What is "acceptable" T.I.R. ??

[Dirtbmw20]

I know ideally total indicated runout would be 0.000 but what is "acceptable" runout when referring to the Taig lathes. Just checked mine today for the hell of it. After a years worth of use from the previous owner and 2 years of use from me, mine is a teeny tad over .001. I have a digital gauge that reads in .5 incriments and it never went past .001. A pic with my manual gauge below. Is that "acceptable" for a 3 year old Taig lathe ??

Sent from my SCH-I535

 

[3kushn]

I know ideally total indicated runout would be 0.000 but what is "acceptable" runout when referring to the Taig lathes. Just checked mine today for the hell of it. After a years worth of use from the previous owner and 2 years of use from me, mine is a teeny tad over .001. I have a digital gauge that reads in .5 incriments and it never went past .001. A pic with my manual gauge below. Is that "acceptable" for a 3 year old Taig lathe ??

Sent from my SCH-I535

I really can't answer your real question. I will ask one or two. Is that pin a precision ground pin? Another is do you put the chuck key in all 3 holes? Assuming there's 3. Doing this better aligns the jaws. Most people don't. Chuck manufacturers may have resolved this issue but old school is do all of them.

 

[whammo57]

I know ideally total indicated runout would be 0.000 but what is "acceptable" runout when referring to the Taig lathes. Just checked mine today for the hell of it. After a years worth of use from the previous owner and 2 years of use from me, mine is a teeny tad over .001. I have a digital gauge that reads in .5 incriments and it never went past .001. A pic with my manual gauge below. Is that "acceptable" for a 3 year old Taig lathe ??

Sent from my SCH-I535

Run out depends on what you are putting in the lathe and how you tighten the scroll chuck. Normal is 1 to 2 thou but if you know how, you can get it better after you chuck it up. Wiggle - tap - spin -shim..... etc....

Anything you can get to spin within 1 thou will be just fine.

Kim

 

[Dirtbmw20]

I really can't answer your real question. I will ask one or two. Is that pin a precision ground pin? Another is do you put the chuck key in all 3 holes? Assuming there's 3. Doing this better aligns the jaws. Most people don't. Chuck manufacturers may have resolved this issue but old school is do all of them.

3kushn....... Yes and Yes to both of your questions. :smile:

 

[Dirtbmw20]

Run out depends on what you are putting in the lathe and how you tighten the scroll chuck. Normal is 1 to 2 thou but if you know how, you can get it better after you chuck it up. Wiggle - tap - spin -shim..... etc....

Anything you can get to spin within 1 thou will be just fine.

Kim

Kim....... Thank you very much, that is exactly the answer I was looking for. I know I don't ask my question is the correct form or manner most of the time. I understand it all depends on what I'm putting in the lathe but you gave me the exact answer I was asking for. Thank you again sir. :thumbup:

Lee

 

[whammo57]

Kim....... Thank you very much, that is exactly the answer I was looking for. I know I don't ask my question is the correct form or manner most of the time. I understand it all depends on what I'm putting in the lathe but you gave me the exact answer I was asking for. Thank you again sir. :thumbup:

Lee

One other thing a lot of people miss is that one hole in the chuck will grip a piece more accurately than the other 2. I put the ground pin in the chuck and put an indicator on it. Number the holes in the chuck with a marker. 1-2-3

Spin it slowly and check the runout. Loosen and tighten using each hole until you see which one gives the best reading.

Scroll chucks are unique.

Kim

 

[Tooler]

One other thing a lot of people miss is that one hole in the chuck will grip a piece more accurately than the other 2. I put the ground pin in the chuck and put an indicator on it. Number the holes in the chuck with a marker. 1-2-3

Spin it slowly and check the runout. Loosen and tighten using each hole until you see which one gives the best reading.

Scroll chucks are unique.

Kim

I also noticed that the rear chuck can be totaly different than the front..... (ie: #2 jaw in the front and #1 on the rear gets me real close).

MSC sells a 1in x 12 ground rod for aprox.$25.

Sent from my DROIDX using Tapatalk 2

 

[Dirtbmw20]

One other thing a lot of people miss is that one hole in the chuck will grip a piece more accurately than the other 2. I put the ground pin in the chuck and put an indicator on it. Number the holes in the chuck with a marker. 1-2-3

Spin it slowly and check the runout. Loosen and tighten using each hole until you see which one gives the best reading.

