[6790] in APO Printshop
More new equipment in the shop, adjusting the platen, and calibrating
daemon@ATHENA.MIT.EDU (Benazeer Noorani)
Thu Sep 25 12:41:29 2014
Date: Thu, 25 Sep 2014 12:41:27 -0400
From: Benazeer Noorani <benazeer@gmail.com>
To: APO Press <apo-printshop@mit.edu>
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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
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<div dir=3D"ltr"><div><div><div><div><div><div>Hi pressops!<br><br></div>As=
I mentioned earlier this summer, I purchased a<b> base for printing with p=
lates</b>, from Boxcar Press. It now lives on top of the boxes behind the s=
pare rollers, on the top of the shelf above where the chases live. <br><br>=
</div><div>I'm <b>planning to adjust the platen</b> either this weekend=
or next, since even with the roller height calibration described below, I&=
#39;m still seeing some uneven impressions. If you're interested in wat=
ching or contributing give me a shout so we can coordinate schedules. <br><=
/div><div><br></div>I also discovered, printing my first plate, that the ro=
llers are very dramatically set at the wrong height. There's a couple o=
f reasons for rollers to be too low: rubber shrinks over time, and the truc=
ks and rails wear. (Rollers can also be too high if you have the wrong siz=
e trucks for=20
your press, or if the rubber is too thick. That's a harder problem to=
=20
solve and as far I have been able to learn, means replacing the part.=20
Luckily that's not the problem we have.)=C2=A0 So<b> I bought</b> <b>a =
roller gauge</b> -- a disk of precision ground aluminum exactly type high i=
n diameter, on a long rod. You can use it to <b>calibrate the roller height=
</b> like so:<br><br></div>1) with the press inked but nothing in the chase=
bed, run the gauge between the rollers and chase bed. The roller should le=
ave a stripe of ink 3/32 of an inch wide on the gauge. Wider and the roller=
s are too low, narrower and the rollers are too high. <br><br></div>2) Repe=
at step one with the rollers at a variety of positions on the rails, and ac=
ross the width of the roller, wiping the roller gauge down between each tes=
t, obviously.<br><br></div>3) If the roller is too low, adjust its height b=
y applying masking tape to the rails, to lift the trucks and roller. You wi=
ll probably need to apply different amounts of tape to the two rails, and d=
ifferent amounts along the length of the rails.<br><br></div>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&=
#39;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! <=
br><br>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 spann=
er wrench. Eventually I'll get around to widening the hole in the gauge=
so I can hang it from one of those pegs. <br><div><div><div><div><br><br><=
/div><div>YiLFS<br><br>Benazeer<br></div></div></div></div></div>
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