>I'm not happy with the way I'm doing bowl bottoms. I tried Bill G's donut chuck and never seem to be able to the the bowl centered. So I'm thinking of getting either a set of cole jaws or a vacuum chuck (I have a vaccuum compressor). Which system do you think would work better? (Jet 1236)
I have a Supernova Chuck, but I noticed Oneway has a jumbo jaws compress to 11", an inch more than Nova's jaws. Will Oneway's jaws fit on a Supernova?
Craft Supplies has a vacuum chuck system called Artisan for about $20 more than the cole jaws. My concern is - Will I still have the same centering problem using a vacuum chuck as I have using a donut chuck?
Also, has anybody have any experience with Artisan's vacuum system?
I started with the Cole Jaws, and went to vacuum after dropping a couple of bowls off the Cole Jaws. I would say that there is no comparison to the holdig power of vacuum over the Cole jaws. To get the bowl centered on the vacuum chuck I have an adapter that threads onto my Super Nova that I can put on the tailstock that alllows me to center the piece before I apply the vacuum. I don't know about the artisan chuck, I bit the bullet and got the Oneway small and medium chucks. They work great!
I have started using a vacuum chucking system and think this system is more versatile than the Cole jaws. I think it offers the ability to hold irregular shaped objects a bit easier than the jaws. The down side is that you must be able to pull a vacuum on the piece of wood you have turned. If the wood is too pourous it might not work.
I have made chucks using PVC pipe sections similar to what Craft Supplies sells as their Artisian line but my most used chucks are made from laminated MDF that I turn to any shape that I need and use closed cell foam on the mating surface to get a good vacuum seal. I fasten the MDF chuck to the headstock spindle by drilling a hole in the mdf and threading it to match my spindle (this step was actually done for me by Jonny Tolly). See the link below for more information on making the MDF chucks.
>I have a Supernova and a set of Oneway cole jaws that I bought on eBay. They fit just fine.
I think that there is a "supersize" Cole jaw by oneway (16"), but I don't know if your Jet head swivels like my Nova. More expensive, but you'll only buy them once.
>Ron - I use Cole jaws on a Nova chuck and also on a Vicmarc chuck (Vicmarc calls them jumbo jaws or something), so I'm not arguing against them. But I also built a donut chuck and really like it, it seems more secure than the cole jaws. Try this for centering if you haven't already: mount the bowl, centered by eye (I turned a set of witness marks in the main disc of my donut chuck, this helps in eyeball-centering). Tighten the bolts just enough to hold the bowl in place. It won't be perfectly centered, of course. Then bring the END of the toolrest up against the outer edge of the bottom of the bowl, so that it just touches it at the nine o'clock position. Rotate the bowl 180 degrees and look at the distance between the edge of the bowl bottom and the toolrest. You want to move the bowl laterally half that distance, with a gentle tap on the rim of the holding plate (the one with the cutout in it) from your hand or a small hammer. Then rotate the bowl half a turn and see where you are - you'll usually have to repeat this a few times. When you finally get it centered, tighten the bolts down.
I hope this makes sense, it's harder to describe than it is to do it. Maybe you've already tried all this. If so, my apologies. But I find this procedure does the trick to get the bowl centered.
If you do get a set of cole jaws, Vicmarc and Oneway's buttons will fit them, i.e., buttons from all three manufacturers have the same thread. Depending on the shape of the bowl, one brand of buttons sometimes works better than another.
>I have the Supernova and Cole jaws, and just recently started using vacuum chucks as well. The Cole jaws are easiest to centre (I've used a donut chuck too) but they have limitations. They won't work on natural edge bowls and there are some diameters they can't handle - the buttons are too close together at one position, too far apart at the next. Best bet with the Cole jaws is to use auxiliary wooden jaws with them, as described in the latest American Woodturner.
You do have a centering problem with a vacuum chuck. One possible solution is the tailstock adapter (still waiting for mine to arrive!) which allows you to mount your Supernova in the tailstock, turn on the vacuum and then remove the Supernova. Another is to mark the centre of the mounting tenon/recess when you rough-turn the outside, then use a cone centre in the tailstock and the mark to centre the piece on the vacuum chuck. Just don't do what I did and saw the tenon off "to save time".
>No. The previous owner may have done it for me, but I had no problems- plug and play.
But you question intrigued me, so I just checked, and there is a small ~1/16" hole on each jaw, adjacent to the two mounting holes. Might be what you refer to? No pins, though.
>Centering a piece for vacuum chucking is quite easy as long as you plan ahead. When I make a bowl, I start between centers (bottom of bowl is at the tailstock end). The mark left by the live center in the tailstock is my future centering reference point. I make it a point NOT to remove it...even if I am turning a tenon at that end. When it comes time to vacuum chuck it, I simply bring the tailstock up to that original reference point and wind it onto the vacuun chuck. Centered perfectly every time.
