# Quickly Aligning A Four Jaw Lathe Chuck



## randyc

Many new hobbyists seem to have little use for this type of work holder, preferring devices that tend to self-align, like a three jaw chuck or some form of collet system. 

A typical 4-jaw alignment experience might go like this:


Work is installed in chuck and the jaws tightened loosely while visually centering the work

Chuck is rotated by hand, checking work eccentricity with DTI and adjusting as required

Repeat , over and over and over and …

Does that seem about right ?  OK, that procedure will get shorter and shorter with practice but it can be improved considerably with just one simple change:

Make another chuck key.
I didn’t take any photos when I made the small chuck key shown at lower right but making the tool is a simple process.  The exterior features are not critical but the same square interface dimensions as the original chuck key are obviously required.  The part is blued using my normal hillbilly process:  position the parts over the gas burners on the kitchen stove and dunk ‘em in used motor oil when the correct color has been reached.





For initial alignment in a four jaw chuck, I prefer a travel indicator rather than a DTI.  This is because the run-out of the work piece is likely to be excessive, at least initially, and would probably exceed the travel limits of a typical DTI.

This one is permanently mounted to a magnetic stand and is parked on the back of the lathe taper attachment when not required.





At this point, for safety sake, disengage the drive system of the machine by loosening the belt drive or placing the spindle drive in neutral.  In this old Sheldon, lifting the lever loosens the belt as can be seen in the photo.





Rotate the chuck (and work piece, of course) so that one of the jaws is aligned with the travel indicator.  With the spindle of the travel indicator touching the center line of the work piece, note the reading (or zero the reading).  Rotate the chuck 180 degrees and note the reading.





Insert the two chuck keys in the near and far side adjustment screws.  _NOTE:  This is a posed photo with the lathe drive train disconnected.  NEVER  leave a chuck key in a lathe chuck.  If the key is in the chuck it needs to have a hand attached to it !_





Using the two chuck keys, one to loosen and one to tighten, watch the indicator while gently adjusting the chuck keys until the work is moved ONE-HALF of the error previously noted.

Rotate the chuck ¼ of a turn so that the other two jaws are now aligned with the indicator axis.  Note the indicator reading then rotate the chuck 180 degrees and determine the difference between the highest indicator and the lowest one.

Using both chuck keys, tightening and loosening simultaneously, move the work one-half of the error distance.

Repeat this one or two more times until the run-out is about .001 or .002.  At this point, we need to do some tightening to secure the work in the chuck.  Continue the process of rotating the chuck, checking the run-out and then rotating 180 degrees and correcting by one-half of the small error.

You might try using only one chuck key to “push” the work away from the high point of the run-out.  Do this a couple of times and the result should be a tightly secured work piece with minimal run-out.

OK, so the work is centered at the location of the indicator, near the chuck, but it’s highly unlikely to be centered along the entire length.  Typically the next step is to move the indicator near the end of the work.  Rotate the work until the high point is found.





Move the indicator off of the work then lightly tap the high point of the work piece with a soft-faced hammer.  Check the run-out and repeat the process as required. 





When the run-out is within desired limits, carefully drill a center hole and then use the tailstock center to keep the work properly aligned with minimum run-out.





If for some reason it’s not practical to center drill the end of the part, a steady rest can provide the support required to keep the work aligned.

This simple process can reduce the time required to align a 4-jaw chuck from minutes to seconds.  When I aligned the test bar for the above photos, I timed the alignment process.  It took less than one minute to align the bar to within .001 !


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## kd4gij

I have been using 2 keys on my lathe at home for about 10 years. The 4 jaw I use at work every day is 20"dia. My arms arn't long enough to reach around it and the work.


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## randyc

kd4gij said:


> I have been using 2 keys on my lathe at home for about 10 years. The 4 jaw I use at work every day is 20"dia. My arms arn't long enough to reach around it and the work.



I don't recall when I started using two chuck keys, it's been a few years but definitely not 10 years ... maybe we read the same suggestion on another forum ?

Fortunately, most of us won't experience your problem of reaching around a 20 inch chuck since this is a hobby machinist forum, right ?  (My shop slab couldn't possibly even _support _a lathe of that size, LOL !)


