Small Standard Bore Holes Measurements???

A

Adilos

Plastic

Joined

Aug 22, 2012

Location

Malaga

• Aug 24, 2012

• #1

Hello, well to begin off im a rookie at this so any help will be appreciated.

I am trying to measure VERY accurately some small bore holes which i have in different types of metals. The diameter of these standard bore holes is about 6-7mm and about 3mm deep. I need to have very accurate metal inserts made to fit these holes, and a perfect fit is vital. If anyone can help me figure out what sor of tolerances can be used fo metal fittings?

My question is what is the cheapest most accurate way to measure the width(diameter) and the depth of the bore holes? Also having a tolerance of +/- 0.001mm.

Again any advice would be much appreciated with regards to specific product names or models too.

Thanks,
Adi.

 

The real Leigh

Diamond

Joined

Nov 23, 2005

Location

Maryland

• Aug 24, 2012

• #2

Adilos said:

Also having a tolerance of +/- 0.001mm.

Click to expand...

Hi, and welcome.

That's roughly ±40 microinches.

To have any reasonable ratio of instrument accuracy to nominal tolerance puts you in gage block territory.

- Leigh

 

A

Adilos

Plastic

Joined

Aug 22, 2012

Location

Malaga

• Aug 24, 2012

• #3

Thanks Leigh, would that mean a depth gage? What type of gage/gauge/micrometer would i need to measure the diameter of the hole with that type of accuracy?

 

The real Leigh

Diamond

Joined

Nov 23, 2005

Location

Maryland

• Aug 24, 2012

• #4

Adilos said:

What type of gage/gauge/micrometer would i need to measure the diameter of the hole with that type of accuracy?

Click to expand...

Sorry. My comments were about the hole diameter rather than the depth.
Are the tolerances the same for both? That's awfully tight.

Is this a blind hole? How will the air escape when you seat the mating part?

On the face of it, it seems unreasonably tight. What's the material? What's the range of temperature in which it will be used?

- Leigh

 

E

easymike299

Cast Iron

Joined

May 1, 2008

Location

San Diego

• Aug 24, 2012

• #5

For the diameters, a Dia-Met comparator will work. Can't answer for the depth.

Diamet Comparator

Gene

 

The real Leigh

Diamond

Joined

Nov 23, 2005

Location

Maryland

• Aug 24, 2012

• #6

That Diamet link has no information whatsoever. It almost looks like a troll, but I'm not sure so I left it alone.

I expect Google would find some info.

- Leigh

 

C

CarbideBob

Diamond

Joined

Jan 14, 2007

Location

Flushing/Flint, Michigan

• Aug 24, 2012

• #7

Oh come on guys, it's a LVDT.
Full scale (ie: off the end of the gauge) is going to be two microns on the high setting.

I would think anyone involved in measuring would have at least one LVDT and amplifier laying around.
How else are you going to show a rookie how much a gage block grows if you hold it in your hand for 10 minutes?
This is one of the first demos I do for a new guy, watch the needle swing as it cools back to room temp.

If your calib. lab can't get you below a tenth of a micron you need better sources.
Tight, yes but certainly doable.

Bob

 

E

ewlsey

Diamond

Joined

Jul 14, 2009

Location

Peoria, IL

• Aug 24, 2012

• #8

CarbideBob said:

Oh come on guys, it's a LVDT.
Full scale (ie: off the end of the gauge) is going to be two microns on the high setting.

Click to expand...

I'm gonna put one on my Bridgeport. I'm lookin' fer accuracy.

 

Putch

Hot Rolled

Joined

Nov 15, 2011

Location

Butler, PA

• Aug 24, 2012

• #9

I think maybe he got inches mixed up with metrics's or sumpthing like that

 

The real Leigh

Diamond

Joined

Nov 23, 2005

Location

Maryland

• Aug 24, 2012

• #10

Putch said:

I think maybe he got inches mixed up with metrics's or sumpthing like that

Click to expand...

The OP is in Spain, so it's unlikely he's working in inches, but not impossible.

- Leigh

 

litlerob

Hot Rolled

Joined

Jun 19, 2009

Location

PDX, OR

• Aug 24, 2012

• #11

The real Leigh said:

Hi, and welcome.

That's roughly ±40 microinches.

To have any reasonable ratio of instrument accuracy to nominal tolerance puts you in gage block territory.

- Leigh

Click to expand...

You could probably get there, or very close with an air gage. ±.00004" is tight but we've pulled it off, it's almost a tenth. Speaking of splitting tenths (high-jackers are us) anyone using one of these?

Mitutoyo America Corporation

Robert