Acceptable run out for lathe
- Thread starter skipthorp
- Start date
I dont know how you can fix it because ive never used one of those, but my south bend is less than .001 it was at .0005 when i first indicated it in, but its moved just a touch now, and holding steady at less than a thou. .004 would not be good enough for most cuemakers ive talked to or read about.
Joe
i'm not to happy but .003 is what I have on my porper model B after new bearings and a new spindle.You can loosen the bolts on the back of the bison chuck and try to get it closer or bore the jaws if you havn't done so already.
My question is who can sand to .003-.004 ? In 30 in.
Put a drill rod or dowel pin in the chuck and indicate it at 1" out, from top. Loosen the three allen head bolts holding the chuck to the faceplate and tighten them slightly so that you can use a mallet to move the chuck by tapping it, but it won't move on it's own due to gravity. Spin the chuck a little bit until the run out is at it's max to the right, and tap the chuck from top until it reaches half way back to zero, then spin & repeat. You'll have to adjust zero a few times but eventually you'll get there. You want to get the chuck to where it spins without the indicator moving off zero. Mine runs .0005". Anytime it's off a bit I readjust it. Takes about 20 minutes. Once zeroed out, tighten the bolts all the way.
I would take the chuck off the spindle, test that the bearings are in good order and that the chuck register (if it has one) is running true. Clean the chuck and reassemble with a test piece. Indicate the test piece and see where it has to be to get the best results.
Try test pieces of different sizes to get an idea of the overall condition of the chuck. If the chuck is in good order, it should be within .001 inches with test pieces from 1/4 inch through to 1-1/4 of TIR (total indicator runout)
I have seen on some lathes ( I have one faceplate chuck setup ) with belleville washers under the capscrews holding the chuck to the faceplate/adapter plate.They allow you to loosen them off a little, then you can adjust to the desired position, then tighten up.
Most chucks will still repeat at a particular size, but not over a range of sizes.
You should be able to get it running as true as the spindle bearing setup allows.
The other option is to put a shim under 1 or 2 of the 3 jaws untill it runs closer to what is acceptable to you. The shims can be steel or brass shim available in some cases in .01 mm increments, definitely in .001 inches increments.The long play video tapes used to be .0012mm thick and was ideal for alot of shim situations.They may be a garage sale item now.
For joint and ferrule repair work, I find anything more than .04mm (.0015 inches) is getting to the too far away from true. I see this on repairs of shafts and handles that are more than this out of round and the finished result is just a compromise of what is there.
You need to remove your spindle & take it to a machine shop that has a big lathe that can fit your spindle though it's chuck & into it's spindle. The face plate needs to be faced center to the spindle before the chuck is installed. This is a huge issue for these machines but folks rarely know because they never indicate their chuck. These things get assembled & expected to be fine, but they're not even close. Mine was .014" off right out of the crate. I called Joe immediately & the guy told me I was an idiot. That's when I realized the warranty didn't mean shit & I was on my own.
I fixed mine by putting loc-tite in the seams between the bearings & spindle, to lock it in place and eliminate all slop except what was natural to the bearings. I removed the chuck. I removed the tool post mounting slot and drilled/tapped new holes on the left side of the carriage, and reinstalled. That allowed me to use the lathe to face it's own face plate, in place. Never had a problem again with keeping the chuck running true. If I had to do it again, i'd remove the entire spindle & pay a machine shop to do it, just because they are better suited & it would have been easier. But what I did worked fine.
I believe I read that these oftentimes have bearing issues....
Thanks for the advice.Its not used often but needs to be better than .003
Is there any rules to how far out you should meassure?
I see 1" mentioned-is this the defacto standard in the US? In case what is it in the metric world-25,4mm or something else?
I thought mine was bad at 0,0006" - but that was done on a chucked up Atlas arbours shoulder... Prox 10mm from the chuck.
K
I see 1" mentioned-is this the defacto standard in the US? In case what is it in the metric world-25,4mm or something else?
I thought mine was bad at 0,0006" - but that was done on a chucked up Atlas arbours shoulder... Prox 10mm from the chuck.
K
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Hi,
I am no machinst and before cues had very little lathe time so take my opinions with a grain of salt.
My friend is a German master machinist and he told me that pros that do ultra precision machine work use soft jaws. They have various presision collar rings that are of various sizes that are chucked up on the ID to locate various openings sizes for the jaw holding during jaw boring.
When they have to hold precision tolerances on a 2 inch stock for example, they use the holding collar on the chuck and the bore the soft jaws for that 2" size. Now the chuck is running true with the spindle bearings and will be as true as that lathe can be.
I got Soft jaws and a precision collar that allows me to bore with live tooling using a diamond grinding shanked tool in my router. Since I have trued this way my chuck usually runs at .0005 or less.
Rick G
I am no machinst and before cues had very little lathe time so take my opinions with a grain of salt.
My friend is a German master machinist and he told me that pros that do ultra precision machine work use soft jaws. They have various presision collar rings that are of various sizes that are chucked up on the ID to locate various openings sizes for the jaw holding during jaw boring.
When they have to hold precision tolerances on a 2 inch stock for example, they use the holding collar on the chuck and the bore the soft jaws for that 2" size. Now the chuck is running true with the spindle bearings and will be as true as that lathe can be.
I got Soft jaws and a precision collar that allows me to bore with live tooling using a diamond grinding shanked tool in my router. Since I have trued this way my chuck usually runs at .0005 or less.
Rick G
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.0005" is acceptable for any lathe for any application that isn't micro level. In other words, that's as good as it gets. There's no practical reason to be any tighter, especially in cue work. The lathe that your point pin was made on likely isn't any better than .0005".
Newton, 1" is pretty common, but I don't think it's necessarily a standard. Personally, I measure at 1" because that is far enough to determine if it's a true reading. If measuring right next to the chuck, it may give you a pretty good reading, but be amplified farther out if the piece is gyrating slightly. Going an inch out lets you know for sure that it's a true reading. The farther from the chuck you get, the worse the run out will be. Getting it tight an inch away from the chuck means it'll still be pretty good on down. Hope that makes sense.
Thanks for the comment.
I know og course that it would get worse the longer distance you move so this is the reason for asking. I used a sanding mandrel as mentioned-which had a shoulder. The part sticking out was not 1" but that's what I had at that time.
Also, I always rotate the chuck by hand when doing this but I know some actually run the lathe and potentially their CNC spindle when measuring. Not my prefered way, I like having control and take things easy- which I feel I loose with live machines. However - which speeds should be used in case of live machines....?
To the OP- good that you got your Porper under control
K
Porper B Runout
Found this while doing searches on topic. Have two questions: Tried magnetic base w/indicator and couldn't find a metal base to secure it to--returned it. Tried flex mount--crap, returned it. Can you rig dial indicator to tool post so it works properly (pictures)?
Any YouTube videos that I'm not finding showing how to adjust chuck as described in above quote?
Thanks.
Code:
Found this while doing searches on topic. Have two questions: Tried magnetic base w/indicator and couldn't find a metal base to secure it to--returned it. Tried flex mount--crap, returned it. Can you rig dial indicator to tool post so it works properly (pictures)?
Any YouTube videos that I'm not finding showing how to adjust chuck as described in above quote?
Thanks.
Find a small round .0005" indicator ( Shars makes one ).
Glue a round wood piece at the bottom ( about 1/4 thick ).
Then glue 4 small earth magnets on the wood ( 12,3,6 and 9 o'clock ).
You can stick that easily on your parting tool .