Happy New Year all —
I have a question for the masses – I’ll try to keep this concise. The shop I work in has a 325 that has forever seemed to have issues. We solved it various ways – extra packing being one, realizing it needed a bed plate was another (that helped!). We also know that when it was moved into the space, it was disassembled and moved (whereas most were hauled up intact).
Whilst printing some large pages recently, I decided something was truly wrong with the press. With some encouragement from my usual support, I disassembled the Trip/Print rack assembly. . .
Long story short, I’ve decided was reassembled mis-aligned. In other words, when on the Print setting, the print cylinder ran too high.
So, the simple question for you is, if you recall (or if you’re feeling ambitious enough to inspect – please do this at your own discretion… I don’t want to hear that you’ve misaligned yours) – does your Cylinder Trip Rack / shaft have one, two, or three dimples on it? (See below) Mine has 3, I’m thinking dimple B should not exist, and probably not dimple A either. These lock with a sprung ball-bearing inside the casing. Furthermore, does dimple C seem to be the proper distance from the the Cylinder Trip Rack? My theory says A and B were worn into the steel over years of misuse, and C is the proper height for print.
The follow-up question then might be: what do I look for to realign the gear and rack to the proper teeth?
Hi Paul, Hi Eric.
Sorry for the delayed response time —
SO, the plot thickens yet again. Here are the issues I can rule out: The screw hole is indeed at 12 o’clock, so all is well there.
What’s thrown me for a loop are your measurements.
From the end of the bar: B at 6″ and A at 9″ (centered)
From the gear: A is 1.25″ and 4.25″. (centered, approx)
There’s a photo of it here.
I think we’re working from different designs… OR – my hole-A is in the wrong spot (possibly worn in through mis-alignment?). What’s more of a mystery is your measurements from the gear though — look at the photo, do we have different gear pieces?
All that aside, I think the actual answer to this is simply to install a longer stop screw.
I believe everything is realigned, and the only issue is that the Print-side stop-screw isn’t stopping… so I’ll trade that out and call it a day….
Any objections to that idea?
I’d also double check the position of the gear/cross-rod. On mine there is a screw-hole on the operator end of the cross-rod (to connect chain for counter). On trip, the hole is at the 12 o’clock position, but on print it rotates 180 degrees counter-clockwise (from operator side) to the 6 o’clock position. If the cross-rod was instead at, say, 1 and 7, the cylinder wouldn’t sit properly on print but would raise slightly (and sit slightly low on trip too).
Yeah, my manual seems to show the same, but different enough that I wondered. I’ll take it all apart again tomorrow and have a looksee.
The safety bar is correct as shown in my manual, Sheet 81. Note the contour on the right end to accommodate the trip wedge.
Ok, so I actually just got back home from the shop, re-assembling the SP-20 we have (one thing led to another and suddenly it was all apart)… So I’m not in until tomorrow to do measurements, but I had a thought.
Is the Safety Bar on my press upside down? (see the note on the image).
Odd. Where exactly is your dimple B located? Measured from the top of the bar, I have dimple B at approx. 6″ and A at approximately 9-3/16″ (centers). Or, from the gear, B at 1-3/4 and A at 4-3/8″. Or, from the stop-screw, B is centered at 7/8″, A at about 4″. When dimple B is engaged, everything is positioned correctly to print. I note that the screw that holds in the spring-and-ball retainer is about level with the surface for me, yours is tighter.
Again, I just don’t see how it can be positioned at this level. After the trip wedge pulls the bar down there is a horizontal bar that keeps the bar from raising during the print stroke. And the stop-screw keeps it from going any lower.
The photo of the dropped trip bar doesn’t jibe with the photo of the gap between stop-screw and housing. They couldn’t BOTH be happening on my own 325. I could see that drop if the stop screw was absent. And the drop will give extra rotation to the gear that turns the eccentrics, raising the cylinder.
It does make me wonder of something is mis-assembled somewhere, but I can’t imagine what!
So there is a problem. My stop screw doesn’t touch.
In print mode, this is what the inside of my trip assembly looks like.
The stop screw sticks out 7/16″ and that is what sets a 7/16″ gap between gear rack and housing. The stop screw should contact the housing.
I don’t see how the trip bar could drop down lower than 5″ as shown in the picture if the stop-screw is present.
The stop-screw is not shown on the 325 parts list sheet 58. Maybe it was added later to prevent cylinder bear-off. But why should you experience cylinder bear-off when the stop-screw is present?
Are you saying there’s supposed to be a 7/16″ gap or that the set screw should touch during the low/Print position?
When the trip assembly on my 325 is in the low/Print position, and the ball clicks into dimple B, the square-head stop-screw leaves about 7/16″ between the gear rack and the housing. And the bar extends 5″ out of the housing (as opposed to 1-7/8″ on trip).
If the bar drops lower than that, then the cross-rod would turn over and start to raise the cylinder again. The stop-screw should prevent that, when properly set.
OK Eric –
You’re totally right. A and B are the correct distances apart, and the correct placement.
However, I still have a problem.
See this image and it’s notes.
Long story short, this happened when I was basically printing large forms on full sheets with (probably) too much pressure. If I printed s-l-o-w-l-y, I could keep the print pressure correct (dimple B). If I printed too quickly, it knocked itself past the the Print setting, pushing the Trip Rack down an extra inch or so (to dimple C) and lifting itself back off of the press bed a fraction…
So now I think perhaps my stop screw is the wrong screw. Mine is about an inch long, and won’t reach down far enough to actually stop and hold pressure. (See the image linked in the previous comment.)
Thanks again for your help.
hi Eric – thanks for your help. Here’s a new mystery to consider then.
I would argue that it is in fact A and C that are present on your press. With the housing and Trip Rack removed from the press and manually adjusted from Trip to Print, the square-headed set-screw does not touch the inside, i.e. the stop doesn’t stop. See here. This coincides with the initial problem I encountered which involved the Trip Connection Tube over-rotating and lifting the print cylinder back off the press bed (since the trip/print assembly merely lifts straight up and down when left to spin freely.)
Thanks for your help – I’ll dig back into it tomorrow.
When the press is on print, aren’t the cylinder bearers in contact with the bed bearers?
On my 325, dimples A and B are present. C would not seem to have any use, as it just could not drop low enough to engage the retaining ball. I doubt it is the exact position of this gear rack that is the problem, though that square-headed set-screw does affect final position when on impression (just as the allen-head set-screw at the top of the housing controls position off-impression). The rack is pulled down by the first trip wedge (flipper) to impression position, and pushed back up by the second trip wedge to trip position. There shouldn’t be any intermediate position, unless there are other missing parts.
To get to Print position, the cross-rod turns 180 degrees clockwise as seen from the gear side. Mine happens to have a vertical line scribed in it, but it probably isn’t a factory mark. The eccentric blocks have two extreme positions, low being Print, high being Trip. When you reassemble the impression mechanism, slide the gear rack all the way into the housing, rotate the cross-rod until the cylinder is at its highest possible position. When meshed, that should be properly aligned.