Measuring inside grooves

[JRouche]

5 very small hands as well (-:

Yes Sir. Very small to get in them tight spots. Like a bore JR

[Bented]

Oh yeah, I have five hands now

5 very small hands as well (-:

[old mart]

At my firm, we had every type of measuring device imaginable, but also, a supply of the fast curing rubber used by dentists for impressions. When it cures there is very low shrinkage, and it was very good for the inspection department to use where anything else was considered unreliable.

[JRouche]

To measure the width of the groove I used a piece of material that I think was .030 thick. Hold it against one edge of the groove and measure depth from the end of the bored piece. The put the shim against the other edge of the groove and measure again, adding .030 to the measurement. Calculate the width of the groove. I used the depth measuring ability of a normal caliper to do this. Takes a bit of finesse to hold the shim squarely

Oh yeah, I have five hands now

Gage pin. I have a bunch of them, they were cheap. I have a 1000 pins. For that job I would use them as Go or No Go pins. JR

[darryl]

Somewhere I have a piece of square stock which I cross drilled and then drilled and tapped one end for a set screw. I used a single roller from a defunct U-joint bearing as a cross pin. Hold the tool against the inside of the bore, push the pin to touch the bottom of the groove, tighten the set screw. Then pull it out and measure the extension of the pin with a conventional caliper.

I rounded over the side of the square piece so it would lay touching the bore for any bore 1 inch or larger. That eliminates the error caused by the curvature of the bore. Simple, and it works well for me.

To measure the width of the groove I used a piece of material that I think was .030 thick. Hold it against one edge of the groove and measure depth from the end of the bored piece. The put the shim against the other edge of the groove and measure again, adding .030 to the measurement. Calculate the width of the groove. I used the depth measuring ability of a normal caliper to do this. Takes a bit of finesse to hold the shim squarely, but a little care takes the error potential mostly out.

[Captain K]

i think either would work, but I have neither. On that note I suppose I could use an adjustable parralell, which i do have.

[JRouche]

For width would a gage pin work? Or is that more work than needed? Gauge block? JR

[tom_d]

Use an inside spring caliper to measure the diameter. Expand it so it just touches the widest point, compress and pull it out, let it expand again and measure it with a mike or dial/digital caliper.
For the width, you could buy a $15 digital caliper and cut off the outside jaws to fit it in the tube.

https://www.ebay.com/itm/15218000550...sAAOSwdzVXlTwM

+1 for the inside caliper. Been doing it this way for many years. Takes a little bit of feel to transfer the measurement to the outside mics, but practice first with a known dimension helps to get it right. Too help with accuracy and repeatability I put a drop of service removable locktite thread sealant on the caliper screw first. That helps to hold the caliper nut in position once set but still allows for slight adjustments.

[Rich Carlstedt]

How do you measure to depth and width of an inside groove? I am building a hydraulic cylinder gland and need to measure the seal groove. 2 3/4" bore, groove will be say 3" diameter and 1/4" wide. Obviously no place for sloppy work so how do I get it right the first time? This is a one time deal so would rather not buy too many expensive tools to complete it.

KISS Principle . If you don't have any special tools.
I assume you have a indicator similar to this
https://m.media-amazon.com/images/I/...L._SL1162_.jpg
?
You want to do it in the lathe or on the mill !
Lets take the mill. Center the quill on your T slot
Lay the cylinder on the table ...in the T slot ( It's now centered.
Put a indicator in the quill and set it horizontal with prob , then lower it into bore and use Y axis to confirm centering on the ID of the tube
stay there and lock quill temporarily while at "0" ! -- Now raise the Quill collar stop ( Not the quill) to hit the moving stop , and then release quill clamp
Take a heavy Duty Mill Washer ( like 3/16" thick ) and measure ID and OD so you know width of washer
Set it in the groove and move the into the washer by raising the quill slightly and finding "0" again
now measure the difference in your quill stop collars and using the washer width , you get depth.
For width of groove , turn the last word prob down ward 90 degrees and using X axis , measure deflection point PLUS diameter of prob. for width measurement

Rich

[gzig5]

How are you going to get the T-gauge out of the groove to measure it?

Exactly. There has to be enough width to rotate the tool back out. May not work with a standard tools, thus the alternative.

[ChazC]

Others beat me to my recommendations: the Mitutoyo Groove Mike (I got a like-new one on eBay awhile back for $120, good ones now go for $150 — $200, new ones $225 — $400 depending on the reach and range; there is one NOS with a rotating spindle and the larger diameter shaft currently listed for $1,000!!!), this is what mine looks like:




and the Indi-Cal (eBay also for around $90 in VG condition, the quality of used ones varies greatly, but a bunch are currently listed) – you supply the DTI:




The base comes flat and is maybe 12 gauge steel: it took some head scratching to get it bent into shape without messing it up.

Parts for the Indi-Cal are getting scarce as the original company is closing down – pm me if interested in buying a new complete set (no boxes available) or parts at significant savings directly from the owner (I do not get anything from this, just trying to be helpful; I would post the contact info but have been asked not to by the owner).

[boslab]

I use a groove micrometer, it has pins not jaws, fairly basic thing, mines Moore and Wright but starret and brown and sharp do better ones ( imho)
chopping a cheap vernier is probably your best option, the grove mic I bought was about £60, not terrible but not cheap ( I did one using a carpenters Mort ice guage, use the two pins and measure over them, crude but works, remove the stick to leave just the staff, stem or whatever the long square bit is called.
mark

[jimsehr]

Some other tools for checking grooves. Costly but if you are doing lots of grooves it’s ‘t worth it. I ran thousands of grooves so I bought or made all.

(jiio

[Fasturn]

Indical, is a cheap ??.. tool that could work for you. They come with different tips. Mueller gage is very expensive but nice. I have used ball bearings too.

[Captain K]

Toolguy, you and I had the same brain wave at the same time apparently. Your suggestion to cut off a calliper was not there when I was composing my post. Great minds apparently 😃