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How much head stock runout is acceptable?

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Forum topic by Bonj posted 07-25-2014 06:03 PM 604 views 0 times favorited 13 replies Add to Favorites Watch
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Bonj

12 posts in 89 days


07-25-2014 06:03 PM

Topic tags/keywords: lathe runout spindle

I have an old General 160 lathe that I bought used. Over the two years I’ve had it I’ve turned a number of bowls and have built up my skill level. However, I always suspected some wobble – particularly with larger bowls. I’ve recently acquired a dial indicator to check the ‘trueness’ of the headstock spindle. I attached my SuperNova2 chuck and zeroed out the indicator on the surface of the chuck. I hand turned the spindle and the needle detected .0045 deflection.

To me, a relative neophyte, this doesn’t sound like a lot – but is it?

While I’ve never posted anything to the Lumberjocks site as yet, I have been following it for about 2 years. I know there’s a wealth of knowledge and experience out there and am hoping some of you gurus can set me straight.

-- Nothing is impossible for those that don't have to do it themselves


13 replies so far

View SCOTSMAN's profile

SCOTSMAN

5421 posts in 2273 days


#1 posted 07-25-2014 07:18 PM

No it is not. Especially on a woodworking lathe where the tolerences are no way near as critical as when machining metal.Have fun and keep safe you will be fine and not notice anything IMHO.. Alistair

-- excuse my typing as I have a form of parkinsons disease

View Arlin Eastman's profile

Arlin Eastman

2118 posts in 1249 days


#2 posted 07-25-2014 08:01 PM

I have read a turning book about this problem.

It said anything under .003 is considered good. From .003 to .005 is something to watch depending on how long the spindle is. The longer the spindle the more wobble at the end of it. From .006 and up it should be fixed.

I have heard it said it is about the same as a drill press also.

-- It is always the right time, to do the right thing.

View Wildwood's profile

Wildwood

1098 posts in 822 days


#3 posted 07-26-2014 11:19 AM

Welcome to Lumberjocks! Probably just the wood you are turning wood does move while we turn.

If have no play in the spindle (worn bearings) check for run out without chuck mounted see what you have. I stick dial indicator just inside the spindle to get a reading. (see Johnny cnc video below) Then add the chuck and measure again. Not uncommon to see a little movement as you add components in or on the headstock spindle.

You want to measure body of the chuck and not the jaws. Whether you pay a little or a lot woodturning chuck jaws can and do flex a bit due to wood movement while turning.

If you had a bad thread adapter (insert) would have problems regardless size of the wood you turned. Since only see a problem with large heavy blanks do not think there is a problem with your threaded insert. If makes you feel better, take it out and reinsert it.

Teknatool does recommends and provides chuck disassembly and cleaning instructions. They do not provide a time table to do this, so unless having problem with opening & closing chuck jaws would not do it. I found using compressed air cleaning my Oneway chucks gets rid of dust build up.

http://www.teknatool.com/products/Chucks/SuperNova2/Downloads/Maintance%20of%20SuperNova2%20Chuck_Oct04.pdf

This Jonny CNC video geared toward pen turners demonstrates how to measure run out. Principals the same for headstock spindles and components we add.
http://www.youtube.com/watch?v=16xBV3PggQI

-- Bill

View johnstoneb's profile

johnstoneb

728 posts in 860 days


#4 posted 07-26-2014 11:52 AM

You need to check for side to side movement on the spindle itself. You don’t know what tolerance the exterior of the chuck was turned to. Every time you add a component you increase the posibility of more movement.

-- Bruce, Boise, ID

View Nubsnstubs's profile

Nubsnstubs

221 posts in 418 days


#5 posted 07-26-2014 01:40 PM

Bonj, I think WW covered all the ways of checking for runout except checking the nutface on the spindle. It’s where the faceplate, chuck or adapter seats on the spindle. I didn’t view his videos, so I can’t say wheter that was covered. ........ Jerry (in Tucson)

-- Jerry (in Tucson)

View REO's profile

REO

628 posts in 762 days


#6 posted 07-26-2014 10:10 PM

runnout has no effect on a turning if it is only chucked once. no matter how far off the chuck is the CUT will alwaysbe concentric with the axis of the bearings. bearing play although often misdiagnosed as runnout can have a huge effect! for a piece that is chucked more than once the interface between successive cuts becomes the issue. It will require more sanding to blend two together.

View Arlin Eastman's profile

Arlin Eastman

2118 posts in 1249 days


#7 posted 07-27-2014 01:49 AM

Good Point REO

-- It is always the right time, to do the right thing.

View Rick M.'s profile

Rick M.

4137 posts in 1068 days


#8 posted 07-27-2014 08:08 AM

To keep it in perspective, 20# paper is about .004” thick

-- |Statistics show that 100% of people bitten by a snake were close to it.|

View TheDane's profile

TheDane

3860 posts in 2351 days


#9 posted 07-27-2014 01:44 PM

Rick M. —Good point, helps put things in perspective. My son-in-law bought a dial indicator and was all bent out of shape when he discovered the fence on his table saw was .005 out of square with the blade.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View Nubsnstubs's profile

Nubsnstubs

221 posts in 418 days


#10 posted 07-27-2014 01:49 PM

Dane, after he found the descrepancy, did he rectify it?..... Jerry (in Tucson)

-- Jerry (in Tucson)

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TheDane

3860 posts in 2351 days


#11 posted 07-27-2014 03:37 PM

Nubsnstubs—He tried … made it worse tinkering with it. I told him that .005 on a tablesaw is no big deal, but he thinks it should be perfect. Go figure.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View Rick M.'s profile

Rick M.

4137 posts in 1068 days


#12 posted 07-27-2014 08:31 PM

Once in a blue moon I calibrate my fence to about .002” out in the back but I’m sure it varies much more than that as often as I take it off. Heck I used it for almost 15 years before I owned a dial indicator and just calibrated it by feel against the miter gauge slot, never had any reason to complain. There are definitely guys out there pushing the limits of woodworking precision but that’s not me. I figure that if the old timers could make masterpieces with a handsaw, who am I to worry about a few thousandths of an inch.

-- |Statistics show that 100% of people bitten by a snake were close to it.|

View Bonj's profile

Bonj

12 posts in 89 days


#13 posted 07-28-2014 03:42 PM

First, thanks all for all the great insights and tips. They’ve been very helpful. I tried the suggestions you’ve made (removing and reinserting the insert, using compressed air to blow out any dust or debris, etc) and the bottom line is I believe the run out I see is definitely acceptable. As Rick M. stated: “if the old timers could make masterpieces with a handsaw, who am I to worry about a few thousandths of an inch?”

I initially went down this path after trying my first few “larger” bowls (10 to 11.5”). After turning the outside and then reversing the piece in the chuck jaws to do the inside, when I started up the lathe there was an easily discernible (though minor) wobble. I’ve since put this down to not taking enough care and attention when creating the tenon: making certain the depth is correct, right angle for the dovetail, and insuring there’s a square shoulder to meet up against the jaws. I mentioned I’m a relative neophyte but am learning where the gotchas are.

The second thing that got me thinking about this was comparing my experiences on my lathe to those of working on other lathes on courses and observing demos at our guild meetings. During those times, when things were reverse mounted they seemed to run rock solid true. My thinking here is that I’m comparing a Lada to a Ferrari. My old lightweight General just isn’t in the same ballpark in terms of mass and tolerances as the Oneways and Vicmarks I’ve used in courses and seen during demos.

Once more, thanks for taking the time to respond.

Cheers

-- Nothing is impossible for those that don't have to do it themselves

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