This machine was the deal of the century for me. I bought it for $100 from a guy who bought the building that used to house a sign shop. I cleaned it up, replaced the cutting strip, bought new blades and did some minor repairs. The previous owner was using some tape to hold the right bale arm down. New springs and an allen screw fixed that. Honestly, the machine cuts well. I ran a job for 3000 4x6 logos and lost about 6% to the problem I described above. A drop of oil in the pen seemed to fix the problem.
I do not think it is the belt or lack of lubrication. I cleaned the rails and bearings with 3 in 1 oil initially. I have no idea how often I should do this however.
The cover for the blade holder I have needs to be taped into position for the correct exposure. The threads are barely in place on the aluminum pen. I think the plastic cap is a bit stripped. I am still cutting and making money with the machine. So far, it does not seem $150 bad. I guess I will buy it anyway. I would hate to go down.
Yes, you got a helluva deal. I paid $10K for mine 14 years ago.
My Envision has been in continuous operation since 1998. I think I've cleaned and lubed the rails twice in all that time. I've replaced the blade holder twice ... each time it was because the internal bearing went bad and there would be a loud grinding sound when the blade would fail to swivel freely. Other than that, I had to replace the entire tool head once and the cutting strip about once a year.
The plastic cap on the blade holder if, as you described it, is stripped, then you should definitely replace the entire blade holder. The cap is used to set the exposed amount of blade for depth of cut control and is marked on the side for .001" per increment. Setting it to the correct depth is critical to problem free cutting and allowing a greater tolerance to your other cut settings.
Are you cutting from Omega? If not, how are you controlling your downforce, cornering, acceleration and speed? There was a downloadable upgrade to the Envision firmware a few years back. You might want to check the GSP website to see if you have the latest version.