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## darkzero

kd4gij said:


> The 4 jaw I use at work every day is 20"dia. My arms arn't long enough to reach around it and the work.



20" chuck, well shoot, then the lathe should be large enough that you could just lay on the bed, after all it is a "bed", then you could use 2 keys. And by laying on the bed, you could also get close up to the workpiece, close one eye & eyeball that sucker to get dead nuts.  I would love to see the look on you're boss' face if he caught you doing that! 




randyc said:


> Rotate the chuck (and work piece, of course) *so that one of the jaws is aligned with the travel indicator.*



When I first started using the 4-jaw I use to chase that sucker around for days cause I was chasing the absolute highs & lows. And if it was round stock that wasn't very concentric it would be weeks. Well I didn't know any better then & I had no one around to teach me. Then one day it dawned on me, just tighten the highs at each jaw, moving half the difference of what the opposing jaw indicated. I was no longer afraid to use the 4-jaw anymore & like using it. I still only use one key though.

I prefer to use just a dial indicator for indicating the 4-jaw too. If I get down to 1/2 thou or less it's good enough for me. I haven't needed to dial something with accuracy better than that so I never use a DTI for that.


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## Bill C.

The 20" diameter sounds like the 36" vertical one I ran sometimes as a operator after high-school.  That old Bullard model might fit in the average size garage.  For its size I recall it spin pretty easily when in neutral position.


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## randyc

Bill C. said:


> The 20" diameter sounds like the 36" vertical one I ran sometimes as a operator after high-school.  That old Bullard model might fit in the average size garage.  For its size I recall it spin pretty easily when in neutral position.



That brings back some memories !  Those Bullards are very cool (unfortunately I never even got to touch the controls on one) !  When I worked at Westinghouse, there was a line of those "small" Bullards in one building and that line of machines must have been 100 yards long !


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## Franko

I think I saw an article (maybe in Home Shop Machinist) where the author made a couple of chuck keys with round handles for centering in a 4-jaw.


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## Bill C.

randyc said:


> That brings back some memories !  Those Bullards are very cool (unfortunately I never even got to touch the controls on one) !  When I worked at Westinghouse, there was a line of those "small" Bullards in one building and that line of machines must have been 100 yards long !



I should say I only used it for one project.  The shop had the job of making forging dies for the old International Harvester plant in Louisville.  They assigned me the job of roughing the forged blanks of steel into useful mold sections for the lathe machinist.  The shop had a hydraulic controlled tracing lathe that he used. I remember breaking many cemented carbide tool bites.  I could never talk and run a machine without problems back then. I was in my teens.  That was the only time. That old machine wasn't used much to begin with but I did like it.  Those were the days.


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## smoa

I honestly never even thought about two chuck wrenches, and I've dialed in thousands of parts. One important note, Never take your hand off the chuck wrench when in use. I know this was probably just done for the picture, but I think a note should be added. I've seen some nasty gouges in ways due to the chuck wrench being left in, not to mention some stiches in side of one lucky apprentices head (lucky it wasn't worse).
Bryan


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## David S

For anything over 13 mm diameter, I only have a 4 jaw independent, and have always used two keys.  But for most stuff I don't use an indicator but rather just place my tool holder loose in the QCTP rotate the chuck backwards and ease the tool in to the close spot then proceed to rotate and split the difference.  I can get pretty close quickly for most stuff that I start turning from scratch.

David


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## Bill C.

smoa said:


> I honestly never even thought about two chuck wrenches, and I've dialed in thousands of parts. One important note, Never take your hand off the chuck wrench when in use. I know this was probably just done for the picture, but I think a note should be added. I've seen some nasty gouges in ways due to the chuck wrench being left in, not to mention some stiches in side of one lucky apprentices head (lucky it wasn't worse).
> Bryan




Bryan,

I never, knew anyone I worked with that, used two wrenches.  Also noticed the stock hanging out further than I was taught.


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## darkzero

No need to police this one guys. If you have seen Randy's other informational threads you will know he is not a rookie. 

