# Is There An Easier Way For Initial Set-up of 4 Jaw Chuck?



## ShagDog (Aug 6, 2020)

I have not yet been able to find an easier way for initial set-up of a 4 jaw independent chuck. I use the concentric lines on the chuck; but, I have difficulty getting to where my dial indicator doesn't go more than full circle, when the part is first put in, unless I get lucky. I have no problems getting the 4 jaw into final alignment within a tenth or less, at least according to my indicator. 

Is there a better way for initial set-up that you are using, and would not mind sharing?


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## Lo-Fi (Aug 6, 2020)

I find just putting a tool or something near the part for initial setup really helpful. Much easier to "eyeball" than an indicator flying around! 

Rings 
Eyeball against something (usually whatever is in the toolpost) 
Indicator

I reckon I can get within a few thou without an indicator, then it's easy with one getting those last few dialed out. That's the method I've developed get through exactly what you're describing. 

I've often thought of building a toolpost mounted fixture with a slider on the end, on which is mounted a bearing which can be run against the work. The other end of the slider designed so you can place the tip of a finger over the hole it slides in, arranging it so the slider is nominally flush, allowing safely "feeling" the runout as the chuck is turned by hand. Call it a "haptic indicator", if you will. You can detect truly tiny movements with fingertips. Would also be great for those whose sight is maybe not as good as it once was.


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## gr8legs (Aug 6, 2020)

First off, if you're chucking round stock and it doesn't have to be dead nuts, switch to your 3-jaw chuck. Less crazy-making.

Otherwise, spot drill (just a peck) at the center of your desired rotation and use a live center in the tailstock to support the part against the 4-jaw chuck.

Manually align the desired major and minor axes gripping points of the part with the 4 jaws, then move the jaws to support the part. This gets you pretty close.

Retract the tailstock and have TWO chuck keys so you can move the part laterally with a pushme-pullyou and still maintain a grip on the part.

Alternate X and Y adjustment by rotating the part until you are dialed in.

JWID, YMMV

Stu


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## mickri (Aug 6, 2020)

At times I have centered the jaws on the tailstock quill/ram (whatever you call it), backed out the tailstock and then moved each jaw the same number of turns in or out to fit the work.  I have also used a square to mark the center of the work.  Then with a dead center in the tailstock adjusted the jaws until the work was centered like gr8legs described above.  This is the method that I use most of the time.


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## benmychree (Aug 6, 2020)

Practice makes perfect.


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## markba633csi (Aug 6, 2020)

As John said, it just takes practice.  The trick is not to snug up any one jaw too tight until you are getting very close, to allow for slight adjustments
The more you do it the faster you'll get


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## Papa Charlie (Aug 6, 2020)

When using a 4 jaw independent chuck. Start by using the lines on the jaws and chuck body to set each jaw at the same place, setting the opening with a rule to about the right size for the part. 

Insert the raw material to be turned, I use brass shims between the jaws and work piece which helps with the adjustments and reduces damage from the jaws.

Then set up your dial indicator and work one set of jaws at a time. Get the one set close then do the other.
I do my initial dialing in close to the chuck, then move the dial indicator out to the end of the piece without the tail stock and bump the piece with a lead hammer to put the piece concentric. 

Note: When adjusting the jaws, try first to tighten the one jaw and if that does not put you where you need to be then loosen, the opposite jaw and then back to the one that you have to tighten. As you get close you may only need to tighten a jaw for minimal movement.

Once you complete that move back to the chuck and double check your readings and make any adjustments.
I then double check again on the outboard point and if any significant adjustment is necessary, move back again to the chuck.

Repeat until concentric.

I hope this helps.


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## Manual Mac (Aug 6, 2020)

Look on the Littlemachineshop *how to* section, they have an Xlnt initial 4jaw set up.


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## talvare (Aug 6, 2020)

I just received this e-mail this morning addressing this topic. I've not used it myself, but will probably give it a try. Seems to be about the same technique suggested by Lo-Fi.




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						Machinist's Workshop
					





					email.villagepress.com
				




Ted


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## BtoVin83 (Aug 6, 2020)

I use a method my dad taught me and without trouble I can get parts within .01" TIR, square, rectangular or hex, even torch cut parts that are egg shaped.


