off-centre box lids

[Tiger]

At the show today, Guilio Marcolongo was turning some nice box lids and inserting some thin stone inlays off centre. He used an eccentric chuck from Vermec which costs around $235. I would like to try this but would only do it sparingly hence I couldn't justify the cost of the chuck. Any ideas on how to do this, ideally but not essential with some sort of repeatability?

[powderpost]

Tiger, I haven't done this myself, but I have seen the jaws of a scroll chuck taken off and replaced with two opposing jaws replaced one screw hole out of position. Be aware those two jaws will only be held by one screw, but then the 25mm jaws have only one screw. Not sure if this makes sense.
Jim

[tch']

I too saw Guilio turning the off centre box lids. But I must admit that I did give in to tool lust and bought an eccentric chuck.

My thoughts were that you could possibly use a larger (than the piece you are turning) sacrificial faceplate to glue the lid off centre for your eccentric turning. Then turn the top of the box, part it off and then mount very carefully in the chuck to finish the underside of the lid.

Hope this makes sense, I can elaborate a little if you need?

Cheers, Tim

[Sturdee]

I too saw Guilio turning the off centre box lids. But I must admit that I did give in to tool lust and bought an eccentric chuck.


Cheers, Tim

So you are also one of the 15 people that bought one at the show.:2tsup:


Peter.

[joe greiner]

Stout shims between the jaws and the tenon can accomplish the eccentricity you seek. No shim at jaw 1 (for example), thickest at jaw 3, and midrange at jaws 2 & 4. All jaws grip the work, although not very well. For better purchase, custom-made shims of precise shape are advised.

For expansion mode, I made some DIY cast lead auxiliary jaws, to turn the outside of a piece eccentric. I attached a single board to my scroll chuck, using all 8 screws. Then turned a tenon of appropriate height, to relieve the rest of the board. Off the lathe, I cut the board into 4 parts (Same as real jaws are made, BTW). Back on the chuck, I attached 4 screws with standoffs cut from brake line and washers at the board and the screw head. The first picture shows the setup for molding, still attached to the chuck. The hose clamp squeezes a thin strip of aluminum, and the small pieces of wood provide barrier walls; also help to position the outside form. The finishing nails identify the jaw numbers.

In the last picture, the second set of 4 screws remain to attach the auxiliary jaws to the chuck, using the original locations. To avoid marring the work, I placed masking tape on the outside of the jaws.

The eccentricity here is along the joint between jaws, instead of in line with a jaw; I don't remember exactly why I did it this way - probably to make the off-axis jaws less weird.

Cheers,
Joe

[mkypenturner]

I have been lucky to had a 3 day workshop with him and the trick we did was to turn a bit of 4 x 4 round between centres ,then on one end mark a x drill hole in center and another 20mm off center thats how he showed us ,a.d we all made some pendants using that method it would also work for most things as well just rember to drop speed to slowest speed

[hughie]

[ I haven't done this myself, but I have seen the jaws of a scroll chuck taken off and replaced with two opposing jaws replaced one screw hole out of position. Be aware those two jaws will only be held by one screw, but then the 25mm jaws have only one screw. Not sure if this makes sense.



An easier method might be to place a packing piece on two of the jaws to 'push' the work piece over, probably best on small items tho' :U

Nice one Joe, you were posting as I wrote mine.

[Tiger]

I too saw Guilio turning the off centre box lids. But I must admit that I did give in to tool lust and bought an eccentric chuck.

My thoughts were that you could possibly use a larger (than the piece you are turning) sacrificial faceplate to glue the lid off centre for your eccentric turning. Then turn the top of the box, part it off and then mount very carefully in the chuck to finish the underside of the lid.

Hope this makes sense, I can elaborate a little if you need?

Cheers, Tim

By the time I got to Vermec, they had sold out, it is a nice piece of equipment though.

[tch']

By the time I got to Vermec, they had sold out, it is a nice piece of equipment though.

Yeah, it seems very versitile and well made. I haven't used mine yet, but I will in the (very) near future no doubt.

[wheelinround]

Tiger if you can get hold of a 4 jaw independant chuck like this one you can also do it.

Steve Tool Exchange - Stanley Planes (http://www.toolexchange.com.au/Stanley-Planes.html) has them $65 it will need an adaptor to suit your machine.

I have the chuck not made the adaptor yet.

http://toolexchange.com.au/images/chuck9123.jpg
http://toolexchange.com.au/images/chuck9124.jpg

[wheelinround]

Stout shims between the jaws and the tenon can accomplish the eccentricity you seek. No shim at jaw 1 (for example), thickest at jaw 3, and midrange at jaws 2 & 4. All jaws grip the work, although not very well. For better purchase, custom-made shims of precise shape are advised.

For expansion mode, I made some DIY cast lead auxiliary jaws, to turn the outside of a piece eccentric. I attached a single board to my scroll chuck, using all 8 screws. Then turned a tenon of appropriate height, to relieve the rest of the board. Off the lathe, I cut the board into 4 parts (Same as real jaws are made, BTW). Back on the chuck, I attached 4 screws with standoffs cut from brake line and washers at the board and the screw head. The first picture shows the setup for molding, still attached to the chuck. The hose clamp squeezes a thin strip of aluminum, and the small pieces of wood provide barrier walls; also help to position the outside form. The finishing nails identify the jaw numbers.

In the last picture, the second set of 4 screws remain to attach the auxiliary jaws to the chuck, using the original locations. To avoid marring the work, I placed masking tape on the outside of the jaws.

The eccentricity here is along the joint between jaws, instead of in line with a jaw; I don't remember exactly why I did it this way - probably to make the off-axis jaws less weird.

Cheers,
Joe


Joe nice work on the chuck:2tsup:

[Tony Morton]

Most chuck brands now have soft jaws these can be mounted on a piece of timber and off set the amount you need then turn the diameter you need as you would turn acrillic.I have several sets one I use for the lattice top boxes the others for essential oil bottles and one for massagers and shaving soap holders .

Cheers Tony

[hughie]

[. He used an eccentric chuck from Vermec which costs around $235. I would like to try this but would only do it sparingly hence I couldn't justify the cost of the chuck. Any ideas on how to do this, ideally but not essential with some sort of repeatability


Yeah, I agree, it something that would spend more time on the shelf with me. If the urge was sufficently strong I would probably build my own.

[Tiger]

Thanks guys for your collective thoughts on this. Some good ideas here.
Joe, nice practical solution as usual with your stuff. Tony, don't know a lot about your soft jaws but I'll do a bit of research. Wheelin, I have a 4 jaw that I use on my metal lathe but the adaptor would be a bit of work for me and Hughie I would probably attempt making my own out of aluminium if I used it enough, do you have a plan for one?

[joe greiner]

Upon reflection, Jumbo jaws (aka Cole jaws), with placement of grippers at incremental radius, could accommodate an off-center piece if the grippers were properly disposed. Most likely, only four grippers would be at ideal locations, but shims might be used at the other four for better purchase.

Cheers,
Joe