New PM1228 Lathe erratic dial test readings on spindle and any chuck

[mikey]

While trying to setup the 3 jaw, I noticed I could not get a smooth runout reading, with consistent boundaries. I tried measuring the spindle at the outer edge of the centric that centers the chuck and the inner taper and I still get the same erratic runout seen in the video below. I've polished the surfaces a little with a quick touch of 1200 grit with slight improvement. I've also tightened the spindle nut just a tad, moved the dial test indicator from the compound and mounted it to the head stock and still the same thing. So far I've managed to dial the pin and Ultra precise chuck (not seen) in at about .0005-.0007", but I can't get the smoothness and consistency of the boundaries as seen in the second Frank Hoose video of the PM1228 and my PM728 mill, where it's rock steady.

You cannot really get any useful information regarding your spindle or chuck's run out while trying to measure it under power. Your numbers are meaningless because you cannot separate out hysteresis, surface roughness, bearing run out, etc.. While it is possible to measure dynamic concentricity (machine running), it requires very sophisticated equipment that most of us will never have access to. What is left to us is to evaluate the machine for static concentricity; that can be done in the shop with readily available equipment.

To save my fingers, see post #8 in this thread. This will give you the procedure to check your spindle run out accurately. I should add that a good indicator stand really helps. The old 2-arm style of holder is the most rigid. The Noga PH2040 is highly recommended.

As for your 3 jaw chuck, measuring run out on a scroll chuck is pointless. A scroll chuck is used for first operations work and in that instance, the work will be turned precisely concentric with the spindle axis. That means there will be zero run out of the work piece provided you do not remove it from the chuck. It doesn't matter if the chuck is a standard or set-tru chuck; for first op work it will produce zero run out during a first turning provided you do not remove the work from the chuck.

 

[matthewsx]

Make the tightest tolerance part you ever expect to need. If the machine can do it then you’re fine, if not then proceed to step 2.

you can find any opinion you want on the internet, what matters is if the results you expect are met.

John

 

[maticulus]

Make the tightest tolerance part you ever expect to need. If the machine can do it then you’re fine, if not then proceed to step 2.

you can find any opinion you want on the internet, what matters is if the results you expect are met.

John

Thanks and I have no interest in opinions on the matter, I can generate those on my own.

You cannot really get any useful information regarding your spindle or chuck's run out while trying to measure it under power. Your numbers are meaningless because you cannot separate out hysteresis, surface roughness, bearing run out, etc.. While it is possible to measure dynamic concentricity (machine running), it requires very sophisticated equipment that most of us will never have access to. What is left to us is to evaluate the machine for static concentricity; that can be done in the shop with readily available equipment.

To save my fingers, see post #8 in this thread. This will give you the procedure to check your spindle run out accurately. I should add that a good indicator stand really helps. The old 2-arm style of holder is the most rigid. The Noga PH2040 is highly recommended.

As for your 3 jaw chuck, measuring run out on a scroll chuck is pointless. A scroll chuck is used for first operations work and in that instance, the work will be turned precisely concentric with the spindle axis. That means there will be zero run out of the work piece provided you do not remove it from the chuck. It doesn't matter if the chuck is a standard or set-tru chuck; for first op work it will produce zero run out during a first turning provided you do not remove the work from the chuck.

This is the kind of clarity I was expecting from PM tech, I appreciate the help I received, but except for the most commons suggested, that I was already aware of, I have not received much in the way of an explanation, or confirmation that what I'm seeing is not something I should be concerned about as being an ominous sign.

I don't like to fuss, I try to be reasonable and give the benefit of the doubt where it's due. I'm not going to name call, bad mouth, or make recommendations as to whether or not anyone else should do business with a company based on my account. I'm trying to keep it as simple as this; I paid the asking price, and I'd like to have in my possession what that asking price dictated in advance I should have. So far I have two bent panels, and a spindle that's about to receive a ticket for DUI because it can't hold its "lane" over a simple, but as you've explained non definitive test, where everyone else's does, including my mill. I've yet to see an example elsewhere that looks like mine.