Scroll chucks are unique.

Kim

Interesting......... I did not know this and have never heard that before. I'll have to play with it and try each hole 1 at a time and see which is more accurate. Thanks again Kim for that info

 

[whammo57]

I also noticed that the rear chuck can be totaly different than the front..... (ie: #2 jaw in the front and #1 on the rear gets me real close).

MSC sells a 1in x 12 ground rod for aprox.$25.

Sent from my DROIDX using Tapatalk 2

Yes.... every chuck is a little different. Rather than chucking a long piece with both chucks, I use the front chuck and a steady rest in the rear. I spins more accurately..

Kim

 

[macguy]

I know ideally total indicated runout would be 0.000 but what is "acceptable" runout when referring to the Taig lathes. Just checked mine today for the hell of it. After a years worth of use from the previous owner and 2 years of use from me, mine is a teeny tad over .001. I have a digital gauge that reads in .5 incriments and it never went past .001. A pic with my manual gauge below. Is that "acceptable" for a 3 year old Taig lathe ??

Sent from my SCH-I535

Although you want a chuck that is as accurate as possible, preferably a 6 jaw that that can be adjusted for perfect trueness. The problem with working on cues is they are wood. Self centering lathe chucks center with a bit of pressure to get all the jaws to repeat accuracy. Not wanting to crush or mark the wood you usually close down on say a cue shaft somewhat lightly, even when using a collet. You may need to do a little tapping on the high jaw a little to get as close to zero as posable even with the best of chucks. As mentioned in another post, find and mark the hole that seems to repeat the best. This will be the case on most every scroll chuck you use.

I have been messing around with lathes for like 45 years and the tapping method is the best way I have found, (Although I didn't discover it I was taught), to get something perfectly centered. You don't tighten the chuck real tight before you tap but once it is centered at as close to zero as posable depending on how truly round what you are chucking is, a little final snugging and you will be right there. By the way, this takes just a few seconds to do as opposed to spending like 5 minutes of trial and error shimming. The problem with shimming, and sometimes you may have to shim is, every time you open and close the chuck it may reset differently till tightly snugged. Even if you do need to use a shim now and then a little tap on the high side will get you close to perfect very quickly.

 

[Dirtbmw20]

Although you want a chuck that is as accurate as possible, preferably a 6 jaw that that can be adjusted for perfect trueness. The problem with working on cues is they are wood. Self centering lathe chucks center with a bit of pressure to get all the jaws to repeat accuracy. Not wanting to crush or mark the wood you usually close down on say a cue shaft somewhat lightly, even when using a collet. You may need to do a little tapping on the high jaw a little to get as close to zero as posable even with the best of chucks. As mentioned in another post, find and mark the hole that seems to repeat the best. This will be the case on most every scroll chuck you use.

I have been messing around with lathes for like 45 years and the tapping method is the best way I have found, (Although I didn't discover it I was taught), to get something perfectly centered. You don't tighten the chuck real tight before you tap but once it is centered at as close to zero as posable depending on how truly round what you are chucking is, a little final snugging and you will be right there. By the way, this takes just a few seconds to do as opposed to spending like 5 minutes of trial and error shimming. The problem with shimming, and sometimes you may have to shim is, every time you open and close the chuck it may reset differently till tightly snugged. Even if you do need to use a shim now and then a little tap on the high side will get you close to perfect very quickly.

So.... take a 3lb sledge hammer and beat the crap out of my headstock,LOL. :grin:

Nahhh, I'm just kidding macguy. Thanks very much for that info, those are the little trade "secrets" that I don't know about. :smile:

 

[macguy]

So.... take a 3lb sledge hammer and beat the crap out of my headstock,LOL. :grin:

Nahhh, I'm just kidding macguy. Thanks very much for that info, those are the little trade "secrets" that I don't know about. :smile:

You lightly tap on the chuck jaw itself, not on the piece being chucked. I just use the back of the chuck key to tap. The jaws float around on a scroll plate as you tighten them. Even the lube inside the chuck that settles between the scroll plate and the jaw is enough to create run out. You can't just squeeze the sh!t out of it like you could if you were chucking a steel bar. This is the same system that you would use if you were chucking up thin tubing. It is not unusual just common machine shop practice. Chucking wood and thin tubing presents pretty much the same problems. You are right, these are tricks you don't usually find in books, they are passed on from other workers.

