Thread: Chuck sizing

Ayao chuck: Ayao 100mm Chuck.

I am in the camp of grabbing a big spigot as opposed to expanding in a recess. I like a 4 inch or bigger spigot, sometimes worked into a foot, sometimes removed when finishing the bottom.

I do 90% or more bowls, my big lathe has 20inch swing. After looking for years for a used chuck I bought a new Oneway Stronghold: https://oneway.ca/Stronghold-Chuck-Body-Only-Package and a set of #5 jaws which grab up to 6 3/8 inches. This holds everything that will fit on the 20 inch inboard.

I have a 350mm swing lathe which came with an original two bar Oneway chuck and I got a used Penn State Industries chuck set for $50, which looks very much like this from Nova: https://www.rockler.com/nova-30th-an...yAAEgISyvD_BwE

This has worked fine with everything I can get on the 350mm inboard.

When I was researching big chucks the majority opinion was the best chuck was Vicmarc, then Oneway, then everything else. My own opinion is that unless one is turning 8 hours a day, 5 days a week with a big 2 HP lathe, Nova or equivalent will do fine.

Several years after I bought the new Oneway Stronghold, two more used ones with #5 jaws showed up at my local hardware for $100. I bought one for the 350mm swing lathe. A couple years after that a box full of 7 sets of jaws for the Stronghold showed up for $75, I bought that.

I recall there was a discussion of Nova chucks here some time ago, do a search.

Not so much size of chuck but more like jaw size and capacity but have a look at page two of this from Robert Sorby it gives a guide of work size to jaw size.

"s there a rule of thumb as to size of chuck compared to size of piece being turned?"

the size of the tenon is 30% of the size of the piece turned
And the best size for the tenon is the size of the perfect round of your jaws (Ø 50 mm jaws => Ø 48 mm tenon => Ø 150 mm plate)

Before larger jaw sizes became available I have turned up to 600mm platters on 100mm jaws.

In my experience it is not the chuck or jaws that fail, but the wood. I have never had a 100mm tenon fail, but prefer 130mm jaws when coring larger diameter blanks. Coring puts considerable torque on the tenon.

If you turn off the tenon/foot to finish the piece then any size tenon that is sufficient in size to hold the blank safely will do.

The video by Richard Raffan on Chucks and Jaws is good if your preferred method is to leave some tenon on the finished piece.

If you retain the foot and hold the piece in a recess to complete the inside, like I do, then you need a swag of jaws and chucks to give you the desirable proportions of the foot to outside diameter.

I've only ever used NZ or Australian made chucks, so can't comment on any others from experience. But of those that I have used (Nova and Vicmarc; about a half dozen of each) I can't say that one is any better than the other.