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Old 12-08-2009, 12:59 PM   #11
tornitore45
 
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Default Re: Truing square stock in a 4 jaw independent chuck?

For "close enough" work I would use Mark approach.
For a part that is already machined and need accurate centering I use a modified version of the flapper.
The pump center technique is no more accurate than your ability to scribe and punch a center based on the diagonals; with rounded corners this is even more sloppy.

I place a piece of old saw blade (tooth ground off) in the tool post laying on top of the corner at its highest spot
place the indicator to swing just a little when the corner lifts the reed.
Smooth no damage to the indicator, works also for threaded or rough parts like HRS when you have little oversize.

Mauro



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Old 12-08-2009, 01:41 PM   #12
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Default Re: Truing square stock in a 4 jaw independent chuck?

mauro could u please post a pic of that setup

i do like mark does my self its pretty darn close



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Old 12-08-2009, 03:24 PM   #13
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Default Re: Truing square stock in a 4 jaw independent chuck?

you people are making it way do hard just use your indicator on the carriage and swing the low spot it is not hard and after you have done it once or twice it is fast and you will be right on center with out a lot of do -dads to make or use can not get any easier

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Old 12-08-2009, 03:40 PM   #14
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Default Re: Truing square stock in a 4 jaw independent chuck?

jonesie,

There are no categorically right or wrong ways to do anything in the home shop. Hearing other people's approach to a given problem often sparks new ideas and creativity.

Let's let the ideas flow without criticism. If it doesn't suit you, ignore it - but do so silently.

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Old 12-08-2009, 04:43 PM   #15
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Default Re: Truing square stock in a 4 jaw independent chuck?

ok sounds good just thought the shortest distance between two points was a straight line, just trying to help, but with 30+yrs as a moldmaker i will keep my thoughts to my self

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Old 12-08-2009, 09:47 PM   #16
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Default Re: Truing square stock in a 4 jaw independent chuck?

Quote:
Originally Posted by jonesie
ok sounds good just thought the shortest distance between two points was a straight line, just trying to help, but with 30+yrs as a moldmaker i will keep my thoughts to my self
I totally agree with you Jonesie that is the best way to indicate square stock in dead on. And I agree once you have done it you will see how easy it really is. I also use this concept of swinging in an edge on the jig bore when you are trying to hold very tight tolerances. It will put you spot on every time.

I have had over 35 years in a tooling shop and have done a lot of progressive dies form dies and blank and pierce dies. And if you need to be spot on my money is on this concept.
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Old 12-08-2009, 11:18 PM   #17
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Default Re: Truing square stock in a 4 jaw independent chuck?

Quote:
Originally Posted by jonesie
you people are making it way do hard just use your indicator on the carriage and swing the low spot it is not hard and after you have done it once or twice it is fast and you will be right on center with out a lot of do -dads to make or use can not get any easier
Jonesie..

Please explain this procedure in English. You have my attention.
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Old 12-09-2009, 03:02 AM   #18
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Default Re: Truing square stock in a 4 jaw independent chuck?

tw set your chuck jaws with a scale somewhere close to the size of your block then put in the block and lightly tighten them up.then set up your indicator on a surface gage and set up on the carriage them more the carriage up to the piece and on to the part . then get a touch with the ind. and then move the chuck back and forth to find the low spot then move the carriage away and rotate the chuck 180 degrees and move ind. back on to the piece being careful that you do not hit the ind. if you are to far off then swing the chuck again and see where the low spot is then move the piece with the jaws until they read the same. then do the same for the other 2 sides with a little practice you will be suprised how easy and fast you can do it . scale the jaws as close as you can and you will be able to ind. the piece in fairly easy and fast and you will be right on center not just close. when you first start to ind. the part you might want to set it close on one side and then rotate the chuck 180 and see which is the high side . it is also easier to do the first few times by using an indicator with alot of travel. try it and you will see how to do it , just remember that you have to move the carriage back so the indicator is off the piece before rotating 180 degrees or you will ruin your indicator.good luck hope it makes sense

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Old 12-09-2009, 03:18 AM   #19
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Default Re: Truing square stock in a 4 jaw independent chuck?

Jonesie...

Thank you. I have a 2" travel DI. It looks like the setup for the DI needs to be pretty rigid to keep the indicator from moving while you are turning the chuck...

Very simple. A DI mount for my tool post would be a snap.

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Old 12-09-2009, 12:54 PM   #20
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Default Re: Truing square stock in a 4 jaw independent chuck?

tw just remember you need to move the carriage back when you rotate the chuck180 deg. to do the other side.also after you have done it a few times you will find that you can eye ball it close and you will not need to but much pressure on the indicator needle. i just use an indicator with .060 travler an interrapid.i mount it on my surface gage and just set it on the carriage. remember also when setting up a finished piece to wk on after you get it centered you need to run the indicator on the front face to make sure it is also running true.



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