Galley Press

Your idea of packing the cylinder might work but it’s not the best way to go because you will change the surface speed of the cylinder slightly. Since the cylinder is geared to the cogged rack on the bed, the cylinder surface, being made bigger, will be going very slightly faster than it should be. In a worst case scenario, this could cause slur (the paper on the cylinder would be going faster than the type), although as I said you may be able to get away with it here.

The easiest thing to do would be to get a galley. They are cheap and plentiful. Another alternative would be to go to a local sheet metal shop and have them cut you a piece of .050 metal the size you need. I Googled sheet metal gauges and brought up this chart: http://www.larsontool.com/formulas.cfm

As you can see, 18 gauge stainless steel is .050, so that would be a good choice. Being stainless, it wouldn’t rust or corrode either.

There are also places online where you can order pieces of sheet metal, and if you live in a populated area, you might have a cash and carry metal store nearby, which caters to small orders and can cut to the size you need.

I owned a Challenge 15 MP and bought a bed plate that was the length of the press bed. The cost was about $65.00, this is your best solution.

I wouldn’t recommend adding extra packing to the cylinder. The packing needs to be placed under the form to raise it type high which would require a lot.

I bought the sheet metal local here in Dallas and they cut it on the spot. They also ground the edges so no metal burs were present as well as hitting the sharp corners.

Casey
Inky Lips Press
McKinney, TX

It’s my understanding that the bed of a proof press does not move? The cylinder passes over a stationary type form. It should not matter what the cylinder is packed to as long as it is enough for impression.

Slur from an over or under packed cylinder only applies to presses in which the bed moves and is timed with the cylinder, such as a Heidelberg. The speed at which the bed moves is a fixed based on the recommended total (packing plus paper) for the cylinder. On my press the total is 1,4mm iirc. Setting the packing so the surface of the sheet s over or under this amount changes the speed of the surface of the paper in relation to the fixed seed of the type bed causing the slur.

Even though the bed of the proof press is geared, because the bed and type form do not move there is no timing between the two. You should be able to print the same Mormon moving the cylinder t different Leeds and see no difference in slur.

Lammy, on the Poco the bed moves under the cylinder, i think the challenge does also but i’m not sure. never paid much attention to it before but i believe most proof presses the type doesn’t move like you said.

I have to agree with Geoffey. Some proof presses have moving beds, some have stationary beds, and Challenge made both types. In either design, if the surface of the form is below bed bearer height, and the surface of the cylinder is above cylinder bearer height, then there can be slur because the cylinder surface will be travelling fast relative to the form, no matter which one is actually in horizontal motion.

I appreciate the comments and recommendations.

The Challenge MP 15 is a clone of the Vandercook SP15. The bed does not move - the cylinder rolls over the top of the type or photopolymer plate.

My hesitation with a galley plate is getting one that is absolutely flat and won’t “rock” as the cylinder passes over the type or photopolymer plate.

As an alternative, I am wondering if i can use deep relief photopolymer plates with a standard depth boxcar base and get the plate closer to the cylinder

thanks again to all

carolinaprinter