Roller Diameter

I am new to letterpress and purchased my Sigwalt 6x9 about a year and a half ago and soon after purchased new rollers. I haven’t printed too much the past year but when I have, it’s never been easy. I’ve stuck pieces of paper behind the chase in order for the ink to hit the plates, and I finally got ahold of a caliper to take exact measurements. It turns out my rollers are .01” smaller than my trucks. I have a piece of paper exactly that width and have carefully taped it under my chase as a temporary solution. Is this issue worth obtaining new rollers for? I contacted the roller company I purchased through and they have very kindly offered to recast my rollers for the cost of shipping only - except I don’t want to waste anyone’s time or money unless it is necessary. It is all for .01” which seems so minimal, but I am learning that it is these details that truly make a difference in the letterpress world. I would appreciate any feedback. Thank you!

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It is not as easy with an old press to say that the rollers need to be the same diameter as the trucks, or even a few thousandths over.
What is important is how the rollers ink the form. Good inking is the absolutely required first step to good printing. How you get there is less important.
In a new press, the rails should be type high, .918” higher than the bed. Then with trucks and rollers the same diameter, one should get kiss inking on the form. With rollers smaller in diameter than the trucks, there will be no contact with the form and no inking.
The old printer who made his own rollers did not have a micrometer. He made his rollers just slightly larger in diameter than the trucks. He may have used a one point lead, 1/72” to measure. Thus the roller may have been 2/72” greater in diameter. Greater in diameter will cause heavier than kiss inking.
Is it necessary to return the rollers to be correctly done?
Maybe. Unless you specified the diameter, it appears that the roller covering company delivered faulty rollers. .010 is way off.
To get satidfactory printing you will either have to have correct rollers, or always shim up the underside of your form .010” or more to get correct inking.
If you shim the underside of the form to get it up to the height to be inked by the rollers, it will also be .010 closer to the platen. You will have to reduce the packing by .010 to avoid smash printing.
Get the inking right first, then adjust the packing.
Now re-reading your post, I read that you have placed a shim paper under the chase. You don’t want it under the chase. You want it under the form before you lock the form in the chase.

It is not as easy with an old press to say that the rollers need to be the same diameter as the trucks, or even a few thousandths over.
What is important is how the rollers ink the form. Good inking is the absolutely required first step to good printing. How you get there is less important.
In a new press, the rails should be type high, .918” higher than the bed. Then with trucks and rollers the same diameter, one should get kiss inking on the form. With rollers smaller in diameter than the trucks, there will be no contact with the form and no inking.
The old printer who made his own rollers did not have a micrometer. He made his rollers just slightly larger in diameter than the trucks. He may have used a one point lead, 1/72” to measure. Thus the roller may have been 2/72” greater in diameter. Greater in diameter will cause heavier than kiss inking.
Is it necessary to return the rollers to be correctly done?
Maybe. Unless you specified the diameter, it appears that the roller covering company delivered faulty rollers. .010 is way off.
To get satidfactory printing you will either have to have correct rollers, or always shim up the underside of your form .010” or more to get correct inking.
If you shim the underside of the form to get it up to the height to be inked by the rollers, it will also be .010 closer to the platen. You will have to reduce the packing by .010 to avoid smash printing.
Get the inking right first, then adjust the packing.
Now re-reading your post, I read that you have placed a shim paper under the chase. You don’t want it under the chase. You want it under the form before you lock the form in the chase.

Sorry folks. I tried twice to delete the duplicate posting. I think I may be a better printer than a puter poster.

Thank you. I think it may be worth it in the long run to replace the rollers. I did not specify roller diameter originally, but I will this time. My trucks are 1.25”. I read somewhere that rollers should be .028 larger than the trucks, but I’ve also seen on another roller company’s website that for 6x9 chase size rollers could be 1 3/8 (which would be .125 larger than my trucks). I’ve also read that rollers should be the exact same size as the trucks. I’m not sure which diameter to specify…

If your “rails” are not adjustable try this, to establish the size difference between roller and truck .
Place a roller height gauge on the bed against the rail ,measure the height difference between the top of the gauge and the surface of the rail ,top middle and bottom of the platen bed to give you an indication of the extent of the overall wear, the difference in height of the twoshould be the same as the same as the difference in diameter of your roller and truck . If you dont have a roller height gauge then use as large a piece of type as you possess and measure from the top of that .
then add a couple of thou to the roller diameter to give the degree of kiss you require ,that bit i will leave to the guys to help you with here as i dont work on these little guys and am actually unsure of the shore rate for your rubber or composite ,all factors to be taken into account in doing this .
sorry , for any language problem i am UK and may have used some odd terminology .

Please! can anyone say me the diameter of the fomous “lollypop” or “roller height gauge”?. I’m from Argentina, where do not exist any tools for letterpress. Movable type has been replaced for the offset system. And nobody knows how to help me, the old typographershas been retired.
So I’m thinking to make a selfmade “roller height gauge” because a have a Victoria Kobold with useless form rollers. I really need to repair the form and ink rollers. I understand that the heigth is 0.918”, but I don’t know the diameter.
Please! Give me a hand! Forgive my bad English… I’m spanish speaker.

Hello Tucuman, have you checked that the type height in Argentina is American based and not German based? Without the information of your type height it’s not much use to get a roller height gauge made. Measure the height of your type with a digital caliper to find out. I presume you mesure in millimeters and not in inches in Argentina.

Roller gauges for .918” type-height would be .918” in diameter, and the width varies, but less than .918” so it can be slid sideways under the rollers without touching; the roller is gauged on the round surface, not across the flat.
The Victoria Kobold might be an English machine intended for .918”, or German machine intended for .928”, but most Victorias have adjustable roller tracks useable with a range of heights.

thomas gravemaker & parallel_imp: thank you so much.
In my country we are… rare, at least. We use both measures, inches and milimeters.
I have a good colection of metal types and surprise: .918”. The national mesurement system is IRAM = originally based on DIN, but we use inches for too many applications. P.e.: pipping, mechanical tools, etc: inches. Construction, paper, photopolymer, etc: milimeters. We are very crazy people, and flexible.
Well: thinking about the roller gauges after post the question I found on the deep of mi mind that my question is stupid… de DIAMETER IS 0.918”, is pure logic. I’m not thinking well.
MANY MANY THANKS to all people for the patience.

No, your question was not stupid. The only stupid question is the one not asked. This is the place to come for help. You do not need to make any apologies. We are just happy that you now see in your head how it works.
Buena fortuna.

Thanks, Inky! You’re right!

Tucuman. I am also from Argentina and also starting up.

Regarding type sizes… it looks that here we had boths standards. US/UK is the 0.918inch and the european as well (0.928inch). The difference not only lies in terms of the type height but ALSO in point sizes!. You may find that an european 10point is not only taller but also bigger.. so spaces and quads will not be useful on other types.. I have only one set of type purchased from “Mercado Libre” (our eBay) and it conforms to the european standard…

If you are in the Buenos Aires area, we may get in touch to share startup experiences. I have a small ADANA hand operated printer at home and just used it a couple of time for fun…

Best!