Metal plates with honeycomb base

Hi Ray,

I just finished printing a book dust jacket using 11-point magnesium plates on a 3/4-inch honeycomb base. I had a problem because the plates did not have a chamfered edge, so my toggles didn’t work right. I ended up using some of Boxcar’s adhesive film to strengthen the bond. The print came out fine.

I told the plate-maker that I would be using a honeycomb base, and I wrongfully assumed they would send me the correct kind of plate. The last time I did this, with a different plate-maker, they sent plates with chamfered edges and the toggles worked great.

Barbara

I make 16 gauge magnesium plates sometimes for crash printing on multiforms but I mount them on wood.

The most common base height is in support of 11 point (.153 thickness) plates. I have the old pre-honeycomb cast iron floored funiture (solid on top) and it runs rings around wood mounted cuts, at least for longer runs on difficult stock (bags). I’ve seen wood mounted 16 pt plates fail miserably in a 1500 piece run.

For running heavy impression on Lettra, a metal base will remove an unforgiving variable from the printing process, provided you have a press that can has the impressional strength, with a decent margin of safety. .

It isn’t that hard to bevel the edges of a plate so it works with the honeycomb toggle hooks (or the many other patent bases). A few licks with a file, once you’ve figured out where the hooks will contact, is just a couple minutes work.There are different ideal angles for the bevel of PMC bases and for Blatchford honeycomb hooks.
If you do a lot more of this, I made a gauge that let me saw the bevels at the right angle on the saw. Or maybe there’s a router bit of suitable angle.

All depends on the type height of your machine.
English type , Dutch type , German type.
The honeycombs come in different heights. To suit the type bed also depends on how high your dies are being made.
Are few calculations will help you work this out
Bed height ? Die height ?
English bed height is 23.30mm standard emboss plate is 6.3mm so really a 16mm honeycomb with some local packing

In the .918” US, there were two basic heights for patent bases: the majority of old bases were for duplicate plates (stereos and thick electros of .1522”), the rest (and perhapsmost of the recently-made) were for 1/4” dies.
They weren’t made for 16-gauge original photoengravings. There was not enough backing metal for a hook to hold such a thin plate securely for a production run. 16-gauge hooks were made for proofing purposes only.

http://www.lawrence.co.uk/shop/Bevelling-tool.html#.UtAalmgWTY0

plate bevelling tool for sale from T N Lawrence

Thanks, parallel_imp and jonathanjeclipse, for the information about beveling my own plates.I thought about doing that, but was afraid to go at magnesium with a file, for fear of it igniting somehow. Is there any danger of that?

Thanks,

Barbara

Barbara,

I looked at your plate photos on Flickr. How do you do alignment/registration with plates & honeycomb base?

Igniting magnesium with the heat generated by a file or even motorized saw would be way down my list of possible diasters (admitting there are many other disasters that are possible in letterpress printing).
You do need to keep the magnesium filings away from any real source of ignition, and separate from lead waste if is is to be reused or recycled. Otherwise its all just toxic waste.

Newbee, all traditional patent base methods I’ve seen had grids marked on the material. That’s how you square up an individual plate, and it also has use registering multiple units and press forms. The real difficulty is getting the image square and consistantly trimmed relative to edges of the unit on which the image is carried. There used tto be precise methods of doing this (optical comparitors, and the Vandercook registration punch), but now it is all guesswork. Does Owosso use precise optial methods in trimming a plate?
The one relaaible way to regiter plates across all methods is to use an acetate overlay registered to the chase. This is part of all Heidelberg chase design, an option on some Vandercooks, and a worthwhile improvisation on any other letterpress machine. Such pin registration was a normal part of photomechanical offset printing.

Thank you parallel_imp.

Is there any special kind of “acetate” for letterpress? Can I use ordinary cellulose acetate (the ones you get at Dick Blick).

have no idea Barbera—-the Lawrence thingy seems to be a tool for peeling/shaving not filing the edges…………….

We cut mag plates all the time on the printers saw, even use a file on them, its not easy to start that stuff on fire, but you can put a small pile of shavings down and lite them with a match, it burns very hot and water will not put the fire out. I have had some chips from the saw get into my Ludlow pot (550 degrees) and never had them ignite.