Copying something precisely.

[JimDawson]

It's very possible.

Measure hole edge to hole edge then add the hole diameter, that gives the center to center distance. Part edge to hole edge plus 1/2 the hole diameter gives the center distance from the part edge. Add that to the center to center distance and that gives you the location of the second hole from the part edge.

This works as long as all of the hole diameters are the same. If the holes are different diameters, you do the same thing but add half the diameter of each hole to get the center to center distance.

You already have a 3D model, just move and size the holes in the drawing to match the actual measurements of the part that you want to copy.

 

[SoIll914]

Ok, thank you! That model is just a stand in for the actual part.

 

[Wreck™Wreck]

Since you can not describe what you mean by "exactly" no one can help you.

 

[JimDawson]

Ok, thank you! That model is just a stand in for the actual part.

Time to make the model look like the real part !

 

[SoIll914]

Well i tried to articulate my question as best i could. Thank you jim for hanging in there.

 

[Wreck™Wreck]

Well i tried to articulate my question as best i could. Thank you jim for hanging in there and not acting like a smartass.

Not smartass at all, "exactly" is entirely relative to what one requires, do you require hole center dimensions in the <>.005 range or the <> .0005 range, this makes a considerable difference when asking for advice.
A better question would be "how do I determine tapped or drilled hole positions within the normal error inherent in such features".

"Exactly" is not possible.

 

[bfd]

how many holes? if its even then measure across two opposite holes and add one hole diameter this gives you the bolt hole circle dia. indicate the part in on a mill table and move over from off center this is where you would place the first hole then index to the other holes. if you start a conversation with me I can give you a lot more det

 

[rgray]

One thing I think I've learned (questionable) is that a drill will not make a truly accurate hole. So then we use a reamer, but the reamer will follow the not necessarily accurate drilled hole. The cure was to use an endmill to make the hole with a more accurate placement first , which can then be reamed to size.
This practice was for critical hole placement (like two parts that must dowel pin together) and is not necessary for most applications where a larger clearance is used.

 

[jmarkwolf]

I use my DRO.
Drop a pin guage in one hole, zero out your DRO, move to each successive hole and do the same. Write down the locations of the hole.
I can "decipher" odd ball mounting hole patterns this way as well.

 

[sanddan]

You could use a transfer punch to locate the hole on the new part. Pick the size that fits snug in the hole.

https://www.amazon.com/Neiko-02621A...74&sr=1-4-catcorr&keywords=transfer+punch+set

You can also make one by turning a point on the end of a bolt. This could be used to transfer the location or by measuring point to point to get the hole spacing.