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9" standard modern utilathe nose spindle thread orientation.
- Thread starter PowderPig
- Start date
Almost certainly a Rh thread. Otherwise the normal rotation of the chuck against the force of a tool mounted in the tool post would unscrew the chuck.
With a RH thread, the chuck will tighten as it is turned against the tool.
I suppose it's possible to have a Lh nose threads but I've never seen it and doubt they even exist.
With a RH thread, the chuck will tighten as it is turned against the tool.
I suppose it's possible to have a Lh nose threads but I've never seen it and doubt they even exist.
One other thing. A 70s era threaded spindle probably has a thread lock of some kind. Be careful removing the chuck lest you damage the threads and locking mechanism.
Not on the 9" Utilathe.
The chuck is probably stuck on there pretty well. The previous owner, who has had that lathe for several years, said he has never removed it and doubted that it had ever been removed. I’ll give it a go today. I may need some tips on how to remove a stuck chuck. I am fairly new to the machining world and I find this site very helpful and enjoy reading the many intetesting posts.
DPittman
Ultra Member
I had an extremely stuck threaded on chuck too on a 12" lathe that also had never been removed since day one. I tried solvents and all the methods I could read about and i think I was very close to breaking something. Finally I used a chunk of wood jammed in the headstock gears and was able to then apply enough torque to the chuck to get it off.
I had read a post from before on one pissible solution for the removal of a seized chuck. A split aluminum collar is fabricated at a slightly smaller diameter than the rear if the spindle through hole and it is clamped onto the spindle to keep it from turning. An impact wrench can then be used to back the chuck off. This is done with the headstock gearbox in neutral. I am fabricating the piece now. I’ll let you know how it turns out. Cheers.
DPittman
Ultra Member
I tried a impact wrench on my chuck and right now I don't remember how I was holding the spindle from turning, but for me getting the spindle "locked" with the wood jam was key to getting the chuck off.
If the chuck is just slightly stuck I think locking the back gear in (if that's an option) works but if it's really stuck I think it's a great way to bust things so be careful.
I am leery of using an impact gun..... (broken gears, brinelled bearings, etc etc)
More inclined to soak a good penetrating oil on the back of the chuck at the threads and use raw torque against jammed gears.
Might be able to get "freeze it" onto the spindle nose through the chuck center to use temperature contraction to good effect. I prolly would not try heating the chuck though.
Have you seen this? It may help.
canadianhobbymetalworkers.com
Stuck chuck on Atlas lathe
I’m in the middle of setting up an Atlas lathe, a th54. I tried to remove the chuck for cleaning and it’s stuck pretty well. It was bad enough the little pin that stops the spindle broke off. I use a heat gun to warm it up to maybe 200f, that didn’t help. Any suggestions? Especially tricks to...
canadianhobbymetalworkers.com
I like the momentum method suggested earlier. It has the least chance of damaging anything.
But it's important to realize you are not using the momentum of the chuck but rather the momentum of the spindle and gear train. The chuck stops, the spindle momentum tries to keep going.
The stouter the bar and post the better. Ideally all steel but may not be possible. A hardwood 4x4 is better than softwood.
If you decide to go the impact hammer route, try to restrain the gear train in such a way as to prevent damaging any gears. For example a strap wrench around the biggest gear against the housing. I like that better than something stuck between gears.
Last but not least, if you really love your lathe, and don't want to take any chances, I'd remove the chuck from the backplate, machine away the backplate, and clean up the threads manually. Backplates are easily replaced while chucks and spindles on old girls like that are not.
But it's important to realize you are not using the momentum of the chuck but rather the momentum of the spindle and gear train. The chuck stops, the spindle momentum tries to keep going.
The stouter the bar and post the better. Ideally all steel but may not be possible. A hardwood 4x4 is better than softwood.
If you decide to go the impact hammer route, try to restrain the gear train in such a way as to prevent damaging any gears. For example a strap wrench around the biggest gear against the housing. I like that better than something stuck between gears.
Last but not least, if you really love your lathe, and don't want to take any chances, I'd remove the chuck from the backplate, machine away the backplate, and clean up the threads manually. Backplates are easily replaced while chucks and spindles on old girls like that are not.