The reason the stock is hanging out so far is he is showing how to dial in a part that would need to be supported with a center. After dialing in the stock at the chuck side & tailstock side you can then carefully center drill it even though stock may be hanging out much further than it's supposed to for that. If the stock is not stout enough and/or the situation does not allow, as Randy mentioned, a steady rest can be used for support to center drill. Sure there's other ways of doing this but this method is not uncommon.


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## Andre

For average 4 jaw work I'll get it centered by eye then bring the cutter up to the work, maybe .010' from the high spot. When you see the work get close to the cutter you know the high spot. Can get it dialed in within maybe 3 thou that way.


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## randyc

smoa said:


> ...One important note, Never take your hand off the chuck wrench when in use. I know this was probably just done for the picture, but I think a note should be added...



Bryan, take another look at the post, I even italicized the cautionary note for emphasis 



randyc said:


> ...Insert the two chuck keys in the near and far side adjustment screws.  _NOTE:  This is a posed photo with the lathe drive train disconnected.  NEVER  leave a chuck key in a lathe chuck.  If the key is in the chuck it needs to have a hand attached to it !_


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## schor

I've used the 2 key method, but I like abom79's method. You need to do it 1000 times and you don't need 2 keys. I think I've done it 20, so I have a ways to go yet.


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## randyc

schor said:


> I've used the 2 key method, but I like abom79's method. You need to do it 1000 times and you don't need 2 keys. I think I've done it 20, so I have a ways to go yet.



I always like learning new methods !  My eyes aren't as good as they once were ... I can't locate a post from abom79.  Can you point me in the right direction


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## JimDawson

randyc said:


> I always like learning new methods !  My eyes aren't as good as they once were ... I can't locate a post from abom79.  Can you point me in the right direction



I think this the one you seek.

http://www.hobby-machinist.com/threads/4-jaw-chuck-alignment-video.7621/#post-62891


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## randyc

JimDawson said:


> I think this the one you seek.
> 
> http://www.hobby-machinist.com/threads/4-jaw-chuck-alignment-video.7621/#post-62891



Thanks Jim.  I was expecting to learn something new but I think that post describes the method most of us have always used.


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## randyc

Franko said:


> I think I saw an article (maybe in Home Shop Machinist) where the author made a couple of chuck keys with round handles for centering in a 4-jaw.



GREAT idea - would speed things up even more !


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## JimDawson

randyc said:


> Thanks Jim.  I was expecting to learn something new but I think that post describes the method most of us have always used.



That's pretty much the way I have always done it for about the last 50 years or so.


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## darkzero

In regards to Abom79. There's no special technique that he uses. It's just the fact he's so good at it that makes him so quick at doing it in front of your eyes. Adam is one of the Youtube machining guys. You won't find posts here about it, although he happens to be a member here but really doesn't come here much. You have to watch his channel to know what he's about.


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## mksj

Also use the twin key method for adjusting a Bison 4 jaw combination chuck (Scroll + Independent). Made two keys for the independent jaws with magnets in the end. The magnets keep the keys in place when turning/adjusting and checking the run out. The combination chuck is a bit quicker to set up then a independent, I set all 4 jaws to a fixed stop/position, then scroll down onto the piece. Check run-out with a dial indicator, and tweak the centering using both keys at once on opposite jaws. Scroll feature of the combination allows doing repeat pieces quickly, and with very little variance (but I still recheck).  I am pretty compulsive of not leaving the keys in the chuck at any time other than when I have my hands on the chuck to adjust it, even if it is to get something else, I remove the key(s).

The combination chuck also works great for square/rectangular stock. Really liking this chuck the more I use it.


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## randyc

The magnets are a very clever idea but I'm not envisioning where they are located and how they are secured.  Any chance of posting a photo with a brief "how to" description ?  Thanks and that's a very pretty chuck !


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## mksj

I bored a 6mm x 1.5mm deep hole in the end of the key with an end mill. Used a bit of metal bonding epoxy to secure a 6mm x 1.5mm Neodymium magnet in the end. Picture of the new keys with magnets and original key. Much easier to setup with the dual keys, and I do not have problems with the keys falling out when I turn the chuck to check the alignment. The keys are not that heavy and the Neodymium magnets can be quite strong when in direct contact with ferrous metals.  The applied hand torque is similar and more even/balanced than the original key, it is also possible to torque the new keys evenly using the square end of each key (fits a 5/8" 12 point socket).  