I remember once working on my car. I had half the front of the engine off when a tenant of mine came out and was watching me. I was working right from a shop manual. He told me that I didn't need to do any of that and showed me the right way to do it. All I had to do was unbolt the air conditioning compressor and move it aside to get at the hidden bolts. WTF, I'm out there for like 3 hours and still didn't have the water pump off and the way he did it it took like 40 minutes total. The reason this was not in the manual was because they don't want you messing around the compressor I guess because of the pressure and you could cause a leak. So they have you taking like everything apart when you really don't need to. You just need to be a little careful moving the compressor.

 

[whammo57]

Although you want a chuck that is as accurate as possible, preferably a 6 jaw that that can be adjusted for perfect trueness. The problem with working on cues is they are wood. Self centering lathe chucks center with a bit of pressure to get all the jaws to repeat accuracy. Not wanting to crush or mark the wood you usually close down on say a cue shaft somewhat lightly, even when using a collet. You may need to do a little tapping on the high jaw a little to get as close to zero as posable even with the best of chucks. As mentioned in another post, find and mark the hole that seems to repeat the best. This will be the case on most every scroll chuck you use.

I have been messing around with lathes for like 45 years and the tapping method is the best way I have found, (Although I didn't discover it I was taught), to get something perfectly centered. You don't tighten the chuck real tight before you tap but once it is centered at as close to zero as posable depending on how truly round what you are chucking is, a little final snugging and you will be right there. By the way, this takes just a few seconds to do as opposed to spending like 5 minutes of trial and error shimming. The problem with shimming, and sometimes you may have to shim is, every time you open and close the chuck it may reset differently till tightly snugged. Even if you do need to use a shim now and then a little tap on the high side will get you close to perfect very quickly.

About 30 years ago a machinist I worked with showed me that trick. I still use it. I use a thread file because it has a rubber coated handle and doesn't mar the aluminum chuck jaws.

Another one is when you are about a thou to big on something you are turning.... take another pass without changing anything. Just push little on the tool holder as you take the pass.... sometimes you get just enough to get the right dimension.

Kim

 

[Dirtbmw20]

I remember once working on my car. I had half the front of the engine off when a tenant of mine came out and was watching me. I was working right from a shop manual. He told me that I didn't need to do any of that and showed me the right way to do it. All I had to do was unbolt the air conditioning compressor and move it aside to get at the hidden bolts. WTF, I'm out there for like 3 hours and still didn't have the water pump off and the way he did it it took like 40 minutes total. The reason this was not in the manual was because they don't want you messing around the compressor I guess because of the pressure and you could cause a leak. So they have you taking like everything apart when you really don't need to. You just need to be a little careful moving the compressor.

Now THIS I can relate to. I have been in the automotive parts business for 35 years, family owned import parts store for 10 of those years, the rest working in dealership parts departments, raced BMW dirt track stock cars for 13 years, run/manage the shop counter at a very large Chrysler/Jeep dealership. I do nothing but deal with technicians, all day, every single day of my life. I'm 1/8 mile away from the retail/wholesale parts counter, never see or talk to the public, no salesmen, no wholesale, don't even hear the phones ring..... nothing but the 16 technicians WE have on our Chrysler side. So I can fully relate to your scenerio.

I'm a very mechanical guy, very mechanically inclined, just never been in the "machine shop" industry so I just never got to be around lathes and mills and machine shop equipment back in my teenage years or high school, I was in Automotive and Horticulture class my 4 years of high school. But being in this business, racing cars, building my own engines before I even had my own drivers license has made me a very mechanically inclined person and I pick up and learn stuff by useing it with hands on experience or by watching someone else do it. I never progressed in education past high school so I don't have any trade education, just a hands on experience trade of the automotive business.

 

[Dirtbmw20]

About 30 years ago a machinist I worked with showed me that trick. I still use it. I use a thread file because it has a rubber coated handle and doesn't mar the aluminum chuck jaws.

