Centering a Round Work Piece in a Four Jaw Chuck

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Richard_W
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by Richard_W »

SteveHGraham wrote:What kind of soft metal? Foil? A bent sheet of something?

I use 1/8" thick copper about 1/2" wide. When it gets hard I anneal it by heating it to a dull red and dropping it in water.


Richard W.
Last edited by Richard_W on Thu Jul 12, 2012 11:10 pm, edited 3 times in total.
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seal killer
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by seal killer »

Richard--

Might a person have a 6"x1/2" piece of aluminum or bronze rod dedicated to the purpose? Does "tap it in" mean like "tap tap tap" as you would put a nail through sheet rock to hang a picture? Or harder? (TAP, TAP.)

Once again we simul-typed!

--Bill
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SteveHGraham
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by SteveHGraham »

I have a sheet of 1/16" aluminum lying around, but no copper.
Every hard-fried egg began life sunny-side up.
Richard_W
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by Richard_W »

seal killer wrote:Richard--

Might a person have a 6"x1/2" piece of aluminum or bronze rod dedicated to the purpose? Does "tap it in" mean like "tap tap tap" as you would put a nail through sheet rock to hang a picture? Or harder? (TAP, TAP.)

Once again we simul-typed!

--Bill
I find that round rods only work well between centers when the tail stock is out of position. Like 1.5" high, low or just off center. (Sometimes the machinery in the shop leaves much to be desired.) Round rods give you an effect like a universal joint. Lets things move more freely than you want. I would stick with flat material. If you check Ebay there are quite a few copper strips 1/8" thick for sale. You might even get by with 1/16 easily enough for your lathe.

You may find what you need in a hobby shop, since they carry some small sheets for various projects.

The tap tap is gentle and just enough to move the part. Start with a light tap and work up until it moves. Its more of a feel thing and is different for every size part and depending on how tight you have the chuck jaws.

Richard W.
Last edited by Richard_W on Wed Jan 18, 2012 8:58 pm, edited 2 times in total.
Richard_W
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by Richard_W »

SteveHGraham wrote:I have a sheet of 1/16" aluminum lying around, but no copper.
If its the soft aluminum it will work, but I prefer copper. It just seems to work better.


Richard W.
sk1nner
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by sk1nner »

seal killer wrote:sk1nner--

That is the same method as the one I found at littlemachineshop.com. However, the video you posted adds a second chuck key, which would be of great help!

Thanks!

--Bill
it seems to be the "best" way ive seen. lucky for me my 3/8 T-handle (for sockets) works great as a second chuck key.
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seal killer
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by seal killer »

sk1nner--

I've been using a 3/8" ratchet as a chuck key on the four jaw. It lets me to all four holes no matter where they are.

--Bill
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SteveHGraham
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by SteveHGraham »

I get the impression that Richard is like Harold. Maybe a tier or two above the video guys, who just want to get the parts made and stay within a thousandth or two.
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BadDog
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by BadDog »

I generally just use one key on the 4 jaw. But if you want more than one, just make what you need. For adjustment, doesn't even need to be hard, or have a large strong handle. You'll do final tightening one at a time anyway, so use the real key...
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seal killer
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by seal killer »

Richard and All--

I have to admit I don't understand the jaw alignment procedure. I wanted to come back and ask intelligent questions after researching 4-jaw chuck jaw alignment, but I could not find anything on the net . . . Google was not my friend.

Here is what I THINK the procedure is . . .

1) Chuck a soft metal (aluminum, brass, bronze, copper) rod and dial it in. (Is it chucked lightly or firmly?)

2) Place a flat piece of soft metal, preferably copper, over a jaw and tap it into place. (Does that process seat the jaw on its ways in the chuck?)

3) Repeat step 2 for all four jaws.

4) Remove the soft metal rod and chuck the intended work piece. (Do the jaws remain "tapped" in place?)

The questions assume I'm stating the steps correctly, which is problematic. Straighten me out.

Thanks!

--Bill
You are what you write.
Richard_W
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by Richard_W »

seal killer wrote:Richard and All--

I have to admit I don't understand the jaw alignment procedure. I wanted to come back and ask intelligent questions after researching 4-jaw chuck jaw alignment, but I could not find anything on the net . . . Google was not my friend.

Here is what I THINK the procedure is . . .

1) Chuck a soft metal (aluminum, brass, bronze, copper) rod and dial it in. (Is it chucked lightly or firmly?)

2) Place a flat piece of soft metal, preferably copper, over a jaw and tap it into place. (Does that process seat the jaw on its ways in the chuck?)

3) Repeat step 2 for all four jaws.

4) Remove the soft metal rod and chuck the intended work piece. (Do the jaws remain "tapped" in place?)

The questions assume I'm stating the steps correctly, which is problematic. Straighten me out.

Thanks!

--Bill
You got me confused here? Are you tapping the end of the part away from the chuck or are you tapping on the chuck jaws?

1. What you should be doing is chucking your part with soft metal pads between the part and chuck jaws on all 4 jaws. The soft metal remains between the chuck jaws and the part until the part is finished and removed from the chuck. (The soft pads should be short and not run the full length of the chuck jaws.)

2. Dial in the part next to the chuck with a dial indicator. The closer you dial in to the chuck jaws the better.

3. Move the indicator to the far end of the part away from the chuck. Dial the part in by tapping the part with a soft hammer or soft metal bar. (copper, brass or lead. Something with some weight that will have some inertia so you don't have to take large swings when hitting the part. Often people use a brass bar about 1" in diameter about 6 to 8 inches in length. Larger lathe with larger parts may require a larger bar or harder swing when hitting the part.) Often time the start of the tap can start as little as 3 to 4 inches from the part.

4. Once dialed in as in number 3, move the indicator back near the chuck jaws. You will find the part is running out a little. Dial it back in adjusting the chuck jaws. Once dialed in go to step 5.

5. Move the dial indicator back to the end of the part farthest from the chuck where you dialed in before in step 3. Redial the end of the part by tapping it until it runs true.

6. repeat steps 4 and 5 until the part runs true in both places. Near the chuck and the farthest end from the chuck. You should easily be able to dial in the part at both ends so that you can barely see the needle move on an indicator that reads in .001" increments. With practice over time this will become automatic and should take about 10 minutes.

If the part runs out in the center then the part is bent in the center and no amount of moving the ends will make the center run true.

Richard W.
Richard_W
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Re: Centering a Round Work Piece in a Four Jaw Chuck

Post by Richard_W »

SteveHGraham wrote:I get the impression that Richard is like Harold. Maybe a tier or two above the video guys, who just want to get the parts made and stay within a thousandth or two.
You have it wrong! I dial in just about everything so that the needle on an indicator that reads to .001 doesn't move. Its just the standard I shoot for and it not hard to do.
SteveHGraham wrote:I get the impression that Richard is like Harold. Maybe a tier or two above the video guys,
I don't consider myself to be above Harold. I have him on a higher plain.

As for the video's that were posted... I don't think you really want to know what I think of the ones I looked at. I will give the guys who made them credit for trying to show the correct way, but they left out more than they showed you. This thread is proof of that.

Richard W.
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