Perfect Binder Gluepot question

I own a Rosback 850 perfect binder which has been discontinued by Rosback due to the fact that the Italian maker went out of business. I emailed Rosback about my perfect binder, but they said they no longer support or service it.

I am going to service my Rosback 850 myself, so perhaps someone here can answer a few questions I have posted concerning adjustments.

The Gluepot
Question: What should the gap be between the roller and the book spine? As I move the gluepot roller up or down what should I look for? When will I know it’s correctly set? What is the purpose of the gluepot scraper and how should I set it?

Can you answer this or send me to a web site where can find out this information?

 

The roller should be 0.5 mm to the spine

 

Thank you for the responce. I appreciate the help. When my (used) perfectbinder machine was delivered it was not adjusted correctly and the books were not binding well. I need to understand what the different adjustments do.

I've noticed that the hotmelt glue seems to get thinner on the roller after about one hour of machine use. My digital readout says the temp is 350 degrees, yet the hotmelt glue is still thinner after about an hour of use. I could lower the temp if I wanted (I can control temp) or I could just let the machine warm up for an hour before use. Either way, the amount of hotmelt glue applied to the book spine changes after about an hour of use because the hotmelt glue gets thinner even though the readout says it's 350 degrees.

The scraper next to my roller, what does it do and how should it be set?

I've read about "nail heading" What is "nail heading"? What does it mean? I've read that the nipper can cause "nail heading" if set too high, and I have read that if the glue roller applies too much glue it also can cause "nail heading."

 

Setting a glue pot roller height is based on feel. You should have a book with around 18-20 mils of hotmelt after binding. With good spine prep and penetration this will get you where you want to go.

The scraper should be controlled by either a set of cams or a servo motor. The purpose of the glue roller scraper is to ensure there is a small gap at the head and foot of the book that has no glue (this eliminates or reduces stringing). This gap with no glue is very small usually 1/16 on the head and whatever is needed on the foot (due to various paper sizes of untrimmed sigs.).

Nail heading can occur for a couple reasons. A bulky spine creates nail head an example would be a smythe sewn book (there are lots of threads and the spine isn't cut off) or a thread seal book. Nail head would look like a mini mushroom if you held your book spine up and observed it. There are three areas that nail heading can occur on a perfect binder. The saws (loose guides), the glue pot ( if the glue pot is set too high the spine of the book will effectively hit the roller and "smoosh" the outter edges of the book away from each other. A clue that this is the cause of your nail head is there is inconsistent glue application), the last way is if the nipper is set too high. If the nipper is set too high, as the base plate arrives at top dead center it will contact the book too heavily. This will cause the front and back pages to move to the sides due to the displacement of pressure. The nips can't drive the spine back into proper shape because the base plate is too high (a clue that this is causing your nail head, watch your book at the nip station when the nip arrives at top dead center it should not drive your book up into the pocket. If you see this action, it is very possible that your nip station is the culprit causing your nail head).

 

Thanks for the information on glue roller settings Bindery_guy. I have a better understanding of the process now.

About the scraper on my perfect binder, it does not move. I can set it in one position only. Perhaps it is not really a scraper. Its purpose is to catch excess glue I think. I am not sure I even need it. Perhaps I should just lower it and forget it. I have played with it, moving it up and down, but I can't see what effect it has.