[Metrology] Stocking up the home shop?

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SCLead

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Hey folks,

Looking for a little advice from those who have set up their home shops in the past.

Long version: I bought my first house in the last year. More accurately, I bought myself a 30x30 shop, and there happened to be a pretty decent house standing out front. I'm not exactly starting from scratch, though I'm now able to organize much better, and add some more substantial tools (i.e. machines) to the mix. I started machining in college about eight years ago, and have been behind mills and lathes at pretty much every job since that point, though I'm far from being a machinist. Thanks to this, I've gradually collected most of the basic individual stuff - 0-1" mic, 6" calipers, a good machinist square, small hole gages, etc. Far from "all inclusive," but I've been collecting stuff as I find deals too good to pass up, or as I need them to complete a job. Now, since I've got a lathe and am on the short list to picking up a mill, I'm looking for the bigger "shop items," which would normally be provided by the employer/shop, as opposed to "individual items" one might keep in their personal toolbox in the shop. I'm curious what everyone finds (trying to keep this on the "metrology" topic) getting a lot of mileage in your home shops? Things that fit this category that are already on my list are things like a good medium-to-large surface plate and height gage (I'm pretty sure I've worn holes in our Rahn plate at work, I use it so much), some larger angle plates and V-blocks, etc. I'm kind of all over the map in the "type" of work I do in the home shop - gunsmithing, automotive stuff to include boring/honing bearing races and the like, random "custom fab" stuff like bumpers, spare tire carriers, etc., and I'm recently taking a keen interest in "tightening up" my work - striving for tenths accuracies on things instead of thousandths. Tool & die work very much interests me, but I've missed that boat professionally, so I expect I might dabble finer and finer in the home shop - unsupervised and unafraid. Obviously a lot of this is "as needed" type things - no point buying tiny pin gages if I never work with small holes, so I'm just kind of curious what I might be overlooking.

Short version: What metrology tools do you find yourself using constantly?
 
6" digital calipers are my go to for general measuring and the mic for those more precise needs. I use a height gauge and surface plate for most layout work. The DRO on the mill has become indispensable, though I have yet to add one to the lathe, mainly due to an impending lathe upgrade. Dial and test indicators are also indispensable for alignment tasks. Hole gauges and adjustable parallels are also frequently used.
 
Sounds pretty on track with what I've already squirrelled away haha, with the exception of the height gauge and surface plate, which are near the top of the list for shop purchases (though honestly shop purchases are nowhere near the top of the overall list). Though no DROs here. Too stubborn to wedge them on to old American iron.
 
My favorite tool is my Mitutoyo Digimatic calipers. They are your standard run of the mill electronic calipers, but have a nice fit and finish, and have outlasted several other pairs with no end in sight.


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In the sad event that those die, I have a no-name mechanical dial caliper which never seems to be short on batteries :p.


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Second most used is my Mitutoyo absolute micrometer. This was a gradutation gift from my dad.


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For tool presetting (CNC) and general measurement, I use this shars brand 8" height gauge. Unfortunately my only granite surface plate right now is a 6x8" one from Tormach designed for tool presetting. Hope to pick up an 18x24" at some point.


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For more precision work, I have a 0-6" micrometer set. Most of these are mismatched but I do have a set of standards with calibration certificates. I use these standards to qualify most of my tools.


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My favorite indicator is my Fowler X-Test Swiss Type. It lost a tip to a keyway a year ago and I finally located the correct replacement tip. Glad to have it back.


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During that year, I picked up a Shars .0005" indicator for something like $30. It works like a charm, but I do miss the swivel stem and double range of the Swiss indicator (Shars sells one of those too). I recently picked up a Noga style base from... you guessed it... Shars.


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For measuring bores, I use a Mitutoyo 155-903 set of telescoping bore gages. These are a must have. For smaller bores I recommend either split tip style bore gauges or gauge pins.


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For measuring depths of internal features or some external features, I have a Starret 0-6" depth micrometer. If you've ever tried to use the back of your calipers to measure depths and found it very frustrating, you need a set of these.


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Less often used but very accurate is a Federal .0001" dial indicator. It is old, but runs very true. Really only used for tramming or measuring runout.


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New for the lathe are a set of thread measuring wires, metric and imperial theard gauges, and a master precision level.


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(honestly this is so sensitive you'll want to pull your hair out)

Finally one last pin micrometer, it is pretty beat up but I trust it for +/- .001" and has saved me on some small and difficult to reach parts.


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I didn't take pictures of the various setup and layout blocks that I use, but having a number of decent quality 1-2-3 blocks, v blocks, and angle plates is a must. I also have a high precision cylindrical square for tramming my mill. I'm sure I forgot others but these are the main ones.

Not shown are a few sticks of a very tough green wax we used in the lab. Not sure what the material is, but we used it for checking inaccessible internal features. Heat it up, stick it on, let it cool then measure.

It is a never ending collection, but the more ways you can measure your part and machine, the more confident you can be as a machinist.

-Mike

 
My surface plate is 18x24" and does about all I need it to do. But my shop is smaller, 730 sq. ft. 3 car garage that still fits one car. Large surface plates can often cost less to purchase than smaller ones. I have seen some really large ones given away. IMO, any surface plate that you have not personally kept track of since its last calibration should be re-calibrated before any serious use. An unknown is just that. However, moving and calibrating larger surface plates is a much bigger job, and the calibration can cost a lot more.
 
I wonder that we may take the issue of calibration a bit too seriously; sure, I take care to occasionally zero out my mikes against the standards that came with them all those years ago (about 50 or so), but do we need to fret over the flatness of a surface plate that we do layout on with a height gage that is graduated in whole thousandths and never has been calibrated and that the marks it makes on workpieces are machined to by eye?
It is one thing to need high accuracy of a surface plate that may be used as a scraping reference surface, and quite another for one used in day to day layout tasks. I have never felt the need for pin gages, and seldom even use drill blanks; perfect sizing of parts that we machine is seldom necessary, FIT is what IS necessary.
 
I wonder that we may take the issue of calibration a bit too seriously

Completely depends on the work you do. If you are making assemblies in the home shop then yes fit is absolutely the most important. If you have a customer print with tight tolerances and no way to check what it fits up to, then you need to measure tight tolerances and know your instruments will read the same numbers as everyone else's. That's where calibration comes in. Also depending on the industry, customers may require calibration certificates
 
Perhaps the name of this forum (Hobby Machinist) suggests that for the most part, we are talking hobby shops and hobbyists, not high tech workers and ultra precision venues.
 
Fair point. I myself only dabble in projects that require accuracy in the realm of tenths, however there are plenty of hobbyists out there who consistently produce very high precision work. Your metrology needs are completely dependent on the kind of work you are doing.
 
I also deal with tenths, but not in the lower numbers of tenths ------- which can be quite problematic to measure, at best.
 
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