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## Mini Cooper S (Aug 6, 2020)

Remember to only adjust out one half of the error at a time, otherwise you will chase your tail tiring to get it centered.  Sometimes it helps to mark two opposite jaws with a marker and as others have said work opposite sets of jaws.


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## Technical Ted (Aug 6, 2020)

When I am putting a piece in the 4 jaw chuck (regardless of its' shape) I measure the OD of the work piece so I know its' diameter/dimensions. Then, using 1/2 that diameter, I "eye ball" across two of the jaws trying to align them with each other and then set one of the other jaws off from center using that dimension. Then, after rotating the chuck 90 degrees, I do that same procedure for the next jaw. Having two jaws set this way, I just make sure the opposite jaws are open larger than the diameter and tighten those two onto the work piece.

I've gotten pretty good at this and can typically get a work piece aligned within a turn of a dial indicator (0.100" TIR). It's quick and easy once you get used to doing it this way. As others have said, it does take practice. 

Ted


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## Tozguy (Aug 6, 2020)

I remember from the first times using an independent jaw chuck how tedious it was. Now it is quick and easy.
What helped get there;
-some more concentric rings were added to the face of the chuck
-a 1'' travel indicator is used when possible, or a dti holder with fine adjust feature
-made a couple of stubby chuck keys for the initial steps

How I do it:
Open the jaws just enough to accept the work using the concentric lines to balance position of the jaws.
Tighten the jaws as Ted mentioned above. It helps to use two stubby chuck keys for this step.
Spin the chuck to eyeball for wobble. Tune out any visible wobble.
Set up the dial indicator. A fine adjust really helps so that you can spin the chuck while easing the dti stylus on to the work.
Keep adjusting the high spots down and easing the dti down until there is least run out.
Tighten the jaws gradually and evenly. Practise makes perfect.


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## Mitch Alsup (Aug 6, 2020)

Use the indicator smartly--figure out how much wobble is on one pair of jaws, then take 2 wrenches and move the par in one direction (or the other) turning both wrenches the same amount at the same time until the dial indicator reads the average. Switch to the other pair of jaws and repeat.

At this point you will be close enough to use only tightening on which ever jaw reads high.

For parts with a hole in the center, you have to be more gentle on the part or you will distort the part by the forces on the jaws.


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## macardoso (Aug 6, 2020)

Honestly, just practice. I can get within a few tenths with a minute or two of effort. Took me 30 minutes a few years ago when I got the lathe.


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## ShagDog (Aug 6, 2020)

Thank's for the good ideas. I will try some of them, and of course, practice.


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## Papa Charlie (Aug 6, 2020)

The fastest person I have ever seen is Adam on Abom79 (YouTube). Great to watch others do it, helps to put some aspects into place. I watch one epesode where he was challenged by someone to see who could do it faster. Adam won by a margin of around 2:1 time wise.

I thought I was pretty good until I watch Adam. Some of the pointers I picked up watching him I called out above. I also got a chance to put some of these tricks into practice and shocked a buddy of mine as to how fast I could set up a piece on his lathe.


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## Illinoyance (Aug 6, 2020)

The way I learned was to use a long trael dial indicator.  Get a reading in line with one jaw. Get a reading in line with the opposite jaw.  Adjust the jaws until the dial reads halfway between the first two readings.  Turn the chuck 90* and repeat the process with the indicator.  That should put the part *very* close to center. Now rotate the chuck 90* at a time. Tweak the jaws in or out one at a time until the indicator hand does not move.


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## HarryJM (Aug 7, 2020)

Center in a Four-Jaw Chuck by Using a Shilhouette by Don Peterson.




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						Machinist's Workshop
					





					email.villagepress.com
				




I received the above tip/link in a Machinist's Workshop email the other day which may be of some help for you.

Just finished reading all of the posts and it looks like BtoVin83 posted the same link.


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## Grinderman (Aug 7, 2020)

I made this little tool for the sizes I use most. It has 1/4-3/8-1/2-3/4” steps. Just slide it up into the chuck and snug the jaws. Remove tool and install part.


