Dif between 3-4 lathe chuck

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Bill my 4 jaw Chuck has independent adjustment on each jaw and allows much more adjustment for non-circular work. Also requires lots more measurement and adjustment in setup.
 
What Ken said, plus:

My 3 jaw is self centering. Just turn the key and done. This works great for work that won't be returning for more work after I remove it.

If I take work off the metal lathe, work on it and then return it to the metal lathe it is a lot easier to get it set up again with a four jaw (independent) and indicator. Not easy, but easier than futzing with a 3 jaw chuck and an indicator.

3 jaws work great on round and hex stock.

4 jaws work great on round, square and octagon stock.

Ed
 
I just bought a metal lathe and am considering adapting my 4 jaw self centering chuck (from my wood lathe) so that I can more easily turn Square stock. Most of the Alumilite blanks that I enjoy turning are square and to turn square stock on a 3 jaw chuck I would have to create a round jam chuck adapter (out of wood), turn the stock round and them mount it in the three jaw chuck for the balance of the work.

That is unless someone has a better idea...
 
The 4 jaw self centering can have 2 advantages over a 3 jaw, as mentioned one is holding square blanks. THe other advantage is better support around the blank or rings when holding thin wall pieces. I Have used the 4 jaw to hold a pen body that was 90% finished to hand finish the joint where two pieces meet when screwed together. Wrapped in once with blue tape and very light hand work.
 
Eric - I use my wood lathe (4 jaw scroll chuck) to center drill the ends of square blanks so I can mount between centers on my metal lathe. Once I have it round on the metal lathe, I hold it in a collet chuck on the metal lathe.

There are times it would be handy to be able to move my wood lathe chuck to the metal lathe, but I couldn't find an adapter that would work. Making my own would likely introduce too much error for what I'm doing.


Ed
 
Sandsini said:
I just bought a metal lathe and am considering adapting my 4 jaw self centering chuck (from my wood lathe) so that I can more easily turn Square stock. Most of the Alumilite blanks that I enjoy turning are square and to turn square stock on a 3 jaw chuck I would have to create a round jam chuck adapter (out of wood), turn the stock round and them mount it in the three jaw chuck for the balance of the work.

That is unless someone has a better idea...
Click to expand...


Eric - My 4 jaw machinist chuck has LOTS less runout than my wood lathe scroll chucks.

The precision expectations are much lower for hand held tooling with a normal wood lathe.

Be prepared to do lots of futzing to get processes and proceedures developed for obtaining the precision expected with a metal lathe.

With a metal lathe, be prepared to pay for the precision, either with cash or time. Most of us can more easily afford the time, but there are few short cuts if precision work is the objective.
 
Sandsini said:
I just bought a metal lathe and am considering adapting my 4 jaw self centering chuck (from my wood lathe) so that I can more easily turn Square stock. Most of the Alumilite blanks that I enjoy turning are square and to turn square stock on a 3 jaw chuck I would have to create a round jam chuck adapter (out of wood), turn the stock round and them mount it in the three jaw chuck for the balance of the work.

That is unless someone has a better idea...
Click to expand...

Never expect the accuracy of the metal lathe 3 jaw from a wood lathe 4 jaw there is no comparison. Horses for courses.

Peter.
 
Ed,
That sounds like a much better solution. I think I'm going to try that first.

Ken,
I wanted a metal lathe for the precision so I guess I should get used to the more involved setup and processes. My inherent impatience will have to take a back seat apparently, but that's expected as I learn the new tools and develop procedures.

Thanks to you both for your contribution.

Cheers,
 
A 4-jaw self-centering chuck on a metal lathe is absolutely great for drilling square (or round) section pen blanks. I wouldn't be without it.
 
3 Jaw (standard is self centering) = fast easy semi accurate holding (very accurate if you want to go the thousand dollar route) and holds triangular, hex or round stock.

4 Jaw, (standard is independently adjusting) can be adjusted to virtually no measurable runout but takes more time (not much time once you get the hang of it) and holds all sorts of shapes and can be set to turn an eccentric for a camshaft or something. You can do everything you can with a three jaw and lots more at the expense of a little more time in setting it up and a little longer learning how to use it.

