Milling a replacement ink disc
I have a CNC and would like to attempt milling replacement ink discs for a Kelsey 3x5 and a Sigwalt #5. I created some CAD models based on pictures of the ink discs and 3D printed some prototypes.
Has anyone attempted to mill an ink disc from aluminum?
My recreations are not exact copies because I lack original dimensions. Is there anyone in the mid-atlantic region with these presses that would let me photograph, measure, and maybe take a mold of the ink discs?
Four criteria for an ink disc for a platen press like the Kelsey or Sigwalt or similar: the diameter of the disc should be equal to or slightly more than length of the roller covering (rubber, etc), its top surface should be level with or very slightly below the ends of the roller rails, so that the rollers transition from the rails to the disc smoothly, and the disc needs a series of radial ridges vertical on at least the side the pawl engages, so that the advancing pawl can securely pull the disc ahead; and the “stem” or bearing shaft of the disc must fit into the disc support bracket’s hole, loosely enough to spin freely but no looser, so it does not wobble as the rollers pass over it. The thickness of the disc is only a function of the placement of the advancing pawl as regards the radial ribs; outside the circle of radial ribs the thickness is not critical but should probably not be greater than the tops of the ribs.
Beyond that it is best to round the edge of the disc to prevent it cutting the rollers.
Bob
Bob, My Sigwalt #5. ink disk has a light wobble - wondering if it needs to be shimmed. any advice?
I have a 3x5 disk and maybe a 6x9 Sigwalt disk in future.
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I have made disks with aluminum.
you can simplify the ratchet marks on bottom, as long as paw can catch on them.
Jag, a slight wobble should not be a problem if the rollers travel onto and off the disc OK. If you lift the lower edge of the disc, how much movement is there at that disc edge? You could get some 80-90-weight stick-shift transmission oil to lubricate the bearing (lack of lubrication is what caused the wear) and the thicker oil will cushion the disc and stabilize it some.
lifting the lower edge it only shifts about 1/16”- side to side about that too. I did lube with some silicone based bicycle grease.
I suspect my Craftsmen Imperial never saw any lubrication-
I rebuilt it a bit with an aluminum ring packed with JB Weld and added a bearing washer too.
before and after photos:
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4467F4AA-B234-4D77-B43F-22D963A573E5_1_105_c.jpeg