Beginner Measuring Devices

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DangerZone

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Yell at me if this should go elsewhere.

I am very new to machining still. I just acquired a lathe. It needs a little bit of effort put into before I'm turning anything, but leveling it is on my radar. This is probably going to be my first project requiring a fair bit of accuracy. My plan is to get it close enough to level with what I have on hand, and then start turning test bar's to check the alignment. Will I be in the ballpark if I spend ~$100 on a 6" caliper? Or should I be looking toward a 6" machinist level, a micrometer set, and some setting standards?

I also have my eye out for a dial indicator, but I'm even more unsure the level of precision I should be looking at there.

Basically, I'm just looking for guidance on how precise of measuring instruments I should be looking at getting before I know what I'm doing. An expensive micrometer will probably serve me well down the road, but at this point, I'm not sure what level of precision I even have the knowledge to take advantage of.

Thanks everyone!
 
A 6" digital cali[per can get you within a thousandth with careful work. A micrometer would be a better choice. If you are turning a test bar, absolute dimensions are not required, only the difference. Many lathes have been set up without the benefit of a machinist's level. If you wish to go that route, you will want a fairly accurate level, something like .0005"/10" but you will still want to run the two collar test.

Re: the dial indicator, a .0005"/div is commonly used. Same for a dial test indicator. I have had decent results with some imports which are a fraction of the name brand indicators.
 
For the two collar test, a micrometer would be best. I suspect you would be close enough using a 0.001" reading mic, but I would use a tenths mic. Used mechanical mics are cheap on ebay, even for big name units. To keep budget down, this is the way I would suggest for new people. Just get the ones you need as you go.

For electronic, I like my Mitutoyo, but it's more money and you have to watch out for fakes. I only have the 0-1" version. My others are mechanical.

Calipers, I still use HF digital and dial. I figure they are good to within 0.005". After that, I switch to mics. I'd like to get a 6" digital mitutoyo, but haven't yet.

Shars has reasonably priced decent indicators for general use.
 
Yes, a 0-1 micrometer would be the best choice, if you could find a tenth reading one on e bay, OK, but personally, I think it is unnecessary, a thousandth reading mike can easily be interpolated within a few tenths by eye. You say nothing about the lathe that you say needs leveling, or call it aligning --- If, like many small lathes, it sits on three points, it really does not need "leveling", if it has a four point footprint, the two collar method is all you need to do. Even the best of calipers do not offer the accuracy you need; I have a SPI (Swiss) 6" dial caliper, it is reasonably accurate and repeats well, but would I trust it for dimensions closer than a few thou? no way! For one thing, there is the issue of "feel", this is difficult with this type of caliper. I also note that I have never owned a dial caliper (over 50 years, a fair number have been "used up" by me, and the OD and ID never have matched up, regardless of brand, I have always had to stone off the ID nibs to get equal readings. I have owned one digital caliper, by Starrett, they offer some advantages, such as zero setting, but short battery life is not so good; I usually slide the battery cover partly off its working position to minimize current leakage and dead batteries.
And, finally, I think that E Bay would be a quite good place to find a decent mike, just look for the cleanest nicest looking one available, they are quite cheap, even for the best name brands, and taken care of, will last several (working) lifetimes. I bought my first, a Starrett #230 with ratchet and lock when I was in high school in 1962 for around $20, I think, and it serves me well all these years, then my mom's uncle gave me his #231 tenth reading with carbide faces also with R&L, I use both often in different locations in my home shop.
 
My first choice for a "precision" measuring instrument would be a digital caliper. Whether the $20 HF caliper or the $120 Mitutoyo, your choice. The Mitutoyo has a great reputation, as long as you don't get taken in by the counterfeits which proliferate. The Harbor Freight calipers have always agreed with my micrometers when I have cross checked them and one personal pair that I used at work passed a NIST calibration. The reason for choosing calipers first is that they will give you dimensional readings to a thou up to the limit of their beam length. They also will make internal, step, and depth measurements which a micrometer will not. The disadvantage of calipers is they are sensitive to operator force due to the cantilevered design of the jaws and it takes some practice to develop the proper touch. Additionally, the cheaper calipers can usually benefit from some rework and tuning.

A second choice would be a 0 -1" micrometer, capable of measuring to tenths although as John said above, it is fairly easy to interpolate a thousandths reading micrometer to a couple of tenths. a big advantage of a micrometer is the ability to measure the diameter at the center of a shaft. A good reason to have a set of micrometers extending the range of measurement. Because the line of measurement is concentric with the spindle, there is no cantilevering effect but the mechanical advantage of the screw thread can lead to excessive measuring force and inaccurate readings. Hence, the use of either a ratcheting or friction thimble on modern micrometers.

An advantage of electronic digital calipers and micrometers is the ability set a zero at any point, useful when making comparative measurements. The obvious disadvantages are the need for batteries and the greater risk of malfunction due to the greater complexity.

