Measuring inside groove diameter (Best tool for)

[Roger]

I've been getting parts lately that have inside grooves with somewhat tight tolerances.  What measuring device do you recommend for this?  I'm looking for something with the

broadest range, somewhere around, 1"-2.5" (interchangeable tips maybe), at an ECONOMICAL PRICE , and easy to use.

What does your shop use?  What brand, etc.

[Guest]

Internal Flange Mics

 

https://ecatalog.mitutoyo.com/Groove-Micrometers-Series-146-C1131.aspx

 

Read it too quick

 

http://www.starrett.com/metrology/product-detail/701A

Edited September 13, 2018 by Guest

[Roger]

5 minutes ago, JParis said:

Internal Flange Mics

We already have those.  Looking for something to measure the diameter of the groove.

[Guest]

Look up Inside Spring Calipers too...

Fowler carries a bunch of them

[Roger]

15 minutes ago, JParis said:

Look up Inside Spring Calipers too...

Fowler carries a bunch of them

I don't think that's accurate enough for this...   (+.001")

[Charlie Pierson]

Thanks for the plug John.

The Starrett 701B is an internal mic for grooves 1.500 - 2.500 range.

[Mark VIII]

Check out mueller gages

https://muellergage.com

[CEMENTHEAD]

INDI-CAL INTERNAL GROOVE GAGE 

These are my groove diameter go-to   --  there are all sorts of tips, and most of mine are ground to suit.

[Goldorak]

CMM with a disc instead of a ball 

[Roger]

22 minutes ago, CEMENTHEAD said:

INDI-CAL INTERNAL GROOVE GAGE 

These are my groove diameter go-to   --  there are all sorts of tips, and most of mine are ground to suit.

This is what I'm currently using.  We're missing some of the tips, and I think it's kind of "hokey"

[Roger]

32 minutes ago, Goldorak said:

CMM with a disc instead of a ball 

Are they ECONOMICAL PRICED??? 

[Goldorak]

16 minutes ago, Roger said:

Are they ECONOMICAL PRICED??? 

Hahahahaha, It is if you already have a CMM 

 

or 2 precision balls that fit in the groove and mesure the distance between with a stack of jo-block 

[AHarrison1]

Hi All,

First time posting here.

Why not finish the bore diameter with the same tool that you are cutting the groove with?

That way the groove diameter becomes tool controlled then all you have to really measure is the bore.

[Mark VIII]

13 minutes ago, AHarrison1 said:

Hi All,

First time posting here.

Why not finish the bore diameter with the same tool that you are cutting the groove with?

That way the groove diameter becomes tool controlled then all you have to really measure is the bore.

That would be a lot of assuming on a part with a .001" tolerance.

[crazy^millman]

11 minutes ago, Mark VIII said:

That would be a lot of assuming on a part with a .001" tolerance.

Yeah I agree you know what you know when you can know what you know.

[Roger]

1 hour ago, Goldorak said:

or 2 precision balls

I have never measured them with anything PRECISION!     LOL!!!!

[Roger]

1 hour ago, AHarrison1 said:

Hi All,

First time posting here.

Why not finish the bore diameter with the same tool that you are cutting the groove with?

That way the groove diameter becomes tool controlled then all you have to really measure is the bore.

Are you familiar with lathe programming?  I'm using a grooving tool for cutting the groove, and a boring bar for the bore.  A grooving tool is not designed for boring.  IMHO.

57 minutes ago, Mark VIII said:

That would be a lot of assuming on a part with a .001" tolerance.

^^^^AND THIS^^^^

[Del.]

If it were me I would verify my OD and then use a micrometer with ball to measure and then do the math.

[AHarrison1]

1 minute ago, Roger said:

Are you familiar with lathe programming?  I'm using a grooving tool for cutting the groove, and a boring bar for the bore.  A grooving tool is not designed for boring.  IMHO.

 

Yes, very familiar actually. A company I used to work for made hydraulic cylinders, multi stage rotary spools, manifolds, etc,etc. for heave machinery for pressures up to 5000 psi.

I did all of their lathe programming.

For some of the oil seal grooves that could not be reached with a measuring tool were then tool controlled by having the groove bar cut a land that could be measured.

This practice was also verified by cmm. 

We used this method to control the depth of any and all grooves whether they were on pistons, glands or rotary spools and it proved very effective. 

If the groove happens to be wider than the tool you are using then essentially you are boring the bottom land of the groove with a grooving tool.

[Roger]

7 minutes ago, AHarrison1 said:

This practice was also verified by cmm.

^^Don't have one.^^ 
 

So, when I send a part out the door to a customer, I don't like it coming back, because I didn't / couldn't measure it.  I think tool pressure is also something to consider....Just saying..

Welcome to the Forum!!  And thanks for your replies!!

[Mark VIII]

I generally try to avoid cutting bores with groove tools. Groovers tend to run slower to avoid chatter. Therefore, your boring tools would also need to run slower. Take into consideration that when roughing a groove you get a lot of pressure, and you cannot verify that you are leaving the same amount of finish stock, as you would for rough boring. That may work fine and dandy for the first 3 parts, but when you rough groover starts deflecting more with wear, it might bite you in the xxxx.

[Goldorak]

I think that Del's method is the best and also the cheaper 

[Mark VIII]

I would rather have a Mueller gage than trust an operator to do the math. There are many ID grooves in the turning world. That gage will check many of them consistently and accurately.

[Roger]

3 minutes ago, Mark VIII said:

I generally try to avoid cutting bores with groove tools. Groovers tend to run slower to avoid chatter. Therefore, your boring tools would also need to run slower. Take into consideration that when roughing a groove you get a lot of pressure, and you cannot verify that you are leaving the same amount of finish stock, as you would for rough boring. That may work fine and dandy for the first 3 parts, but when you rough groover starts deflecting more with wear, it might bite you in the xxxx. 

EXACTLY!

[Roger]

16 minutes ago, Goldorak said:

I think that Del's method is the best and also the cheaper 

I agree.  Where can you get balls in different sizes?  (I would need one between .118"-.139").  Groove depth/width control what size.  I also have parts with other dimensions.

16 minutes ago, Mark VIII said:

I would rather have a Mueller gage than trust an operator to do the math. There are many ID grooves in the turning world. That gage will check many of them consistently and accurately.

We're looking into this.  We've not been able to see a price yet.  (I'm the operator/programmer, so I don't have to trust anyone else.)