# Need Advice on a New Chuck



## swany (Jan 11, 2021)

What's up guys. I have a Grizzly G4000 9 x 19 as a starter lathe to learn how to use a metal lathe, and it's going well so far. My main problem(s) is when I turn thin-walled tube (304 SS, 316 SS, 416 SS, and 17-4ph). Obviously, I have discovered that using the 3-jaw self-centering chuck that came with the Grizzly will almost always deform tubing. I have a friend who purchased a 6-jaw, 4" chuck for his mini-lathe because he uses his similar to what I use mine for (turning thin-walled tube). He said that the 6-jaw chuck is awesome and he is able to turn tube no problem and it doesn't deform his workpiece(s).

He is a more accomplished machinist than I am...to the point that he was comfortable making the adapter plate that was needed to install the new 6-jaw chuck. I do not have this confidence. I need to find a better chuck (preferably self-centering) that will help me to turn and part thin-walled tube. It doesn't have to be a 6-jaw chuck...I'm not opposed to other ideas or even some tricks that could help me turn some tube with what I already have. 

I also have the Grizzly 4-Jaw 6" chuck, but I haven't learned how to use it yet because the jaws are individually adjusted. I can't find the tool that is needed to do that so I may have to order one. *So, I need a chuck and corresponding plate that will allow me to use the chuck (without having to modify parts). *

This is the 6-jaw 4" chuck my buddy purchased: *





						Lathe Chuck, 6-Jaw 4", Self-Centering 2276 - LittleMachineShop.com
					

Lathe Chucks 2276 6-jaw self centering lathe chuck; 4" (100 mm) diameter; Includes chuck key and mounting bolts; Plain back mounting; Excellent for ho...



					tinyurl.com
				



*
By the way, my budget is like < $250

Thank you.


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## stupoty (Jan 11, 2021)

Have you tried using some sort of material bung inside the tube to stop it from collapsing when clamped ?

Stu


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## Jim F (Jan 11, 2021)

You are going to have to machine a backplate, no way around it.


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## C-Bag (Jan 11, 2021)

I think Stu has a very good solution if you are doing a lot of the same size tubing. Aluminum or even pvc would work.

I have basically the same lathe, a 9x20 HF. Mine came with a 5” 3jw and 6” 4jw And the original 4” 3jw. The guy I bought it from had tricked it out according to Steve Adair’s 9x20 page. But as I used it, it became evident he had not done any of the preliminary things like truing up the backing plates of the 5” or 6”. So truing up the backing plate is just basic and is what’s expected when you install a new chuck.

I’m not sure what you mean by the proper tool to use the 4jw but I assume you mean a dial or test indicator to dial in the tube in the chuck. There are a lot of good vids on YouTube on how to dial in a 4jw. It’s time consuming at first but it’s basic to becoming a machinist. if you don’t have a good indicator and either a magnetic base or a mount for the tool post that is basic tooling that would make the 4jw you have work right now. Maybe your buddy can help you do your first setup with the 4jw?


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## projectnut (Jan 11, 2021)

C-Bag said:


> I think Stu has a very good solution if you are doing a lot of the same size tubing. Aluminum or even pvc would work.
> 
> I have basically the same lathe, a 9x20 HF. Mine came with a 5” 3jw and 6” 4jw And the original 4” 3jw. The guy I bought it from had tricked it out according to Steve Adair’s 9x20 page. But as I used it, it became evident he had not done any of the preliminary things like truing up the backing plates of the 5” or 6”. So truing up the backing plate is just basic and is what’s expected when you install a new chuck.
> 
> I’m not sure what you mean by the proper tool to use the 4jw but I assume you mean a dial or test indicator to dial in the tube in the chuck. There are a lot of good vids on YouTube on how to dial in a 4jw. *It’s time consuming at first but it’s basic to becoming a machinist.* if you don’t have a good indicator and either a magnetic base or a mount for the tool post that is basic tooling that would make the 4jw you have work right now. Maybe your buddy can help you do your first setup with the 4jw?



Dialing in a 4 jaw chuck, or any independent jaw may be time consuming the first few times you do it.  There is a learning curve, but it isn't all that steep.  I hated them when I first started for the reason C-Bag mentioned.  It only took a few days to get comfortable with the process and do it considerably faster.  Now I use the 4 jaw independent chucks almost exclusively (as opposed to a 3 jaw scroll chuck) on my Sheldon.  It's easy to dial in within .001 for rough work, and not much harder to dial within .0002 for finish work.

