Platen Height, Adjustment levelling.

Hi,

Does anyone know the exact measurement the platen should lie parallel to the bed?

I’ve seen theres’s a tool someones made but I think postage to the UK might be a little high and am quite happy making something myself.

I was thinking about having a piece of steel ground down (family friend favour=free) to the exact depth and big enough to only need a pair of quoins to lock it into the chase and work from that.

Thanks

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Doesn’t really matter. Anywhere from .04” to .08” will work. If you want to be able to print thick substrates or put on a die-cutting jacket, leave your undercut larger. I believe the platen leveling gauges sold recently here were .968” or .04” deeper than type-high, but I could be remembering incorrectly.

I suggest that you don’t really want something to lock into a chase. You want something you can move and feel with.
Packing plus tympan sheet is about .050” That plus type high (here in the colonies) is .968” A metal piece of about 3/4” across will do well. This is to be fitted to a stick. Threaded to a metal rod is very good.
Lower the platen with the platen screws. Close the press with the impression on. No packing or tympan sheet. Place your measuring device between the platen and bed near one of the bottom platen screws. Adjust that screw to the point the measuring device will stay in place. Not tight-tight, just snug. Then do the other bottom corner. Then the two top corners. Then go back to the bottom corners as the top adjuetments will usually affect the bottoms. Then back to the tops. When all feels good, tighten the platen screw nuts.
For normal paper weights, once the platen is brought parallel to the bed, you should never have to adjust it again. All future work is done in the packing and special makeready.
Now get some ink on your shirt.

You are correct Modernman. The gauge I make is typically .968, but, I have made some at a different dimension and the exact dimension is not critical. (few people pack their press the exactly same) This dimension allows for 50 thousandths of packing. Your design may work just fine on your press, but, remember you need to be able to see the bottom two corners, and there is another issue described below. That is why I went to individual cylinders. You might ask your friend to mill down a small rectangle maybe 1” wide that would span the height of your platen and have him put it on a rod to hold like the other roller gauges and my platen roller gauge combo. I would be wary of locking anything up.(unless your are doing the traditional type method) I recommend being able to move my gauge slightly when adjusted correctly. If you try to lock up against something solidly, you don’t know if you locked up harder on one corner or the other. I found this out by experimentation. I recommend being able to move my gauges slightly for correct adjustment. Yes, it takes a certain feel, but, I believe it is better than locking up solid. When you are making a gauge for your own press only you can think differently than when trying to make one work on everyones press. In any design though, I think you need to see the bottom. If its a really big favor you could have him make two rectangles and hang them on your bed to be able to make adjustments to all four corners at once. That was an early design I tried before going to the one lollypop type. IMHO

JF

Inky,

I was composing while your were posting! If I had known, I wouldn’t have bothered. You covered it all better than I.

JF