the throw off mechanism on my C&P OS is not working. I noticed that they had the arm upside down in the back, so I put it back right side up. Now there is a 1.5 cm gap between the chase and platen when the trow off lever is engaged, and disengaged. A friend recommended I disengage the entire throw off bar in the back altogether, but i would rather not do this. I would try to level the platen, but I dont’ think thats the issue if the gap is the same when the lever is engaged and disengaged…Any suggestions….please.
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It may be that I’m not understanding you, but there is supposed to be a small difference in the bed position between the two throw-off positions. Forward (toward the operator) is engaged and back is disengaged.
Put some type in the chase and add that to the mixture. If you get an impression in the engaged position and not in the disengaged position then you’re good to go.. The chase is never going to hit the platen.
You may still need to level the platen to get a good impression. Search the archives here and on letpress; its been described often.
Arie, Sorry for the vague post.
I did as you suggested and nothing. The gap between type and paper is 1.5 cm…
The thing is that when I remove the throw off mechanism in the back, it makes a perfect impression.
I am new to letterpress and have been printing without the throw off lever mechanism, but would like to use it… I have searched through every post with “throw off lever” in it, and have not found one that would help. I think I may need someone with mechanical knowledge to assist me.
Thank you very much for taking the time to reply, I so appreciate it.
OK, try this then. Standing on the flywheel side of the press, put the throw-off on impression and then off impression and watch the back shaft. That’s the big fat shaft on which the side-arms are attached. The side-arms are attached in a position offset from center and it is that motion around the center of the back shaft that is supposed to move the bed back and forth a bit to take the type on/off impression. You should be able to see this movement.
A few photos of the connections of the throw off saddle, the side-arm attachment to the backshaft, etc. would help.
Also, where are you? Maybe there’s a printer nearby that could take a look and get this working for you quickly.
I was away and just returned. I did as you suggested and as I watched from the side I noticed there was a “hiccup” every time I would engage/disengage the throw off lever. Upon closer inspection i noticed the throw off saddle is about to break in half. I unscrewed, and sure enough, it had been welded previously on the bottom and has now “given up”. I am suspecting this to be the cause of the cylinder not being able to adequately rotate. I am now in search for a replacement throw off saddle.
Thank yo so much for your time, it is very appreciated.
I would suggest repairing your part. If brazed by a qualified shop, you will come out money ahead.