American Tempo

[domineight]

Bought this as a bit of nostalgia. I actually did a part of my apprenticeship on it a long time ago.

I don't remember it being so clunky though. It's had a bit of a hard life after I had it from almost new, so far I've only chipped a few kilo of ink off the top of it, thrown a new vacuum motor into it, and replaced the motor/drive belt.

It starts and stops, but has an issue I'd call "binding" whereby on a slow squeegee stroke it seems to be a bit jittery and not a smooth action through the last 1/3 - 1/4 of the flood stroke.
I've greased all the internals, lubed up the chains, but haven't actually touched or adjusted anything, yet.. It LOOKS fine in there, but did wonder if that jittery action could be sign of cam wear, although running a finger over the cam lobe it doesn't have a feel of being worn, at least not worn so it would translate into the jittery action.

Before I go tearing into the squeegee carriage - There are a few roller bearings either side of the carriage that run inside the aluminium top "arms" that could well be causing this, or possibly what the bearings are running on? Hopefully they screwed a plate in there so the bearings haven't gouged out a track in the Ali.. - Is there anything else I should be looking at?

Ta.

[CGS]

Usually it is a loose cam or taper bushing that secures the cam in position, take a look at that. Also take a look to make sure when the head is in the down position the cam follower is just slightly off the low area of the cam.

There are also microswitches that have an arm that ride along the output shaft. One of these are 1/2 and 1/2 which change between the squeegee and flood speed potentiometers. If that is in the wrong position, you could be changing between the two speed pots at that specific point, and if they are set at different values it could cause that sudden slow down or jitter you are talking about.
 

[domineight]

That's good info, thank you very much!
I'll take a good look at what you've suggested.