[AnvilJack]

With about three weeks experience in this world of milling and lathe work behind me (I lie: lathe ownership), I am starting to assess my needs in setting out work.

First, for measuring, I have one 2.5 cm micrometer, and a set of digital callipers. So far I have used the callipers almost exclusively. Traditional machinists would have a set of at least three external micrometers, and other internal micrometers of various sizes, and depth micrometers. I wonder if I am not understanding something here. I can measure internal and external dimensions, and depths up to about 200 mm with my callipers: will I survive long with this strategy?

Next, I have a dial test gauge and a dial gauge, and seem to be using the dial test gauge for nearly all alignment and "comparative" measurement. Does one really need both? (Too late, this question, I know, but it is an example I am not sure I want to repeat.)

I have no plans to buy a set of gauge blocks, or 1-2-3 blocks, cylindrical square, or genuine surface plate (sheet of 10 mm plate glass for me, at this stage). How often are these needed?

I have a set of engineer's squares, an engineer's 150 mm rule, engineer's scribe, and an "automatic" centre punch, and seem to be measuring and marking OK just now. I also have a series of callipers for marking out, and a precision protractor, but theses haven't been out of the drawer yet.

I will need a height gauge, I'm thinking, but this is one project to have a go at, before buying one.

Much of this stuff I am learning from books and a bit of Internet. While they describe the use of these tools, it is not apparent to me just how often some of them are used.

If I just wait and see, and buy only as I need it, will I be heading out into bad habits, inherently inaccurate practice?

[WerkSpace]

If you want to learn about accuracy, check out this guy's videos.
https://www.youtube.com/user/tryally/videos
The videos are not in English but he includes English subtitles.
I know, I know... I hate subtitles too, but it's the details that matter.


This is the best book that I know of, for setting up and running lathes.

[Oddjob83]

Get a set of Bore gauges, good for measuring any kind of difference of bore sizes from deflection in longer thinner tubes or using longer thinner boring bars.

[blaz]

I have been a machinist for 16 years now. I will give you a couple of answers.

Digital callipers are not as accurate as a micrometer. With a Micrometer I can measure to an accuracy of + or - 0.0001" (0.0025mm). This may seem too much but as you start dealing with bearing fits you will require this accuracy. In the "machinist world", callipers are called vernier guessing sticks.

Test dials are fantastic for dialing in, but not great if you want to move a set distance. Examples being, if you want to set up to cut an eccentric on the lathe or even a taper.

Here are my must haves;

0-1" micrometer.
1-2" micrometer.
2-3" micrometer.
A set of telescoping gauges. (Inside micrometer, tube style when $ is available)
A combination set.
An edge finder.
A center gauge.
**Machinists hand book**

Learning how to measure accurately is a must. Like welding, PRACTICE, PRACTICE, PRACTICE, PRACTICE! Don't just turn a diameter, try and hit a size every time. Doesn't matter what the size is, just hit it.

Once a Journeyman asked me what I made today. I said "CHIPS"!

[AnvilJack]

I have spent a few hours watching the tryally videos: I can only aspire toward his passion and skill level. I'll wager he didn't get those skills and insights together "overnight". Thanks for the tip.

I will get the "How to Run A Lathe" book, since you have referred to it before, and I do value the Tabletop Machinists, even though my toys are a bit bigger. Again, thanks.

And it looks like I had better get to love micrometers. Is it where the digital callipers set on the work piece that makes them just "average accuracy"?

[noddybrian]

While machining often goes hand in hand with welding, they are different trades with different specialist tools - how many of them do you need ? - depends on the nature of what your doing - if your primarily a welder that needs to machine an occasional part that is not by nature a precision piece then basic measuring tools will suffice - if your primarily a machinist making precise parts but has to occasionally weld something then this calls for another level of measuring - ( & true machinists may not like to hear this - but they tend to be a bit anal ! )

simple answer on caliper versus micrometer - as you say the caliper gives a wide range of internal / external & depth measurement - micrometers usually are limited to 1" measured range ( but can cover much more with interchangeable anvils ) but the caliper is only as good as the consistency of how you hold it - the thing itself is accurate - but it's not repeatable - the micrometer has a slip clutch built into the thimble & applies a consistent pressure on a wider jaw creating reliable / consistent readings - it is always worth collecting micrometers if you see one for sale - I'm lucky in that I bought a "job lot" of measuring equipment from a school so I have several of almost everything - but truthfully don't use much of it regularly so if I were starting out I would'nt buy it all new - I think the best plan is to start simple & just add tools as you find the need to for the type of jobs your doing - just watch out on quality - Never buy anything import ! they can copy any amount of things cheaply - but not measuring tools - only foreign stuff I'd consider is Japanese ( ie Mitutoyo ) I'm not sure what makes are valid stateside -but here you look for Moore & Wright for general things - there are others but they are consistently good.

Things you likely won't use include height gauge & micrometer depth gauge - you may occasionally use a sine bar & gauge blocks - but not often enough to justify the price - I would though say a small surface table is worthwhile - & micrometers you really want both english & metric - ( I use both but I'm sorry to tell you metric is simpler on many jobs ! ) in my opinion I would measure in the units on the machine - so if it's a metric lathe & your machining an english sized part convert the finished size to metric 1st then work in the metric units of the machine - your less likely to slip up that way - & if the machine is marked in both - be wary - they are rarely precise in the conversion from one to the other ( OK a Bridgeport with the geared dials is )

Happy machining !

[jwmacawful]

don't want to hijack your thread BUT;you better hang onto all those machinist's measuring tools. i predict their going to become museum pieces. the trades of machinist and welder are dying out. in this country anyway.

[noddybrian]

Oh your right there - most of my measuring equipment & smaller lathes / mills have come from local schools because it it no longer taught - I consider myself lucky to have bought them at a good price & will keep them despite being regarded by some as old fashioned ! No one is interested in these traditional skill as they don't like getting their hands dirty & they think it's OK if a robot / CNC machine makes everything ( probably in China ) - I'm old fashioned in outlook on alot of things - but people still come to me when they need a one off obsolete part making & although I'm not a radical guy with a bunker I do have alot of common ground with "preppers" - in that I like to have stock of most things I use & the tools & ability to make what I need - you can't prevent progress / change - but I resist it as much as I can ! still drive a mechanical injection stick shift diesel - if I can find diesel / cooking oil / hydraulic oil / kerosine etc & a hill to bump start then I'm still driving after any kinda disaster !

[jwmacawful]

i remember hearing old guy's complaining about how f@#$%d up the kids of today were. i guess they were right lol. they all want to play for the nba, be rappers and or make a million bucks playing tournament poker. hang onto that machine. it may be old but those cnc machines make unskilled slaves out of the worker's who simply "serve" them with raw material. we had openings for machinist and welder and couldn't recruit young people. average age of my co-workers as at least 50. sorry for ranting. i'm on vacation in sunny fla and miss work after 1 day. i'm a very sick man!

[Oddjob83]

My boss calls verniers Very-Nears

[Otto Nobedder]

My boss calls verniers Very-Nears

I bet your boss doesn't know what a slide-rule is, much less how to use one.



Showing my age...

Steve S