Runout - the lathe kind, not the 9-ball kind

[td873]

I'm using a dial indicator to guage the runout on my lathe. When I use the "centering bar" provided (used to center the tailstock), I get .005 movement. For the repairs I've been doing, it doesn't seem to make a difference. But practically speaking, will this small amount of runout make a difference when building cues? If so, can I adjust the jaws of the chuck, or should I just shim accordingly?

-td

 

[Murray Tucker]

I'm using a dial indicator to guage the runout on my lathe. When I use the "centering bar" provided (used to center the tailstock), I get .005 movement. For the repairs I've been doing, it doesn't seem to make a difference. But practically speaking, will this small amount of runout make a difference when building cues? If so, can I adjust the jaws of the chuck, or should I just shim accordingly?

-td

Make sure that what you are measuring is actually round. Take a piece of aluminum round. .625 to .750 dia and about three inches long. Chuck it up so that about 1.5 inches is sticking out and take a light cut on it making sure it "cleans up" 100%. Turn it around and chuck on the part you just turned and make a light cut on that half. Turn it around again and chuck on the part you just turned. Now you can use your dial indicator on the part and measure your true run out.

 

[Pancerny]

Is the center bar you are referring to a small hash mark on the tailstock that gives you the rough center??? Sounds like you are trying to center the offset on your tailstock. If you're chucking and re-chucking...any indicator reading will be subject to how well the piece is re-chucked. I think there is a more accurate method. ...center drill the piece on both ends and turn it down between centers, removing enough to get a clean cut along the whole length. Measure the piece at both ends...if your tailstock is off, then the piece will be tapered....move tailstock position in or out by half of the difference of the 2 measurements (if tapered). This will ensure your tailstock is set-up correctly. Any drilling or tapping operations with an offset tailstock will cause you other problems, even if you bore the hole to size before tapping, which is the more accurate than just drilling and tapping. (the steps are drill (undersize) bore to size, tap) If you are getting movement in the tailstock when it's locked down, you will need to replace some parts....005" is quite a bit.
There is also a chatroom for cuemakers on Yahoo, look under "cuebuilders"...you may find it a valuable resource.
Mike

 

[macguy]

I'm using a dial indicator to guage the runout on my lathe. When I use the "centering bar" provided (used to center the tailstock), I get .005 movement. For the repairs I've been doing, it doesn't seem to make a difference. But practically speaking, will this small amount of runout make a difference when building cues? If so, can I adjust the jaws of the chuck, or should I just shim accordingly?

-td

Lathe chucks are designed to self center on a scroll plate under quite a bit of pressure more then you can put on a piece of wood without crushing it. Even the truest chuck may require a little tightening and re tightening to get it close to zero. If say you are even cutting down a tip, .005 is a lot of run out in my opinion, it will constitute a wobble and can mess up your work. First, what kind of lathe do you have as well as what kind of chuck are you using?

 

[hadjcues]

Make sure the tailstock is centered, then you could cut a piece 10in. length and measure both ends... the difference indicates a tapered cut. Check how far you have the tram out of the tailstock, make sure it is going in and out of it straight. Another thing to look out for is there may be a twist in the bed. Make sure your lathe is level. Because of this, the chuck could be misalligned with the ways of the bed, which could increase you run out the farther you move the tailstock from the chuck. Check all possibilites, only then can you decide how to go about the problem

Hadj

 

[td873]

I was a little unclear in my first post. I am checking the runout on the chuck, and not aligning the tailstock. To check for runout on the chuck (3-jaw) I am using a 3" long .5" diameter steel bar. (This bar was provided with the lathe as is inteded to center the tailstock with the headstock). When this bar is sticking out of the chuck 1", the runout is .005".

Will this .005" cause any problems for other tasks (say drilling and tapping for a joint pin)?

-td

 

[macguy]

I was a little unclear in my first post. I am checking the runout on the chuck, and not aligning the tailstock. To check for runout on the chuck (3-jaw) I am using a 3" long .5" diameter steel bar. (This bar was provided with the lathe as is inteded to center the tailstock with the headstock). When this bar is sticking out of the chuck 1", the runout is .005".

Will this .005" cause any problems for other tasks (say drilling and tapping for a joint pin)?

-td

.005 is a lot. Again, what kind of chuck is it? It is best to have a 6 jaw that can really be trued. A good 6 jaw Buck type chuck can cost $500 or $600 but are well worth it.

 

[cueman]

I was a little unclear in my first post. I am checking the runout on the chuck, and not aligning the tailstock. To check for runout on the chuck (3-jaw) I am using a 3" long .5" diameter steel bar. (This bar was provided with the lathe as is inteded to center the tailstock with the headstock). When this bar is sticking out of the chuck 1", the runout is .005".

Will this .005" cause any problems for other tasks (say drilling and tapping for a joint pin)?

-td

If it is a Cue Smith lathe you probably need to touch up the jaws with a boring bar. If you need instructions give me a call. 770-684-7004
It should have less than .002" run out after boring.

 

[Sheldon]

I'm using a dial indicator to guage the runout on my lathe. When I use the "centering bar" provided (used to center the tailstock), I get .005 movement. For the repairs I've been doing, it doesn't seem to make a difference. But practically speaking, will this small amount of runout make a difference when building cues? If so, can I adjust the jaws of the chuck, or should I just shim accordingly?

Providing detail will allow people to help you.
What kind of lathe is it.
What kind of chuck is it.
How is the chuck mounted.
.005 is unacceptable, IMO.