see the image but, the polished look will be gone.

Thank you! Your additional insight and debate is really appreciated.

It was a successful night as I adjusted the platen impression bolts for the first time. It worked perfectly as I ensured that I adjusted each bolt equally. I am impressed with how responsive it was to even the slightest adjustment.

By adjusting the bolts, I was able to maximize the impression on one side while removing any visible impression “mark” on the other side.

I definitely want to control the press using the methods provided by the press itself. I was simply trying to use this approach as a last resort. I’m excited as I have even more confidence in my ability to control the press.

To answer your question, Eric, this is a New Style C&P press. I like your idea for using sandpaper to reduce the sheen and may test that too.

Kluge girl, thanks for the link. I’ll certainly read that to enforce my learnings.

Duplexing was not an option for this project but I did recommend it to the client. She wanted to use Lettra 220 this time but we will explore heavier weight stocks for future projects.

Hello everyone.
I am having a similar problem - the impression is just too deep, marking through card and on to a piece underneath, or through both sides of an envelope. I have tried various options with packing, but it is obviously not that that is the problem.
I have an Adana T/P48 that is working fine in all other regards. I realise I am probably going to have to adjust the back platen. Seeing as I am not mechanically minded at all, this is a bit intimidating for this beginner. Anyone got any tips or hints to help me avoid problems?
Thanks
Natalia

Natalia,

Based on my limited experience with this, it seems most important that you keep track of how far you turn each impression bolt so that they all move the same amount (assuming they are all correct to begin with).

I wrote down notes on each printed sheet after making each adjustment so I could keep track of the moves. I also put tape on the bolts and marked with a pen so I could see the amount that I turned from the original starting point.

Hope this helps.

Dear JJdewitt

Thanks for your reply (and sorry I am so late getting back to you).
That really helped. I have also been doing a lot of work adjusting the packing, sheet by sheet if necessary. Amazing how much difference one sheet makes!

just a follow up. if your platen bolts happen to be 1” dia X 18 threads per inch, each FACE on the hex is just about : .010 inch

Thanks for the great pointer, Eric.