Mini-lathe 3 inch chuck

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rfresh747

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Question: I have a HF 7x12 mini-lathe with the standard 3 inch chuck. From what I've read, the chuck should hold a round piece of material up to 2.5 inches in diameter.

I have a 2 inch diameter delrin rod and when I open up the jaws to try and insert the rod, a jaw comes completely out of the chuck. In other words, I can't get this chuck to hold a piece of 2 inch diameter material. Am I doing something wrong?

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I thought about that but the jaw 'teeth' have an arc or curve in them. When I reversed one of the jaws, it wouldn't screw down? I figured it was because the curve was 'upside down'?
 
Rfresh, you need to reverse the jaws correctly. To do that, look at the teeth on the bottom of each jaw. One will have the teeth start near the tip of the jaw, one will be spaced further back and one will be in the middle of the two. The first is jaw 1, the one with middle spacing is #2 and the one with the teeth furthest back is #3. Insert jaw 1 in slot 1 if they are numbered. Bring the start of the thread on the scroll so it just begins to show in slot 1 and push jaw 1 in until it bottoms. Turn the scroll and it will engage jaw 1. Now do the same for the other two jaws and they should be synchronized.
 
+1 on what Mikey said. I have multiple small 3 jaw chucks that you swap the jaws around on to hold larger parts. It works fine.
 
rfresh747 said:
I thought about that but the jaw 'teeth' have an arc or curve in them. When I reversed one of the jaws, it wouldn't screw down? I figured it was because the curve was 'upside down'?
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Billh50 is right. HF mini lathes come with 2 sets of jaws. You need to use the other set. You can't reverse scroll chuck jaws with curved slots.

Tom
 
+1 on what Bill and Tom said. There should be another set of jaws.

"Billy G"
 
I finally figured out that my other set of jaws is what I needed to use...the first time I tried to use them, they would not screw in enough. I had to put some pressure on to turn them down past about the 60% point. This is the first time I used these jaws so they needed to be 'broken in' in the chuck. So I screwed them in and out several times and now they work better...still needs more pressure to turn them than the other set needs but they are working now.

FYI I am aware of how to properly sequence the #1 #2 #3 jaws into the chuck.

Thanks everyone.
 
When you change them again check for burrs on the scroll and jaws. This will cause them not to close properly.

"Billy G"
 
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