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Letterpress - Busted!
Broken Press, Stalled Job 4/2007
I have long since discovered that despite having a pretty large chase area (~7x11), the Pilot is quite limited in how much total pressure and thus printed area it can manage if you want an even and full impression. I've done quite a few jobs where I was really pushing the limits of the press. When you get in this situation, the time you need to spend adjusting platen jack screws, cutting and pasting many layers of overlays, and fine tuning the packing to get a good print can easily grow into multiple hours for one setup. As the total pressure climbs for a larger printed area, the press parts start to deform unevenly and this leads to a lot of fiddling and makeready to compensate. If you are printing with black ink or don't care what the shade of the color comes out to be, putting more ink on the press helps with this. But if you are trying to get a pantone color, loading up the disc with ink is not a good option since then the color will come out way too dark.

For this job, I was using a fairly textured and not very soft paper from Paper Source, which needs relatively more pressure to print than something soft and creamy like Somerset paper. Also the printed area of the block with the trees and lanterns on the main card is in retrospect too big for the Pilot to do well. The main card is 5x7.


The job that broke the Pilot's back

PDF Version

So after a lot of fiddling and setup I got things arranged so that the print was reasonable, though it still could have used a bit more pressure. I started printing, and as usual with a large printed area I was nearly hanging on the end of the handle to make the impression. I got through about 80 cards when I head a big pop during one print. At first I couldn't find anything broken, and I thought maybe a tool had fallen onto my metal cart or something. Soon enough it became obvious what had happened though; the main right side casting had cracked where one of the shafts goes through.


Boo Hoo!


Zoomed out view of problem area

Needless to say this is a very distressing development. My feeble attempt to doctor it up with a hose clamp was totally useless. I have a heavy duty U bolt coming from McMaster tomorrow that I will try, but I don't have high hopes. I can't believe I was able to break that casting with just manual pressure. Even with the leverage of the handle, I can't have been putting more than 180lbs on the handle since thats how much I weigh. I'd have to analyze the linkages on the press to calculate mechanical advantage, but it couldn't be more than a factor of a few x. The section of the casting that failed was about 0.5 x 1 inch, and some quick web research says gray cast iron should have a min. tensile strength of around 20,000 psi. Bugger!

Anyone know of a good place to get castings repaired? If I can't find a replacement or a good place to get it fixed at reasonable cost I guess I'll try to braze it at home. Given that cast iron is notoriously finicky to repair, I don't relish that prospect. Or maybe I can mill off the stump of the broken casting and fab a big plate of aluminum or something to bolt onto the side of the casting and capture the shaft. None of that stuff sounds good to me though... Dang.

Update: Rescued by Bow & Arrow 5/2007
In response to a plea for help on the LETPRESS mailing list, I received a very generous offer of help from John Pyper, the non-resident tutor of Bow & Arrow Press. This operation is a Harvard student letterpress shop located in the basement of a Harvard dorm, and mainly makes use of a Vandercook and an enourmous assortment of old blocks and all sorts of type. John graciously offered to show me how to use the Vandy and help me run my job.


From left: My Hero - John Pyper, Letterpress nerds


John tucking some type into bed


Bow & Arrow's recently acquired C & Ps

It will come as no surprise to most that the Vandercook did a much better job than my Pilot, with almost zero setup and makeready time. It may have been slightly slower to actually run each page, but not by much, and this was more than made up for by the ease of setup and lack of fiddling with makeready and constant reinking needed by the Pilot.

It was also fun to meet some other letterpress nerds, and a pleasant change to see someone's eyes not get all glassy as soon as I start talking printing.

I did everything but the envelopes at Bow & Arrow, and was able to use a 3/8 U bolt with a custom machined 1/4 x 1/2 stainless plate to hold my Pilot together well enough to do envelopes.

The results of the job can be seen in the Portfolio section. So thanks again to John Pyper and Bow & Arrow Press!

Design partially original and partially ripped off from other websites
by Holly Gates