Grizzly DF-1237G/G1003/Busy Bee Spindle/chuck Upgrade

Wood is usually a workable approach, or a length of old leather belt- something sacrificial to protect the gears. Be cautious when applying force- I would try also heating the chuck perhaps with some high wattage light bulbs or a heat gun
I feel that making a D1 adapter may be an exercise in frustration. Personally I would just make backplates to fit the existing threaded nose. If you can buy them semi-machined you will have a fairly easy time.
Mark
ps it's hard to advise someone on how much force to apply, some folks can stop just short of breaking things and others have no feeling for it at all (my brother for one) and go right past it with bad results. Try not to be like my brother. :)
 
So far I've put a bar through the chuck and tapped on it pretty good. There is no rust, it's just on tight. I'm very familar with mechanical things, and know that with a long enough lever, a whole lot of torque can be back-fed through the gearbox, hence the request for guidance. That's a good idea about applying heat and will give that a try.
 
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Mark, the use of wood or leather in an extreme circumstance is normally OK, but in this case there at 2 very small bearings that can be damaged. I am trying to encourage the correct use of the back gear/back gear lock that is intended for this purpose. He can't harm the gears using the correct procedure.

Right. First put the gearbox into back gear.

Second rotate the spindle in back gear until the the locking bolt can thread into the back gear body.

Third, use either the chuck key or a bar in the jaws to provide a surface to use a RUBBER hammer - not a 'dead blow eurothane' or other harder hammer. If you don't have a rubber hammer, you can cushion your chuck key with a piece of softwood.

When the back gear is engaged and the back gear locking bolt in inserted and tightened, the weakest link in the system is the back gear locking bolt - not the gears. There are 4 gears engaged to lock the spindle, in 2 pairs. If you use a 1 lb sledge or 16 oz framing hammer - on the wood - or a 1 lb rubber hammer, hammer so that the chuck rotation is counter clockwise. Keep persistent blows until it is free.

There is nothing to jam on the spindle, it is just being held on with old grease or possibly swarf. by repeated blows in this manner, the worst that can happen is to shear the locking bolt. You then have to extract the bolt and replace it with another, etc, until the chuck is free.

I know that there are machinists that are overbearing and tell you that 'their way' is 'the only way' - I'm not one of those guys (check my posting history), but... THIS IS THE ONLY CORRECT WAY TO REMOVE A STUCK CHUCK IN THE DF1237G LATHE - anythin else, including wood in the gears will result in damage, probably to the little gear bearings in the centre shaft.

Note: it is impossible to remove the spindle/bearings/seals until the chuck is removed anyway. kb58, I wish I was in California (for lots of reasons), then I could come over and assess/help you out directly.
 
Thank you for the detailed response. I'll investigate further and let you all know.
 
I should have said using a 4X4 of cedar or other soft wood on the corner hitting the key or rod is a good alternative to a rubber hammer - providing you don't wail on it.
 
Came right out :)

292879
 
It looks exactly like my lathe! congrats! -- it is a really good lathe!
 
In case this thread turns into something substantial, here's the manual in case others are looking for it.
 
The plan to rebuild the Grizzly DF-1237G took a brief turn when a Clausing Colchester in good condition showed up locally on CL. Alas, it was apparently already sold by the time I saw it, as the seller did not return my message. A Hardinge HLV-H also showed up, and while I drooled over its specs, the $12,000 asking price is simply a bridge too far. Even if it wasn't, the reality is that I don't make anything requires such precision. Oh well, it's hard to not always want "the best".

Back to my lathe, replacement oil seals are onhand, so the teardown will proceed - and I'll stop looking at CL. I changed my thinking regarding replacing the chuck with a D1-4 chuck, because it'll make the process far easier. The new plan is to replace the existing chuck with either a Buck or Bison "Tru Adjust", using the existing backplate. This gets around having to fabricate a new backplate in order to gain what's probably a questionable amount of precision. The only question now is how much the backplate might have to be modified.

Speaking of the factory chuck, does anyone know what came with the Grizzly DF-1237G as-delivered? The reason I ask is that when I got it, it had an 8-inch 3-jaw on it. I kinda doubt that's normal. The chuck has no markings, so I don't know what brand it is, and the engineer in me has to ask, "How do I know that it's not already a high quality name brand chuck?" Well, I don't, but I think if it was, they'd proudly display their name or stamp on it. I also think that most people wouldn't make that change, but since I'm considering it, who knows.

Regarding the backplate, I actually have three! One for the 3-jaw, one for the 4-jaw, and another more generic one with a bunch of slots in it (which I need to confirm if it threads onto the spindle. I removed the 4-jaw backplate to see what it looks like. It has an 80mm bore that's a press fit into the chuck, but what's odd is just how rough the backplate threads are. It's as if it was threaded, then sandblasted with 1/8" sand, because the threads are very rough, like 60-grit sandpaper. Makes me wonder what the history of this backplate is. Anyway, this backplate is maybe 6" in diameter, with four mounting holes at mid-radius. The 3-jay backplate is 8" and has 3 mounting holes out near the edge. The third backplate with the slots is at least that big, maybe even larger.

Anyway, the whole chuck thing is for later, because in order to get there, the lathe has to be rebuilt first. Given some of the comments, getting the bearings out of the head could be difficult, and hopefully I don't ruin them or anything else.

I'm considering doing a YouTube series of the rebuild. I doubt there are very many people considering rebuilding one of these, but producing the videos would be good experience for me since I plan to do others (drawbar and car-related).
 
Getting the bearings out will be interesting to everyone that owns that model lathe manufactured from 1979 to 1984, as we all have seal problems! So a youtube series will be very helpful! My understanding is that it is likely that the right bearing is going to be ruined in the removal. If they are a standard tapered roller bearing they should be available in the 200-300 range.

My 12X37 came with an 8" 3 jaw, and an 8" 4 jaw chuck, on backing plates. Mine are Taiwanese (noname) chucks and mine at least are as good as a Bison (but without the tru-adjust feature) Both of my backing plates have moderately rough threads - but I have seen far worse. My 3 jaw runs with .002 runout at 3/4" and .005 runout at 2". This is almost as good as a $1600 Pratt-Bernerd chuck, but not as good as the high-accuracy tru adjust PB 8" chuck that sells for $3000 CDN... I am thinking on how I can swap the 8" 3 jaw chuck over to my new 14X40 lathe and give away my 6" chuck (from the 14X40) when I sell my smaller lathe.

-- It is likely that your machine is a similar vintage as mine, and has the same chucks. Therefore you have a decent quality Taiwanese 3 jaw scroll chuck. More power to you if you upgrade to a Bison Tru-adjust! I'd love a 6" Bison 6 jaw tru-adjust myself - I just can't afford it.
 
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