I noticed that on our SP-15 the ink drum was not getting any ink on one end of the drum while inking fine on the other end. My suspicion is that the spring has weakened to the point where that end of the drum is lower. Are there other conditions we should look at which would cause this condition? If it is a weakened spring, is the replacement a difficult job?
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paul – pretty sure I adjusted a sp-15 ink drum this way, although it’s been a minute
Yes, it was an SP20, thanks for helping me remember. The 4 has no drum adjustments. I did get to see a 20, two in fact in the last week, so it can be done at least on that model.
Paul,
I saw you do at one of your workshops back in 2004 at the Minnesota Center for Book Arts. You adjusted the hex screw on the low side and the low end of the ink drum rose up and then it had even ink coverage. They were very grateful that you fixed the problem. So you did do it there. It was either an SP20 or #4. I was just at the Hamilton Type Museum today and they have an SP15 with this same problem.
Just looked at Daniel Morris’s two SP15s. The hex screws do not allow the drum to adjust side to side. But I swear I did this once on an SP20. (I will see one again this weekend.) So the thing to do is replace both springs for equal tension. Perhaps also the rear roller is undersized, it should be 2.5″ in diameter.
Well, I for one am hoping you are right and you’ll find some neat little gizmo which enables an adjustment of the ink drum by fine tuning those screws. You would have thought a provision for adjustment would have been built-in, given the weight of the motor on the farside.
I understand that there were several design changes during the production run. I will see another SP15 in Brooklyn in the next couple days, but I’m prepared to be wrong (again).
Hi Paul
The bracket is threaded all the way through which means the screw just tightens the core to the bracket. The shaft through the core has no thread. Nice idea though!
There may be a variance between earlier and later models maybe?
The manual from NA for the SP15 does include the sheets I mentioned. I am in Rochester, New York at the moment looking at an SP15 which looks exactly like yours. The flange I was referring to is what you are calling bracket (A)–perhaps a more accurate term. It was my understanding that screw (B) pushed off bracket (A) in the same manner as the roller bearing blocks, and because the screws are not long the adjustment isn’t dramatic. As often is the case, there may be more than one factor at play.
I’m glad this has came up because I have a query regarding the balancing of the ink drum too.
Referring to an annotated image I’ve put up on flickr:
http://www.flickr.com/photos/8286330@N03/3463842670/sizes/o/
On my sp15 the ink drum is fixed to the motor unit with a hex head screw (B) which passes through the ink drum shaft (C) and screws into a bracket on the motor carriage (A). There doesn’t seem to be any flanging to control the height. As a work around I’ve balanced the ink drum by inserting more plastic washers (D) and homemade card ones (E) at the unit pivot (F). My query is this – am i missing a part or is my hex head screw different?
Oops, sorry for the misdirection.. my SP15 manual isn’t terribly legible. I’ll have to buy another press and get myself up to speed (grin*)..
Kyle/Paul, Thanks for the information. I’ll remove the cover plate and check both the spring and the adjusting screws.
Paul, You mentioned a reference to sheet 282-A of the manual. The manual we got with the press is very limited (only has sheets 246, 247 and 248). Does the manuals offered by NAGraphics include the sheet reference you listed?
In addition the springs, the side to side balance of the drum is adjusted by hex head screws on either end. The bottom of the screws contact a small flange: right raises and left lowers. See Sheet 282-A of the manual.
When you remove the vented cover plate behind the ink drum you’ll find that the SP15 motor sits on a plate that extends under the drum where it secures the lower end of the springs. When the drum is pushed downward the motor and plate raises up.
You’ll see also that the SP15 has a belt and not a chain driving the ink drum from the motor.
There are 2 springs holding up the cylinder on an SP20 (and presumably the SP15s as well), one on each end. Ours has broken repeatedly, on both sides, over the past 4 or 5 years.
I keep replacing it with something that is the same length/size from the hardware store, but I know for a fact that a specific spring is sold by NA Graphics for it (I’ve been advised to switch over, but I’m always in a pinch when it breaks, then forget).
It’s a little frustrating to replace, but is necessary. It’ll be easy to spot on whichever side of cylinder isn’t inking. It hooks onto a stud sticking out of the side-rails, and on a stud sticking off the cylinder support. If it’s on the chain side, you’ll probably be hearing a new rattle too… (loose chain). Order a new one and swap it out. I recommend using a pair of needle-nosed vice grips and a screwdriver (to fit in where your fat fingers won’t) when reinstalling.