stripped threads on spindle and/or chuck

[linkindustries]

Hello, I seemed to have stripped the threads on the spindle of my AR Pro v5 and can't get the chuck out. I'm afraid the threads are indeed mangled. I can get it to screw in a bit and back (with effort), but not enough to get it out completely. The collet is well set and it's not what's binding it (I can rotate it with my fingers).

I tried heating up the chuck and using long wrenches. I clamped a piece of wood to the table to secure one wrench while working with the second one. I'm afraid of putting too much torsion on the spindle and getting things out of alignment.

Does anyone know if there's a way of removing just the threaded part of the spindle? Am I looking at replacing the whole thing? 

Of course I'm in the middle of a project with a deadline. Ah, Murphy, why won't you rest for a bit?

Any thoughts or advice are much welcome.

[eagle55]

Don’t know if this will help in your situation, but on cars with thread/nut issues I have had good luck with Liquid Wrench. I have seen times when it would destroy the nut if I kept going, but spray this on and let it soak in and maybe reapply and I could get it off. Also sometime going both direction with increasing limits will smooth up the rough threds and likely alow it to come all the way off at some point. As far as fixing the shaft (if the problem is the shaft, I haven’t got a clue, but don’t have a good feeling) Maybe the problem will be the nut which is the lesser of the two costs.

[linkindustries]

Aug 15, 2023 17:06:54 GMT -5 eagle55 said:

Don’t know if this will help in your situation, but on cars with thread/nut issues I have had good luck with Liquid Wrench. I have seen times when it would destroy the nut if I kept going, but spray this on and let it soak in and maybe reapply and I could get it off. Also sometime going both direction with increasing limits will smooth up the rough threds and likely alow it to come all the way off at some point. As far as fixing the shaft (if the problem is the shaft, I haven’t got a clue, but don’t have a good feeling) Maybe the problem will be the nut which is the lesser of the two costs.

Thank you Eagle55, it's worth a try with the liquid wrench. I'm afraid I did strip the threads on the shaft itself  

but it will give me some satisfaction to at least remove the chuck. I am not that strong and didn't think I could possibly cause this kind of damage!

[grossmsj]

You will probably be able to use the spindle again once you get the collet off. The steel on the spindle is very hard compared to the collet. You may just have a big mess of collet swarf that's binding the collet on.
There are ways to clean the threads on the spindle. If you don't feel comfortable doing it a local machine shop would probably be able to do it. You'd have to remove the spindle, of course.

[linkindustries]

So I just got off the phone with Axiom and they will ship me a whole new spindle. Any tips or concerns while replacing the spindle? They assured me it's an easy job, but it's good to hear from people who had to go through the process.
And yay for Axiom's quick tech/customer support! Finger's crossed I get this new spindle quickly and the machine up and running again without any trouble. And thank you for the help here. I'll see if I can salvage the old spindle, once it's out of the frame.

[grossmsj]

Good to hear. Yes, Axiom support is really very good.
I can think of two things to think about.
1) When you refit the coolant lines to your spindle you'll need to get the air out of there. Once the coolant starts to flow through the spindle, check the coolant reservoir to make sure there is adequate coolant there. There are other threads on the Forum about getting bubbles out, but you don't have to go nuts.
2) It's possible your new spindle will not have perfect alignment. The process for getting it there is tramming and there are a number of posts on the Forum you can find about this. dadealeus posted an excellent tramming video. If it were me, I'd look to see if I had any significant issues that come from a spindle that's not aligned right and then decide if I need to tram it.

[linkindustries]

Thanks, grossmsj.
Yes, When I first got the machine I did some reading on both the coolant bubble issue and the tramming, hoping I wouldn't have to deal with either any time soon.
I agree with the strategy of trying the spindle before going too crazy with the tramming. As it is now, it's not perfect (slight ridges when surfacing), but it's plenty precise for the work I'm doing. I'll do a simple surfacing test and if it's any worse that what I've had, then I'll deal with it.

On that note, does anyone here have recommendations for a technician or experienced cnc person who might be willing to do this job? I'm based in Brooklyn NY. Given my newbyness and the fact that I'm on a deadline, I want this whole thing to go as smoothly and quickly as possible.

[dadealeus]

Aug 16, 2023 13:37:32 GMT -5 linkindustries said:

I agree with the strategy of trying the spindle before going too crazy with the tramming.

When I first got my machine, I loathed the idea of having to perform maintenance or repairs on it as well; being new to CNC machines in general, everything just felt so daunting and overwhelming. However, I have found that it's all pretty simple and straight-forward. Oiling and greasing my machine takes me a couple of minutes and is something I do constantly and regularly now when I originally felt I wouldn't do it outside of every 6 months or so.

