Homemade Colejaws

I have no direct experience with Cole jaws, either homemade or from the factory. I have used a shop-made Longworth chuck, which holds the workpiece in a similar manner. My advice if you go with either of these types of chucks is to plan to also use the tailstock as much as possible to keep the bowl in the chuck. In my opinion, these types of chucks are useful for the last finishing cuts and sanding on a bowl bottom, but they shouldn't be trusted for anything but the lightest cuts and slower speeds. Also, if the bowl rim is warped at all, it will prevent the jaws from getting as good of hold as it should.

That said, a set of homemade Cole jaws will cost next to nothing if you have some good scrap ply laying around, so I'd say give it a try. Just be aware they're not the perfect holding solution (nothing really is), and turn with a bit of caution when using them.
 
I built one which is pretty easy and can be done with scraps laying around the shop. They are easy to do but that being said I did not like it and gave it away. I didn't like it because as Vaughn said I also had a few pieces fly around the shop. So tailstock support is warranted. I went to a donut chuck but now use a vaccum chuck. Some will swear by them.
 
A vacuum chuck is way up on my "wish list" after I get a bigger lathe.
I've seen the donut chucks and they definitely hold considerably better than the colejaw which looks to hold a lot better than a longworth.
My purpose is exactly as you mentioned, just to clean up the bottom of a bowl or vessel, low speed (500 is the lowest my lathe will go:() and to finish sand the same area.
 
In my opinion there are two critical things to making your own Cole jaws.

1. The attachment points to the chuck jaw carriers need to be created in a manner that provides sufficient strength for the centrifugal and cutting loads that will be applied. I.E. if using Fibre Board or Ply a metal insert or plate is desirable to strengthen the fixing holes.

2. For the jaws to work well and not give you frustration with run out, the button fixing holes/threads must be positioned with care both on radius and location around the PCD.

Not easy to achieve if you do not have access to some form of dividing head or indexing system.
 
I have made my own Cole Jaws and mounted them on a SN2 chuck with the big 130mm jaws. As for marking the button holes etc, I simply mounted the plwood jaws on the lathe and cut the PCDs with a parting tool and drilled off the lathe. All in all a couple hours work, bit of a no brainer when you get into it.
I can PM you the run down one how it was done from scratch if you wish.
 
I own a set of aluminum cole Jumbo jaws from PSI, also a plastic (it's a much heavier plastic and plastic probably isn't the correct material name) extension set for the jumbo jaws... I use the pretty extensively. The Jumbo jaws will take a bowl up to about 8 1/4"... the extension will allow for about a 13 or so....but has to be turned outboard... I use them pretty regularly, but also very cautiously.

I also have a home made long worth... I use it some, but not without the tail stock.. especially since I got konked by the bowl that flew out of it....
 
I made a set once and used them a couple of times. The plywood didn't hold up well and I ended up scraping the idea and I bought a set. The wood ones though a neat idea just don't have the holding power of the machined ones or the balance.
 
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