# hand made 4 jaw chuck for lathe



## scottw (Jan 27, 2011)

Heres the 4 jaw chuck that i finshed making today. Alredy tryed it out to see if it was going to turn true and it does. If anyone would like the planes for it feel free to ask me and i can send them to you.


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## john lucas (Sep 18, 2007)

That's what machinist's call a spider chuck. They have some cool options for out of round pieces. The downside is, they don't hold very well.


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## scottw (Jan 27, 2011)

Thats what i was worried about so that is why i addes the extra nut on it to lock it in place so it would not come loss on me and i am even thinking of adding another nut on the inside for a little addes securty


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## H. A. S. (Sep 23, 2010)

Yep, spiders have saved my ass more than once.








Second thought, that statement makes for an interesting visual.:yes:


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## Manuka Jock (Jun 27, 2011)

Puts me in mind of the Australian song about the redback spider on the toilet seat  :furious: 



:laughing:


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## H. A. S. (Sep 23, 2010)

Man, that sounds like personal experience, no?


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## john lucas (Sep 18, 2007)

It's really not the screws coming loose it the small contact area between the screws and wood. The screws will compress the wood to a certain point and then grip. As you turn the wood it creates vibrations that will flex the wood. This in turn compresses the wood further. If this happens enough the wood simply comes out. 
The same thing happens with the 4 jaw woodworking chucks but they have a much larger gripping surface. fortunately on those they are self centering so you can stop periodically and retighten them to prevent the wood from coming loose.


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## scottw (Jan 27, 2011)

Ok. Then would it be better if i added a small steal plate at the end of each screw for a better griping area


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## sawdustfactory (Jan 30, 2011)

I'd also make the base a bigger diameter so those screws are completely within the outer dimension of the plywood, otherwise you might get quite the rude awakening if you get a little too close to one of those at speed


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## scottw (Jan 27, 2011)

yes they are inside the plywood base it just dont look like it in the pitcher


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## john lucas (Sep 18, 2007)

I would think something like a T nut glued onto the end with the big end out might hold the wood better. This should work quite well for short pieces. If your trying to turn a piece like you have in the photo I think you better use a tailstock to support it as long as possible. 
When I first started turning I puchased on of the 4 jaw independant metal working chucks. It was supposedly called a wood working chuck. The jaws are narrow and about 1 1/4 long. They would not hold a 4" long piece of wood worth a darn. The problem was just like I mentioned above. you could see the crush marks in the wood where the vibrations must worked the wood loose. 
A good self centering chuck that is designed to hold wood works so much better. I would look at the Grizzly chuck that sells for $104. You can get longer jaws to fit it because it takes the same jaws as the Vicmarc chucks.
http://www.grizzly.com/products/4-Jaw-Wood-Chuck-1-1-4-x-8-TPI/H6267
You may have to order a different model # to get the thread size you need for your lathe. This is a very versatile chuck and you'll use it for many years which makes it easier to justify the price.


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