Reinstalling the spindle and tramming it is not nearly as bad as that video makes it look. That video is basically for perfection, however there are several other methods of tramming that will get you plenty well aligned for 95% of users out there. Here's another tramming video from an author I enjoy watching (he now actually works for Shapeoko - a company that makes budget-level CNC mills that use hand routers). However, his methods are sound and the one starting at 6:00 minutes in is cheap, easy, and pretty accurate if you don't want to go the route of purchasing an expensive or complicated piece of equipment:



All-in-all, I'd recommend you just dive in with YouTube as your teacher. If you can figure out how to run your machine, I'm certain you can swap out the spindle and align it without much trouble. It seems daunting, but it's really not and once you get your feet wet, you're going to feel a lot more comfortable with all your other maintenance and/or repairs (if you have any in the future).

Machines are great, but they can and will break from time to time. Maintenance and repairs are just a normal part of machine ownership and usage; there's no reason to be anxious about performing them.

[linkindustries]

Thanks for talking me down from my anxiety, dedealeus.
Since I've gotten the machine, I've had to learn so many different things. Just when I feel I have something figured out, a new issue pops up that I hadn't considered before. I'm quite diy for all the work I do, but I'm an artist and in my work there isn't usually so much precision, or potential for injury or costly damage, hence the concern. I never imagined that I would need an expensive new spindle just from messing up the unscrewing of the nut (those damned long wrenches)! So now I'm a little extra shy. But I'll get over it. I do love this machine and what it has allowed me to do.

[dadealeus]

Aug 16, 2023 16:13:59 GMT -5 linkindustries said:

Thanks for talking me down from my anxiety, dedealeus.
Since I've gotten the machine, I've had to learn so many different things. Just when I feel I have something figured out, a new issue pops up that I hadn't considered before. I'm quite diy for all the work I do, but I'm an artist and in my work there isn't usually so much precision, or potential for injury or costly damage, hence the concern. I never imagined that I would need an expensive new spindle just from messing up the unscrewing of the nut (those damned long wrenches)! So now I'm a little extra shy. But I'll get over it. I do love this machine and what it has allowed me to do.

I do certainly agree that it's odd about the spindle stripping, but to me that sounds like potentially a manufacturing defect (unless you somehow cross-threaded it very badly when installing the collet nut). I have two different machines that I use, both of which I've put a lot of pressure on and I've never encountered nor heard of those threads stripping out.

However, I just recently purchased a brand new truck (11 miles on it) and it has a host of issues, too. I think quality control in businesses the world over has just suffered quite a bit since COVID, honestly. Either way, I imagine the new spindle is going to serve you well without further issues.

I don't think it was from cross-threading, but I'm pretty paranoid about that on mine; I always gently hold the nut to the base of the spindle head and then spin the spindle head slowly with my finger until I feel the threads click into place, then I spin it the other way to make sure it's aligned properly. It should go on very smoothly until it's almost completely tightened. If you feel any pressure before that point, it's either cross-threading, or the threads have debris on them that should be cleaned off with a brush.

Anyway, you should be good to go with the new spindle once you get it popped on. I don't know if it's possible, but you may also want to consider keeping the old spindle as a backup and try re-threading it if you can find the right size die for the threading. Something like this (with the appropriate sized threading die, of course) should work:

www.amazon.com/38mm-1-5-Handle-Wrench-Slip%EF%BC%88New/dp/B073ZX58PH/ref=pd_bxgy_img_sccl_2/140-9326074-5946806?pd_rd_w=rQsDT&content-id=amzn1.sym.26a5c67f-1a30-486b-bb90-b523ad38d5a0&pf_rd_p=26a5c67f-1a30-486b-bb90-b523ad38d5a0&pf_rd_r=YAJS8PS71Q9A57Q6792N&pd_rd_wg=p7YVH&pd_rd_r=f1e19e4a-ef9d-48cf-9cdf-32534e8419ae&pd_rd_i=B073ZX58PH&psc=1

[linkindustries]

