Versachuck jaw flinging woes

[simonmac2]

i'm still fairly new at the lathe, and have a query on the versachuck i have.

i've put the 50mm jaws on it, and generally, all goes well, BUT a couple of times recently, when using the spindle gouge (possibly with too much pressure) - one or 2 of the jaws got flung out (rapidly!) - luckily PPE in the form of my trend facemask prevented facial dents - but my trust in that chuck has now dropped (it happened a couple more times, but only with 1 Jaw)

it seems to be jaws 4 & 1 that get flung.

any ideas/similar experiences/solutions?

Thanks

Simon

 

[Rhossydd]

I've never had a jaw come loose on my Versachuck in ten years.
It shouldn't be possible if you're using the chuck correctly;

Make sure the correct jaw carriers are in their correct slots and that they meet perfectly in the centre when fully would in.

Ensure that the jaws are securely bolted onto the jaw carriers.

Never work with the jaw carriers protruding beyond the chuck body.

Make sure the work is tightly held in the jaws before starting.

 

[Doug B]

It sounds like you are using the Chuck with the jaws open too wide

 

[Orraloon]

Think we need more info. What exactly do you mean by the jaws get flung. Do they open during turning? Was there a catch? Did something break? Also what were you turning. Size of workpiece and was the tailstock supporting the other end. Pictures would help explain.
Regards
John

 

[graduate_owner]

Jaws coming out of the chuck body sounds like they are opened too wide and so not being gripped by the scroll. Make sure you insert them properly - insert no. 1 jaw when you see the scroll just appearing in the no. 1 slot on the chuck. Then do the same for the other jaws in sequence. When clamping the work you should not have the jaws opened so far as to risk insufficient grip by the scroll of the chuck - either turn the work to a smaller diameter or use different jaws.
Finally, take a look at the chuck with jaws removed, and look for any damage to the scroll. And - I assume you have versachuck jaws, not a different brand which might not be compatible (unlikely, I know, but a possiblity)

K

 

[Rhossydd]

I assume you have versachuck jaws, not a different brand which might not be compatible (unlikely, I know, but a possiblity)

That's not as straightforward as you might think. The default jaw carriers take Versachuck's own jaws, but are also compatible with Axminster chuck jaws. In Toolpost years the Versachuck jaws were pretty crude and poorly finished compared to the Axminister ones with less price difference than you might expect.
Further, there are a range of alternative jaw carriers available that allow almost any jaw system to be fitted with the appropriate carrier.
If the chuck was purchased new, the owner should know the spec, but a secondhand chuck might(just) have carriers for other makes.

However the OP's problem is most likely to be due to having the jaws open too far.

 

[Katomi woodsmith]

Sound like problem I had the jaws not located fully.
Mine was the number 4 jaw I did not allow the scroll to engage.
Suggest op take the jaws out
Clean
Inspect for damage
And re fit in order and
Finally inspect, test that all are located BEFORE putting back on lathe
Other than that, sorry I have no idea
Ps
If I have thought granny to suck eggs..... sorry working on limited knowledge, so covered the basics first

 

[Paul Hannaby]

You should be sizing the spigot on your piece of wood to fit the chuck jaws when they are opened to around 5-6mm. If you open the jaws too far, the carrier comes off the end of the scroll and the jaw is thrown out.
Correctly sizing the spigot will also maximise grip and reduce the chances of the wood being dislodged if you get a catch.

 

[simonmac2]

thanks all - a bunch of things to check.

i got it second hand, and the carriers do "seem" a nice tight fit.
i'll remove all jaws, clean and re-insert in order (and confirm the jaws and carrier numbers are correct.
i didn't think the jaws weren't over extended, but will mark up a 5mm line on the carrier as my future no-go point

if the jaws come out again - i'll retire the chuck.

many thanks for all suggestions

 

[Phil Pascoe]

We're assuming of course that the jaws including the slides/carriers came off, not just the jaws alone?

 

[Phil Pascoe]

I've three versachucks and I've never had a problem.

 

[Paul Hannaby]

Unless either the scroll or the carrier is broken to the point where there are missing sections of the mating parts of one or other, the jaws won't come out of the chuck.

If the chuck and carriers aren't broken, the only way the jaw will come out is if you wind it out too far.

 

[Rhossydd]

i didn't think the jaws weren't over extended, but will mark up a 5mm line on the carrier as my future no-go point

No. You don't seem to have understood that the jaw carriers should NEVER protrude beyond the jaw body.

With standard C type jaws in the Versachuck there's 10.6mm total travel which is enough to grip a correctly sized spigot without running the carriers out of the body.

 

[Duncan A]

To clarify, the 5mm opening referred to by Paul Hannaby is between each of the four segments of the chuck jaws. At this point they should form a true circle.
I appreciate that you are in IoM where there may not be many other woodturners, but it sounds as if you really do need some hands-on advice before you end up hurting yourself.
Apologies if this sounds a bit harsh.
Failing all else, get a copy of Keith Rowley's book "A Foundation Course"
Take care!
Duncan

 

[Vulcan]

There are a few things that some turners misunderstand.

The Chuck Jaws (some call carriers) must obviously be installed in the correct order. But in spite of any numbering system it doesn’t matter which slots they go in, in the Chuck Body - all the slots are the same.
The same applies to the Top or Accessory Jaws. These are numbered and do need to be fitted in the correct sequence. They can be fitted to any of the Chuck Jaws, provided the sequence is followed, the numbers on them don’t need to match.
It does of course though make it easier for those that don’t understand that there isn’t any matching between the chuck slots and the Jaws.
I’ve got six or seven chucks and only two have numbers on them. My last purchase, a SuperNova 2 doesn’t have any. Nor do the Chuck Jaws actually, but they do have “dots” (1-4) cast into them!

In spite of the need for greater precision, I’ve never seen a metalwork chuck with any numbers for jaw location. But they may exist?

I did read once though that sometimes you can achieve better accuracy by putting Jaw one in a particular slot in the chuck. I did try this once and I couldn’t see much if any different with a DTI on a test piece. I did though mark the body with a number 1 on the last setup as runout seemed pretty good at that point.

Edit: I did read somewhere that for metal work chucks that at least two of the teeth on the back of the chuck jaws must engage with the scroll wheel for safety reasons.

Some pictures of Axminster Chucks show the Chuck Jaws extended outside the Chuck Body but I believe they have enough tooth engagement to remain safe.

 

[Robbo3]

Lots of generalisations within the above answers. As this is the Wood Turning & Lathes section we should restrict our answers to wood turning chucks.
Axminster make some longer carriers which means they may possibly protrude safely beyond the chuck body but until I check I don't know whether that is the case. The design may be that the jaws are mounted further out on the carriers so that the carriers have no need to protrude.
One chuck I owned had a (removable) roll pin to stop carrier 4 from being extended too far therefore the carriers had to be entered so that carrier 4 ends up in the right slot. Sorry can't remember which chuck.
I also had another chuck where the carriers were numbered wrong & had to be fitted in the order 1,3,4,2.
The other thing that is confusing for beginners is using different names for the same thing. Chuck jaws & carriers (Axminster's terminology & what I use) are two different items. Jaws are attached to the carriers by means of screws or bolts. The teeth on the underside of the carriers mesh with the scroll on the chuck to move them in & out.
If you have an unnumbered set of carriers, the front tooth on number one will be furthest forward with each front tooth being slightly further back than on the previous carrier.