Slipping Tympan

Is the topsheet moving or the packing? The topsheet should be clamped under the bails at the top and bottom. If the balis are loose you may be able to bend them slightly in the center towards the platen so they exert more pressure on the paten when you lock them down. If the packing is slipping out from under the topsheet the topsheet is not tight enough. There are several ways to get it tight.

Or do you mean something else? What specifically is the problem you’re experiencing? If this has something to do with an automatic feeder on the Craftsman someone with experience with those will need to help you.

Rich

Front Room Press
Milford, NJ
http://frontroompress.com
http://frontroompress.blogspot.com

The top sheet that clamps at the top and bottom. First I set the bottom clamp to hold my top sheet. Then I pull it taught to clamp the top and the bottom slides out. I’ll try bending the bail in toward the platen. Just didn’t know if that, some tape around the bail or something else was the most often used reco. Bending sounds good for more pressure in the center of the bail. However my top sheet seems to be slipping more toward the right hand corner of my sheet.

You could also try increasing the thickness of the paper you are clamping under the bottom bail by adding some additional draw sheets folded with the bottom lip. Or try making the bottom lip by folding the tympan two or three times at that edge, if the sheet is large enough.

Brian

The bails should clamp tightly. Manufacturers usually supplied a gripper wrench that often on one end had nubs that were used to interlock on the bails and act as a wrench. Some printer’s made their own, others used a screwdriver. There should be more than the thickness of the topsheet causing friction that holds the sheet and bail in place. The bails should press against the platen and have to spring out a bit in order to clamp down in place. Besides not holding the topsheet, if the bail is not tight it could open up while the press is running with predictable and messy results.

Rich

Front Room Press
Milford, NJ
http://frontroompress.com
http://frontroompress.blogspot.com

The bail locks into place firm enough to not flap open when the press is running (spring loaded). The bail is just not tight enough on the bottom to keep the top sheet from slipping when pulling taught. I have tried rolling the sheet over for twice the thickness but it still tends to slide. Unfortunately there is not enough sheet to fold three times.

SC

Besides the obvious regarding clamping, the grain direction of your packing material, for any press, should be parallel to the rollers to prevent slippage.

Gerald
http://BielerPress.blogspot.com

you could try clamping a sheet or two of your packing on the bottom with your topsheet, i have also used tape on the bail, but the tape don’t always help. gerald, i would never in a million years have given the grain a thought, but that is a good point and i can see how that could cause the packing to slip, good luck dick g.

Clipping the corners of the packing is a common practice to improve the hold of the bales. I always have a couple hangers clamped in as well, carefully folded with a straight crease. After setting the bottom bale, I grab the topsheet and gently pull to see if here is any slippage or twist.
I worked on one old press whose bottom bale was too loose to clamp, and shop practice was to insert the tail of the topsheet from below, tape it to the bale, then bring it up over the bale and platen to the top bale, which thankfully, did hold.