I'm hoping some Tersa head owners can comment on the fact that my Tersa knives on my planer are VERY difficult to slide out sometimes. I suspect it's pitch or rust. Is there a need to keep the head gibs lightly lubricated ?
Thank you

If the wedges are tapped down they should slide out without any issues. Maybe try blowing it out with an air hose first? What kind of wood are you using and how often to you change out your knives?

I worked with a SCMI planer that had a Tersa head, had the same issue. I would hook the claw of my hammer on the end and pull the knife out. Should have cleaned them out with some kind of solvent, but never did.

Hi Gary, Yo need to keep your tersa heads clean and slightly lubricated.
Blowing out with air as well as some sort of soft bristle brush with solvent to clean any pitch. You need to be careful the brush you use to clean the gibs doesn't shed bristles and stay in the slot. The gibs should move freely so spray lube is good. I use wd400, 3in1, whatever is close by really. Martin machinery manuals will say to use a mixture of light oil thinned with petroleum. To me thats basically wd40. Just let the planer run for a minute to disperse any extra oil before you put wood to it.
Check for a burr on the ends of the knives as well. I believe the knife stock is sold in coils. And they cut to order. Some sellers may be using a poor blade to cut. The burr is bad news as it can scrape metal away in the gib. You may need to file it lightly to remove the burr. I only buy from tersaknives.com. They do pretty good up there. Sometimes the knives still have an arc to their length which may not make they slide smoothly, not that you can fix that.