Shopsmith Forums

I don't recall having ever adjusted the eccentric.

Would someone please try to bring me up to speed. What is the purpose of the eccentric adjustment? My guess is that it is the adjustment for poly-v belt tension. What symptoms are there indicating a need to make this adjustment?

BigSky,

Your guess is correct. The Owner's Manual under maintenance explains how to check the belt tension and adjusting it. The link below is for the Mark V 500 Summary Manual from here on the Shopsmith Website and page 55 has the Belt Tensioning information.

EDIT: Link below no longer exists.

https://www.shopsmith.com/getting_start ... Manual.pdf

Reason for adjusting - belt slips under load.

Since this adjustment involves the idler shaft does it in any way effect the motor belt and/or idler pulley?
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BigSky wrote: ↑Sat May 27, 2023 6:30 pm Since this adjustment involves the idler shaft does it in any way effect the motor belt and/or idler pulley?

I would say yes, but more in theory than in practice. Most common adjustment is in the direction to tighten the upper belt. That moves the Idler a tiny bit closer to the motor shaft, lowering belt tension which will then be countered by the spring, moving the sheaves very slightly closer together to remain in balance with belt tension. Resulting in a slightly higher speed at the various spindles. Not enough to matter, but probably enough to measure with a digital tach.(?)

A note for those that may search and find this thread, the discussion revolves around Poly-V conventional headstocks. The use of the Eccentric Adjustment is slightly different on both Gilmer and PowerPro headstocks.

- David

JPG wrote: ↑Sat May 27, 2023 1:30 pm Reason for adjusting - belt slips under load.

Poly-V slips?? or drive belt slips in the sheaves.