# Considering making my own pin gage set



## erikmannie (Dec 25, 2019)

So I just got my first lathe all set up, a PM-1030V with a PM DRO. I don’t own a pin gage  set, and I currently have more time than money.

Has anybody ever heard of somebody making their own pin gage set? Really the only question I have is about material and heat treatment.

I also have a mill, a PM-25MV. I imagine that I would make the base for the pin gauge set with the mill, perhaps out of aluminum.

I just do this for fun. I’m just looking to learn how to hit a length and diameter.


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## Ulma Doctor (Dec 25, 2019)

i have not heard on a hobby guy making his own pin gauges, but there is nothing stopping you from trying! 

do you have a range of measurement in mind?
what accuracy do you intend? .001", .0001", metric?
thousandths will be easier, tenth's not so easy

do you have means to grind the pins?

you may wish to consider a steel that doesn't oxidize quickly, otherwise 303 stainless comes to mind

go on one end & no-go on the other end type gauges would be a cool addition to the plan


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## benmychree (Dec 25, 2019)

Another question might be, what would be the intended use for them?  I have been at the trade all my working life (going on 75 years soon) and have never seen a need for pin gages; transfer punches are perhaps more useful, and step gages are also handy for setups and I mostly use them in conjunction with the lathe carriage stop, a set of two of them have steps from 1/8" to one inch by sixteenths of an inch.


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## erikmannie (Dec 25, 2019)

Ulma Doctor said:


> i have not heard on a hobby guy making his own pin gauges, but there is nothing stopping you from trying!
> 
> do you have a range of measurement in mind?
> what accuracy do you intend? .001", .0001", metric?
> ...



I was thinking Imperial and thousandths. For example, .010” to .500”. That range would be 491 pins. 

That is a good idea to use 303 SS.

I have no means to grind the pins.


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## Liljoebrshooter (Dec 25, 2019)

I can't imagine how aggravating this would be.  I guess you would get lots of practice trying to hit a specific size.

Joe Hynes


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## erikmannie (Dec 25, 2019)

benmychree said:


> Another question might be, what would be the intended use for them?  I have been at the trade all my working life (going on 75 years soon) and have never seen a need for pin gages; transfer punches are perhaps more useful, and step gages are also handy for setups and I mostly use them in conjunction with the lathe carriage stop, a set of two of them have steps from 1/8" to one inch by sixteenths of an inch.



I had to look up step gages. I don’t even own feeler gauges.

I would use the pins to check the diameter of a drilled, bored or reamed hole.

I do not currently own an inside micrometer or snap gauges. I will be buying some snap gauges soon, however.

I also do not currently own any transfer punches or transfer screws. I bought a mill & lathe and about 50 tools to accompany them. I ran out of money before I got the above as well as a sine bar, gage block set and .0001” graduation test indicator (0-4-0 type).

I bought four used Starrett items on eBay, but the overwhelming majority of my auxiliary equipment is from Shars and Precision Matthews. It was either that or going without.

Generally speaking, I find the import tools to be barely good enough. I only do this as a hobby, so I am tooled up enough to make a lot of things for myself, family and friends.


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## erikmannie (Dec 25, 2019)

When I went to school, they recommended spending a lot of time practicing being able to hit a dimension. A pin gage set would be a lot of practice turning to a diameter and facing to a length.


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## erikmannie (Dec 25, 2019)

erikmannie said:


> When I went to school, they recommended spending a lot of time practicing being able to hit a dimension. A pin gage set would be a lot of practice turning to a diameter and facing to a length.



The beginning of the project would be easy because I could just turn some round stock to a smooth finish (I may use a smooth file or emery paper), measure it, and odds are that I would need that diameter for my set. Chamfer, part, face to length (1”?), chamfer the second end and repeat that process.

At the end of the project, it might be challenging to nail the remaining diameters.

I wonder if I would be able to successfully make the base with 491 holes in it on the first attempt. Talk about drilling practice!


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## Bob Korves (Dec 25, 2019)

Pin gages are used for checking small hole diameters.  They are about the quickest accurate way to do that.  Building your own set may be possible if you are young enough and live long enough that you won't die before getting them done.  Imperial small holes gages typically go in .001" increments.  I have pin gages from .010 to .500" -- 490 separate gages.  If you buy stock, it will likely be 36" long for each diameter.  That will cost WAY more than buying a set of pin gages.  How would you grind them down accurately *round* to an appropriate accuracy and lack of taper -- all properly tested, of course. Unverified pins are essentially worthless.

They are somewhere around 2" long.  The sets are laid out in order in nice boxes to make them easy to deal with.  With holes over .500", other methods can be faster and about equally accurate.  I can think of a whole lot of projects I could do that would be easier, quicker, cheaper, more accurate, and more likely to be completed than what you are asking.  I could make a Crescent wrench copy, but why would I want to?  I think I have well less than $200 in my 4 sets of gage pins, only use them a few times per year, and consider them a bargain and a good resource.


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## extropic (Dec 25, 2019)

How can I approach the subject in a positive manor? . . .
Where are you going to get your raw stock?
Lets say you want to make 500 pins, each 1 inch long (damn short), .250 max diameter, from 303 stainless.
That's 42 feet of raw stock.
From McMaster-Carr, 1 each of the 7 smallest diameters (3/32 to 5/16 x 6 foot long sticks), of the cheap 303, adds up to $63.73+S&H & Tax. With cut-off allowance and some stock left in the chuck, 42 feet won't be enough.
A 1/16 wide cut-off blade will waste 31.5" in 500 cuts. Add another stick of raw stock.
Of course, you're already set-up to grind and freshen the HSS tool bits you'll need.
How much wet-or-dry abrasive paper will you need (about $1 per sheet) to polish those pins?

