Turning off a Stuck Backplate

jaker4p17

jaker4p17

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Does anyone have experience turning off a stuck backplate? I've tried all the methods and gone through all the threads for getting this thing off to save the backplate, but it is truly stuck. I've seen people mention turning it down to the screw but no post from people who have actually done it or anything to look out for. Another method I saw was using a slice down the side of the backplate and putting wedges inside to snap it and loosen the tension on the screw. I don't have a mill however, so this operation would probably have to be done with an angle grinder and a cut-off wheel which doesn't sound like the most fun operation.

Any have any tips for cutting this thing off? I'm not exactly the most excited to be stuck using a 3-jaw forever.

(edit: Moving my reply I made with more information here for future people:

Thanks for the responses guys. I should lay out a few things. I have been oiling it daily, but I don’t think rust is an issue here, maybe chips stuck in the threads, . I had been using an Allen key in the chuck and a strap wrench to stop the spindle from moving and tried torquing and hammering to no avail. From there I made a large bolt with 3 flats to fit into the chuck and tried both an impact and then a 2’ wrench using full force on both the strap wrench and the 2’ and striking it with a sledge. No movement from that, even with the addition of heat. The jaws are starting to get a little beat and I really don’t want to hurt the spindle. I don’t have a ton of time to get this off and I have some projects I need to get the 4 jaw on for. The 3 jaw isn’t the nicest anyway and I’m okay with destroying the backplate in order to get what I need to get done, done. If I had more than a month left before I have to leave for school I’d be more than okay with leaving it to sit for weeks.)

(edit final: I will probably disappoint some of you guys but I ended up cutting it off using Stu's method who commented below and made his own post about doing this a while back, which worked beautifully and quickly. We used our Milwaukee porta-band which cut through it quickly and safely and everything went really smoothly, we cut a small wedge into it to get the cold chisel in, and with a few whacks the crack went down to the threads. I put the chuck back on and with about 15 seconds of torquing the chuck came off very easily. All in it only took about 20 minutes. Some of the threads in the backplate were chipped/marred and I think that was the root of the issue, combined with some chips in the threads as well. All said and done I'm glad I used this method, I was going to buy a new 3-jaw anyway so I'm not losing out on much. I may try my hand at machining my own backplate as a project in the near future. If I wasn't in the time constraint I'm in I definitely would have taken longer than 2 weeks of oiling with pressure overnight. Thanks again, guys, I hope this thread can help someone in the future.)




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Hi and welcome,

Are they still running the kart track at Ravenna? I always meant to get down there when I lived in Michigan but never made it.

When you say you've tried all methods for getting this off how long have you been working at it? My one experience with a stuck chuck it took weeks of patient effort but finally got it loose. It's worth taking more time if you've only been working at it a few days since it appears undamaged in your photos.

I guess if I were going to try and turn that off I would just cut it down until I only had maybe 1/2" left then cut a slot perpendicular to the spindle as close as I dared. With that, a few blows with a cold chisel should break the cast iron and get if off.

But, I'd really try a little harder before giving up. I'm sure someone who's actually had to do what you suggest will come along with better advice than me soon.

John
 
So welcome, you're new here.
Let's start with the basics.
Have you tried wedging the bull gear with a wedge of wood? Then mounted the chuck back on the backplate and tried tightening a hex or square depending on 3 jaw or 5 jaw into the chuck and wrenching on the hex/square?

if you look on here you will find someone recently put a wrench on and cheater bar and left it overnight or days and it worked. Which is what many here recommended.

If you've done these things, I can give you a next step. which will be less destructive than what you are proposing.
 
matthewsx said:
Hi and welcome,

Are they still running the kart track at Ravenna? I always meant to get down there when I lived in Michigan but never made it.

When you say you've tried all methods for getting this off how long have you been working at it? My one experience with a stuck chuck it took weeks of patient effort but finally got it loose. It's worth taking more time if you've only been working at it a few days since it appears undamaged in your photos.

I guess if I were going to try and turn that off I would just cut it down until I only had maybe 1/2" left then cut a slot perpendicular to the spindle as close as I dared. With that, a few blows with a cold chisel should break the cast iron and get if off.

But, I'd really try a little harder before giving up. I'm sure someone who's actually had to do what you suggest will come along with better advice than me soon.

John
Click to expand...
I wouldn't try that as a there is an easier way to turn it off. Much easier. And what I propose if all else fails will leave you with a spindle nose guard.
 
Re-mount the chuck and thread in reverse, everyone says that will make the chuck come off..........
 
It’s tough to believe you have tried everything. I remember being new, and dealing with a stuck chuck. Seems like I “tried everything” too and couldn’t make any progress for days and days. Mr. Pete 222 on YouTube has a video on removing stuck chucks. Have you tried all of them?

Hanging a levered weight and spraying weekly with a penetrant has been one of those painfully slow but perfectly suitable methods.

I would reinstall the chuck first off. That is the primary mechanism by which you can apply leverage to the backplate.

I suggest not cutting that backplate off. If it turns out to be truly impossible to remove, then you can just leave it on and swap out chucks on that backplate.

But as already mentioned by others, use the chuck to apply leverage to the assembly after blocking up the spindle so that it’s immobile.
 
First from the locker if very bad experiences, triple check there isn't a set/grub screw!!!

Another opinion. I just read in a 1940's LeBlond manual to use wood on the chuck, at this point you may as well simply drill a 2X6 to match the backing plate, long enough to cross the bed, and bolt it on. LeBlond suggests a good swing to jar the plate using the bed, or even running the lathe in back gears.

IMHO it is most likely the plate was cut very close to the register diameter and that's where it's stuck. The most successful method I've read of, and suggested by Logan, is to use a 4' leaver, or as long as practicable. Hang a weight on it and use penetrating oil. This is where it's important to remember the oil has to pass through the register shoulder & backing plate and then between the plate & spindle register. So it will take a while.

Many sources recommend a 50/50 mix of acetone & power steering/ power break fluid. The acetone will evaporate quicker than the fluid, so keep the container well sealed. Next is Kroil, Liquid Wrench & PB Blaster. The difference between Liquid Wrench & PB is tiny. So I tend to use PB because it has an ingredient specifically to dissolve corrosion. YMMV

Good luck.
 
Have you tried some of the more serious methods? Not trying to imply that you haven't. Sometimes even they dont work. There is the old bucket of scrap trick on the end of a long handle. This has worked in many cases, including, I think mine, once upon a time. I've never had to turn a backplate off. I have never even had to make a wrench out of a split and bored block. If you really torque on this, make sure to put a plug in the spindle bore so you don't collapse it. Yes, I know, sometimes even this doesn't work, but I have always been successful before reaching this point even if it it took several weeks.
 
Thanks for the responses guys. I should lay out a few things. I have been oiling it daily, but I don’t think rust is an issue here, maybe chips stuck in the threads, . I had been using an Allen key in the chuck and a strap wrench to stop the spindle from moving and tried torquing and hammering to no avail. From there I made a large bolt with 3 flats to fit into the chuck and tried both an impact and then a 2’ wrench using full force on both the strap wrench and the 2’ and striking it with a sledge. No movement from that, even with the addition of heat. The jaws are starting to get a little beat and I really don’t want to hurt the spindle. I don’t have a ton of time to get this off and I have some projects I need to get the 4 jaw on for. The 3 jaw isn’t the nicest anyway and I’m okay with destroying the backplate in order to get what I need to get done, done. If I had more than a month left before I have to leave for school I’d be more than okay with leaving it to sit for weeks.
 
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