I keep hearing guys spending the time to dial to within .0001", but I question the necessity.  I can't remember the last time I needed something that precise, but then again I can't remember what I had for breakfast, and I think that was only a few hours ago.  In any case I think you'll like an independent jaw chuck once you try it and see how much closer tolerances you can turn.

Keep in mind a 3 jaw scroll chuck is meant to be used when everything can be completed in one setup.  The average out of round tolerance on this style chuck is in the .002" to .003" range.  That essentially means a part can't be removed and reinserted with any confidence it will have the same runout as the original setup.  With an independent jaw chuck the work piece can be removed as many times as you like, reinserted in any orientation, and dialed back to near 0 runout.


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## mattthemuppet2 (Jan 11, 2021)

easiest way to learn to dial in a 4 jaw is with 2 chuck keys and a DTI mounted to the tool post. Takes a bit of practice but it only takes a couple of rounds of adjustment (after using the rings on the face of the chuck to get it close) to get within 0.001. I can't say I ever work to 0.0001 TIR, but 0.0005 is doable and not much harder than 0.001.

to swany - I'd get comfortable with the 4 jaw first as a) you already have it, so you're only out the cost of another chuck key and a DTI and b) you'll need it later anyway as your get more ambitious with your projects. Then you can get a 6 jaw too!


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## DavidR8 (Jan 11, 2021)

I fully support becoming familiar with using your 4-jaw chuck. Something I learned is to start indicating when a pair of jaws is horizontal. One of the adjusters will be at the far side of the chuck so using two keys is a bit more challenging. I only use one key (mainly because I only have one), but I make a mental note of which direction the jaw needs to move.


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## mikey (Jan 11, 2021)

I can appreciate the problems the OP has. I had a project to complete for a friend that involved turning and parting off a number of pieces of thin walled tubing and a 3 jaw just doesn't work well - distortion and the possibility of the part camming out of the jaws. The 4 jaw doesn't work much better; still have distortion. Finally went out and got a 6 jaw Pratt Burnerd and the distortion problems went away. I can also hold Delrin/nylon parts without camming out with heavy cuts, so a 6 jaw does have its place in the shop.

So, given that a 6 jaw within his budget is available from LMS as the OP linked to, the real issue is that he doesn't know how to mount a chuck to a backplate. 

@swany, mounting a chuck to a backplate is a common task a hobby guy has to eventually learn to do. There are lots of videos on Youtube about this very thing. I'm sure the guys will also be able to help you with this job. If you still have questions after that, PM me and I'll give you a hand.


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## C-Bag (Jan 11, 2021)

mikey said:


> So, given that a 6 jaw within his budget is available from LMS as the OP linked to, the real issue is that he doesn't know how to mount a chuck to a backplate.


Problem is LMS says that chuck is on back order. It might show up at the end of the month and it might not. Never know with the erratic tariff situation.


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## mikey (Jan 11, 2021)

C-Bag said:


> Problem is LMS says that chuck is on back order. It might show up at the end of the month and it might not. Never know with the erratic tariff situation.



What a pain! Little 6 jaws aren't plentiful on ebay, either. I guess a call to LMS might be in order. 

I can tell you that a 4 jaw is not much better than a 3 jaw if distortion is the issue.


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## mikey (Jan 11, 2021)

A 5" is available on Amazon. The same seller also has a 4".


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## mattthemuppet2 (Jan 11, 2021)

DavidR8 said:


> I fully support becoming familiar with using your 4-jaw chuck. Something I learned is to start indicating when a pair of jaws is horizontal. One of the adjusters will be at the far side of the chuck so using two keys is a bit more challenging. I only use one key (mainly because I only have one), but I make a mental note of which direction the jaw needs to move.


the second chuck key can be alot smaller, mine's a couple of inches or so wide with a sliding handle. Very easy to make if you have a lathe or even just a drill press. The plus with the 2 keys is that you can precisely halve the difference between two opposing jaws without the piece becoming loose. You can also tighten the two jaws against each other without affecting the reading.


