Appreciating the 4-jaw chuck

[mcdanlj]

I started this machining journey by buying a used HF mini-lathe about a year ago. If it hadn't been substantially improved by the original purchaser, that might have been an exercise in frustration to drive me away from the hobby, but instead it led to me also buying his (also improved) HF mini-mill, and then to making some upgrades...

The mini-lathe came with a 4-jaw chuck, but I never used it, even when I learned the hard way that the 3-jaw isn't perfectly concentric. Last month, I used the 4-jaw on the G0709 for the first time. I started using it occasionally after that, but each time I used it, part of cleaning up for the night was putting the 3-jaw back on for next time, as the default chuck I was most likely to want.

Yesterday I had a setup already in place in the G0709, and then discovered that I needed to turn some small brass rod for the setup, so I turned to the mini-lathe. I needed very good concentricity, so I switched to the 4-jaw chuck. When I was done, I left it installed.

Today, I used the 4-jaw again on the G0709, and for the first time left it on the lathe when I cleaned up, because I felt I was just as likely to use it as another chuck for whatever I do next.

I don't think I would have gotten there without a Noga and a decent DTI though!

 

[Nogoingback]

The more you use that chuck, the better you will be at dialing it in. If you set up a dedicated QC tool holder to support your
indicator, you'll be able to do it even quicker. Congrats on learning something new.

 

[Moderatemixed]

I think I might just “follow suit”. Thanks for a bit of inspiration. Cheers.


Sent from my iPad using Tapatalk

 

[P. Waller]

4 jaw chucks are required for work that can not be easily held in a scroll chuck.
If you have to make time on round concentric parts a 3 or 6 jaw adjustable scroll chuck is the way to happiness.

I often have to use an independent chuck for off center turning, this is a slow and tedious process that should be avoided if possible.




Any cheap indicator holder will work for small parts, there is little to be gained by spending money on name brand tools such as Noga for indicating parts in a lathe,

Recently bought a Noga articulated magnetic base holder without an indicator for $175.00, you may ask why and the answer is that I needed one 30" tall and they make one. It is well made but I am not sure that it will endure an entire year in a job shop. Add a $150.00 3" Dia. dial indicator and the package is well over 300 bucks. I also used a $49.95 indicator/holder on the same job, it worked just as well merely will not extend far enough for much of the work.
A 3" diameter drop indicator is excellent if like myself you have 60 year old eyes and the dial is 60" away (-:

 

[Shootymacshootface]

If I could only have one chuck for my lathe it would definitely be an independent 4 jaw. Also, after I got my rotary table I found a 4 jaw for that. I have noticed that all of the rt/chuck package deals come with a 3 jaw scroll chuck, and I'm not sure why.

 

[mksj]

They all have there place, my primary gripe with a 4J independent was the time to dial in parts and also was a real pain if you had multiple parts. I switched to what is known as a combination chuck, which has 4J on a scroll and each one is independently adjustable. The scroll repeats to about 0.001" so very quick to switch parts out and then zero out any deviation. I rarely use my 3J high end chuck, mostly the 8" combo and a 5C. I also have an 8" Taiwanese D1-4 direct mount from QMT which is I also use for bigger round stock, it also works very nicely. Having a few high quality chucks really makes turning fun.

Bison 8" combo and QMT 8" D1-4 independent

 

[mcdanlj]

Thanks y'all!

@mksj I have an 8" 6-jaw tru-set clone but man that's heavy to lift repeatedly. I keep looking at the combination chucks as a best-of-both-worlds that would reduce chuck swapping for me, and I expect I'll get one some day, but as a newbie of slightly less than a year total experience I'm investing in other tooling right now. It's not a bad thing right now to take a couple minutes to dial it in, good practice for me at this point. I see $1500 - $2500 seems to be the range for an 8" 4-jaw combination chuck?

@Shootymacshootface I'd also like an independent 4-jaw for my dividing head on the mill; already a few times I've wished for one instead of the 3-jaw it came with. But I don't think the 8" would fit very well! ☺

@P. Waller I've used it both for precise adjustment and for boring square pieces, as you show. As a newbie hobbyist, I'm not doing much "making time" yet.

@Nogoingback with a magnetic mount set on the cross slide, how would a dedicated tool holder on the QCTP make it faster? I don't doubt you, but I don't have a picture of how it would be faster. I engage the magnet, loosen the knob, put the indicator in place just above the surface, tighten the knob, and then dial down the indicator until it indicates as I spin the chuck. I can indicate inside a hole for boring or to the outside of a piece for turning equally easily. What's the corresponding easier/faster way with a dedicated tool holder?

 

[P. Waller]

They all have there place, my primary gripe with a 4J independent was the time to dial in parts and also was a real pain if you had multiple parts. I switched to what is known as a combination chuck, which has 4J on a scroll and each one is independently adjustable. The scroll repeats to about 0.001" so very quick to switch parts out and then zero out any deviation. I rarely use my 3J high end chuck, mostly the 8" combo and a 5C. I also have an 8" Taiwanese D1-4 direct mount from QMT which is I also use for bigger round stock, it also works very nicely. Having a few high quality chucks really makes turning fun.

Bison 8" combo and QMT 8" D1-4 independent

I often get mail for pointing out other methods of doing a job.
Often it is "we are hobbyists not professionals, we do not have to make time"
You can not have it both ways.

 

[Nogoingback]

Thanks y'all!


@Nogoingback with a magnetic mount set on the cross slide, how would a dedicated tool holder on the QCTP make it faster? I don't doubt you, but I don't have a picture of how it would be faster. I engage the magnet, loosen the knob, put the indicator in place just above the surface, tighten the knob, and then dial down the indicator until it indicates as I spin the chuck. I can indicate inside a hole for boring or to the outside of a piece for turning equally easily. What's the corresponding easier/faster way with a dedicated tool holder?

You probably right, but I guess I was suggesting that a dedicated tool holder can make setting up quick and easy.



This indicator set up is permanently secured in a boring bar holder, so I just drop it onto the tool post and I'm GTG. The OD of the pin is sized for different diameter snugs. There are, of course lot's of ways to accomplish the same thing.

 

[SubtleHustle]

I ordered a independent 4 jaw 6", and a 3 jaw scroll 6", at the same time, about 6 months ago...my first 4 jaw. The 3 jaw is still in the box, only opened to inspect it. I really dont see me ever using it now. I love my 4 jaw! And as mksj stated, their great for holding irregular work. I just used it today, for that purpose.