Letterset printing - Davidson Dualith

My understanding (I could be wrong ;-) of “letterset”, also called “dry offset”, is that it allowed use of a relief wraparound plate on the plate cylinder, which would be inked by the regular roller train, with the dampening system disabled. The image was then transferred to the blanket and thence to the paper in the usual offset procedure. It would require a right-reading plate just as offset does. Because the plate would not contact the paper there would be no chance for “deep impression”. I’m not sure how the image transfer system was adjusted for the plate thickness.

I don’t know what the Davidson system used, but “Dualith” implies to me a fairly simple change-over.

Bob

Back in the early nineties I had a total of 3 Davidson machines, two 241’s, and a 251. I never had or never saw the necessary segments to do letterpress, or “letterset” as it may well be, as Bob describes. I do have some literature somewhere that explains the process, and I’ll try to find it.
I can’t promise I’ll find the literature I’m looking for, but I’ll try sometime today.

Bob is correct. The auxiliary “segment” replaced the plate segment and was simply recessed to offer the ability to mount a relief plate. It may have had grooves to allow some means of locking the plates in proper position.

I never had the opportunity to test that application, but did run a Davidson 221 for a time and thought it was a good press for a couple reasons. It had a good inking system and the paper path was straight through the machine so it would run a bit heavier stock with good register.

Adjustments, I seem to recall, were a bit difficult when switching from another press to the Davidson as some of the adjustments seemed backward due to the plate/impression cylinder being one big cylinder, but after the first couple, you got in the swing of it.

Ok, I found the manual and uploaded 13 pages of it that describe the relief printing capabilities of the Davidson “Dual” (1955 term which was changed to “Dualith” at some point, possibly when ATF took it over from Merganthaler Linotype Co.)
I did not see the term “letterset”.
There were several accessories that could be purchased as optional equipment to achieve different relief printing functions with the dampener system removed.
You could print DIRECTLY from rubber plates, specialized T-slotted type, milled lino slugs, curved electros, and they claimed that you could do imprinting, numbering and perforating simultaneously.
Dry offset was also possible.
It seems entirely possible that one could have adapted it to the use of photopolymer plates, maybe with shimming, although I didn’t try to figure it out, but the dimensions are given for rubber plates.
I believe the accessory segments are exceedingly rare and that you might be better off starting a collection of hens teeth. But, I could be wrong—-if you found the right source tucked away in some cloistered pocket of hard-core Davidson operators/collectors. They may be out there.

The entire set of manual pages may bore most to tears, but it’s all there, 13 pages concerning letterpress (one page covers Dry Offset though).
Reading it may be easier by clicking on the image so that it loads in the “light box”, then selecting “view all sizes” in the upper right to see the larger original size.
I could have assembled a small .pdf, but I don’t have a host to upload it to.

Start here:

http://tinyurl.com/3pss6ef

For those who have no idea what a Davidson Offset Duplicator is, there was one on eBay that ended unsold the other day, which I just discovered:

http://tinyurl.com/4x5vy4a

If I were ever going to get another offset machine, it would be a Davidson, because I’m familiar with how it works and I agree with jhenry that they were good presses.

David:

It is interesting to note that the photo of the nameplate on the press listed on eBay indicates that the Davidson Company was (at least when this press was made) a division of the Mergenthaler Linotype Company. That gives us a real letterpress tie whether or not we have the appropriate relief printing segments.

Thanks for posting the manual pages. That was indeed interesting stuff.

John Henry

The “specialized T-slotted type” David mentioned might be better known as “Multigraph type.” I don’t know when the Davidson Company started building presses, but as early as the early 1920s (or maybe the teens) they were building a feeder for the Multigraph press (which used the short T-base type but could also take plates of various sorts). So presumably Davidson had a good working relationship with Multigraph and a good understanding of how the Multigraph rotary letterpress worked, and it would have been logical for them to continue with something similar for their press.

Hen’s teeth not withstanding, if anyone ever does run across an available railed type segment for a Davidson, I’d love to find one for my Davidson 221, as it would be a nice tie-in with my Multigraph collection, and I do have plenty of T-base type to experiment with.

