Sp-15 Carriage “hopping” down the bed
Wondering if there are any hints for me- just toward the end of my most recent project, I found that the carriage was “hopping” down the bed, somehow the gear on the ink roller was becoming disengaged from the gear on the bed of the press, causing it to misfeed all the way down. It sounded like someone running a finger along a comb. Also, I found that I had to adjust the roller height much more frequently right before this happened (the back roller would ride low and heavy). Maybe these are related? HELP! Thank you! Ann
Some SP-15s have a hold-down for the rear roller, a spring between posts on the roller bearing block and the outside of the cylinder carriage, on the gear side of the press. Spring may not be present. Also check theay the setscrew in the gear is tight, since such vibrations have a way of working things loose.
The SP-15 also has a starting tooth at the beginning of the roller gear rack, a short pivoting gear segment that aligns the gears. There should be a spring under it.
And many SP-15s have poor control over roller settings. In the roller bearing block there is a lock screw (might be hex-head or allen) that should be loosened when turning the adjusting knob, and tightend otherwise. Some just don’t hold tight any more, especially if people have not been loosening while adjusting, or if excess oil has gotten into the threads. One thing people have done is to mark the knob so you can tell when it shifts.
It could certainly be something relating to the starting tooth. Is it moving freely? Is it in good condition?
You may also like to check out whether the rollers have been cast to the correct diameter. If you are having to set them too high then the gear won’t properly mesh with the gear rack and will do that awful chattering thing you describe.
Are the Nyliners in place on the roller core ends?
Daniel Morris
The Arm Letterpress
Brooklyn, NY
Hi Ann
In addition to Eric’s and Daniel’s suggestions, you might be running too stiff an ink and you might be moving the cylinder much too fast down the bed; I’d suspect a combination of the latter. These can also throw your roller height settings out of kilter. Nice and easy it does it with the Vandercook, it’s not made for production and hurrying it along is somewhat counterproductive.
Gerald
http://BielerPress.blogspot.com
Thank you for your suggestions- I’ll look into it and post again!