Choosing the Right QUOINS

different quoins take different keys. i think the hi speed quoins are the best, but more expensive. i use mostly hi speed but have many wickersham quoins that i still use, you can get by with 2 or 3 quoins but sometimes you will need a couple more, i’d try for 6 quions. Dick G.

friend printer,
I have a dozen surplus regular quoins plus key I can ship
for $50 postage free. SAL

.

If you have a windmill then you should really consider the high speed quions. That is what they were made for. Any press that will produce production speeds above 1000imp/hour. The windmill can reach 5000imp/hr.

high speed quoins set up much faster and hold better, i have access to all you could want. from 2 inches to 6 inches. there are a few keys available. but you can get them new also.

quoins_key.JPG

If you use the high speed quions be careful not to over crank the key, you can crack a chase.

Some photos of different types of quoins & keys:

http://excelsiorpress.org/forsale/fundraising.html#quoins

Challenge High-Speed Quoins are the best - and most expensive - that you can get. New quoins and keys are also available from Bar-Plate and other suppliers to the die-cutting trade.

And, for the Heidelberg Windmill, you really SHOULD ONLY use high-speed quoins.

- Alan

In the trade in the uk we all use regular cornerstone quoins , they are adequate and only a problem if you overtighten them to the point they spring the forme, this can happen regardless of the sort you use , alternatively the only other problem is if you overtighten to the point that you strip the thread out of the wedge in the back of them both problems are only through error on your own part not the design of the quoin .They only need nipping to the point of tight you are not in competition to do them up so tight no other beggar can release them easily , i have a problem with a minder that gets through loads of quoins he is stripping the threads all the time and it pees me off . I am sending you some that we use all the time ,if you dont have a quarter inch square key i wiil soon hear and will sort that too. If the quoins you have in that illustration are hih speed to you then you welcome to them they operate on an eccentric bar/ cam they come loose on long cylinder runs which is why we use cornerstone quoins , under no circumstaces would we ever use the harrild design ones that have two little springs that close them and these were similar in operation using a cam . they fine for storing a locked forme away but not for running the press . It should be noted that many of the quoins around are premotorisation and therefore not to be used on later motorised equipment. You can lock up a hand cranked proofing press with two opposing wooden wedges and its no problem but you would not do the same with a heidelberg platen or vertical miehle.

Challenge high speed quoins work on the principle of two opposed stepped horizontal wedges, with a spring that prevents slipping, not eccentric cams. Those of us who use them know they do not work loose.
Cornerstone quoins can use the same key as the common Wickersham quoin, or less-common Hancock, Notting, or Tru-Forme quoins. The last three use a vertical wedge action similar to that used in the Cornerstone quoin. The one thing Cornerstone had above other similar designs was a key, the Click-tight, that prevented over-tightening.
I’ve never had either style of quoin come loose on platen or auto-cylinder. High-speed quoins and keys are still being made new, a rare thing in letterpress.

You can still get new cornerstone style, but they are basically of poor quality construction not as good as the original ones so i hoard the old ones. The new ones were £15.00 each and basically crap , the company supplying them also sold second hand cornerstones for £7.00 each , criminal really when they are on E bay for next to nothing.
Whilst i would recommend cornerstones you have to be careful of those that have an alloy wedge in them if they have been over tightened they can be dodgy. i use both wedge types but then i am not charles atlas .