Like the designing "Vacuum Tube Amplifiers"... Have lots of tubes and run some Cary 805AE amps with modified Quad electrostatic speakers, too chicken to build anything running a 1000+volts.


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## randyc

Many thanks, it's very clear and again a very clever idea which I intend to steal 

Glad that you liked my book; I designed all of my high-voltage supplies and they are limited to 450 volts.  At one of my previous employers, we used a HUGE vacuum tube amplifier to drive a 500 pound vibration table up to 20g acceleration.  The amplifier made the lights dim when the plate supply was enabled and the 400 SF room would heat up about 10 degrees F in the fifteen minutes or so required to make a vibration run.  I often wondered about the courageous tech that serviced that amplifier.

At the other extreme is this little dual triode that I intend to use as a preamplifier for the piezoelectric transducer shown beside it.  This will be used on an old Gibson J-55 guitar.  The preamplifier will be built into the guitar cable as a small module very near the guitar jack to minimize high-frequency attenuation from cable length.  Note that the vacuum tube is smaller than the guitar jack.


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## randyc

mksj said:


> ...Much easier to setup with the dual keys, and I do not have problems with the keys falling out when I turn the chuck to check the alignment. The keys are not that heavy and the Neodymium magnets can be quite strong when in direct contact with ferrous metals...[/ATTACH]



A final question:  is the body of your chuck keys non-magnetic (i.e. titanium alloy) ?


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## taycat

cheers for that.
put my 4 jaw on this morning just to try it. although had to cut bit of plate to use as only one key.
what a difference.
now ordered spare key.


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## mksj

The keys are aluminum alloy and stainless T bar held in with a set screw, just what I had on hand. But could also use steel. I can use much shorter keys because the independent jaw adjustments move with the scroll, an independent only chuck would need longer keys. Once set, the repeatability with the combination chuck is quite good, but I still verify TIR as small variances in jaw pressure or material size can change the center. Yet, one can zero the piece very quickly with the dual keys.


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## BoliverShagnasti

I started with the 3 jaw chuck and it was about .005 off from the beginning.   Not bad for most of what I was doing, but for precise work, every time you re chuck you add the concentric errors.
I would mark the work to fit it to the chuck for return cuts and use the indicator to get it back.  But the part held in the chuck is centered different than the part of the work I just cut.
You can also use a homemade lathe center with dog and cut it each time you use it.

Once I started using the 4 jaw, I will never go back to the three jaw.  The 3 jaw is more work to maintain concentric parts. 
It seems like it would be less work; but if you want precision, you have to work around the reality of this design. 

When doing production parts, you can turn two of the jaws out the same number of turns (or half turn or whatever is required), to release the part.
Then put the next part in and turn them down the same number of turns, then dial it in fast.

I have one key now and have been looking for a second.

Just some thoughts.


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## Chrisvn

I have made this tool to make the alignment quicker, especially on non-round material, but it also works well on round stock. The hardened tip is spring-loaded to compensate for the change in length  as you get closer to the center. The tail is made from 6mm mild steel and is about 250mm long and the square portion is 12mm key steel. The tail allows for quite a lot of flex to swing with the material out of center. The tail is just clamped in a chuck in the tailstock with the spring-loaded tip put in a punch pop mark in the material. This mark can be in the center or out of center if you want to turn eccentric. The square head allows for a nice flat surface to locate the DTI on. Works like a charm. Initially, you do not even need a DTI to get it close, you can just eyeball it.


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## pipthepilot

A slight variation on this that works very well is to setup the dial gauge indicator then rotate the chuck 360 degrees by hand. As it rotates make a note of the minimum and maximum needle movement then average them, if the minimum is 0 and the maximum is 0.8 then the average is 0.4. Now rotate so the indicator lines up with the jaws and using two keys adjust until the indicator shows 0.4, now rotate 90% and repeat. In less than two whole turns on the chuck the work is perfectly centred.


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## bill4227

This is the method that I use. 



. I can set up a piece in less than 2 minutes.


