[PLJack]

Good evening, Jack. I'll give a shot at some possibilities.

Maybe it could be the amount of tension you have when tightening down the spring-loaded tensioning bolt. If it's too tight, it's going to do more than just pull the gear into the racks. Think about it in the "way out there" extreme - like it would be possible to tighten the tensioning bolt so tightly that you could break off the gear mounting bolt. Before it would break, it would try to bend. Before it would bend, it would bind. Get the idea? If the tension were too tight, it could be setting up a wear inducing bind. Keep in mind that the small gear sit pretty far away from the main body of the drive, relative to everything else. I suppose the gear could be acting like a sort of lever, which could accentuate an already existing bind.

On the Saturn I sent back, the frame tubes were not square. Out-of-square tubes means there is necessarily a disrelation between the mounting plates/drives and the gear racks. If your tubes are also out-of-square, it could account for the wear pattern. It would take what is in the paragraph above and make it worse.

The amount of belt tension may be another cause or an additive cause. If the belt is too tight, it's going to translate to the bushing, etc.

As an aside, I believe oil impregnated bronze bushings (e.g., Oilite) are what is generally used for an application like this, rather than brass. Oilite Plus is an iron-based counterpart. I've never seen brass used, but I don't pretend to have seen it all.

That's it for my input.

Gary

Yep. Bronze is a better guess.
Early on I think I may have had the tension too tight. Now a days I tighten by hand and give it about 1 1/2 turns.
This machine is definitely not perfectly aligned. I can hear a change in tone as it gets to the back side. If I remember correctly they rails splay out by about 2mm or so.


Thanks.
Jack.

[mactec54]

If I remember correctly they rails splay out by about 2mm or so. Thanks. Jack.

I feel for you guys that are struggling with these machines, having the rails out by 2mm is no joke, they need to be within .001 to work correct

[wmgeorge]

I feel for you guys that are struggling with these machines, having the rails out by 2mm is no joke, they need to be within .001 to work correct

Really? We did not know that, thanks for stopping by to share that information with us, as its never been discussed here at all. :tired:

[ericks]

Great work!!

[PLJack]

Great work!!

Thanks Ericks.