Today I was finishing up a walnut bowl and noticed the low end speed of the G0766 is whacked. From dead stop to about 80 rpm on low speed belt config, it's OK, but a hair above 80 rpm, and it shoot to 800 rpm. No in between. What should I do? I blew out the belt compartment and also to outside of VFR, but no change. HELP please.
Sounds like a speed pot fail.....try unplugging the lathe for a bit, and allow a reset......if that does not work, contact Grizzly and talk to tech support......they can walk you thru a replacement.
Mark, when I first got my lathe, occasionally I would find a dead spot on the speed control. The speed would go to zero and if I wiggled the knob, it would jump up to what it should have been. Over the next month or so it got worse until the lathe really wasn't useable. The most likely culprit is the speed potentiometer. However, it could also be something like a loose wire somewhere. Grizzly sells the pots for $2.50 I think. I posted on my own replacement steps on November 10 in the thread called : "Replacing speed control potentiometer in new G0766 lathe" . The link is "http://www.sawmillcreek.org/showthread.php?237392-Replacing-speed-control-potentiometer-in-new-G0766-lathe". The old "pot" is soldered in and is a bit of a PITA to get at. The new pot has about 2-1/2" wires on it. So, if you cut the wires to the old pot and leave them long enough, you can make a "pigtail" and screw on a small wire nuts (3 of them).
Brice, Thanks for the link. Very helpful. Could you post a picture of the modified service loop you installed. I sit next to EE's at work, and I am sure I can have a connection made in minutes. Are wire colors necessary to maintain? Are the connections Poka-Yoke? Where I work we have to make stuff mistake proof, or we know what can happen - YIKES.
I went to radio shack and got a pot for 3.49 and replaced mine in a couple hours including drive time, but it is a pain with sausages for fingers but it can be done. maybe teach the wife and her smaller hands to solder. yea that is the ticket.
Mark, in regards to the service loop, you will find when you take off the four screws holding the switches and speed control pot that their interval wires are fairly short and you can't immediately pull out and get at the stuff you want to. To accomplish this, all you need to do is go around to the back of the machine and push the black cable through the strain relief. Keep pushing in cable until you get enough slack (or "service loop") that you can move things around on the front-side. After you have changed out the pot, you will want to reverse the procedure with the cable service loop. That is, you will want to go behind the machine and take the slack out of those same cables and ensure that the cables don't touch the spindle. on to part 2
Part 2 IIRC, the components on the speed control/switch assembly were all either soldered or crimped. The original pot was soldered in. Three wires and three different colors. I cut the leads close to the pot but left maybe 1/4 inch of the insulation so that I could refer back to the colors and orientation. I made sure that when I replaced the pot that each colored wire attached to the same physical position on the new pot. The grizz replacement pot came with 3-4" wires already attached and (may have) come with small wire nuts. If the colors on the new pot are different than the original (or if you buy from radio shack, it will come bare) just made sure that the original wire that attached to the center of the three leads still connects to the center on the new pot, etc. etc. It isn't a hard job. But there wasn't a lot of room for my fat fingers. I'll look to see if I have any pictures ...
Brice: I did see the pictures already, and thanks for the tutorial. I will call Grizzly tomorrow and have a new pot sent. I'll ask at work, there may be a better pot not being used that I can put into place, keeping the replacement from Grizzly as a spare. Seems to me, if I was the designer, I would have made a non-reversible connector (Poka-Yoke) with soldered leads to facilitate quick, correct installation, and easy serviceability. Might have added 25 cents, though. I guess as engineering and designer types we try to design for quality and ease of service. At least I do. I used to own a Chevette, and that was so poorly designed I never could change the oil for 70,000 miles.
Well, I got the package yesterday, and installed the new pot tonight. Brice, thanks for tips on how to replace it. What a cheesy plastic control box!! gosh, I lost the screws in sawdust on the floor (thanks to lights and magnets, I found them and the washer from the front). I'd have put a box with captive screws or knurled thumb screws, but that's just me as a designer. I tried to test the old pot, but my cheap HF tester may be to weak on battery power to test for conductivity. I should be back to turning this weekend after the flat work I have to do. Thanks again, everyone.
Mark, did you do a power-on test to determine if the original problem went away? Hopefully you are up and running again. BTW, internally there are fine wires wrapped around a circular form. Kind of like a donut (toroid) but with a very thin width to height ratio. The "wiper" on the pot is a piece of metal (perhaps a plated steel) that rubs against the copper wire. It position on the many turns of wire determines the resistance setting of the pot -- which controls the lathe speed. So, whenever you rotate the pot, it is rubbing the metal against the very small/fine copper wire. There are at least two common failure modes - - the wire finally breaks/wears through or a "gob of junk" keeps the wiper from properly contacting the wire (like a noisy volume control on a radio). Good luck!