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## Diecutter (Aug 7, 2020)

I have a group of different diameter jobs which keep coming up repeatedly.  Lightly center punch the face of the chuck at each jaw where there is a sharp edge (on the side easily viewed while adjusting) after the job is accurately indicated, and in the future you can  be very close right off the bat.


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## tmenyc (Aug 7, 2020)

nice!  I'll make one!  And, that will get me using the 4-jaw one of these days.
Tim


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## Suzuki4evr (Aug 7, 2020)

gr8legs said:


> TWO chuck keys so you can move the part laterally with a pushme-pullyou and still maintain a grip on the part.


This helps A LOT.


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## BGHansen (Aug 7, 2020)

Not adding anything, but doing it over and over definitely speeds things up.  The two chuck key method is a big help.  I primarily use a 3-jaw set-tru chuck and have two hex keys on opposite sides when truing up the work.

I'd recommend numbering your jaws 1, 2, 3, 4 if they're not already numbered.  Lightly hold the work and do jaws 1 and 3.  Zero the indicator on jaw 1, then rotate to jaw 3.  Adjust the jaws until the number is half-way between the initial reading and zero.  Reset zero on jaw 3, swing back to jaw 1 and repeat.  Then repeat the process on jaws 2 and 4.  Two keys work great for this exercise as you can put a little pressure on the jaw that's being tightened and very slowly loosen the opposite jaw for good control.  When you get within 0.001", don't loosen a jaw, only tighten the appropriate jaw.

Bruce


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## GunsOfNavarone (Aug 7, 2020)

You probably have heard of abom79...
Setting up a 4 jaw


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## Papa Charlie (Aug 7, 2020)

Love watching Adam, here is a video where he chucks up round stock in a 4 jaw.

8in Roller Lathe Work Part 1


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## DavidR8 (Aug 8, 2020)

For me it was about practice. When I first tried it took ages. Now I can get to a thou in under 2 minutes. 
What I had to learn (and I’m embarrassed to say this) was how to read the indicator and what direction to move the work 


Sent from my iPhone using Tapatalk


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## westerner (Aug 8, 2020)

All very good advice. 

As most have said, when I first started messing with the 4 jaw, it took FOREVER to get close. 
After I admitted to myself that I had to get it figured, I left the 4 jaw mounted and used it whether I needed it or not. The 3 jaw stayed on the bench  for over a year. 

I no longer worry about it. If I need the 4 jaw, I hang it and run it, and it is no big deal. I simply needed to gather the patience to learn how to use it. 
To be honest, it may go back on, just cuz the Chinese POS 3 jaw I have is NOT as accurate as I am on a 4 jaw


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## Papa Charlie (Aug 8, 2020)

It is hard to convince someone to use a 4 jaw over a 3 jaw scroll chuck that has fought one. But the best advice I and others here have given is to bite the bullet and just use it. Before long you will come to appreciate it and how accurate your work will become as a result of it. Plus, when you really need to use it, especially for those odd shaped parts, you will be way ahead of the curve and appreciate your efforts.
I haven't used a 3 jaw scroll chuck in years, there isn't a 3 jaw scroll chuck out there that can match the accuracy of a 4 jaw used properly. I haven't used the lathe I have in storage yet, but plan to remove the 3 jaw for the 4 jaw before I put it into service. The 3 jaw will no doubt become one of those artifacts that sits there on the bench, that I just don't get rid of because.


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## ErichKeane (Aug 8, 2020)

Yep! Using a 4 jaw comes down to practice.  The 1/3 then 2/4 method WORKS, but you get better results if you choose the pair that is furthest out.  

My process is getting close with the rings on the chuck.  THEN I put a tool in the tool holder and get it close by eye there.  By then I'm within the ~50/100 thou that makes the dial indicator method easy. I spin it until I find the 'high' spot, then rotate the chuck 180 degrees.  I split then difference, so I get it 1/2 way between both measurements.  Then, I do the same on the other 2 jaws.

THEN, repeat the process (find the high pair fix that, then fix the other).  I've never had it take more than ~4 cycles of that.