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## catskinner

Franko said:


> I think I saw an article (maybe in Home Shop Machinist) where the author made a couple of chuck keys with round handles for centering in a 4-jaw.



That sounds like a heck of an idea. I'm going to check now and see if a 1/4 or 3/8 drive ext. will fit my chuck. Then use those thumb wheel ratchets with the ratcheting part disabled with a drop of Super Glue.


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## Bob Korves

I have never had much trouble with a 4 jaw.  Early on I was getting confused, but took just a little time to analyze what was really going on.  Turn the chuck key clockwise and you push the work away, counterclockwise to pull it toward the key.  The rest is just doing it...


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## Round in circles

Being a " Born again chipstian " I found that informative .
Thanks


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## markknx

I use one Key and a broken yard stick!  No really I have been meaning to make a second key but I just never have.But I do the rest the same as Randy. Franko I saw the same article in either HSM or MWS. nice with like a thumb screw head.  
Randy Thanks for taking the time to write this up and post it. even though I have a grip on this. It was write ups and you tube guys that got me this far. so I like that you did this for some guy like me to find and make his life easier. Even for guys that have other ways of doing this it is good to read. The more ways you know to skin a cat the more likely you will get that cat skinned.
Thanks again for the post
Mark


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## randyc

markknx said:


> I use one Key and a broken yard stick!  No really I have been meaning to make a second key but I just never have.But I do the rest the same as Randy. Franko I saw the same article in either HSM or MWS. nice with like a thumb screw head.
> Randy Thanks for taking the time to write this up and post it. even though I have a grip on this. It was write ups and you tube guys that got me this far. so I like that you did this for some guy like me to find and make his life easier. Even for guys that have other ways of doing this it is good to read. The more ways you know to skin a cat the more likely you will get that cat skinned.
> Thanks again for the post
> Mark



Thank YOU, Mark, I sincerely appreciate your opinion !  It's always nice to know that the information is useful and the time spent is appreciated


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## markknx

Randy did you see bill 4227's Post of a youtube vid. another pretty cool way to skin that cat.


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## markknx

catskinner said:


> That sounds like a heck of an idea. I'm going to check now and see if a 1/4 or 3/8 drive ext. will fit my chuck. Then use those thumb wheel ratchets with the ratcheting part disabled with a drop of Super Glue.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 99987


Catskinner, this may not work if your jaws move independent Only. when you get to larger dia. parts the spinner/thumbscrew may interfere with the end of the jaw sticking out. Just a thought.
Mark


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## catskinner

markknx said:


> Catskinner, this may not work if your jaws move independent Only. when you get to larger dia. parts the spinner/thumbscrew may interfere with the end of the jaw sticking out. Just a thought.
> Mark



That is true might have to add an extension of  the appropriate length to make it work.


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## Bill Gruby

My  way to set a four jaw, centered or offset is LOTS OF PRACTICE. I set mine either way, centered or offset in less than 60 seconds with a single wrench and magnetic based indicator..

 "Billy G"


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## randyc

Bill Gruby said:


> My  way to set a four jaw, centered or offset is LOTS OF PRACTICE. I set mine either way, centered or offset in less than 60 seconds with a single wrench and magnetic based indicator..
> 
> "Billy G"



No offense but why would I want to move a single chuck key to two different locations when I can adjust the two jaws at the same time, one pushing and one pulling ?  Using two chuck keys, just two to three iterations are required to get within .002 and that's a matter of ten or fifteen seconds, maybe thirty seconds for a novice.

But heck, I'm no missionary trying to convert someone who has been doing this for years - whatever works best for the individual is the "right" way in my opinion.  Two chuck keys just happens to be WAY better than one for _me_


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## Bill Gruby

I was taught never to reach over the chuck, even when it's motionless. Also, I have trouble finding one key when I need it, two, forget it. 

 "Billy G"


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## randyc

Bill Gruby said:


> I was taught never to reach over the chuck, even when it's motionless. Also, I have trouble finding one key when I need it, two, forget it.
> 
> "Billy G"



As I posted, I always disconnect the drive system before adjusting the chuck.  But I hear you, loud and clear, Bill !  Every time I reach over the chuck the little voices in my head (from habits learned fifty years ago) tell me that I'm going to lose a hand.