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## swany (Jan 11, 2021)

stupoty said:


> Have you tried using some sort of material bung inside the tube to stop it from collapsing when clamped ?
> 
> Stu



Yes, I have done that. It sorta works.


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## swany (Jan 11, 2021)

C-Bag said:


> I think Stu has a very good solution if you are doing a lot of the same size tubing. Aluminum or even pvc would work.
> 
> I have basically the same lathe, a 9x20 HF. Mine came with a 5” 3jw and 6” 4jw And the original 4” 3jw. The guy I bought it from had tricked it out according to Steve Adair’s 9x20 page. But as I used it, it became evident he had not done any of the preliminary things like truing up the backing plates of the 5” or 6”. So truing up the backing plate is just basic and is what’s expected when you install a new chuck.
> 
> I’m not sure what you mean by the proper tool to use the 4jw but I assume you mean a dial or test indicator to dial in the tube in the chuck. There are a lot of good vids on YouTube on how to dial in a 4jw. It’s time consuming at first but it’s basic to becoming a machinist. if you don’t have a good indicator and either a magnetic base or a mount for the tool post that is basic tooling that would make the 4jw you have work right now. Maybe your buddy can help you do your first setup with the 4jw?



I'm referring to the tool that is inserted into the chuck to adjust the jaws.


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## Jim F (Jan 11, 2021)

swany said:


> I'm referring to the tool that is inserted into the chuck to adjust the jaws.


Chuck keys are easy to make.


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## talvare (Jan 11, 2021)

Another option may be to purchase a 5C hex collet block as in this set:






						Amazon.com: 5C Collet Block Set With Case: Home Improvement
					

Buy 5C Collet Block Set With Case: Tool Holders - Amazon.com ✓ FREE DELIVERY possible on eligible purchases



					www.amazon.com
				




and then buy the appropriate size 5C collets  for the tubing you are working with. The hex block can be mounted in a 3 jaw chuck or the square block can be mounted in a 4 jaw chuck. The collets will provide good support for your tubing. Just some food for thought.

Ted


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## fitterman1 (Jan 11, 2021)

How about an expanding mandrel that fits the size of tubing he's machining?
What sort of tolerances are we talking about here?
I gather they're not too long or he'll have trouble parting off.


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## C-Bag (Jan 11, 2021)

swany said:


> I'm referring to the tool that is inserted into the chuck to adjust the jaws.


My chuck keys(1 small 1 normal for adjusting the 4jw at the same time) work in all my chucks. I thought one key fits all chucks.


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## Jim F (Jan 11, 2021)

C-Bag said:


> My chuck keys(1 small 1 normal for adjusting the 4jw at the same time) work in all my chucks. I thought one key fits all chucks.


Nope, I have 2 different sizes, 1 about 3/8 for the 3 jaw, and 1 about 5/16 for the 4 jaw.


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## fitterman1 (Jan 11, 2021)

C-Bag said:


> My chuck keys(1 small 1 normal for adjusting the 4jw at the same time) work in all my chucks. I thought one key fits all chucks.


No, my old MacPherson had a 3/4" Allen key and a pipe handle on that.
Bear in mind the chuck was 36" diameter.


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## C-Bag (Jan 11, 2021)

Jim F said:


> Nope, I have 2 different sizes, 1 about 3/8 for the 3 jaw, and 1 about 5/16 for the 4 jaw.


Hmm, all I’ve ever seen is 3/8.


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## Jim F (Jan 11, 2021)

C-Bag said:


> Hmm, all I’ve ever seen is 3/8.


Some use a square socket, allens, all sizes of squares, depends on the chuck.


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## C-Bag (Jan 11, 2021)

I stand corrected.


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## swany (Jan 12, 2021)

fitterman1 said:


> How about an expanding mandrel that fits the size of tubing he's machining?
> What sort of tolerances are we talking about here?
> I gather they're not too long or he'll have trouble parting off.


The pieces aren't too long. I order raw materials by the foot, and I usually part them off into thirds before I start creating parts....this way I usually don't need to use the steady rest. 

What I'm doing is parting off spacer material in various sizes. So, I'll turn the OD to whatever I need for it to be, and then I'll cut several pieces from it.....usually a 1" piece, a 2.5" piece, and a bunch of .500" and .750" pieces. The thing that sucks is I don't have the reversable jaws that are suppose to come with the 3-jaw chuck on this model Grizzly, which enable me to hold much larger workpieces. Since I have to use only the jaws that I have for the 3-jaw chuck, I can't work on anything larger than 1.5" OD. Anything larger and the jaws just fall out. Stupid.

