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Kearney Trecker 307 S12 Wiring Diagram needed


Mar 20, 2014
Syracuse NY
Recently purchased this 307 S12 Vertical


Serial 16/9261 - #16 of 40 units in lot 9261 from December 1962

I've been cleaning it up and checking operation. Spindle works, all 4 powerfeeds + rapid works, but speed control on the spindle has some issues and controls are not wired correctly.

Currently the following behavior is present:

Master Start (On main electrical box) -> Starts Spindle (Powerfeed motor off)
Spindle Start (On control pendant) starts powerfeed motor
Spindle stop (On control pendant) does nothing. It engages the white contactor (non-original) when pressed, but nothing happens.
RH/LH Direction Change (On main electrical box) turns machine off if engaged while running, as intended

Low speed gear changes seem to work, but sounds like some gears aren't meshing easily at first
High speed gear changes don't seem to want to engage. This may or may not be related to the electrical issue.


I've started testing hydraulic pressures but the cheapo gauges probably aren't the best. I've ordered some new liquid-filled gauges and will test it properly this week.


Would like to get the electronics working as intended first then finish testing hydraulic pressure. Though it's unclear how to adjust column lube pressure on my model without the adjustment screw.

dana gear

Hot Rolled
Feb 27, 2013
Northern califorina, usa
Vintage machinery has a S-12 electrical diagram in their machinery manufacturer reference section.
Not sure how close it is to yours, clearly there have been changes to yours, the Allen Bradley mag starter is one along with the primary controller, so it appears.