But, following normal precautions, I'm OK with reaching over the chuck in this case.  I'm old school just like you (e.g. no long-sleeve shirts when operating a lathe) and I don't think that there are any disagreements between you and me 

As far as finding chuck keys, of course that's a perpetual problem.  I tried to help myself a bit by making the second chuck key smaller than the original to make it easier to park both on the gear box:


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## stupoty

I used to use the two key method but I was constantly dropping one key behind the lathe, hummm

I didn't meen to bullit point it i hit the format button acidentaly opps

I saw somone on youtube that said somthing I try and do when I'm setting stuff in the four jaw, thats to only go one way,  i.e. Only reduce towards zero, it kinda helps. (I think).

Also stepping up dti's or don't start with the one that reads 10th's 

Stuart


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## atlas ten

At machine shop that I worked for last summer, they tought me no gloves when operating machines and never leave chuck wrench in the chuck. As for using  2 wrenches would have been  hard to do with 3/4" wrench. And only one wrench at each machine. Mainly used 4 jaw for drilling large holes (4.5") in up to 10" dia material. To use  2 wrench for me i would  have to  stand on the lathe (large Russian  stanco).  Only learded about the 2 wrench style from YouTube. Might have to try for my next project. 
Jack


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## randyc

atlas ten said:


> ......As for using  2 wrenches would have been  hard to do with 3/4" wrench. And only one wrench at each machine....



Several have mentioned problems using two chuck keys on large lathes to which I respond that this is a HOBBY machining forum.  I think that most members expect to read posts oriented toward machine tools that a _hobbyist_ might be expected to own - NOT machinery that wouldn't even fit in our garage !

Lacking a second chuck key, one might do the same as I did and _make_ the second chuck key


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## kingmt01

Great tip. I use to do it like this & still do at times depending on my mood. However now I usually start off just a little different. Holding the piece between two jaws I center it between the other two basicly using them to point at center. Usually at this point it is really close. I can usually just finish with the indacator by just snugging up at that point.

This is my first time here & it seems like a nice place. I look forward to learning from you guys.


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## itsme_Bernie

Hah hah love the two wrenches thing!  Funny how those "how didn't I think of that" ideas are often the best and most clever


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## atunguyd

Randy,

I do similar to you but with one modicifation:

I start by indicating on jaw one and zeroing the indicator. Now I indicate on the opposite jaw 3 lets say I get 0.10, I then turn the workpiece untill the indicator reads half that error (0.05) and I now rezero the indicator,
I then got to each jaw and adjust it down to zero on the indicator.

It is exactly like your method except you dont need to remember a number, just aim to get your DI to zero.

It does require that you have a rigid DI mount, I have one that mounts into my QCTP.


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## The Liberal Arts Garage

C'mon-- couple  of screw driver  handles two pieces of suitable scrap, big file. 
Paint bright nauseous color.   ......BLJHB.


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## Bill Gruby

There is only one way to speed set a four jawed chuck. Two Chuck Keys, 1 Chuck Key makes no difference. The word is PRACTICE. I use one key an can dial it in, in 30 seconds or less once the piece is in the chuck.

 "Billy G"


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## Tozguy

Heck I go real slow. Don't want it to be over too quickly cause machining is fun. 
Start with dial indicator, switch to .0005'' dti, then to .0001'' dti. Then take a nap.


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## savarin

I really like the round key idea. I keep trapping my finger on the chip guard using the rear key.


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## kingmt01

Tozguy said:


> Heck I go real slow. Don't want it to be over too quickly cause machining is fun.
> Start with dial indicator, switch to .0005'' dti, then to .0001'' dti. Then take a nap.


I try to take as few of steps as I know how & I'm still really slow. I don't have time to get anything finished as it is. I don't need to find ways to drag it out. I have more fun when projects are finished.


