Misplaced jaws ... dangerous ?

[Sawdust Maker]

Mobyturns post about the chuck mishap reminded me of this

I noticed this setup at the men's shed the other day

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Not sure why this was done or what it was used for (if at all) but I shudder at what might have happened

[Pat]

Just when you thought you've seen Stupid, someone does something even more Stupid.:no:

[chuck1]

I wait in anticipation for a follow up post!

[brendan stemp]

I kinda admire the ingenuity but....

[wheelinround]

Now whats the jaws that Nova sells which you can only fit one set of screws to??


I can see the logic of "It won't fit in" "I don't have a big enough dia set of jaws" BUT yep its got DANGER all over it.


The alternative is to use a face plate and glue, screw or both to the item.

[Sawdust Maker]

Now whats the jaws that Nova sells which you can only fit one set of screws to??


...

there's this set 25mm jaws (http://www.carbatec.com.au/teknatool-25mm-jaw-set_c19363)
and these pin jaws (http://www.carbatec.com.au/teknatool-pin-jaw-set_c19369)
and I think that some of the newer mini jaws might be affixed with one screw

but at least with these they are meant to be properly seated whereas the 50mm jaws as per the men's shed weren't
have to admit they were on pretty tight

[Mobyturns]

Sadly we are seeing more of this sort of "ingenuity." I am wondering if the jaws are even for that model chuck? I guess they are???

It is very unfortunate that we are loosing the "common knowledge" about work holding methods, techniques and safe turning processes in some clubs and men's sheds. In times past an apprentice would be given a clip over the ear & a stern talking to for doing something so unsafe / risky.

It is very risky, but it is hard to be too critical when we don't know the full story. A lot of the silly things we see occur develop because there is not appropriate equipment and accessories available to perform the task using proven safer methods. There is often a genuine lack of advanced skill & knowledge within the group so the turners make do as they often do not know any better and do not endeavor to learn from other sources.

I believe there is too high a reliance upon the use of chucks, particularly when there are limited jaw set options available, as in many instances a face plate and the knowledge how to use face plate techniques is a "better" & "safer" option.

[Rod Gilbert]

Sadly we are seeing more of this sort of "ingenuity." I am wondering if the jaws are even for that model chuck? I guess they are???

It is very unfortunate that we are loosing the "common knowledge" about work holding methods, techniques and safe turning processes in some clubs and men's sheds. In times past an apprentice would be given a clip over the ear & a stern talking to for doing something so unsafe / risky.

It is very risky, but it is hard to be too critical when we don't know the full story. A lot of the silly things we see occur develop because there is not appropriate equipment and accessories available to perform the task using proven safer methods. There is often a genuine lack of advanced skill & knowledge within the group so the turners make do as they often do not know any better and do not endeavor to learn from other sources.

I believe there is too high a reliance upon the use of chucks, particularly when there are limited jaw set options available, as in many instances a face plate and the knowledge how to use face plate techniques is a "better" & "safer" option.

A big +1 from me Moby.
Regards Rod.

[Christos]

How many wood turners at the shed? And why are they not members of the forum. These are the types of questions that should be asked. Prevention is better than cure.

[Sawdust Maker]

I very rarely use the lathes at the menshed

There are three I've seen use the lathes - there would be more using them as I only go one particular day

Two of them are like a bull at a gate and it is impossible to tell or show them anything
the skews have more bevels on them than the hope diamond

[wheelinround]

How many wood turners at the shed? And why are they not members of the forum. These are the types of questions that should be asked. Prevention is better than cure.



I'd say because the "Men Shed" has its own forum.

[wheelinround]

Yes more thought should have gone into extending them or the club should have bought a Cole Jaw set and extended them

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[Sawdust Maker]

there is a set of cole jaws

[Mobyturns]

One of the most significant issues with this sort of "make do" ingenuity is not visible. The over extension of the chuck should be obvious but the internal damage that may also be done to the chuck scroll is hidden and may not become an issue until some time in the future for another user in a club or men's shed environment.

I have serviced chucks for others where a fair section of the lead into the scroll is missing completely. That can only occur from operating the chuck with the stop pin removed and / or the jaws over extended. It is basically abusing the chuck. Continued use in that manner can cause one backing slide to actually separate from the chuck body to become a high speed projectile, with possibly the work piece in hot pursuit.

[Sawdust Maker]

One of the most significant issues with this sort of "make do" ingenuity is not visible. The over extension of the chuck should be obvious but the internal damage that may also be done to the chuck scroll is hidden and may not become an issue until some time in the future for another user in a club or men's shed environment.