VicHobbyGuy
Ultra Member
If the bull gear can be easily accessed, something like this can work:
I made something similar for my lathe in a few minutes with 'QuikWood epoxy putty and a piece of plywood for a handle. The good part is that it will break before the gear will. A good strap wrench (is there such a thing? MIne are rubbish only good for oil filters) would probably be as good or better, as @Susquatch suggests.
I was lucky - didn't know better at the time- when I removed the chuck from my Logan, using the back gears to lock the spindle. I won't do that again, but of course, now that the chuck(s) have been off and on, lubricated, etc, they're easier to remove.
Well folks I’ve tried just about everything I can think of to remove the chuck backing plate from my 9” standard modern utilathe. I tried heating the back plate and cooling the spindle. No luck. Impact gun didn’t work. I fabricated a jig attached to the back plate and put a large wrench on it and locked a pipe wrench to the rear end of the spindle. Applied lots of pressure and also struck the wrench with a hammer for some impact blows. Nothing. I think it is welded in place. I never used the gears as s stop. Left the gearbox in neutral at all times. I believe I may have to go the route that Susquatch suggested and machine it off.
Attachments
Jesus!
But what kinda hammer did you use.....a baby carpenter hammer or a proper 3lb'er
And might want to put a piece of leather or something between the jaws of that pipe wrench and the spindle, pipe wrenches can make some pretty good gouges...not that it matters back there, just looks crappy
But what kinda hammer did you use.....a baby carpenter hammer or a proper 3lb'er
And might want to put a piece of leather or something between the jaws of that pipe wrench and the spindle, pipe wrenches can make some pretty good gouges...not that it matters back there, just looks crappy
A backplate is under 50 bucks at Amazon. Don't know what size you need but lots of different sizes at this link:
HHIP 3900-3212 3 Jaw Chuck 1-1/2-8 Threaded Backplate, 4" https://a.co/d/5IDN2j0
Since you will machine the backplate to fit your chuck, no point spending a lot on it.
HHIP 3900-3212 3 Jaw Chuck 1-1/2-8 Threaded Backplate, 4" https://a.co/d/5IDN2j0
Since you will machine the backplate to fit your chuck, no point spending a lot on it.
Unless you put a tight fitting piece of round stock in the end of the spindle I'm pretty sure it will be severely out of round and as @phaxtris says it will be badly marred by the pipe wrench.
I see three choices but there has to be more:
1 - as Susq suggests, machine it off
2 - Split the BP with a dremel, that will relieve the pressure and allow you to spin it off. Being careful not to hit the threads.
3 - remove the spindle and put it in the freezer for a couple days to get a good soaking, then use the soft jaws to secure it in the vise and heat the BP with the propane torch. Use your jig (which should be still attached) and wrench to unscrew the BP.
Number three is what worked for me and the BP was fine to reuse but the whole process was a bit of a pita, I did however gain good understanding of the inner workings of the machine. My machine came from a school (of hard knocks) and had the gouges in the compound to prove it, I don't think it ad ever been off the spindle. It will come off, you just need to find the least destructive method to do it.
If you don't have the manual it can be downloaded from SM for free. https://standardmodernlathes.com/resources.html
Good luck
I see three choices but there has to be more:
1 - as Susq suggests, machine it off
2 - Split the BP with a dremel, that will relieve the pressure and allow you to spin it off. Being careful not to hit the threads.
3 - remove the spindle and put it in the freezer for a couple days to get a good soaking, then use the soft jaws to secure it in the vise and heat the BP with the propane torch. Use your jig (which should be still attached) and wrench to unscrew the BP.
Number three is what worked for me and the BP was fine to reuse but the whole process was a bit of a pita, I did however gain good understanding of the inner workings of the machine. My machine came from a school (of hard knocks) and had the gouges in the compound to prove it, I don't think it ad ever been off the spindle. It will come off, you just need to find the least destructive method to do it.
If you don't have the manual it can be downloaded from SM for free. https://standardmodernlathes.com/resources.html
Good luck
I do not recommend this but you can do what some people have done to remove a stuck crankshaft pulley:
You put a wrench on the pulley bolt and block the other end against the floor or the frame. Then you use the starter motor to turn the engine (DO NOT START IT, JUST TURN IT) for at most one or two revolutions of the crank. Just enough to break the bolt loose.
You put a wrench on the pulley bolt and block the other end against the floor or the frame. Then you use the starter motor to turn the engine (DO NOT START IT, JUST TURN IT) for at most one or two revolutions of the crank. Just enough to break the bolt loose.