4 Jaw Chuck for Mini Lathe

[RMS]

Hey guys,

I am thinking about buying a 4 jaw chuck for my MicroLux mini lathe. But I saw two types and now I am wondering what one? One says self-centering here: http://littlemachineshop.com/products/product_view.php?ProductID=3424&category= and here is the other one http://littlemachineshop.com/products/product_view.php?ProductID=1175&category=566826475

Anyone know anything about these and what one should I get? Basically I just need to turn stuff off center.

Thanks,
Rob

 

[bp]

If you need to turn stuff off centre you need "the other one". The self centring one would be like a three jaw self centring chuck, but with four jaws.
cheers
Bill Pudney
Adelaide, Australia

 

[cfellows]

I'm assuming you already have a 3 jaw, self centering chuck? Probably a 3"? A four jaw usually has independently adjustable jaws. This lets you hold irregular work, off-center work, and to mount round stock (and other shapes) with the highest degree if precision. By using a dial test indicator, you can adjust each jaw as needed to position the work where you need it.

Chuck

 

[RMS]

If you need to turn stuff off centre you need "the other one". The self centring one would be like a three jaw self centring chuck, but with four jaws.
cheers
Bill Pudney
Adelaide, Australia

OK I see now, a self centering 4 jaw chuck would be used for square stock I am assuming. But since I am turning stuff off center then I will get the other one!

Thanks,
Rob

 

[RMS]

I'm assuming you already have a 3 jaw, self centering chuck? Probably a 3"? A four jaw usually has independently adjustable jaws. This lets you hold irregular work, off-center work, and to mount round stock (and other shapes) with the highest degree if precision. By using a dial test indicator, you can adjust each jaw as needed to position the work where you need it.

Chuck

Hi Chuck,

Yes, I do have a 3" 3-jaw chuck now. But now trying to build my first model steam engine, I can see I need to get some other items, such as a dial indicator.

Rob

 

[Andrew_D]

FYI.....

For my minilathe, I had the 3" 3-jaw that it came with and then ordered a 3" independent 4-jaw.

I did come across a few projects where they weren't big enough, so also have the 5" versions. (3-jaw and independent 4-jaw.)

I decided to skip the 4" size, and haven't regretted it yet, although the 5" jaws can hit the ways with large jobs if you aren't careful...

I've even chucked up the 5" 4-jaw in the 12" 3-jaw on my big 20" lathe if I have small 4-jaw work to do and don't want to muscle the 16" 4-jaw onto the big lathe. I can just barely lift the 12"...can't lift the 16" by myself, so it takes some planning to get it on the lathe!! :big:

Andrew

 

[Tin Falcon]

a four jaw independent can still be used for square stock a and round stock on center. as well as rectangular and odd shapes, off center etc.
Tin

 

[RMS]

FYI.....

For my minilathe, I had the 3" 3-jaw that it came with and then ordered a 3" independent 4-jaw.

I did come across a few projects where they weren't big enough, so also have the 5" versions. (3-jaw and independent 4-jaw.)

I decided to skip the 4" size, and haven't regretted it yet, although the 5" jaws can hit the ways with large jobs if you aren't careful...

I've even chucked up the 5" 4-jaw in the 12" 3-jaw on my big 20" lathe if I have small 4-jaw work to do and don't want to muscle the 16" 4-jaw onto the big lathe. I can just barely lift the 12"...can't lift the 16" by myself, so it takes some planning to get it on the lathe!! :big:

Andrew

Hi Andrew,

This is a good point and now you got me wondering if I should move up in size. Did you make an adapter plate or buy one? I can get a 4" w/ adapter plate but they don't sell an adapter for the 5" to fit my lathe that I am thinking has a 72mm registration boss since the 5" has a 95 mm diameter registration boss. So I would have to make one unless you know another place to get it from.



Thanks,
Rob

 

[Dunc]

I chose http://littlemachineshop.com/products/product_view.php?ProductID=1697&category=566826475 (4 inch independent with adapter plate for mini-lathe). The company also has 5 inch and adapter plates. I considered the 5 inch but felt it would be limited in use due to the jaws striking the ways. Dunno for certain but I think a 5 inch would be a heavy piece of "iron" to hang onto the headstock (based on one I have for a larger lathe).

Usual disclaimer: I have no interest etc in LMS other than as a satisfied customer.

 

[RMS]

a four jaw independent can still be used for square stock a and round stock on center. as well as rectangular and odd shapes, off center etc.
Tin

Hey Tin,

I never used a 4 jaw independent chuck before so to me it seems like it would be tricky to set up. I can picture myself swapping chucks back an forth and only using it when I have to, or are there people that use 4-jaws independent chucks for everything?

Thanks,
Rob

 

[RMS]

I chose http://littlemachineshop.com/products/product_view.php?ProductID=1697&category=566826475 (4 inch independent with adapter plate for mini-lathe). The company also has 5 inch and adapter plates. I considered the 5 inch but felt it would be limited in use due to the jaws striking the ways. Dunno for certain but I think a 5 inch would be a heavy piece of "iron" to hang onto the headstock (based on one I have for a larger lathe).

