The lathe electronics failed, specifically for:
In the OEM Wiring layout, the Master Start Switch in the headstock casting, has two sets of contacts. A Normally Open set (1 to 2) is used to pull in the armature on the contactor,
and the other set (3 to 4) is Normally Closed and when STOP is pushed the circuit opens, allowing the armature to fall.
On paper it works.
In the real world of industrial electricians, the best way to run contactors is
to open the L2 ( or Neutral in a single-phase circuit, but "Neutral is a poor choice of words, it being single phase...) When the N wire is discontinued from the A.C. supply,
the magnet and the A.C. Hot all de-energize because the designer had them use the Auxiliary Set in the contactor.
Grizzly first of all has a contactor in this lathe WITH a set of AUX contacts. Grizzly second of all has a start/stop switch with the ability to run four different wires to it, PLUS a fifth and sixth to energize the bulb in all these switches.
Thirdly Grizzly uses silicon-plastic 21 gauge wiring, but only three (3) conductors go to the Start/Stop switch. The Hot A.C. is piggy-backed to the Hot terminal of the OFF set of contacts.
The result is the full a.c. load of the 8K goes through the Start/Stop Cheesy wires, and after a hundred or so operations the tiny set of actual contact points in the switch get hot and the metal's electrical resistance changes slightly. The result is firstly a
diminished voltage input to the contactor set of terminals. The second result is the Master Start/Stop switch Normally Closed set of contacts on the STOP set of switch contacts becomes intermittent.
All this was observed by monitoring the voltages with both a Simpson 260-8 analogue multimeter and a Fluke 89-4 digital recording voltmeter.
The lathe is spinning.
Switch set 3-4 points get hot.
Voltage to the contactor declines visibly.
Lathe spindle slows down.
The next operation was to completely disconnect all electrical
connections in the headstock and wiring cabinet, remove the motor
and the cabinet, then remove the master switch in the casting up
front, and then to individually operate every control and measure
the resistance across all contact points.
The Master Switch is defective. Intermittent visibly. Didn't even think of
spraying it with De-Oxit 5D because of how many steps it took to get to it
this one time. Grizzly part number 1001617.
The continual operations before the monitoring test affected the VFD module. The +5 Volt DC buss supply failed. One or more of the MOSFETS failed. There is no repair locally or with Grizzly. They had a new module, though, this one is "V2."
Needless-to-say the wiring design is now completely reworked into a higher ampacity version with 14AWG XHHW-2 Stranded, Gas & Oil resistant and 600 volt insulation. Using a set of colored Kennectit DIN rail splice terminals and soldered quick disconnects where
applicable. ALL bi-metallic connectorized or non-connectorized stubs and junctions get a dab of No-Ox-Id "A" (Special) anticorrosive paste. One molecule thick is enough for any connection. There just aren't any other lathes out there I could replace this with,
that have anywhere near the specs on the SB layout, and if I scrapped this, all the junk would have to go.
So if you are the proud owner of a Grizzly SB-1001 (8K) lathe, it might be in your best interest to rework the wiring and check the resistance of the master switch while you're at it.
Piece-by-piece, the spare parts at Grizzly are being distributed to 8K owners who need to repair. Grizzly themselves told me last week that they DO NOT plan on any 8K parts replenishment. Many line items are discontinued and the spares already sold.
Thank you to the members herein who afforded me ideas and assistance with making the decisions to address this.