Tour of the Dial Indicator

After thirty years I think I have my dial indicators finally dialed in so to speak. Its not that it took that long but rather a slow series of optimizations and additions that make it feel right, at least until something better comes along. I have quite a collection of dial and test indicators in my tool collection. The very first indicator I bought was a Starrett one inch travel dial indicator. I remember well that it was expensive. To add insult to that you can currently buy a pretty good "Tecklock" or "Aerospace" for less than twenty dollars and it will probably come with its own magnetic base to boot. How these can be made for this price and shipped here is beyond me. A life lesson is don't compete making commodity items. Stick to unique and innovative devices and technologies. There is always somebody out there willing to work cheaper than you.

Well I still have that Starrett indicator, and because I paid in a painful to my pocket way it gets treated with the respect commensurate with its price. As a counterpoint I have probably broken or damaged more than one of the offshore brands during the same time period partly because I didn't need to be careful because of the price.

The use of this indicator has morphed over the years I've owned it. In the olden days I used to use this one and a twin brother with two inches of travel a fair amount on the lathe to keep track of Z positions. Now it gets used mostly to monitor weldment movement or perhaps the true X component of the compound rest when threading with the rest set at thirty degrees. The other place it sees some use is when I need to use the tailstock with fine depth control for some reason. With the mighty magnet I can snap it on the side of the tailstock and add a kantwist clamp to the tailstock quill as a rest for the tip. Presto instant tailstock ARO. (Analog Read out)

The next indicator I bought way back when was the classic test indicator. For many years I used this Starrett last word as my primary test indicator everywhere in the shop.

If this is the only test indicator you know then fine. Its a decent well priced test indicator with a large and long     following. I didn't realize how much better a test indicator could be for a long time. My first inkling was when I had occasion to borrow a workmates test indicator for some long forgotten reason. Sorry to say that my last word is now relegated to certain lathe jobs where small is right. I keep it on a small pot magnet so I can snap it on to the Aloris tool post quickly. Other than that It doesn't see much use.

The small pot magnet makes it really quick to get in the machine. Also the last word is one of the more rugged test indicators. It will take the vibration from tapping a part into alignment with a hammer without complaining.

 The difference in the action of test indicators is marked. Visually the Alina and the last word are virtual copies of one another. I don't know which came first, the chicken or the egg but the Swiss interpretation is superior. I quickly added an Alina to my growing stable of test clocks. The one in the picture above stays setup for quick insertion into the height gage. One advantage to having more than a handful of indicators around is the savings in time locating and connecting all the diabolical jointed accessories needed to adapt the indicators to each specialized use.

I sometimes get the feeling that all the indicator manufacturers didn't talk to each other very much. At least the AGD stepped up and (American Gage Division) set some useful standards for dial indicators. I leave a few indicators setup for each of the most common applications in the shop. Over the course of a year that might be a significant amount of changeover time saved. At least that's my excuse when I see another one I want.

Another indicator I have been using more lately since the four jaw chuck was mounted for a long period of time is the old standard issue back plunger type. The upper indicator is a Starrett button back, but Lufkin, and Mitutoyo also make a nice one. I like it because it has a no messing around contact spring in it and .200 (5mm) travel. The large diameter button contact point doesn't see every little imperfection in rough stock like a fine tipped test indicator. It rules the roost for tramming the milling machine head as the button glides over the tee slots like they aren't even there.

Once I discovered Alina test indicators I was keen to try some other models from the same maker. This K-24 became my defacto go to test indicator for many years. It has a crisp action and never seems to get sluggish or gummy. It has the added advantage of the small dovetail along two surfaces on the body so you can use a variety of clamping options. I still use the heck out of this one. In particular when I have the chuck in the mill and a small feature to probe. The ball joint is snug and it stays put when I twist the bezel to zero the dial.

Now we come to the nirvana of test indicators. If you haven't test driven one of these then you shouldn't unless you feel like spending $200+. The Interapid has some distinct advantages over some of the other indicators that I have shown. Two of the best features are the long range of movement, .060 (1.5mm) and no  shift lever to go from one direction to the other. The action is like polished glass and as smooth as silk. About the only thing I can find fault with is the placement of the alternate mounting dovetails. For most of the time I leave this indicator set up in an Indicol holder. The holder allows me to sweep something in the mill without removing the tool. It also happens to fit on top of the Aloris toolpost as an alert You Tuber noticed the other day.

A simple trick I learned from a workmate not that many years ago was a simple way to position the indicator using the Indicol holder in the milling machine that saves time and headaches.

For maybe a thousand years I would just throw the Indicol holder and indicator on the spindle and indicate away. The only problem is when you sweep around the back you are bobbing and weaving to see the dial face that's hidden from view.

I've seen some guys use a mirror for this situation. I was too lazy to grab a mirror so I just did the bob and weave. Well one day I walk up to talk to this particular guy (Manny) and causally look at his setup. I mutter under my breath, crap. Manny asked me what was wrong? Oh nothing I replied, I just realized how lame I am. Crap I had even bought a vertical model of the Interapid indicator to "help" solve my problem. Now don't laugh too hard at me at least I can still learn a new trick once in a while. This is why I always say, keep your mouth shut and your eyes open.

Okay its pretty obvious when you see it right. The dial is facing up for the entire sweep,. I felt like a dunce for not figuring it out on my own.

The only other thing I think is worth mentioning is about magnetic bases. For many years I have used a Starrett double jointed rod type mag base. It has two knobs that have to be secured to lock the indicator in the desired position. Once again if this is all you know then everything is fine. The solid rod type is better than the ball jointed snake like holder that uses an internal cable to stiffen the ball segments. Great idea, but not quite superb execution.

When you have gotten used to riding a Honda for many years everything is hunky dory. Well when you hear a  Ducati in the parking lot you always look. And one day you finally walk over for a closer look. Well now you have to have one.

Somebody let me try their Noga indicator stand. Immediately you feel the advantage. Its silky smooth and locks in any contorted position with a single knob which is just what you want with an indicator. I bought one  straight away. In fact I like it so much I recently splurged and bought the little brother to my original. These holders can handle 3/8 (9.5mm) shanks and the test indicator dovetails without any loose adapters!

Here is the last indicator I want to show you. I saw this at a flea market and had to have it just for the USSR on the dial. I don't use it much since its metric. This thing is built like a Russian T-34 tank.  I often think about  machine tools and instruments from the former Soviet Union. They had a high level of technical prowess and manufacturing ability. Where are all the machines and equipment? I guess Russian machine tools and hardware is more readily available in Europe. We rarely see anything here in the United states. That was part of the appeal of this indicator. I tell people it came from a T-34 tank factory in the Ural mountains. I don't think its true but it sure makes a better story.

Thanks for looking.