Platen adjustment snafu

I have been steadily attempting to restore my grandfather’s C&P NS 10x15 for the last year. I realize I should have left well enough alone, but I attempted to remove the platen.
At some point in history, the upper Right corner of the platen was broken and repaired. It is smooth on top, but was very rusted underneath that area. I wanted to remove the platen, get the rust off and paint it to protect in future.
I could not get it off because at some point in the removal process a couple of the impression screws stopped turning. So I then tried to get it back where it originated and just paint what I could reach.

Now I can’t get the corners level again! It binds up and hits the rails when the throw-off lever is tripped to print. As soon as I get the bottom or top to not hit, and try to adjust the other side, the opposite end of the platen binds. How should I go about fixing this if the screws (mostly the top two) stop wanting to turn? This is the last major issue to work through before installing new rollers and giving her a go. Any help would be greatly appreciated.

Log in to reply   10 replies so far

It sounds like your platen is way too high. I would screw the studs back in, (Clockwise), and start over with the adjustment. If you have 4 of the same letter, figure, number, etc, lock these up in each of the corners of the chase. Put your makeready sheet and tympan down over the platen. Now bring the platen up(Counter Clockwise) with the studs. Go easily. You will find that as you bring up the platen, it will “Teeter Totter” a bit, as the studs are not directly under the end of the corner, Bring the platen up to equal pressure on your images. Make sure you are snugging the nuts for the studs when checking pressure. When you think you are in a good place, Tighten the bottom 2 nuts, then watch closely as you tighten the top 2. Watch for the nut possibly “Pulling” the platen down. Look for any gap between the studs and rocker. You are ballancing 4 studs so it is possible to have one out of balance. Ever have a 4 legged chair or table that rocks? This needs to be corrected so the platen is not just level, but Balanced.

Mari23, have you fully loosened the nut on each stud? When you look at your top two platen bolts, the piece in the center is the adjustment, the piece on the “bottom” is the tightening nut. Im wondering if you are bottoming out the locking nut as you adjust it, you may just need to loosen it more. Like ericm said, screw the bolts back in clockwise as much as you can, and start over on the adjustment.

Also, from experience the platen is very heavy. Like think 100-150 lbs, and it isnt a fun piece to take off or put back on. Once you sort out these adjustments, it is probably is best to leave it alone. Good luck! If you need more specific help, feel free to message me through briarpress. Photos may also be useful to help with the issue.

Adding to BComstock, have the bolts been fully tightened before test impression? An associate did all testing with nuts still loose, with false results.

Thank you all for the responses. I will try to post pictures tonight.

I have loosened or removed the locking nuts. I think I need to raise the platen so that the same amount (approx.) of threads are showing for all four screws and then very systematically try to lower the platen.

So sayI start with the top Left screw, are you saying I should go clockwise (Left top, Left bottom, Right bottom, right top) or counter-clockwise? And should I be tightening the locknuts after every small turn? Or wait until at least 1 round tightening each bolt before turning the flywheel to check?
I have not tried to test an impression yet, as at least one side of the platen keeps binding and hitting the rail, so the flywheel won’t turn over. My press is also missing the top Tympan bale ( I think easy to have manufactured locally) and I have no Tympan yet! Grandpa made it work somehow, as a chase is still set with the letterhead for his farm from 40 years ago.

Thanks again for the advice, I will keep you apprised.

Another approach:
- Loosen the adjustment screws.
- Lock up a form with a large character in each corner. Since you are missing a bale, place some packing behind the form. Put the press on impression and turn the wheel until the press is closed.
- Now tie the wheel so the press will not move. You’ll be working inside the press and you don’t want it to turn!
- Push the platen from underneath until it makes contact with the form and turn the screws until it is snug.

This should get you to a fairly level position, and you can fine tune from there.

Figuring things out slowly. The culprit seems to be the front Left impression screw. I ended up removing the platen. This particular screw seems tighter than the rest. I tried all the other screws in this hole and it gets almost impossible to turn about 3/4 of the way in. Not sure if I just need to clean the hole out really well and lube it, but I will see what I can do and have someone help me install the platen this weekend. See where we end up.

image: Platenoff.jpg.JPG


This sounds to me as though one or more of the adjusting screws is distorted or even slightly bent from an accident in the remote past (possibly from the incident which nipped the corner of the platen). There may be a machinist near you who can “dress” the threads, both internal and external, to resume normal adjustment. And above everything, don’t force the screws back into the platen; that might result in cross-threading, which in this case would be serious, and might result in stripping some thread. Lots of luck!

Even into the 80’s, the platen adjuster screws were quite tight. When I mentioned this to engineering, they said it was so the screw would stay in place. 2 reasons. 1) the screw would stay in place during adjustment so that only 1 wrench was needed. 2) The screw would stay in place if the lock nut came loose.
When I run a tap into the platen, and a die over the screws, the inserted screws are very loose. I then need 2 wrenches to hold the screw in place and tighten the nut. I think there is some sort of slight “Interference Fit” on purpose.

Fixed! The press will now turn over without binding. The only little things to fix now are the ratchet pawl for the ink disc. The little piece of metal is worn so it is not catching the disc and can’t turn it. Should be easy enough to fix. And reinstalling the roller holders. Saw something online about using a small length of pvc pipe to hold the spring while you insert the pin.

Thanks everyone who responded with advice. I’m in a rural area and there is no press shop anywhere near. I truly appreciate it. I’m sure I will ask about something else at some point.

image: 10FD13FF-B4CE-4C6C-AD57-E9347CDF0AF6.jpeg


As you are in a rural area….lots of old farm machinery eg seed drills etc used ratchet and pawl mechanisms… might be possible to adapt you find on something old and abandoned?