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Finding center of 3/4 rod

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umahunter

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#1
Ok tell me if I'm thinking correctly say I want to find quick center on a say 3/4 small rod. if I put that rod in a 5c collet block shouldn't I then just be able to find the center of the block thus putting me on the center of the rod or pretty close. I know this all depends how accurate the collet and block are but am I thinking correctly or am I off ???? I just need to drill a cross hole a bolt will go in to hold a rod in a plasma cutter circle cutter so it doesn't need to be NASA accurate lol
 
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Bobby Bailey

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#2
Yes, you can do it that way.
 

P. Waller

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#3
Measure the part diameter, if it is .735 edge find it and move 1/2 this diameter, done deal.
 

higgite

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#4
You could certainly do it that way, but I’m curious why you would do that instead of just finding the center of the rod? Maybe I’m missing something, but it seems that one would be just as quick as the other.

Tom
 

Franko

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#5
I'd clamp a V-block in my mill vise and visually locate the center with a center drill.
Clamp your rod in the V-block and make a dimple or starter hole with the center dril.
Then chuck your chosen drill bit and drill the hole.
 

P. Waller

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#6
You could certainly do it that way, but I’m curious why you would do that instead of just finding the center of the rod? Maybe I’m missing something, but it seems that one would be just as quick as the other.

Tom
This is how you find the center, 1/2 the diameter from the OD, when finding center of a part held in a collet block in a mill find the center of the part rather then the center of the tool holding device thus reducing any errors in the part holding.
 

Charles Spencer

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#7
Unlike the end there is no one center on the side of a cylinder. Every spot for 360 degrees around it has the potential to be the center. Since tolerances aren't too tight I think I would proceed by:

1. Bluing the side and the end of the rod
2. clamping it down
3. Using a 3/8" block, scribe the end and the side
4. clamp it in a vee block using the scribed line on the end to ensure that it is perpendicular to the spindle
5. mark the hole's location with a center punch
6. make your hole
 

MarkM

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#8
Scribe three chords. Divide the length of each chord in half and using a square scribe lines. Where they intersect is the centre.
 

kd4gij

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#9
^ All that just to find the center of a rod? ^ I just use an edge finder on the side of the rod and move over half dia.
 

MarkM

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#10
I guess I should have read the post properly. I Thought the o.p. Was referring to the face of the rod. Ya I agree I d just touch off and move half plus half the diameter over since Nasa wasn t waiting.
 

higgite

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#12
Build a round bar center finder?

1) dig an iron mine
2) make charcoal
3) smelt
4) etc etc.

=OR=

https://www.mscdirect.com/product/details/76416528

:)

MetaKey
I have one of those gizmos. Works fine, but not NASA approved. ;) I haven't tested it against the edge finder +1/2 diameter of work + 1/2 diameter of edge finder since I haven't needed that precision, but it's better than my eyeball and it's quick.

Tom
 
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umahunter

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#13
Lol I did it I just found the center of my block quick stripe of dykem scribed a line located line spotted and drilled hole thanks for all the replies
 

Chip Hacket

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#14
Mount the rod with V block in vise.
Put flat bottom end mill in collet.
Lower quill until it just barely makes a flat on the rod. That’s the center of your rod. Drill there.

Using edge finder then moving over 1/2 is still better I think. But this works pretty well.
 
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umahunter

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#15
Lol totally space this was sitting at the back of my drawer
 

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westerner

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#16
Lol totally space this was sitting at the back of my drawer
Oh, boy, THAT'S funny! It happens around here more and more. Best part of that is SWMBO is unaware of this development (we hope).
Might make for some awkward conversations later. "Don't you already HAVE one of those:cautious:?" LOLOL. I have certainly been there!
 

hman

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#17
I have and occasionally use a center finder like that. It's pretty good within +/-.005". To increase accuracy, I'll usually "find center" from one direction, zero the DRO, approach from the other direction and compare. Then just for fun, I'll rotate the spindle 180º and repeat.
 
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