Broke my Grizzly G0765 7x14 lathe - HELP!

Be thankful it was only lathe gears. A year ago, I took out the low range gears on my tractor. It involved splitting the tractor. disassembling the entire transmission and rear end, including removal of the pto, hydraulics, rear wheels, and fuel tank. All that in 100+ temperatures and 90+ RH.
 
tjb said:
What's that?
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Actually, one of the service techs sent me a maintenance manual for a similar tractor. It's close enough that many of the components are similar if not the same. Unfortunately, I didn't get it until after the job was done.

Whether it's tractors or lathes, most of the time there is a logical sequence to disassembly. Occasionally. though, you have to get inside the designers head to see what he was thinking. The ones that are really fun are those that were never meant to be serviced. Locking tabs, glued joints, and hidden fasteners and the like.
 
This Old Tony has a couple of mini-lathe videos which include replacing spindle bearings and gears. He is doing it as an upgrade, but should show you how things come apart and go together.



 
Aaron_W said:
This Old Tony has a couple of mini-lathe videos which include replacing spindle bearings and gears. He is doing it as an upgrade, but should show you how things come apart and go together.
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I will check the videos. Thanks!
 
Firstram said:
You'll have to pull the head stock and the spindle to change those gears. LMS sells steel replacements, use the steel one on the spindle and buy 2 plastic ones for the jack shaft. When it happens again you won't have to pull the spindle to change the plastic gear, and you'll a spare on hand! I can change mine in 30 min or so.

I have read not to use both steel gears due to the noise and the fact a crash will break the next weakest thing$$$
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THIRTY MINUTES! That seems incredibly fast. What parts do NOT need to be removed to get it apart? I think the gearbox itself needs to be removed to access the gears from underneath? Is this correct? It seems as if the speed selector can only be accessed and removed from the bottom??

I will try to come up with a ~4" diameter pipe and threaded rods going to the flange on the spindle. I don't know how hard I can pull with 3x simple M6 x 80mm threaded rod.

-Tony
 
Sorry for the giant photo!
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On a stock Mini I think you need to remove the speed control and lead screw, I don't remember. Be aware of the wiring! I have relocated that to the back and can pull the head stock with it attached. My wiring is long enough to lay the assembly (head stock/motor controller) on the table behind the lathe.

Remove banjo, feed direction tumbler, double nuts and gear (from spindle), aluminum belt cover, belt and sprocket. I don't know if you can access the 3 socket head bolts holding the head stock to bed without removing the motor. (I can, I have a jack shaft where the motor would be) They need to come out to pull the head stock.
Lift the head stock off. Remove the clips holding the counter shaft and slide it out of the head stock. Keep up with the key stock that drives the gear!

From this point I would be able to reassemble using a new plastic gear on the counter shaft.

Do not pull on the spindle flange with 3 bolts. Use 1/2" threaded rod thru the spindle with a washer on the small end. Grind, file or sand the washer so the OD is just smaller than the spindle. Use a 8" pc of PVC pipe that just fits over the chuck end (3"?). A 2x4 with 1/2" hole will cap the assembly. Tighten nut and pull spindle out. Clean/lube everything up and reassemble using a steel gear on the spindle!

The first time will take a while! Tear into it methodically, keep the parts organized and it will all fall into place. Just ask for help if you need it! I've had lots of practice with mine in the last 10 years and it's actually worn out now. I haven't done it because there are other mods I want to do and don't want to tear it down twice.
 
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On a stock Mini...
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The first time will take a while! Tear into it methodically, keep the parts organized and it will all fall into place. Just ask for help if you need it! I've had lots of practice with mine in the last 10 years and it's actually worn out now. I haven't done it because there are other mods I want to do and don't want to tear it down twice.
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Thanks for the pointers. I have some acme threaded rod on hand. It is part of a spring compressor set. I think it is 1/2" diameter. I don't recall how long the rods are. 12" to 14" as I recall. But that may be enough to get the spindle released. I probably have some 1/2" steel plate that I could use instead of a 2x4. I will look for some 3 or 4 inch PVC pipe.

Good suggestion about a steel combo gear on the spindle! Will that cause more wear on the plastic gear on the layshaft than a plastic-on-plastic mesh?

Does the spindle need to be pressed back on or will the nuts on the spindle pull it up properly?

I feel almost up to this procedure once I get the parts for the puller
 
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