Should I try holding my workpiece (tube) on the inside of the workpiece? Haven't tried that yet.


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## fitterman1 (Jan 12, 2021)

Yes, Have a look at these, or better still custom make one for the job at hand. A much safer and efficient option in my view.


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## swany (Jan 12, 2021)

fitterman1 said:


> Yes, Have a look at these, or better still custom make one for the job at hand. A much safer and efficient option in my view.


They don't look large enough to do 1.5" OD tube....what are they called so I can google them and do some homework?


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## fitterman1 (Jan 12, 2021)

Expanding mandrels.
You'll have to find one that matches the bore of the tubes your machining.


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## Jim F (Jan 12, 2021)




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## stupoty (Jan 12, 2021)

swany said:


> Yes, I have done that. It sorta works.


how thin is the part your trying to make ? the last thin walled thing I did was a aluminium shim for my bikes seat post. 

If it's very thin you might need to core the entire part.  This could be like a mandrill that you super glue it onto for working it so you can hold the mandril in the chuck jaws.

Stu


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## swany (Jan 15, 2021)

stupoty said:


> how thin is the part your trying to make ? the last thin walled thing I did was a aluminium shim for my bikes seat post.
> 
> If it's very thin you might need to core the entire part.  This could be like a mandrill that you super glue it onto for working it so you can hold the mandril in the chuck jaws.
> 
> Stu



1.375" OD x 0.035" Wall x 1.305" ID Stainless Round Tube 304 Seamless

1.5" OD x 0.035" Wall x 1.43" ID Stainless Round Tube 304 Seamless


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## stupoty (Jan 18, 2021)

swany said:


> 1.375" OD x 0.035" Wall x 1.305" ID Stainless Round Tube 304 Seamless
> 
> 1.5" OD x 0.035" Wall x 1.43" ID Stainless Round Tube 304 Seamless



Yeah thats fairly thin  and in stainless steel too. Double the fun.

I would make a mandrill for the work to be glued onto , being stainless you  can't really take the risk of rubbing the tool and work hardening it if your trying to take small bites at it to avoid deforming the part with tool pressure alone.   At least with a mandrill of sacraficial material you can work it like it was a solid bar.

If your doing the I.D. also you would need to make some sort of reverse mandrill or pot chuck.  

Glue like Cyno Acrylic (super glue) should brake lose with very little application of heat so you wont have to destroy the part fitting it to and removing it from mandrills.

Stu


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## swany (Feb 10, 2021)

I ended up getting the 6-jaw 4" chuck from LMS and it is amazing with thin-walled tube! Also, the back plate adapter on my 3-jaw fit the back of the 6-jaw perfectly.


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## fitterman1 (Feb 10, 2021)

Looks good, as it stands the finish on your work is chattery.
Dial your speed down a bit


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## swany (Feb 10, 2021)

fitterman1 said:


> Looks good, as it stands the finish on your work is chattery.
> Dial your speed down a bit



Copy! Thank you for the tip.


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## fitterman1 (Feb 10, 2021)

Are you using inserts or hss?
I use inserts for aluminium that have a positive rake and are very sharp.
Works great for finishing ss.


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## swany (Feb 12, 2021)

fitterman1 said:


> Are you using inserts or hss?
> I use inserts for aluminium that have a positive rake and are very sharp.
> Works great for finishing ss.


I am using carbide insert tools. My parting tool, turning tool, and all of my boring bars (many different sizes) are all carbide inserts. I haven't tried HSS yet. I really need to take a day and learn about tooling, and more specifically, how the angles and "rakes" affect the overall machining experience.

I am still *super* green with all of this stuff. I'm kinda surprised I've been able to actually make some usable parts since I first plugged this thing in almost 3 months ago!

I wanted a metal lathe because I am somewhat of an amateur gunsmith. I very much enjoy building my own form-1s, which I can only imagine how many machinists on this forum have or at one point had the same intentions. They are a blast to make! This is the first one I completed on my Grizzly. I finished it a few days ago. The cones are 7075, and the tube and end caps are 6061.