No wood lathe chuck is going to give the accuracy on a metal lathe that a real metal lathe chuck will. Hack and whack accuracy, yes. Precision part making accuracy, no.
 
magpens said:
A 4-jaw self-centering chuck on a metal lathe is absolutely great for drilling square (or round) section pen blanks. I wouldn't be without it.
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I have a self centering four jaw chuck for my Sherline lathe as well as a three jaw chuck and an independent adjusting four jaw chuck. I have never seen a self-centering four jaw chuck for an engine lathe. Since you have one I believe they exist but just never saw one. I have several three jaw chucks, 2 - 4" chucks a 5" chuck and a 6" chuck. I'd like to use one of them on my wood lathe but have not found a backing plate to fit the wood lathe.
 
Rockytime said:
I have a self centering four jaw chuck for my Sherline lathe as well as a three jaw chuck and an independent adjusting four jaw chuck. I have never seen a self-centering four jaw chuck for an engine lathe. Since you have one I believe they exist but just never saw one. I have several three jaw chucks, 2 - 4" chucks a 5" chuck and a 6" chuck. I'd like to use one of them on my wood lathe but have not found a backing plate to fit the wood lathe.
Click to expand...

I use this adapter to use my 3 jaw metal lathe chuck on the wood lathe.
https://www.pennstateind.com/store/LABAR418.html
I'm sure some accuracy is lost but it can't be much, the insert threads register well.
 
When I used a four jaw chuck on the metal lathe it was usually to turn something off center, you can't do that with a 3 jaw, or if I needed to put a lot of pressure with the jaws on the part. Another reason is big four jaw chucks are much cheaper than 3 jaw chucks, a big 3 jaw self centering chuck can cost as much as the entire shop.
If I wasn't doing that I took it off and put the three jaw back on as it is self centering and saves money in time spent centering the part.
 
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There are 2, 3, 4 & 6 jaw chucks for metal lathes, that come in scroll and independent flavours and, as I just found out when looking, both independent & scroll in the same chuck. There are also many special chucks for special work holding too. The scope of chucks for metal lathes is staggering and makes the choices we have for wood lathes seem pitiful.

My metal lathe came with the standard faceplate, a 3 jaw scroll and a 4 jaw independent chucks. I've added a 4 jaw scroll and a 5C collet chuck to the mix and if I ever have the need I'll add a 6 jaw chuck.

The standard 3 jaw scroll is for quick clamping of round objects but the concentricity and consistency is limited by the quality of chuck. 4 and 6 jaw chucks do the same with the 4 jaw having the ability of also holding square material. The 6 jaw is meant for thin wall stock to reduce deformation.

Indépendant jaw chucks are meant to either centre stock more accurately, to hold odd shapes and hold parts off centre.

The chucks you buy beyond the ones that come with your lathe are dictated by what you are turning.
 

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Most Chucks come that way, "plain back" you buy or make and adapter plate that bolts on to the chuck and fits your particular lathe. My 12-36 lathe takes a d1-4, My atlas took1 1/2 x8 or 10 x 1 for the 6inch version. IF you know what kind of thread or mount you need for the lathe it fits on check Shars.com for backing plates. What does the lathe you want to fit it on have for a mounting system?
 
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mredburn said:
Most Chucks come that way, "plain back" you buy or make and adapter plate that bolts on to the chuck and fits your particular lathe. My 12-36 lathe takes a d1-4, My atlas took1 1/2 x8 or 10 x 1 for the 6inch version. IF you know what kind of thread or mount you need for the lathe it fits on check Shars.com for backing plates. What does the lathe you want to fit it on have for a mounting system?
Click to expand...

I have a 7"X20 Maximat 7. I happen to have an extra back plate for it. I don't know what the spindle thread is. I don't have a thread gauge large enough to check it with. I am guessing it is perhaps 1 1/2 X 6. Not sure. The lathe manual I have states it as EM 39 and Din 800. I have no idea what that means. I don't really need the chuck on my wood lathe but thought it might be useful sometime. I sold my 12 X36 lathe a few months ago along with my Bridgeport. Getting too old for larger projects. Got to start down sizing. The 3" chuck was mounted on a rotary table which went with the mill so it is just sitting on the shelf.

Thanks for your interest. This kitless stuff does interest me. May give it a whirl one day.
 
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