Starrett Small Hole Gages

CatHead · Jun 21, 2006

Bought a set of these (#829) on Ebay new...have never used them before...im assuming you put them in the hole in question, tighten the screw until you get a snug fit, remove and measure?...

SND · Jun 21, 2006

Yes indeed. Although not all people have the same feel for them.

toolmkr · Jun 21, 2006

I have a set, been in my box for 25+ years.
Hardly ever use them.
Measure many times and take an average.

chadillac · Jun 21, 2006

toolmkr,

What do you use to measure smaller holes then?

SND · Jun 21, 2006

Plug gages for me. Or other go/no-go gages that I make for special sizes.
I rarely ever use the small hole gages.

chadillac · Jun 21, 2006

I guess I still don't have enough tools - small hole gauges are all I've got for smaller holes. I can see where plugs would probably be more repeatable, but there's an infinite number of hole sizes. Do you make a custom plug for odd sizes then?

Bobw · Jun 21, 2006

Chad, you only need to get so close. A set of plug gages will get you very close. If you're working from a print with tolerances, a go/no go will do you, its seldom that you get a hole less than .0005 tolerance, and most(most not all) of the time when you see that its because of an engineer getting their rocks off. Most of the QC departments I deal with realize that.

A set of Chinese pins is cheap. I've seen .011 to 1.000 for as little as $360. If you need to get closer or go bigger by a bit, you can use the 3 pin method. I have a spreadsheet at work that has it mostly figured out, I can e-mail it to you or anyone else thats interested. Its just easier than figuring it out each time.

Its pretty simple and can be done with a single set of pins, and using average size pin, it puts you off by a couple of millionths using pins from one set. Its a really easy formula, pen and pencil and in 5 minutes you'll have it. I learned this trick from a real smart guy I used to work with that pops up here once in a while.

As for the small hole gages, I'm assuming your talking of telescoping gages, personally, I think they suck. As TOOLMKR said, measure many times and take an average, then get somebody else to do it, and they will be off from your measurements, horrible little things, very very inconsistant. Good for a ballpark estimate, but I wouldn't trust them for any sort of accuracy.

dennh · Jun 21, 2006

The 829s are the split ball type. With reasonable feel, you can get within 0.002" and within 0.001" with a bit more care. As someone said already, it's all in the feel, just like old calipers.

Because of the range covered in the compact little case, they are pretty handy but if I were running a business, I'd use something else. Den

Davis In SC · Jun 21, 2006

Anyone notice the red plastic snaps on the Starrett pouches that hold the small hole gages.? I built the molds that make those red snaps... :cool:

CDiPrecision · Jun 21, 2006

I have a set of Full Ball type...you need a 1X Diameter depth hole to use them unless you have the flat bottom kind...I have had both and I like the full ball type...

I also have pins out to 1", I use both..it just depends on what Im doing...I can normally pick up within .0005 or so...Hole finish is important...

eKretz · Jun 21, 2006

Davis, sorry. Mine are Old Skool. Brass snaps. Leather case. But congrats on your achievement!

The small hole gages work fine for most purposes. If you can't hold better than .001" with both small hole gages and telescoping gages, you either need more practice or you have a ratty set of gages. If I need a closer fit than .0005" I use a bore gage, but otherwise small hole gages or telescoping gages.

bluchip · Jun 21, 2006

Anyone notice the red plastic snaps on the Starrett pouches that hold the small hole gages.? I built the molds that make those red snaps...

Well done Davis!! I'll remember that. Really, that will pop in my head every time I open the t-gages. not the small hole jobs...mine are like toolmkr's, pristine and unused. I use plugs for that stuff.

Peter S · Jun 22, 2006

Anyone notice the red plastic snaps on the Starrett pouches that hold the small hole gages.? I built the molds that make those red snaps...

Davis, I won't hold you personally resonsible, but I have got to complain that while the snaps hold up well, they rip out of the plastic pouch after a while!!

Maybe I should lube them and lower their "snap" threshhold...its too late now.

Actually, it mainly my telescopic gauges that have done this.

Starretts use of plastic is the least impressive part of their tools, I reckon).

I have the flat ended small hole gauges, the round-ended ones were no good for shallow bores. It is all about feel and the application. We had Tesa and Bowers internal mics (beeauutiful!!) for internal grinding, but I still preferred the crappy little Starretts when boring and jig grinding on the mill.

Davis In SC · Jun 22, 2006

Davis, I won't hold you personally resonsible, but I have got to complain that while the snaps hold up well, they rip out of the plastic pouch after a while!! Maybe I should lube them and lower their "snap" threshhold...its too late now.

I just had to do some work on those molds a few weeks ago.. Odd thing is, our customer was complaining that the snap action was too low.. I tightened things up a wee bit, a matter of a few tenths. Those same parts are also used in a variety of other products, quite a few different colors. 95% of them are white in color. Red only runs a few times a year...

Super Dave · Jun 24, 2006

...tighten the screw until you get a snug fit, remove and measure?

No, not a snug fit, unless you want to crank your micrometer to a snug fit as well. You should tighten it just until you feel it contacting then mic it to the same feel.

There's a time and place for any type of gaging method. You might want plug gages for making new holes in a production job. But if you need to know how badly a hole is worn and how far out of round then those small hole gages are perfect. I use them for that purpose from time to time.

Super Dave
Rapid CNC

toolmkr · Jun 24, 2006

Chad Webb,
I use pin gages for small holes.
but I can see where you could use them as Super Dave says

Davis in SC- I have several red pouches with those snaps-- on one telescope gage set, snap outlived one of the gages.
Radius gage pouch is in three pieces, but snap still works - my bad, those snaps are metal.
Small scales case is still good.

Forrest Addy · Jun 24, 2006

You guys are giving ball gages a bum rap. They are a tranfer tool depending on the touch and sensitivity of the operator fo their accuracy.

With care you can use the ball gage (and half ball) to determine hole size to +/1 0.0003" or so, finer with greater care and optimum conditions. Much depends on the hole finish and the sensitivity of your touch. A smooth clean hole honed to an 8 microinch finish is easier to get a consistant reading on than a reamed or bored hole for example.

No-one can expect to take accurate readings with a touch sensitive transfer tool like a ball gage without some practice with holes of known size. Take a half dozen readings using the Olympic System where you throw out the highest and the lowest number. Your middle readings with a little practice should lie very close in a range. The consistance of feel between the hole and the measuring tool is what results in accurate readings.

These skills will fade with time and have to be re-acquired. With a few moments to practice one can take ball gage reading adequate to fit dowel pins in lapped holes in a die set etc. With some esperience he can rival dial camparative gages.

donie · Jun 24, 2006

The only way to develope a feel on this type of gage is to test yer stuff on master ring gages.
There is simply no other way to know for sure.

toolmkr · Jun 24, 2006

could you imagine trying to qualify the use of these gages for spc?

eKretz · Jun 24, 2006

I can. If I measure 3 times with these gages, I get the same number within less than 5 ten-thousandths every time. If I take my time, even closer than that. It's like Forrest so eloquently worded it...this type of gage is no more or less accurate than its operator.

Starrett Small Hole Gages

Hot Rolled

Diamond

Hot Rolled

Hot Rolled

Diamond

Hot Rolled

Diamond

Stainless

Diamond

Cast Iron

Diamond; Mod Squad

Stainless

Diamond

Diamond

Cast Iron

Hot Rolled

Diamond

Diamond

Hot Rolled

Diamond; Mod Squad

Similar threads