Thread: Recess Cut

Originally Posted by

Joe. The face of the jaws is the main "register" in woodturning chucks.

It is to ensure that you have the most support for the piece with little "leverage" effect.

True enough for compression mode on a tenon. For expansion, I'm not so sure. If the outside isn't flat and parallel to the bottom of the hole, shallow would be better, and I stand corrected. However, if they are parallel, the outside shoulders (nomenclature?) provides more support, i.e. a larger radius.

Cheers,
Joe

Don't want to overly dwell on this issue but maybe my thoughts were misunderstood. If one cares to look at the Barracuda2 lathe chuck system site it can be seen that the jaw design is not tapered. I have one of these and find it excellent for recesses where it is not easy to get the right taper. The dovetail type are only as good as the ability to make an angle that matches the chuck jaws. Will now back out of this informative discussion.

Originally Posted by rsser

MJ, we tested the Conchuck not so long ago on a hefty lump of Elm, unsupported by the tailstock (cost it overhung the bed on the swivel head) and it held well. So Con (and Skew) are on the ball with this. That said, it has limitations with a nat edge bowl, as do shark jaws cos you can't reposition the lump the align the high points or the low points.

Ern,
I made no mention of a conchuck , you did .
You also spoke of shark and spigot jaws . It is with those , being used in expansion mode in recesses made with forstner bits that I advocate the use of tailstock support for irregular blanks etc. , when possible .
That is what the thread is about is it not .

Originally Posted by Sturdee

They are now made and sold by Pops Shed as the Con Chuck.

Thanks, Peter. I've had mine literally for years, having bought them off Con. I lost his contact details (and forgot his name) so it's good to know they're still available.

Originally Posted by Manuka Jock

Ern,
You also spoke of shark and spigot jaws . It is with those , being used in expansion mode in recesses made with forstner bits that I advocate the use of tailstock support for irregular blanks etc. , when possible .

He also specified a 48mm forstner bit, which to my mind more or less rules out spigot jaws; they're usually a much smaller dia.

Shark jaws would work, but whenever I've had a piece of wood which needs their grip, it also needs to be tightened pretty heavily... which is something I dislike doing in expansion mode. Any natural fault in the wood and... "KERPLUNK"

Personally, I'm of the school of thought that expansion mode is usually a "second best" form of mounting. Different horses for different courses, I guess.

Andy, not sure what you mean by spigot jaws. Have assumed just the Nova equivalent of the Shark Jaws.

My small set of Shark Jaws are 45mm OD so they'd work fine in a 48mm hole. In the past I've just drilled 2" with Forstner bit.

But, they only extend 27mm so to avoid the jaw mount flanges fouling a wave or bit of bark in a natural edge top a bench chisel has to come out to chip away some bark and sapwood in order to get the jaws well in and the faces against the hole bottom.

This is where the ConChuck works better. No flanges so just drill, insert and tighten. And there's a decent length to hold.

So have we heard again from the original poster or have we scared him off? ;-}

There's two kinds of mounting we've been talking about, bowl blank top and bowl bottom once the outside's been shaped. Bit of difference there.

Originally Posted by Skew ChiDAMN!!

Personally, I'm of the school of thought that expansion mode is usually a "second best" form of mounting. Different horses for different courses, I guess.

I'm of that mind too .
For me , expansion modes , and woodworm screws , with the tailstock brought into play there too , are for holding 'natural' blanks untill a tenon has been cut for jaws used in compression mode .
And even then if the chunk is way out of balance I used the tailstock there too .
Outboard , I use faceplates with long screws in the first stage .

Originally Posted by rsser

Andy, not sure what you mean by spigot jaws. Have assumed just the Nova equivalent of the Shark Jaws.

Sorry, I had a bit of a brain fart there. I was actually thinking of pin jaws, not spigot.

Ah, k, that explains it. So many widgets, so many names, so little time ;-}

Re expanding dovetail jaws into a bowl bottom recess, it's worked fine for pro turners like Terry Martin and Richard Raffan. Even recesses of just a few mm deep on wide pieces.

It's been my std method and since getting quality dovetail jaws & chuck I've never had a failure.

It does impose design and aesthetic limitations though which were canvassed in the earlier thread on this.

Where those don't apply there's an efficiency bonus .... you can shape and finish a bowl or platter outside and don't have to remount to clean up a foot.