Dave

Dave,

There was a lot of T-base type for sale on eBay a few weeks ago, and I did not recognize it until I looked at my manual last night. It even came with several holders as shown on one of the pages.
I will definitely keep my eye out for a rail type segment.
I talked to an equipment dealer a while back and he mentioned that most of the used Davidsons he was selling at the time were going to Mexico. That might be a good place to look for this stuff.
I was searching YouTube for Davidsons and found that most of the videos there had Spanish in the titles and descriptions. Here’s one that shows a numbering operation:
http://www.youtube.com/watch?v=LyUiNdAulBM&feature=related

Also, thanks for the correct term T-base type. I wasn’t aware of the Multigraph application, and the connection does make perfect sense. They called it T-bottom in the manual but I’m going to correct it to T-base on my Flickr pages. T-slotted type was a misnomer, and it was late.

Dave

Dave, any idea how the T-base type was listed on eBay? I’m always interested in more, but don’t always have time to wade through everything in “letterpress”, and admit I’ve almost never searched “Davidson” on eBay. Also, any chance I could get a copy of the scans of your manual?

It looks like Davidson pretty closely followed Multigraph practice as far as railed segments, type, line lock clips, and so on. And, while I tend to use the term “T-base type” as sort of a generic name for the stuff, I’m not sure what the correct term really is, if there is one. Multigraph, of course, pretty much referred to it just as type, or as Multigraph type, although they did mention something about it being “milled” to fit the Multigraph slots or rails (which it wasn’t, it was cast that way!). “T-bottom” or “slotted” probably makes just as much sense as “T-base.”

Dave

As I recall, it was simply listed something like “Big Lot Letterpress Printing Type”.
The seller obviously didn’t know exactly what it was, and neither did I, at the time, but I knew that I couldn’t use conventionally, as it was obviously not type high. There must have been at least twenty holders, (these seemed to be rails of some kind maybe from a Multigraph typesetter? Not sure). Many of them with type loosely set in them, and other type seemingly pied, can’t remember if they were in some kind of container or box, but it was a fair amount. It all seemed to be about 12 point or close to that.
It did sell, and I thought to myself somebody bought something that they didn’t know what it was either, but maybe they did !
I have no idea on how to access the ended auction…

There is precious little info on the internet about Davidsons.
You can still get rollers for them as far as I know, from Syn-Tac through http://printersparts-nc.com/

I would be happy to scan the manual, but alas, no scanner.
I’m seriously thinking of making a few decent copies of it though. There are 116 pages. The ones I posted were pics. The cover is in awful condition with ink all over it, but the contents are intact. I could actually use the back cover for front and back, but it’s just reverse graphically.
It doesn’t mention the 221 specifically, but they were very similar to the 241 & 251…the 241 and 221 share the same feeder.
But I’ve also been thinking of getting a decent scanner lately as well, or I could try to put together a .pdf from pics….I don’t know yet, but I’ll definitely keep you in mind. I’ll try to contact you off the forum…

Dave

(Following is excerpted from the 1955
Davidson Offset for Letterpress Manual p. 59.)
They describe, through the use of different optional accessories, how relief printing could be accomplished on the machine in addition to offset printing.
It could print from rubber plates, short T-base Multigraph printing type, MILLED LINOTYPE SLUGS, and curved electros.
It could be set up to do imprinting, numbering and perforating simultaneously.
I am of the opinion that these capabilities were not easily sold to the printing trade at large, and the necessary accessory segments required to do these tasks are rare, and would be very difficult to locate.
Davidsons are very good old presses and are capable of excellent offset duplicating with very good ink coverage and registration.
The Davidson Corporation was a subsidary of Merganthaler Linotype Co., then later bought out by ATF.
I REMEMBER SOME HOW DISENGAGING AND STEPPING OVER THE CYLINDER AND PUTTING LINO SLUGS (10 PT. MAXIMUM) IN THE GAP OF THE CYLINDER AND LEADING THEM OUT WITH TAPERED LEADS (SHIMS) TO COMPENSATE FOR THE CURVATURE OF THE CYLINDER. We did millions if post cards then which were a good advertising medium in the 50’s.

I opine that to get the mortgage loans from banks you ought to present a firm reason. However, once I have got a auto loan, because I wanted to buy a car.