That said, when it comes to indicating in square things in the 4 jaw, I am awful!  I always forget to pull the plunger back on 1 and screw up my setup.


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## Lo-Fi (Aug 9, 2020)

ErichKeane said:


> That said, when it comes to indicating in square things in the 4 jaw, I am awful! I always forget to pull the plunger back on 1 and screw up my setup



Joe Pie has an alternate method that avoids that issue:


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## Eddyde (Aug 9, 2020)

BtoVin83 said:


> I use a method my dad taught me and without trouble I can get parts within .01" TIR, square, rectangular or hex, even torch cut parts that are egg shaped.



Please tell us the method you use?


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## ErichKeane (Aug 9, 2020)

Lo-Fi said:


> Joe Pie has an alternate method that avoids that issue:


Neat, thanks!


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## stupoty (Aug 9, 2020)

you can use a scribe on a block and visually dial it in to less than the movement of the dial indicator.
Just keep halfing the error aproximatly by eye.

I see a lot of "oldy timey" films where they are using chalk to mark the high spots. 

If you wan't to have a lots of fun with a four jaw chuck you should use a 10th's indicator


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## BtoVin83 (Aug 9, 2020)

Eddyde said:


> Please tell us the method you use?


This may seem laborious to set up but once done dialing in a 4 jaw is simple

Running a 32” machine with a 24” chuck using two chuck wrenches is impossible and a pretty lame method in my opinion. This is the method my dad showed me and it works really well.

First you have to have the 4 jaws numbered, this can be challenging as they are usually hardened. I used a die grinder and put 1 through 4 lines on the side of each separate jaw.

Next you have to number each slot so the correct jaw always goes in its proper spot. I used a center punch and marked the area at the top of the screw, slot 4 depicted.


Now chuck some stock in your chuck, for an 8” chuck use maybe something around 2”. Use something good and round not hot roll. Indicate the stock so it is running as close to 0 runout as you can and also make sure the stock is running true not wobbly.

Once you have it running true the last step is to mark the jaw screw, as these can be hardened also, I used a die grinder and made a radial mark on the head of the jaw screw. The radial mark needs to be the same relationship for all the screws I.E. all of them at 12 o’clock or 3 o’clock.


Now when you put a piece of round stock in the chuck eyeball the jaws so they are equally spaced from one of the radial face lines on the chuck, just close so you are not one turn off from another. When the lines on the jaw screws are aligned such as 3 o’clock the part is centered. The same applies for square stock.

For rectangular stock let’s say jaws 1 and 3 are at 10 o’clock but 2 and 4 may be a 9 o’clock


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## epanzella (Aug 11, 2020)

I do a quick eyeball using the rings or the projection of the jaws out side the chuck body. Then I take whatever tool is in the holder and run it up to the part adjusting with 2 chuck keys for consistent gap.  In 30 seconds the part is well with in 1 rev of the DI.


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## gr8legs (Aug 22, 2020)

Long ago I acquired ( eBay perhaps?) this bit of alignment tooling to supposedly get parts centered by gently 'nudging' the part into center using the crossfeed. It's just a ball bearing mounted to a tool mounted in a tool holder set to center of work height. Have the part a bit loose in the chuck, *manually *rotate and as you move the crossfeed inward you are moving the part to center. Tighten the jaws once you get as close as you want. I rarely use it anymore but it's there in the quiver if needed.

This gizmo does sorta work on square stock in a 4-jaw also. Then you're 'nudging' the corners of the stock.

I'm still enough of a 'hacker' that the 3-jaw is close enough for most of my needs on round stock and only get out the 4-jaw for odd shapes.


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## Splat (Sep 25, 2020)

*This* method has worked the fastest for me. I can get pieces held in my Asian made chuck that came with my g4003g dialed in about 2 tenths in short time compared to other methods I've tried.


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## NortonDommi (Sep 25, 2020)

BtoVin83 said:


> Once you have it running true the last step is to mark the jaw screw, as these can be hardened also, I used a die grinder and made a radial mark on the head of the jaw screw. The radial mark needs to be the same relationship for all the screws I.E. all of them at 12 o’clock or 3 o’clock.


I like it.  Job for this evening.


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