Only if you accept the design limitation of a spigot foot closely matched to near closed jaws in compression mode can you get the same bonus with a clamp mount.

Originally Posted by rsser

So have we heard again from the original poster or have we scared him off? ;-}

.

Yeah...he's gone very quiet, which is sad because he was/is a newbie looking for info and not here to start a hissing comp. Interesting to note a lot of posters preface their arguments with 'I always'....well I always stand up to pee, but then I only represent about 50% of the population....however, on to the real question....I have read and re-read the posts and find everyone jumping in to say 'i always use this or that, and it's the only way to go'...OK fine, whatever works for you ,go with it, but don't shove it down our throats as THE WAY.
I always (sic) used to use a faceplate and then went on to use a pin chuck but had too many failures....but I think the point everyone is missing (and feel free to shoot) is that the guy was trying to find out how to mount a blank prior to turning the outside and a foot....be it an internal dovetail recess or an external spigot, and in this case I have to go with Ern and the ConChuck although until now I had never heard of it.
The poor guy is probably running off into the woods now yelling 'all woodturners are wankers'.

Cheers
John M

Originally Posted by ravna

Yeah...he's gone very quiet, which is sad because he was/is a newbie looking for info and not here to start a hissing comp. Interesting to note a lot of posters preface their arguments with 'I always'....well I always stand up to pee, but then I only represent about 50% of the population....however, on to the real question....I have read and re-read the posts and find everyone jumping in to say 'i always use this or that, and it's the only way to go'...OK fine, whatever works for you ,go with it, but don't shove it down our throats as THE WAY.
I always (sic) used to use a faceplate and then went on to use a pin chuck but had too many failures....but I think the point everyone is missing (and feel free to shoot) is that the guy was trying to find out how to mount a blank prior to turning the outside and a foot....be it an internal dovetail recess or an external spigot, and in this case I have to go with Ern and the ConChuck although until now I had never heard of it.
The poor guy is probably running off into the woods now yelling 'all woodturners are wankers'.

Cheers
John M

???

Yes John M, quite right.

As they say opinions are like ar*seholes; everyone has one. Everyone's works for them but mostly we don't provide enough contextual info that would help to explain why.

And there are a great many variables in the work of producing a piece of woodturning.

Oddly, expert turners are often the hardest to learn from, cos they're in the realm of 'unconscious competence' and while they can describe what they do, they may struggle to explain why they do it that way.

But to be fair to the forum, the original post was not that clear about the context either. There's a skill, and some courtesy, in explaining with this medium of communication what it is you are wanting to know or what kind of help you need with what you're struggling with.

Originally Posted by ravna

Yeah...he's gone very quiet, which is sad because he was/is a newbie looking for info and not here to start a hissing comp. Interesting to note a lot of posters preface their arguments with 'I always'....well I always stand up to pee, but then I only represent about 50% of the population....however, on to the real question....I have read and re-read the posts and find everyone jumping in to say 'i always use this or that, and it's the only way to go'...OK fine, whatever works for you ,go with it, but don't shove it down our throats as THE WAY.
I always (sic) used to use a faceplate and then went on to use a pin chuck but had too many failures....but I think the point everyone is missing (and feel free to shoot) is that the guy was trying to find out how to mount a blank prior to turning the outside and a foot....be it an internal dovetail recess or an external spigot, and in this case I have to go with Ern and the ConChuck although until now I had never heard of it.
The poor guy is probably running off into the woods now yelling 'all woodturners are wankers'.

Cheers
John M

Actually DIY Dan has been here longer than you. He only gets on occasionally.

Yeah, I realise that ...it was not meant to denigrate....I made the fatal mistake of

assuming something...I.E. he was maybe new to turning.

As Ern said, 'there's a lot of skill and courtesy required' when offering replies or opinions to

questions, no matter how they are couched.

Cheers

John M

Well if he's been reading these posts and decided not to jump in and clarify his problem, I take that amiss.

Good forums are a kind of conversation, and that implies reciprocity, however minor that might be.

When someone posts a query, gets some replies but doesn't come back with at least an acknowledgement, they get added to my ignore list. Example: Hen on turning plates.

So yeah, I'm getting old and grumpy in my reactions to minor discourtesies.

Of course the web is for the most part anonymous and distant and I can see why folk would go fishing and not bother with the obligations entailed in even minor social interactions.