When I got it, my SP-15 had springs attached to the rear roller(photo attached). I’ve noticed that the tension causes the roller height to decrease rather than helping to hold it steady. There’s no spring shown in the manual & it looks like someone long ago added a bolt that would anchor the end of the spring. Is this a practice that others have noticed? Was it considered a ‘fix’ for the tendency of the roller height to get out of adjustment? I’ve had the springs off for a few weeks now, and it seems better without them.
Oh, just a further note in this regard. These are not production presses, they are proof/repro presses. If you are trying to edition with them that is not what they were designed for. That is your thing, not theirs. You have to figure this out for yourself. Basically, if you are editioning, learn the squat position at the end of the press, and learn to love it.
Yes there is a tendency of the back spring to pull down so the roller height decreases on the back roller. The correction to this is just a matter of monitoring your roller height on a very regular basis during a print run. OR. If this is a serious concern and I am not sure why, you could simply build in steel braces for both front and back rollers to prevent any movement. And adjustable two-part braces if you like to allow you to make subtle movements. There are enough threaded holes on the SP-15 for this purpose and if not, drill and thread.
It won’t work though.
Thanks Eric for the advice to keep the springs…I ordered a new pair from Fritz because I’m sure the ones on there were not the originals & had too much tension. Like some of us using the press. Great description of making sure that tightening the screw increases only the grip in the bearer block: I have tuned them a bit with good results.
I would keep the springs. Their purpose is to keep the roller in solid contact with the ink drum; you can’t get good ink distribution and supply without that. If the roller height is slipping, it isn’t because of the spring, but more likely an expansion of the slit in the bearing block so that it doesn’t actualy tighten into a fixed position, which is very common.
As I wrote in an earlier thread: “You need to tighten just the inner end of the slot, not the outer end.
I’ve done this by placing feeler gauges at the outer end to fill the space, then carefully hammering above the spot where the slot meets the throat. That directs the force where it is needed. And it will reform the block so that tightening the screw will bear against the threads not the slot.”
Thanks for the manual page Paul…
I see some other differences in that 1969 photo…the nylon wiper assembly for one.
I’ll leave the springs off a few more weeks and see how it goes.
Sheet 283-A is dated 1969, but I have seen these on slightly earlier presses.
An earlier post mentions that the hold-down springs were added when the SP-15 changed to a lighter oscillator…I wonder if mine was built before that…the press is operating well without the springs, which didn’t seem to be original. Serial number is 24611, circa 1964.
This spring appears on Sheet 283-A of the SP15 manual.