Usual disclaimer: I have no interest etc in LMS other than as a satisfied customer.

Yeah, I was considering weight as a factor as well, that is on the bearings. I will have to take some dimensions on how much the jaws extend and add that up to see if the 5" would be worth the extra weight vs what I might gain or loose in clamping dia. based on jaws hitting the bed. Though we did get one vote for the 5" from Andrew, so I think its worth testing.

Thanks for the link!

 

[shred]

Hey Tin,

I never used a 4 jaw independent chuck before so to me it seems like it would be tricky to set up. I can picture myself swapping chucks back an forth and only using it when I have to, or are there people that use 4-jaws independent chucks for everything?

Thanks,
Rob

I swap in the 4J when necessary, but the tip from Marv of making a second, shorter chuck key for the 4J is spot-on. Makes setup a whole lot easier since you can move two opposite jaws at once.

 

[RMS]

I swap in the 4J when necessary, but the tip from Marv of making a second, shorter chuck key for the 4J is spot-on. Makes setup a whole lot easier since you can move two opposite jaws at once.

Thanks, where did Marv post this tip? ...maybe I missed something not sure.

 

[shred]

Thanks, where did Marv post this tip? ...maybe I missed something not sure.

Sorry, it wasn't posted in this thread.. I thought it was on one of the links, as it's occasionally posted all over here but it appears not.
Basically make a clone of your 4-jaw chuck key so you can adjust two opposite jaws at once-- tighten one while loosening the opposite one. Makes it a whole lot easier to get centered.

Here's one good thread on the subject: http://www.homemodelenginemachinist.com/index.php?topic=284.0

 

[Ken I]

are there people that use 4-jaws independent chucks for everything?

Well I certainly do - although I have a three jaw self centering chuck I only use it for repetetive work where the O.D. is to be machined and concentricity is moot.

I don't care what people say - there is no such thing as an accurate 3 jaw chuck (some are way better than others but none can beat an independent 4 jaw for accuracy.)

Sure it takes a little longer to set up but if the O.D. doesn't matter I just true visually to the tool as good enough.

If it needs to be spot on - out comes the dial gauge - if you need that kind of accuracy then a 3 jaw isn't going to do the job in any case.

I hardly ever remove the 4 jaw - My Son on the other hand always pulls it off in favour of the three jaw and the &*?!#$ never puts the 4 jaw back. ???

Regards,
Ken

 

[mklotz]

RMS,

Here's the URL for my treatise on 4J centering...

http://www.schsm.com/html/centering_work_in_the_four_jaw.html

 

[cfellows]

If you look here, starting at reply #37, you can see some mods I made to my 3-jaw chuck which lets me adjust it for TIR, much like a 4 jaw chuck. I've also found that once I set it to zero TIR with a 1/2" bar chucked up, the TIR doesn't change much at different diameters... maybe a maximum of .0015" out to 3/4". Haven't checked any further.

http://www.homemodelenginemachinist.com/index.php?topic=9016.15

I find that I am using my mini lathe more and more for small, precision work and my modified 3-jaw chuck stays on the lathe all the time. I would highly recommend this mod for anyone wanting precision, repeatable holding of round stock for turning and boring. It's mitigated my need for an er collet chuck on the mini lathe.

Chuck

 

[RMS]

Sorry, it wasn't posted in this thread.. I thought it was on one of the links, as it's occasionally posted all over here but it appears not.
Basically make a clone of your 4-jaw chuck key so you can adjust two opposite jaws at once-- tighten one while loosening the opposite one. Makes it a whole lot easier to get centered.

Here's one good thread on the subject: http://www.homemodelenginemachinist.com/index.php?topic=284.0

No problem, thanks for clarifying that. I have a ton of learning to do in the Machining world!

 

[RMS]

Well I certainly do - although I have a three jaw self centering chuck I only use it for repetetive work where the O.D. is to be machined and concentricity is moot.

I don't care what people say - there is no such thing as an accurate 3 jaw chuck (some are way better than others but none can beat an independent 4 jaw for accuracy.)

Sure it takes a little longer to set up but if the O.D. doesn't matter I just true visually to the tool as good enough.

If it needs to be spot on - out comes the dial gauge - if you need that kind of accuracy then a 3 jaw isn't going to do the job in any case.

I hardly ever remove the 4 jaw - My Son on the other hand always pulls it off in favour of the three jaw and the &*?!#$ never puts the 4 jaw back. ???

Regards,
Ken

Hi Ken,

I will do the same once I purchase my new chuck, just leave it on and get familiar with the whole process.

I used to do the same stuff that your Son does to my dad also but with hand tools when I would repair my bike, I would be in such a rush to get out riding and never put the tools back!! Now my kids are still too young yet to mess with my power tools though the other day he was digging a hole with my slag pick in the back yard and clocked his brother in the forehead. The wife was not happy with me!


Rob

 

[RMS]

RMS,

Here's the URL for my treatise on 4J centering...

http://www.schsm.com/html/centering_work_in_the_four_jaw.html

This is great, I got so much more more info here than I would have imagined!