Originally Posted by
RecceDG
I concur, but that appears easier said than done.
I have a Minipro belt drive kit that is going on. It replaces 206 with a straight shaft with a longer top extension. The pulley mounts to the OD of this shaft. The inside of the shaft is broached to fit the quill spines. OEM-sized bearings (205 and 207) are pressed on to this shaft, and it looks like the Naichis I bought (6209ZZE Nachi Bearing Shielded C3 Japan 45x85x19, 6007ZZE Nachi Bearing Shielded C3 Japan 35x62x14) are indeed for this outer shaft.
They are also permanently greased from the factory (?)
But as I look deeper into this, the collet is 246 and the only way to drive it is though the quill spines engaging with the interior splines on 206 - unless 206 is replaced with a solid assembly with solid "pucks" that take the place of 205 and 207, 246 is redone with a round shaft (instead of splined) and at least one more bearing is installed at the top of the now-round 246 shaft between it and 206, to support the top of the shaft against pulley loads (as the pulley now connects to 246 instead of 206).
That's a lot of work... and I think that the existing design already does a good job of isolating driveline loads from machining loads.
The fact that the only thing keeping the 249 spindle assembly from falling out is the 236-237 quill lock is hokey, but I don't see any other way to secure it.
So that returns to this: which are the aftermarket bearings to replace 248 and 248-1? (not 251 - that's the preload nut - my bad)