The platen portion of the Kelsey Letterpress is made up of two main castings, the platen and the platen back. These two pieces are held together with a very strong spring held in place by a dowel. The screws on the platen back are not for holding the pieces together, but rather for adjusting the impression pressure.
BEFORE:
When I first removed the dowel platen back, the dowel holding the spring in place was deformed and the impression screws had been stuck in place by the bad spray painting job.
As with all the press parts, I sandblasted the paint off and primed and repainted both the platen and the platen back. The original impression screws were old round headed “stove bolts,” covered in spray-paint and rather beat up. So we decided to replace them (and the nuts). We went with stainless steel socket head cap screws. The advantage to this type of screw head is that it holds the hex key captive and allows for a more precise adjustment for the impression screw. We chose stainless steel both for its durability and because it matched the stainless steel rod we got to replace the original dowels holding the press parts together.
(we also replaced the nuts with new stainless steel ones and added washers between the nut and the casting to avoid wear on the contact point.)
Getting new screws was easy, but figuring out how to re-compress the spring AND re-insert the dowel was more complicated. Luckily Doug has access to a machine shop and scrap aluminum. He managed to create a little spring compression jig to hold the screw in place while inserting the dowel:
He drilled a hole in a chunk of aluminum that was just wider than the spring holder/guide on the platen. He then cut two grooves into the jig (wider than the hole for the dowel pin). We then put the jig into use with the Arbor press:
An arbor press is a small hand operated press that is typically used for punches, inserting rivets, and things like that. In this case, we used the strength of the arbor press to compress the spring. We fit the platen and platen back together, put the spring over the spring holder/guide, and topped it off with Doug’s new aluminum spring jig.
The arbor press compressed the spring easily, and the grooves that Doug cut were just deep enough to expose the hole for the dowel pin.
The dowel slipped in nicely and when the pressure was removed the spring was in place and perfectly tensioned. I should probably mention that I used the original spring. I just removed all the old paint, cleaned it up, and rubbed some paste wax on it to protect it and minimize rust.
The final assembly came together very nicely! The shiny new hardware looks great against the new black paint job.
Coming soon, the final assembly of the whole press!
