The trucks on my Pearl #3 are not rotating at the mid-point of the rails (midpoint as measured from bottom to top). My general question is: Should trucks and rails have oil on them or should they be dry?
I read Briar topics #16129, 17671, 17893 looking for answers to my general problem and to my specific question about oil.
Rollers are 1-1/2” and the trucks are 1-3/8” which is factory spec. I tried trucks that were larger 1.425” and the rollers touched the frame at the bottom and they still didn’t roll except at the top and bottom of the rails. All of the trucks spin easily on the roller cores and there is plenty of clearance between them. I oil this clearance and the saddles. There is good tension of the saddle/hook springs. They are the originals from their appearance.
Conditions: The trucks turn easily in the saddle hooks and the rollers turn easily inside the trucks when rolling over plates/type, but slurring occurs at the first line of type encountered by the roller (bottom of chase as installed in the press) since that’s where the roller first begins to turn. The trucks slide over the rails and don’t turn, except at the top and bottom of their travel. The trucks are touching the rails (tested with tissue paper feeler strips).
I tried adding black friction (no pun intended) tape and it improved the situation somewhat, leading me to the question about oil on the rails and trucks.
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Rollers should not be turning freely within the trucks. (Some Kelsey rollers were designed that way, but it is bad design practically requiring the roller bearers Kesey also sold.) There should be pins, or lugs crimped into the roller core, that fit into slots or recesses in the truck, fixing their relative position. Otherwise the roller may not turn until it is driven by contact with the form, with slurring at the lead edge.
Surfaces of tracks and trucks should be clean, not oiled, which will cause slipping.
parallel_imp is correct that the trucks should not turn on the roller core/shaft. If there is no other way to secure the truck to the roller, one can put the truck on the roller shaft with a piece of string between the truck and shaft (this may require some oomph (but not a lot) to get the truck on, the idea being the bind the truck to the core—while still being able to remove it later as required.
You should secure the trucks to the cores so they rotate as one. I’ve done this successfully with a couple of lengths of waxed dental floss run through the truck alongside the core. If the truck won’t slide right over it you can drive it on with a rubber mallet.
You don’t want any oil on the trucks or rails, just a drop where the core rotates in the roller arm.
The Arm Letterpress
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