Advice on large chuck jaws please

[Lightweeder]

I need to invest in some large chuck jaws - the type with rubber feet - for holding bowls while working on the base. I assume most will fit into my scroll chuck. Is there one that you guys can recommend please ?

 

[duncanh]

It depends on the make of chuck you have - Nova jaws will only fit the Nova chuck (and Versa chuck if you have the Nova slides), Axminster jaws will probably only fit the Axminster chuck etc.

Which chuck to you have?

I actually rarely use my button/cole jaws as I tend to make work that doesn't fit in them.
If you want to save the expense you could reverse chuck and use the tail stock for support. This allows you to turn away most of the chucking point and then hand carve away the final tail stock support area. This is what I tend to do.

Duncan

 

[jaymar]

I have Axminster chucks and use their accessory mounting jaws. These allow me to screw mdf onto them which I then turm a dovetail into and then hold the bowl. A bigger bowl just needs bigger pieces of mdf. I cut a circle of the mdf and then quarter it

 

[SVB]

Try a google search for 'longworth chuck'.

May give an economic alternative as the cole / button jaws are quite expensive for the job they do.

Also, another alternative is to make up a vac - chuck system. If you use ebay and a bit of home metal work / plumbing you may come out cost neutral and have a far more versatile set-up.

Just a thought :wink:

Simon

 

[wizer]

The longworth chuck is yet another accessory on my list. Along with steady rest, disc sanding platform, home made jaws for holding box lids, etc, etc, etc

 

[richburrow]

I use these for the sorby patriot.
They are great, a little fiddley to set up but nothing major to worry about.
You have to go easy if your bowl is thin and take small cuts.

 

[TobyB]

I have the big axminster set on a versachuck and it works OK - have had to do some shimming with bits of paper to get the 4 faces flat - don't know if thats the chuck or the jaws though. Works OK if I'm careful

 

[Lightweeder]

If you want to save the expense you could reverse chuck and use the tail stock for support. This allows you to turn away most of the chucking point and then hand carve away the final tail stock support area. This is what I tend to do.

Duncan

Sorry if I'm being dense Duncan, but I don't understand. I do want to reverse chuck, in order to do exactly what you describe, but need something on the headstock end - can you give me a better idea what you mean I've got Charnwood scroll chuck.

Jaymar - I appreciate your idea - I've made a sort of ridged faceplate out of an old breadboard. I load it onto a screwchuck and offer the piece up, supported by the tailstock, but I can never get it to run true, even with that sticky plastic stuff under it.

Rickburrows - I like yours, but it looks expensive.

Thanks all. Appreciate your time.

 

[CHJ]

LW, Cole Jaws are not cheap but do add a great deal of ease & versatility to holding stuff, as mentioned you do need to get ones compatible with your Chuck Jaw carriers..
After some months getting frustrated with the limitations or time involved with other methods, not to mention the lack of large pieces of wood for jamb or support chucks I bit the bullet.

They do have limitations and you might know the next item you turn is just not quite the right diameter to match a preferred button option (jaw travel/diameter overlap) but this can be overcome with home made button sets.

The Longworth Chuck option has its uses but Usually needs tailstock support for safety as it is very difficult to get a strong grip on the outer diameter due to the geometry of the device, but it is a quick way of getting an item centralised (within limits, not perfect)

 

[duncanh]

There are several option in this pdf which I just found

I use a variant of the jam chuck which always requires tailstock support.
Depending on the item which I'm turning I make a wooden dome, a disc with a curved edge or a flat surface out of some scrap wood. This either fits inside the item that you want to reverse chuck or, if the item has a level rim, fits up against the item. Before putting the dome/disc in contact with the item put some router mat or other non-stick surface over it so that it doesn't slip.

To make it easier to centre the item when reverse chucking you can put a locating point (a small hollow with the tool) in the centre when you turn the chucking point.

After a while you'll end up with several sizes of wood to reverse chucking.

I was sure that there was a good explanation on this site somewhere but a quick search didn't reveal it

Ok. Having written all that out - if you watch these 2 videos from Bob you should get a clearer picture...
video1 - from about 6.50 shows the making of the jam chuck.
video2 - shows using it

Duncan

 

[Lightweeder]

Thanks Duncan. Bob's video's (as always) are brilliant - but he just manages to get his centred first time :? :? Mine are never out much, but enough. The Longworth in your pdf looks like something I would like to have a go at, and husband thinks we could make something similar. Alternatively, I could make an MDF jig each time I need one - ie not trying to aim for a universal solution. I'm sure I can find something among these Duncan - much appreciated.

LW

 

[wizer]

LW: If you make the spigot ever so slightly concave and make a visual mark at the dead centre, then you shouldn't have too many problem with alignment. I must say, I've only reverse turned once but it wasn't too much of a problem. I think the only slight problem I had was that the bowl had gone out of round a touch.

 

[loz]

but he just manages to get his centred first time :? :? Mine are never out much, but enough.

hiya !

Are you marking a centre dimple when you create your chuck point,?

this is then used when you reverse back to centre up with ( put the bowl base and dimple against the tail, then slide up the tail towards your jam )

It will be damn close enough if you do this.

 

[Lightweeder]

but he just manages to get his centred first time :? :? Mine are never out much, but enough.

hiya !

Are you marking a centre dimple when you create your chuck point,?

this is then used when you reverse back to centre up with ( put the bowl base and dimple against the tail, then slide up the tail towards your jam )

It will be damn close enough if you do this.

Yes Loz, I'm doing that OK. It's the headstock bit that's difficult for me.

Having said that, I've done it twice this pm 8) 8) 8) I used a jam chuck to revive an old box, but before I 'jammed' it, I shaped it properly and formed an exact tenon on the jam chuck to take the rim of the box. I also took a bit of time with my spinning breadboard jig :wink: :wink: and managed to reshape a bowl I've never liked. Still don't like it much. It's one of my first pieces, and I oiled the outside with linseed but I never did the inside, so now the inside's pink and the outside's a sort of puke colour :roll: Gorgeous, eh :?:

 

[Paul.J]

LW.
I made me own cole jaws using 1/2" birch ply,the good quality stuff.
I used T-nuts to take the bolts which hold wine bottle cork,or plastic.
It all works quite well
I also use the jam chuck method as mentioned now.Just seems quicker. :?

 

[TobyB]

My problem with these is getting it "centred" - until I shimmed the jaws with paper and decided the versachuck was single-use only I might not get the bowl flat so the base was in a single plane because the jaws weren't perfectly aligned on the supernova. Even now the rim might have warped slightly by the time its reversed so the base isn't cutting symetrically. And it might not be centred either, even if I use the tailstock centrepoint guide ... don't know if this is warped rims, different density/deforming of the rubber clamps or what ... but I find it difficult to get the perfectly-centred setup ... I usually accept the best I've managed after 3-4 tries of different positions/rotations. I tried a jam-chuck once, on a small bowl where it should have been "easy" and that was even worse. maybe it's practice? Doesn't make me want to rush out for a vacuum chuck system, even if I had the cash, since that looks even more difficult to centre ... or am I wrong?

 

[Lightweeder]

Toby - I've never got it right until this afternoon I think I was possibly rushing at it. But by taking it slowly, I got it right both times And if I can do it, you can do it :wink:

I guess the 'versachuck' might be single use only, but if it's large enough, you can have several rebates cut to fit different bowls.

 

[TobyB]

You've more confidence than me!

 

[loz]

Guys,

Just seen this and thought it might interest you.

Loz.

http://www.woodworkersinstitute.com/page.asp?p=633

 

[wizer]

Brilliant, thanks Loz