Shore Hardness on Table Top Rollers

Mick, greetings from Minnesota.
When I first started ordering letterpress rollers I was told to specify the hardness in degrees of durometer.
Later on, I was asked what degree Shore my rollers were?
being easily confused I wanted to know what the difference was.
The answer;

The durometer scale was defined by Albert Shore, who developed a device to measure Shore hardness in the 1920’s. The term durometer is often used to refer to the measurement as well as the instrument itself.
Both terms are typically used as a measure of hardness in polymers, elastomers, and rubbers.
My roller manufacturer in Minnesota, USA recommends a 23* to 28* hardness for my Pearl #3 and Pilots.
Given all the other considerations that can come into play such as rail height, roller diameter, ink, paper, type or plates & makeready I tend to like mine on the harder side = 28* +
Jon/printer/Mpls

Mick, After my last posting I actually looked online for materials and their corresponding Shore hardness.
The scales I found show a typical pencil eraser has an ‘A’ scale Shore hardness in the 45 degree range.
There are A and D scales.
Even though my roller maker says my rollers are 28* I have never had them tested.
By looking at the online scales 28* looks like it would be on the soft side and I like them on the hard end of the scale.
I’m sure someone here will give us better insight.
JD/printer/still in Mpls

Shore hardness of between 25 and 30 is considered ideal for modern letterpress printing. I have used harder rollers with good results, and of course traditional composition rollers would read much softer, so there is a considerable useable range.

As an aside, Mick, last weekend was the Annual Winter Dance Party at the Surf Ballroom in Clear Lake, Iowa. There was quite a good contingent of Brits in attendance.

For those not in the know, The Winter Dance Party in 1959 was the last show played by Buddy Holly Richie Valens and “Big Bopper” Richardson, as they died in a plane crash shortly after their plane took off. The event was remembered in the Song “American Pie” by Don McLean as “The Day The Music Died” many years later.

John Henry

2001 Fred, Thank You good start, re my query and efforts, I used *Shore* as my only point of reference, (then) lot more to go on Now, but win, loose or NO result, with just one pair of rollers, re-cast in the order of 30 - 35, Shore hardness, will be able to experiment with Photopolymer plates, compared to original (process etched) Zincos, and Line Blocks.

Re your Pencil Eraser, comment, interesting, set the memory banks back several years, including the method and system adopted by and for erasing tiny >edits< on Litho Plates, rather than new plate, for one word or figure.???

****
J.Henry, Thank You also, especially re Your take on Harder rollers for some operations, as I have tried to imply here U.K. there seems to be little or no info, for the Shore hardness with regard to Table Top machines.

****
Re The Winter Dance Party, Sincere and Heartfelt Thank You, for that, I suspect that You have, noticed one of my Ramblings before.???

To possibly recap, my apprenticeship was from `54 - `60 hence, Coffee Bars, Saturday nights were the order of the day for many of us.

Juke Boxes, were appearing in reasonable numbers in our Coffee Bars, exclusively U.S. origin, Row Ami, Rockola, Wurlitzer (of course) and SEEBURG amongst others.!!

`57, `58, our Best Coffee Bar had the First,
V 200 SEEBURG, in town, (Eastbourne Sussex U.K.)
so we were playing Buddy Holly, J.P. & Ritchie Valens, etc.etc., even before the Sad Day.

I have a living reminder and tribute to Buddy Holly, my Daughter is christened Maria Elana, After Maria Elana Santiago, !!

J.H. Thank You again.
2001 Fred, Thank You also.
Mick.

I had a durometer gauge available to me at work, or in my desk, for many years before I retired, and used it many times, so durometer is quite familiar to me.

This is a long but pretty good article on durometer, if you care to read it

http://www.imperialrubber.com/imperial-rubber-hardness-of-rubber-rollers...

With regard to the hardness of lower speed handfed letterpress rollers, I would stay in the 20’s, and personally I like the mid to lower 20’s. This is for 3 reasons:

1) as the article referenced above says, albeit in a somewhat different context, “…once the roller reaches a particular hardness range, it doesn’t transfer ink properly,…”

2) roller manufacturers cannot make rollers to the exact durometer that you specify. The industry standard is + or - 5. That means if you ask for a 25 durometer roller, if the supplier makes it anywhere between 25 + or - 5, which would be between 20 and 30, then they have made an acceptable roller and met your requirement. As in the article above, some roller manufacturers may have tighter tolerances, but you won’t know unless you ask. Because of this, I would ask for a roller that is a little lower in durometer rather than a little higher, because a higher roller is more likely to be a problem than a lower one.

3) rubber rollers can sometimes get harder with time, especially if they are not stored correctly. So, if you get one that is on the low end of your acceptable range, and it slowly gets a little harder, you are more likely to be able to use it longer