Another one is when you are about a thou to big on something you are turning.... take another pass without changing anything. Just push little on the tool holder as you take the pass.... sometimes you get just enough to get the right dimension.

Kim

Another nice little bit of advice. Not working around lathes my whole life like you guys, little stuff like that doesn't "occur" to me unless I'm told or accidentally stumble on it myself.

On the hammer part, I'm gonna make me a little delrin hammer to use. Just something else for me to practice on making and have fun with.

Thanks again guys for sharing some of the little secrets.

 

[conetip]

I have a piece of copper round, 1 end has a piece of delin pressed into it.
Cooper or plastic, works well.
The copper end does tend to mushroom easily, so I just squeeze it back to aprox shape in the vise.
I do not like tapping a chuck jaw myself, I prefer to have the chuck mounted onto a faceplate, then use belville washers under the screws to keep a constant pressure.
Then just loosen slightly and move the chuck to the new centre. Re tighten good to go.
With the Taig chucks there are not that many options.
All the Taig chucks I have would not repeat to a thou. That was untill I did a mod on them. But even then, they only are close on that dialed in size.
Now I have a home made spindle with an ER40 collet system, and another set up with the 5C taper. I prefer the Er40 over the 5C at this stage.
I also moded a Taig 4 jaw ind chuck with the 32 tpi thread. I have made an adapter so I can use it on the front of the ER40 spindle(M50 x 1.5 ) if required ,or mount it onto the back of the head stock spindle witch is the 32 tpi thread.
I find that all the repair stuff I work on is not round at all. Some can be as much as as 0.008 inches 0.2mm from being round.
In these cases, I find a wood collet to be very useful in getting to the average of what is there.
When checking the run out of the chuck, you need to check close by the jaws and also about 3 inches or so out from the jaws. The outer value will show the swash in the chuck. By making a not of where the high side is relative to the chuck over several test pieces, a map of the error can be created. If you find that the high side is predominantly in a small radial range, then a correction can be made to the body to re-align it.
Some chucks just can not be fixed and they are what they are.In this case, I bored mine true to hold 30mm diameter. I then made a series of 30mm bushes with varying id's to do different things.
As they say, lots of ways to catch a mackerel.

 

[Tooler]

I was thinking of swapping out the 3 jaw chuck for the 4 jaw. I would think these would be easier to dial in. ...? Just curious.

 

[It's George]

Have you found one that's not self centering?

 

[scdiveteam]

Hi,

My six jaw on my Enco lathe indicates about 3/4 of a thou run out with a 1/2" dowel rod.

When I install my pin, I shim the OD of my tapered collet with Zig Zag paper until I read zero. When I install my pin it is alway abot a 1/4 thou run out on the nose of my pin 1.250 off the face of my joint face. It only takes a minute or two to shim so I feel that's ok.

I tried to zero my chuck dead on several times but it always ends up the same error. I guess thats the bearing run out on my spindle bore. All in all I feel the that is not too bad for a china lathe. Not making a spacecraft parts just a pool cue.

If your pin indicates with in .001 you will never have a problem. Less than that and you are gold.

Speaking of Gold, Joey Gold has a tool room collet chuck on his lathe and it is crazy accurate. The dial indicator hardly wiggles on the .0005 line, pretty awesome!!! The accuracy of his shop equipment is unreal.

Rick

 

[macguy]

I was thinking of swapping out the 3 jaw chuck for the 4 jaw. I would think these would be easier to dial in. ...? Just curious.

Most defiantly, you can get it centered perfectly. It can get old after a while though, especially if you are doing a lot of things like making parts that may not need to be perfectly centered, you will wish you were using a three jaw. Say you are just parting off a pieces of a rod or something for later use. One trick is to mark two of the jaws with some white out or paint. Once you have something centered after you make your cut or what ever you are doing, only loosen the marked jaws.

If you are putting in the same size pieces, when you retighten the two marked jaws the chuck will repeat perfectly for that job. I have no problems with a 4 jaw, I can center something in just a few seconds. You get a pretty good feel for how much to move the jaws with some practice and can get it real close on the first adjustment, then you just tune it in.

I just looked and found this video on youtube. Not a bad one there are more to check out.
http://www.youtube.com/watch?v=vsIaYm7g9nA