I have serviced chucks for others where a fair section of the lead into the scroll is missing completely. That can only occur from operating the chuck with the stop pin removed and / or the jaws over extended. It is basically abusing the chuck. Continued use in that manner can cause one backing slide to actually separate from the chuck body to become a high speed projectile, with possibly the work piece in hot pursuit.

good point

I've now decided to service the chucks at the local menshed

This is also for my own wellbeing as I and others are often in the line of fire if something goes wrong

[KBs PensNmore]

That's the trouble with a lot of places, the equipment is there, but members either don't know where it is kept or can't be bothered looking for it.
I help out at the local Day Centre in a shed that is there for the clients, some of the things I've seen make me shudder, using the bandsaw at its maximum height, because they can't see the line, a 4 prong drive centre mounted in the 4 jaw chuck gripped at its narrowest point. The main culprit was reprimanded several times over these, eventually he lost several fingers on one hand, fortunately/unfortunately he did this at home. Hopefully he has learnt his lesson. Sorry for being blunt about it, but sometimes that is the only way some people learn.
Kryn

[Colin62]

That can only occur from operating the chuck with the stop pin removed and / or the jaws over extended.

To be fair, the jaws aren't over extended in that picture, and the tension on the jaw inserts would be no more than that on a cole jaw with a similar clamping radius.

And having said that, no, just no!

[Mobyturns]

To be fair, the jaws aren't over extended in that picture, and the tension on the jaw inserts would be no more than that on a cole jaw with a similar clamping radius.

And having said that, no, just no!

I agree that the jaw slides are within the recommended ranges so potential damage to the scroll is not likely in this example, BUT if they are doing this it does not take much a stretch of the imagination & ingenuity to extend them a little further - just this once.

The hazard & risk associated with such practices is relative, so turners must assess the whole operation and likely events.

Whether the jaw placement on the slides is potentially unsafe depends entirely upon what work piece is being held, its size, mass, operating lathe speed, turning operation etc. It may be quite safe if this "work around" is for a thin disc & light cuts but it would be potentially quite hazardous and very high risk if it was for a large bowl with a turner known for aggressive cuts etc.

Definitely not a recommended work practice though.

[Sawdust Maker]

Ok, an exercise for everyone

take your chuck with your standard jaws
remove 1 (one) jaw
move it out one bolt hole
securely affix it to chuck

essentially you cannot because the 'ridge' (?) precludes proper seating except where it should be seated (hope this makes sense)

the whole exercise just hurts my sensibilities as the jaws and chuck were not designed to do this and ...

[Mobyturns]

Sadly we are seeing more of this sort of "ingenuity." I am wondering if the jaws are even for that model chuck? I guess they are???


Ok, an exercise for everyone

take your chuck with your standard jaws
remove 1 (one) jaw
move it out one bolt hole
securely affix it to chuck

essentially you cannot because the 'ridge' (?) precludes proper seating except where it should be seated (hope this makes sense)

the whole exercise just hurts my sensibilities as the jaws and chuck were not designed to do this and ...

That is why I made my original comment. I prefer QLD made Vicmarc chucks so not knowing or having first hand experience with some chucks on the market made me immediately question how this was achieved. Maybe their ingenuity extended to removing the locating ring from the rear of the jaws too???

[Sawdust Maker]

no locating ring still in there

I went to service the shed's chucks yesterday only to find that one of the supervisors did them on Tuesday (no doubt as a result of this)

oh and no one has said "I did that" :no:

[Oldgreybeard]

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This thread encouraged me to check my chucks. Fortunately all screws were very tight - more good luck than good management because I am guilty of not checking them often enough.

But one chuck - an old Bonham (old and in need of some TLC:B) had fitted a set of jaws with only one screw in each jaw and obviously manufactured as such.

Curiosity got the better of me, so I got a Nova jaw and checked if it could be mounted to the Bonham Chuck: YES - it could be fitted with 1 or 2 screws (see image 1). Further the jaw sat flat on the slide - not tilted due to the ridge as Mobyturns experienced. (see image 2 top view and image 3 bottom view). The ridge was located neatly at the end of the slide - as if it was meant that it could be mounted in this fashion.

Apart from all of the risk factors mentioned in the above posts, if you look carefully at image 4 the ridge does not fit tightly against the end of the slide (indicated by arrow) and any attempt to "centre" the jaw immediately loosened the screw.:oo:

Any experienced operator, and I have been using metal and wood lathes for 30+ years, would not consider mounting jaws in this fashion, but I can understand an inexperienced turner doing so, particularly if it looks as though it was "intended" to be an alternative mounting option.

While it is easy for us to blame the operator, I feel that some blame must be attributed to the manufacturer. Top quality manufacturers ensure that the jaws can only be fitted in the correct manner or it is very obvious by not seating properly, for example, that this is not the correct way to fit the jaws. While operator error or lack of training is most often reposible for the use (or abuse) of the chuck in this manner, it is also a serious safety concern which needs to be addressed by some manufacturers.

Bob