Additionally, I would look at acquiring a dial indicator and/or a dial test indicator. They are extremely useful for setting up work on the mill, making simple height measurements, centering work in a four jaw chuck, tramming the mill, etc. The dial indicator and dial test indicator or two different instruments and their use differs. The test indicator is really a comparative instrument as the reading varies depending upon the angle between the contact point and the dimension being tracked. It also has a very limited range compared to a dial indicator. If I am centering work in a four jaw chuck, I will use the test indicator. If I am measuring travel of my carriage , I will use the dial indicator.

I have mechanical and digital indicators reading in tenths/div. to a thou/div. A .0005"/div. is a good compromise. A Noga type indicator holder with a magnetic base increases the versatility.
 
At this point, you just need some basic tools. How much you spend on them depends on your budget and if you think cheap is good enough. Given that you have just the lathe at this point (it would be good to tell us what lathe you are working with), I suggest a basic set of tools to start with and you can grow the list from there:
  • 6" dial or digital caliper. This will be your most used measuring tool for many tasks, especially measuring basic diameters on the lathe. Most of these instruments will be good to 0.001". For lathe work, this would be the first tool I would buy and given how useful it is and how often you will use it, I would buy a good one.
  • Micrometer - a 0-1", tenths-reading micrometer should be part of your kit for lathe work. At some point, and it will come soon, you will be working beyond 0.001". You can use a less precise mic and interpolate; many of us can interpolate within a tenth. However, you have no experience with this and will not be very accurate at it for a while. I would just buy a decent tenth-reading mic and dispense with the guess work.
  • Dial indicator - for almost all lathe work, a 0.0005" dial indicator is more than enough. You will need this to center work in a 4 jaw independent chuck, center your tailstock and many other tasks down the road.
  • Dial test indicator - You can put this one off for now but when you do buy one, get at least a 0.0005" model for general work. For checking the accuracy of a spindle, you need a 0.0001" model.
  • Machinist's level - buy an import level 10-12" long, even if you own a smaller lathe now. You will likely buy a larger lathe at some point in the future and that length will come in handy. At minimum, look for a level with at least 0.0005"/10" sensitivity. Less sensitive levels will work but will take more time to level a lathe with. You can get a 0.0005" level on ebay for $88.00 and you will use it many times over the span of your years in this hobby.
If you have not found them yet, go to Long Island Indicator Service and do some reading. Want to know which is the best tool in any class? Go to LIIS and you'll find that info.

As a hobbyist, budget usually plays a large role in what you get. Many hobbyists use import tools and seem to get along just fine. However, most pros and advanced hobby guys buy better tools; they are more reliable, last longer, stay accurate longer, are usually repairable and in the long run, are cheaper to own.
 
Spending a ton of money on measuring equipment is easy and not necessarily the best route for everyone. I started with some harbor freight mics, a $20 dial caliper, a $30 dial indicator and base and then added more expensive items as I found them at garage and estate sales. I now have some name brand, high quality tools and the more I use them the more it becomes apparent that for hobby use the chinese stuff is entirely adequate. I picked up a $160 6" caliper for $20 and a several dial test indicators for a similar price.

The thing is you have to decide what you need now vs what you can wait for to pick up as you find it. It doesn't always happen fast or in the order you need them.

As for leveling, I set up my lathe using a carpenters level and then made a test bar. I tweaked the leveling a bit and ran another that was within .002 over 12". It is cool to be able to say you are producing parts with .0001" tolerances but really most of what we do doesn't require that sort of accuracy. Someday I may need to work that tight but it isn't today.
 
As some of you mentioned, I didn't state what lathe I got. Uglydog was getting rid of his big Gisholt No. 5 turret lathe, and i have room for it. I'm new to machining, but wound up with a 5,000 lb lathe. I only got 3 leveling feet with it, but I think this will be supported on at least 4 points no matter what I do. Uglydog has a few threads here with his time with it. It sounds like carpenter level and a test bar is as much as I need if I have the time to put into it, but what I'm hearing is that I shouldn't be afraid to jump in and start buying decent quality stuff. like a few of you have said, I really don't "need" to be turning parts within .0005", but it's hard to figure out where the line is for the price. I'll definitely start looking at ebay for some good condition brands.

Since I haven't posted much on here about the Gisholt, first order of business is replacing fluids. I've figured out the fluids I need, but of course the headstock alone takes 6 gallons of fluid. That's not looking terribly cheap. Next up, motor or phase converter. I'm just keeping an eye out. It came with a 10hp 3 ph motor. I'm thinking if I find a 5 hp single phase cheap, I'll get that to run for the time being. 20hp phase converter's aren't cheap or plentiful. Then I will level. Might be a ways out. But I can start collecting tooling and measuring instruments in the time being.

Again, I'm still just learning. I have goals of what I want to build one day, but I don't want to make any un-reasonable expectations for myself until I know better what I'm doing.
 

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Dangerzone,
Welcome.
You asked a good question and received some great information from some of the smartest guys in the Forum.
It's tempting to pick up cheap tooling and measurement instruments. The cheap calipers won't repeat and you will end up zeroing them every time you use them. Not a big deal, but just know, most of us buy quality sooner or later on this subject.
 
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