Finding center...

I Just use an electronic edge finder with a cylindrical (NOT ball)end. With the spindle locked so that the finder touches the arc of the circle (anywhere), the DRO is zeroed on this side of the circle. Then without moving the height or unlocking the spindle, move around the part to the other side of the circle. Bring the edgefinder in contact again, recheck and then use the DRO reading at this point to divide by 2. Then raise the spindle out of the way and run the DRO to this calculated number. BAM! Your are within .0002 (or whatever your machine will really do) of the center. I do this constantly when drilling centered holes in round stock or doing keyways. Fast simple and as accurate as your equipment.
 
barrydc1 said:
I Just use an electronic edge finder with a cylindrical (NOT ball)end. With the spindle locked so that the finder touches the arc of the circle (anywhere), the DRO is zeroed on this side of the circle. Then without moving the height or unlocking the spindle, move around the part to the other side of the circle. Bring the edgefinder in contact again, recheck and then use the DRO reading at this point to divide by 2. Then raise the spindle out of the way and run the DRO to this calculated number. BAM! Your are within .0002 (or whatever your machine will really do) of the center. I do this constantly when drilling centered holes in round stock or doing keyways. Fast simple and as accurate as your equipment.
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Wonder if you could do the same thing with a wobbler? At some point it would be kicked out of kilter by the radius. If it were repeatable it may be a good solution.

Chris
 
Shadowdog500 said:
Wonder if you could do the same thing with a wobbler? At some point it would be kicked out of kilter by the radius. If it were repeatable it may be a good solution.Chris
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I don't know about a wobbler, but thesame thing can be done with a edge finder. It just should be a cylindrical one.
 
I've never used a wobbler, but I do the same thing with a standard edge finder, but it takes longer by a few seconds ; ) but it is my first choice for plastics.
 
In order to find center, I feel it's necessary for your actions to be in-line with your values; and your values should be centered toward fairness to yourself and others... Oooommmm, Ooooommmm, Oooooommmm....

(Sorry. My brand of humor rearing it's head again...). LOL


Ray
 
Ray C said:
In order to find center, I feel it's necessary for your actions to be in-line with your values; and your values should be centered toward fairness to yourself and others... Oooommmm, Ooooommmm, Oooooommmm....

(Sorry. My brand of humor rearing it's head again...). LOL


Ray
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Good one! I was going to tell him to "use the force"

Well, you got plenty of ideas, did you get it done yet?
If so, what method did you use.

chris
 
A nother good way is t o mount a DTI in the spindel ad set it up to sweep a 3/4" circle turn it to the left and find the lowest reading then turn 180 deg anf find the lowest reading when the 2 are the same you are on center.
 
I had an almost similar situation. I mounted a DTI in my minimill chuck and dialed the surface of the ring that was on the bed to find the approximate center (maximum reading on DTI). Continued to move it further along until I reached 10 on DTI, "zero"ed X axis dial of the minimill, and then turned X-axis knob backward until it crossed the same null or center point, kept moving until I once again got the next 10 on the DTI dial. Calculated the total movement between the two 10's. Divided this figure by 2 and got the precise center point along that axis.

Prasad
 
An edge finder is just faster, use a piece of accurate round, TGP will work fine for this, measure it, touch it and move accordingly to center, done. you will easily be within .001" depending on your machine accuracy of course.
 
Wreck™Wreck said:
An edge finder is just faster, use a piece of accurate round, TGP will work fine for this, measure it, touch it and move accordingly to center, done. you will easily be within .001" depending on your machine accuracy of course.
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What if the edge in question is not straight? Would the edge finder still work when it is facing a curved edge like a round machined wheel (edge of a wheel is obviously not straight edge)? I have tried using an edge finder intentionally away from the center line of a wheel and it sure did find an edge but it was not on the center line that I was looking for. I hope I am explaining this properly.
 
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