Yeah, I'm still perplexed by what happened. I had issues with not tightening the nut enough when using a 1/2" in bit and having the bit slip and eventually break. I called axiom about the slipping issue and they recommended getting longer wrenches and told me it's basically impossible to over tighten the nut. After that I also got quite paranoid about keeping the nut & collet super clean.
On the day of the damage, I had finally successfully cut hard maple using a 1/2" bit. I took out that bit, again cleaned and inspected the nut and then made an easy cut with a 1/4 inch bit. When loosening it, there's that first loosening and then it tightens again slightly and in that interval it's a little awkward with the long wrenches and I believe that the wrench slipped and got the nut to cross thread. Since I was expecting resistance I just pushed and that's when I think I caused the damage.
Either that or there was already some debris in there and I just ground it in.
I've yet to remove the spindle and really force the nut out, which might give me the answer. It really is hard to believe that as a 115lb, small and not super strong person, I could inflict such damage.
I will see if I can salvage the old spindle (I will not try to re-thread it myself!), maybe to keep as the back up I'll never need or to sell. I tried to see if axiom would take it back, but no dice.
Thank you again for your words of encouragement. It's been great to have the support of the axiom community.

[Bob]

You can take Dremel and a small grinding wheel and carefully make a slit on two sides of the nut. You can then split the nut. Try not to grind into the spindle shaft. It appears that your problem is caused by galling.

www.google.com/search?q=galling+metal&rlz=1C1UEAD_enUS1036US1036&oq=galling&aqs=chrome.2.69i57j0i433i512j0i512l8.5552j0j7&sourceid=chrome&ie=UTF-8.

(This can be caused by over tightening)

Be sure to use an anti seizing material.

www.google.com/search?q=how+to+prevent+galling&rlz=1C1UEAD_enUS1036US1036&oq=how+to+prevent+gallin&aqs=chrome.0.0i512j69i57j0i512l3j0i22i30l4j0i15i22i30&sourceid=chrome&ie=UTF-8

I'm speaking from direct experience here...

[linkindustries]

ok, managed to get the nut off of the spindle! 

I removed the spindle from the machine, clamped one of the wrenches in a vise and worked it back and forth for a bit with silicone lubricant and it finally yielded. I was just about ready to go at it with the dremel, as suggested by Bob, but I could tell the threads on the spindle were gone anyway, so preferred the wrench approach.

Lesson learned (hopefully!) boys and girls: when loosening the nut, beware of cross threading between the 2 stages of looseness! It's often an awkward moment when switching hands with the heavy long wrenches. I need to figure out a better choreography so I can also hold the bit to prevent it from falling out of the collet.

New spindle should arrive next week and then it will be the coolant replacement and tramming adventure.

And one of these days I might even get back to work!

Anybody wanna buy a spindle with mangled threads? It's only been operating for less than 2 years on fairly light jobs. If you can recut the threads, it will be as good as new.

Including the pic here as cautionary tale. Trigger warning, it's gnarly!

[eagle55]

Just a curiosity, but from the picture doesn't show that many damaged threads other than the first one or two threads where the nut was mangled on down further. It almost makes me think that the nut may have been defective. Was that an "additional nut" or one that came with the machine? If you are going to through it away, I might be interested in trying to salvage it. (one of my faults... try to save anything with any intrinsic value.. lol) But all in all maybe a lesson for all of us to keep our threads clean and wiped down with 3in1 oil and maybe be more mindful of the pressure used in tightening. Also, I almost wonder if the threads could have been in the process of failing when you were having problems with the slipping bit which prompted you to start using the longer wrenches.

[linkindustries]

Hi eagle55, while most of the damage was on the last few threads on the spindle, there are a couple of other spots further up as well (about 5 turns up or so). 

The nut was the original one that came with the spindle. I don't think the nut is salvageable (prob not worth the effort), but i would be quite interested in saving the spindle! Seems crazy to bin the whole thing because of the threads. I'm trying to find a machinist around the NYC area. Though given the precision & balance demands, I'm a bit skeptical.

I don't know if the nut was defective, but it would explain some things. I was advised to get the longer wrenches because I'm small and couldn't get it tight enough for the 1/2" bit. I only had problems when I tried to use a 1/2" ball nose spiral, which is much longer than the surfacing or box core that I had used successfully. It is entirely plausible that the slippage and bit break caused some damage or weakness to the nut and it took a bit to fully fail. Maybe there was some debris in there that all my cleaning didn't quite get.

I figured it was just a lack of strength. I thought I was being careful with keeping nut & collet clean. I do know that it happened while loosening the nut to remove a 1/4" bit.

I'm going to do some tests with the bigger bits and see if I can find the sweet spot for tightness.

Anyone else using the longer wrenches? Have you figured out how to work with them in an efficient and graceful way that doesn't get all awkward and causes them to slip?

But the good news is that I received the new spindle, installed it and ran the surfacing toolpath. It seems solid from a tramming perspective. I'll do some more tests, but, fingers crossed, I'm back in business!