This cone size is a little larger (1.145" OD), and will be for .223/556 supers. This is a tiny bit smaller than the more standard size of 1.5" OD / 1.355" ID or 1.372" ID. I chose this size because as many of you know, typical free-floating MLOK handguards have an interior diameter of (roughly) 1.35". So, unless you feel like doing some major modifications to a brand new handguard (I've done this way too many times!), the next logical application would be to build something that will just barely fit inside of most handguards. This way I can recess the can as far back into the rail as I want. This will most likely live on a standard carbine with a 16" barrel. Length will be 7.5". 

The metal is pitted like that because my dumb ass decided to clean it up with a wire brush in my drill press.


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## sdelivery (Feb 12, 2021)

talvare said:


> Another option may be to purchase a 5C hex collet block as in this set:
> 
> 
> 
> ...


This is the way I would suggest you go.
You will be able to hold work without damage and there must be a hundred of choices for 5c collets, depending on diameter, shape and collet accuracy.


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## fitterman1 (Feb 12, 2021)

swany said:


> I am using carbide insert tools. My parting tool, turning tool, and all of my boring bars (many different sizes) are all carbide inserts. I haven't tried HSS yet. I really need to take a day and learn about tooling, and more specifically, how the angles and "rakes" affect the overall machining experience.
> 
> I am still *super* green with all of this stuff. I'm kinda surprised I've been able to actually make some usable parts since I first plugged this thing in almost 3 months ago!
> 
> ...


Your work is pretty good for someone green.
Like you I use mostly insert tools but also hss for form tools, such as for forming a radius or a particular shape in a recess where a normal boring bar cant fit.
Over time you will come to the conclusion that there is a relationship between the feedrate and the radius of your tool at the cutting edge. This impacts the finish of the completed product, so you don't have to do much rework to make things look prettier. This is important both when power feeding and more so when hand feeding on surfaces such as tapers.
If you want to polish surfaces use an emery tape with some lube, i find this more efficient than wire brushes and there is no metal transfer from brush to work in the case of dissimilar metals, particularly when machining stainless steel. I envy your ability to be able to make form ones. Can't do it in my country due to the wankers in power.
Keep up the good work.


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## swany (Feb 15, 2021)

sdelivery said:


> This is the way I would suggest you go.
> You will be able to hold work without damage and there must be a hundred of choices for 5c collets, depending on diameter, shape and collet accuracy.



the 6-jaw chuck allows me to clamp down as hard as I want on thin-walled tubing and it doesn't deform the workpiece at all, besides some minor surface scratching where the jaws contact the metal.


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## swany (Feb 15, 2021)

fitterman1 said:


> Your work is pretty good for someone green.
> Like you I use mostly insert tools but also hss for form tools, such as for forming a radius or a particular shape in a recess where a normal boring bar cant fit.
> Over time you will come to the conclusion that there is a relationship between the feedrate and the radius of your tool at the cutting edge. This impacts the finish of the completed product, so you don't have to do much rework to make things look prettier. This is important both when power feeding and more so when hand feeding on surfaces such as tapers.
> If you want to polish surfaces use an emery tape with some lube, i find this more efficient than wire brushes and there is no metal transfer from brush to work in the case of dissimilar metals, particularly when machining stainless steel. I envy your ability to be able to make form ones. Can't do it in my country due to the wankers in power.
> Keep up the good work.


Thanks! I appreciate the advice. I have noticed that my lathe is still cutting a slight taper when I am turning round tube. I have checked to make sure that the lathe is level, which it is. I checked this using some 1-2-3 blocks and a $200 machinists level. Gibs have been tightened and the machine is working great, other than that stupid taper. Basically, my cut gets deeper (when turning outside) as I move my cutting tool closer to the chuck. Could this be happening because I am not using a follow rest?


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## fitterman1 (Feb 15, 2021)

Don't think so, i would check headstock spindle axis against the bed axis for parallelism.
No matter what you clamp in a chuck there is always distortion of some sort.
Either the work is distorted or the chuck becomes distorted.


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## fitterman1 (Feb 15, 2021)

You need to be sure these two axis are parallel to be confident of dimensional accuracy.
Use a mandrel and a tenth indicator to verify this.


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## slodat (Feb 16, 2021)

Give this a try.


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