[6791] in APO Printshop
Re: More new equipment in the shop, adjusting the platen,
daemon@ATHENA.MIT.EDU (Leonard H. Tower Jr.)
Thu Sep 25 22:25:12 2014
Date: Thu, 25 Sep 2014 22:25:08 -0400
From: tower@alum.mit.edu (Leonard H. Tower Jr.)
To: apo-printshop-manager@mit.edu
Cc: Benazeer Noorani <benazeer@gmail.com>, apo-printshop-operators@mit.edu,
apo-printshop-journeyman@mit.edu
Reply-To: tower@alum.mit.edu
Molly:
* Leveling the platen, if not done very carefully, could damage the
large press and leave it unusable for a very long time.
I am opposed to Benazeer trying. But the decision is the active
members, They have trusted you to manage the Press Shop. Consult the
other actives?
Let us know what you decide.
Questions?
(I am out of town until next Thursday 2 Oct 2014, but am reading email
most days.)
* If you decide to let Benazeer do this, I can offer her some guidance
to lessen the risk.
* The shop is for the use of students. Both presses have fulfilled this
need as they are. Quite well. Without being "finely tuned". Neither
press can be restored to do really high quality work (even close to
factory new condition).
Better to have the press working for the 99% + jobs people want to do,
than this high quality job alumnus Benazeer wants to do.
* The small press was damaged this way, when an attempt was made to
level it's platen. By an alumnus with a mechanical engineering
degree, and much experience designing and building machines with
gears, etc. Machines like the presses.
The alumnus also had more experience printing in the shop that
Benazeer has had. The alumnus was sure they knew how to adjust the
platen. The alumnus didn't.
It took a while to replace the damaged bolts. We eventually had some
machined. Expensive in time and money.
* Both presses have excessive wear. Though not as bad as presses that
have been used for die cutting. (Though I have wondered, if this was
done some at the presses prior homes.)
======================================================================
Benazeer:
* Please do not try to adjust the platen until we hear from Molly. It's
likely you'll break it.
* I'm not opposed to the other things you want to do.
* There are some Morgan Expansion Trucks in the shop. And maybe some
replacement rubber "sleeves". I'm not sure what condition they are
in. They are another solution to roller shrinkage/wear. I think they
are in one of the two drawers in the desk above the left of the large
press.
* It's better to use metal tape, than masking tape, to "pad" the rails.
It lasts longer. But the Morgans are an easier way to go.
* There are other presses in Boston, in better condition than ours. And
you would find compatriots in doing fine art letterpress printing.
yiLFS -len
Date: Thu, 25 Sep 2014 12:41:27 -0400 From: Benazeer Noorani
<benazeer@gmail.com> To: APO Press <apo-printshop@mit.edu>
Subject: More new equipment in the shop, adjusting the platen, and
calibrating roller height
Hi pressops!
As I mentioned earlier this summer, I purchased a* base for printing
with plates*, from Boxcar Press. It now lives on top of the boxes
behind the spare rollers, on the top of the shelf above where the
chases live.
I'm *planning to adjust the platen* either this weekend or next,
since even with the roller height calibration described below, I'm
still seeing some uneven impressions. If you're interested in
watching or contributing give me a shout so we can coordinate
schedules.
I also discovered, printing my first plate, that the rollers are very
dramatically set at the wrong height. There's a couple of reasons for
rollers to be too low: rubber shrinks over time, and the trucks and
rails wear. (Rollers can also be too high if you have the wrong size
trucks for your press, or if the rubber is too thick. That's a harder
problem to solve and as far I have been able to learn, means
replacing the part. Luckily that's not the problem we have.) So* I
bought* *a roller gauge* -- a disk of precision ground aluminum
exactly type high in diameter, on a long rod. You can use it to
*calibrate the roller height* like so:
1) with the press inked but nothing in the chase bed, run the gauge
between the rollers and chase bed. The roller should leave a stripe
of ink 3/32 of an inch wide on the gauge. Wider and the rollers are
too low, narrower and the rollers are too high.
2) Repeat step one with the rollers at a variety of positions on the
rails, and across the width of the roller, wiping the roller gauge
down between each test, obviously.
3) If the roller is too low, adjust its height by applying masking
tape to the rails, to lift the trucks and roller. You will probably
need to apply different amounts of tape to the two rails, and
different amounts along the length of the rails.
I have already done this, and have seen a dramatic improvement in how
easy it is to get a clean impression. I've gotten far fewer filled in
characters or smudgy impressions. Yay! That said, all the rollers are
differently worn, and it's not wrong to recalibrate for every
job. Feel free to play around with this -- the masking tape won't
hurt the press and is easy to remove!
The roller gauge right now lives on a tiny shelf underneath where we
put torn off edges of LSC posters and where we hang the grippers and
spanner wrench. Eventually I'll get around to widening the hole in
the gauge so I can hang it from one of those pegs.
YiLFS
Benazeer