I will follow the guide you linked to, thank you for that and thanks to everyone else for taking the time to read my post(s) and provide input. My screen name is functional, I'm wired like that so this issue is definitely a sticking point. I'm also married and have enough challenges that come along with that already. This lathe was supposed to be therapy. I it seems I have two wives right now and neither will do what I say. Looks like I'll be buying another couch to sleep on, don't want to wear the old one out.

 

[Firstram]

I agree, this is not right at all. Hopefully PM gets it sorted in a timely manner!

 

[mikey]

This is the kind of clarity I was expecting from PM tech, I appreciate the help I received, but except for the most commons suggested, that I was already aware of, I have not received much in the way of an explanation, or confirmation that what I'm seeing is not something I should be concerned about as being an ominous sign.

We do not know you have a spindle that is out of spec until you measure and confirm that it is. If you find an issue and can tell PM exactly how you measured and found the problem then PM will work with you to resolve the issue, I'm sure. It may turn out that the spindle is fine and th3en you can move on to learning to use your new lathe. I truly hope this turns out to be the case.

 

[maticulus]

We do not know you have a spindle that is out of spec until you measure and confirm that it is. If you find an issue and can tell PM exactly how you measured and found the problem then PM will work with you to resolve the issue, I'm sure. It may turn out that the spindle is fine and th3en you can move on to learning to use your new lathe. I truly hope this turns out to be the case.

I don't know what, if anything is out of spec. I've posted some of my findings here after first contacting PM, providing video as requested and so far still not having an explanation, or idea of what is most likely the cause. I have not been instructed to tear into a machine that has a warranty, in order to remove and measure a spindle. My suspicion is the bearing (first time I've stated that here), or some form of contamination of the bearing, causing the erratic deviation/ irregular, irregularity of the runout.

The instruction manual does not include a break-in procedure, unless it was contained in a different set of instructions that fell out of the crate when it was cracked during shipping, since the instruction booklet I have was hanging out on arrival. I have run the lathe at medium speed for 20+ minutes a few days ago. PM didn't ask any break-in questions.

So I didn't just tell PM, I showed them and now I'm here, because I get the impression the person I've been in communication with doesn't have any idea of what's causing what I'm seeing. Perhaps an experienced member of this web site does and that's my reason for posting on the issue.

 

[mikey]

Correct me if I'm mistaken but the video you posted showed you measuring run out with the lathe running. That is not a valid method for checking spindle run out so what are you asking of PM?

 

[maticulus]

Correct me if I'm mistaken but the video you posted showed you measuring run out with the lathe running. That is not a valid method for checking spindle run out so what are you asking of PM?

It's no different rotating the chuck manually. Hopefully your question is rhetorical, but if not, Is there a problem with my inquiring of PM regarding why I can't duplicate in similar fashion what there are countless numbers of other lathes doing in the exact same test, including others like my own, deliver a steady, repeatable readout on a DTI?

 

[matthewsx]

I still say make some chips. The true test of any tool is if it performs as desired.

We are here to help and @mikey is one of the best on here.

You aren’t the first on here to measure something and question the precision you paid for. The procedure Mikey gave above is valid for testing what you’re asking about.

John

 

[maticulus]

I still say make some chips. The true test of any tool is if it performs as desired.

We are here to help and @mikey is one of the best on here.

You aren’t the first on here to measure something and question the precision you paid for. The procedure Mikey gave above is valid for testing what you’re asking about.

John

Thanks John and earlier I thanked Mikey for that info and agreed to do as instructed in the thread he linked to. I have a $700 chuck involved here, that was purchased under the influence of high precision capable advertising statements. I need to see order, no matter how basic and insignificant. If I can't get a reasonable explanation for what my brain is telling me is not right, I can't justify keeping it and would be better off returning it and taking the 20% offense fee.

I will install the standard chuck and run some cuts to see what happens. I can't use the Ultra chuck because that would void my ability to return it.
I'm just looking for answers, and Mikey's last post is giving me the impression I've crossed the line by asking questions here, after not getting a reasonable explanation thus far from what is an honored and loved company on this forum. I spent a pretty good bit of money for extras in addition to the cost of the machine and now I'm feeling I spent way more than it is worth.