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## chips&more

4 jaw chuck? What the heck is that? But really, in my shop the 4 jaw chuck collects a lot of dust. Yes, when you really need it, there is no substitute. But, I use my 3 jaw Buck for just about everything! Our ancestors were master artisans. They made works of art from the simplest of tools, basically stone axes. They did not have the internet to buy all the gadget toys for our shops. Most of the toys today are just hyped up ads. When you get the widget thing in the mail it goes in a draw never to be seen again. Do I need two keys for my 4 jaw…no. I can make the chuck work with just one key. But it’s a good idea. I would rather keep things simple in my shop like my ancestors did. I find the simplest method works the best and yields the best results as well. I often sleep on it/the project for a night. Then start the next day with the simple approach, works for me…Good Luck, Dave.


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## Silverbullet

Bill Gruby said:


> My  way to set a four jaw, centered or offset is LOTS OF PRACTICE. I set mine either way, centered or offset in less than 60 seconds with a single wrench and magnetic based indicator..
> 
> "Billy G"


That's the reason abom79 , ( Adam ) is so Quick he uses them daily , when you do something repeat ally it comes second nature . It's practice makes perfect. That's why trap and skeet shooters shoot almost daily if they can . If they don't keep up with the practice they dont win .


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## Tozguy

Franko said:


> I think I saw an article (maybe in Home Shop Machinist) where the author made a couple of chuck keys with round handles for centering in a 4-jaw.



Along these lines, in the initial stage of zeroing work in a independent chuck, I use a regular chuck key but without the cross bar. I work it like a screwdriver and can reach around the back of the chuck quite well. It reduces the amount of chuck turning required and prevents me from over tightening the jaws during the adjustment period. Obviously the jaws have to be tighter than that for turning so they get snugged up evenly and gradually before starting the lathe.


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## uncle harry

randyc said:


> Thanks Jim.  I was expecting to learn something new but I think that post describes the method most of us have always used.



You can also locate Abom79 on utube.  He is approaching his 100th video. Several of his videos show him very quickly centering a 4 jaw with very little needle movement.


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## HMF

uncle harry said:


> You can also locate Abom79 on utube.  He is approaching his 100th video. Several of his videos show him very quickly centering a 4 jaw with very little needle movement.



I will add that to our video library if I don't have it already. I know we have tubal cain's version.


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## uncle harry

Tozguy said:


> Along these lines, in the initial stage of zeroing work in a independent chuck, I use a regular chuck key but without the cross bar. I work it like a screwdriver and can reach around the back of the chuck quite well. It reduces the amount of chuck turning required and prevents me from over tightening the jaws during the adjustment period. Obviously the jaws have to be tighter than that for turning so they get snugged up evenly and gradually before starting the lathe.



On my SB9a I use a socket driver with a screw driver handle on the back jaw. I have also used a socket handle to "firm" up the chuck in unison with the regular key on the front.


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## HMF

Here are some videos:


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## Tozguy

Found a compact chuck key kit at Lowe's this afternoon, in the plumbing department. It is a perfect fit in the socket. Woodrow seems to like it too
	

		
			
		

		
	



	

		
			
		

		
	
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## markknx

Tozguy, Genius! Some times the simple way is right in front of us.

Mark


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## Franko

Nels said:


> Here are some videos:



Thanks a million, Nels. Those were awesome,
(with the exception of Tubalcain's video, which contained no useful information.
At least he got right to it and didn't get sidetracked and start going on and on about his opinion of cordless drills or something else totally unrelated.)


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## HMF

I'm trying to add more videos to our library every day.


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## kwoodhands

Here is another tip to go with the rest. To get the part centered quickly and very close, do this.
After establishing a center and installing in the 4 jaw, bring a live or dead center up to the part. Now adjust the parts center to the tailstock  center . This takes a few seconds or so and will get you within .005 / .010 . Now you can indicate the part for perfect alignment. I use a rod 3/8" x 8" with a 60° point on one end and 60° hole for the center on the other end.
This placed between the parts center and the tailstock center for indicating. My indicator is mounted on the tool post.
You will find the actual time to indicate the part to within .0005 or less after the rough indicating with the tailstock center is less than one minute.
mike


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## cascao

I always use same method (with some improvements sometime). To me, this can lead to a better trained and automatic behavior and faster times.


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## epanzella

Always looking to get where I'm going with the least effort possible, I made a pair of keys for my 4 jaw by welding a cupla hunks of 3/8 stock 
together. Under $ 10 at HD.

.


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## cascao

Little video of two keys centering method


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