1970s Knoll arm chair  

sorry but you need to post...
sorry but you need to post photos somewhere. your description is vague.

Photo attempt
My son tells me this should either bring up the image or direct to it. Thanks for any help.
[IMAGE REMOVED]

That's a Knoll Stephens Chair...
Not sure about the channel and upholstery method... Looks like it would be fairly easy to recover them... I've always liked this chair... The arm chair is goodlooking too...

these are good chairs. i like...
these are good chairs. i like them. i don't see why they would be too hard, but i am not an upholsterer.
maybe you should contact alfie at humemodern.com. he does a lot of modern furniture restoration.

Did you figure it out?
I saw your post and I'd like to know if you figured out how to re-cover the chairs. I'm looking for info on how to re-cover mine.
Thanks!

Hi
I am almost sure you...
Hi
I am almost sure you are talking about the Stephens office chair. They are not a cakewalk to recover, but worth it. I think they must be near the end of the perishable latex foam that always hardened. The plastic shell is stapled to the wood form. Glue bonds the foam and fabric to the top side. The bottom side will take patience to fit in the new bottom cover. The top will take some scraping and cleaning.
The new foam will need to be thin, this requires a custom sawn foam, and the fabric will be best if its a strechable type. These chairs rarely bring big money, and the recovering will be the most expensive part.
They were my first experience with finding out about Knoll furniture. My local library had them as seating and it was always a pleasure to go there and study on Knoll furniture.
Good luck