You can buy a chicom set on eBay (.061-.250, delivered to your door) for less than 303 raw stock. The chicom pins won't be (very) hard, but harder (more durable) than 303.

When I was about 12 YOA I built a go-cart frame using 3/4" pipe and fittings. It was what I could get my hands on. To finish the rectangles, I ground out the female thread from the last fitting, slip fit the pipe and only had to pay for a small amount of welding to secure it. That old welder was kind to the little kid. That thing was crazy heavy but made it around the block many times. I understand having more time than money but I only made one of those, not 500.

Please think of a different project.


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## Bob Korves (Dec 25, 2019)

A pin gage is not a turning job made on a lathe, it is a cylindrical ground precision tool.  They will need to be accurate within at least a tenth and also parallel within .0001" or so.  They are hardened to resist wear, and made from steel with more chromium, etc, so they will be less likely to rust.  They also need to be straight.  Maybe it would be worth making the first 5 smallest ones from .010 to .015" first and see how that smaller project goes for you...  Do not cut yourself any slack, each one needs to make the specs...


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## erikmannie (Dec 26, 2019)

I now believe that this is not practical, if for no other reason than the import set is less expensive than the raw stock.

I can practice turning to a diameter and facing to a length on the scrap that I already have.

A similar argument goes for making a gage block set.

Thanks to everybody who weighed in.


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## pontiac428 (Dec 26, 2019)

If you still want to try it out, you can make gauge pins as you need them, based on projects.   You can try a go/no go gauge or a fixture pin on an as-needed basis and still get the experience you're after.  A toolpost grinder would probably work well enough for a home shop, but it's a long, long way to commercial grade accuracy from there.


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## eeler1 (Dec 26, 2019)

I once made a set of go/no go gages to check ammo, in my case, pellets for my pellet rifle.  These were to be used to check the size of holes that would tell me if the head of the pellet was a specific diameter, as there is (or was) some variability in head size and certain sizes shot best in my airguns.  Pretty important for competition purposes.  

I needed sizes of 0.173", 0.174", 0.175" etc up to 0.179", for six total (airgun barrels are generally choked a bit).  Actually, I worked in tenths, with each one to be within - 2 tenths of the desired size but not oversize.  It was pretty easy to get a few done, as no matter what, I would end up with something that met my requirements in one of my sizes.  But, hitting those last few was incredibly difficult, especially the last one.  Turns out hitting 0.1768-0.177" is not that easy.  I ended up with multiples of the smaller sizes, since i could always take just a little more off.  And I may have fudged a bit on the biggest one, looser tolerance since it was bigger, I guess.

It was a semi fun and semi frustrating project.  You might have an easier time with a new lathe than I had with my beater Logan.  And yes, it would be good practice for you.  But don't expect to be able to make a full set of gage pins.


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## petertha (Dec 27, 2019)

Just to give a feel of something similar, I just finished making a dozen valves for my 5-cyl model radial engine from 303 stainless. And I'm real glad that's over with. They stems are nominal 3mm (0.1181) and I held myself within +/- 0.0001" because they must fit a matching reamed hole in the valve cage. The skinny aspect ratio requires that it be supported with live center. You wont be able to turn skinny pins down cantilevered from the chuck without some kind of end support. That's another difference between a regular lathe and centerless (or somehow supported) grinder where gage pins are made.

Grinding wasn't an option for me so they were turned down ~0.002" oversize, then a series of simple split laps were used with finer grade pastes. Its messy time consuming work. I used a 3mm gage pin (price about 2$) to calibrate my lapping block as it needs to be redressed with wear. Stainless typically doesn't like to be crept up on thou by thou (it can work harden). It also can get pretty warm with heavier cuts so in this range you either have to account for expansion or wait till it cools to reference temperature when measuring. 

Anyways, its good to have some experience like this, it facilitates making some useful things. Make a few do-dads just to learn & have some fun, but I'm guessing the novelty of making a set will wear off in a hurry. And even if they are bang on diameter, you are left with something relatively soft compared to real pins which are hardened before being ground.


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## Caffeinated6492 (Dec 27, 2019)

You could modify a height gage scribe to accept a small pin, held parallel to the surface plate.  Then as long as you can hold your bore parallel, you can measure the bore and add the diameter of your pin.  Modify pin as necessary for feature.  You could even modify it to accept m2/m3 threads and screw in cmm probes or whatever.


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## Cadillac STS (Dec 27, 2019)

It would be nice practice getting a good surface finish on your new lathe.  

Early on it would be very easy to get them going because if you need all sizes you can just stop with any size once it looks good and it will be one of the sizes.  Will be more challenging with needing to make exactly the right size for the missing sizes needed but after a couple hundred you will have better skills.


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## MrWhoopee (Dec 27, 2019)

There are lots of useful tooling projects you can make for practice. Spindle stop for the lathe, vise jaw stop and table stop for the mill. The list is nearly endless. Any of these would be more useful, educational and entertaining than making gage pins.


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## erikmannie (Jan 11, 2020)

I will buy a pin gage set one day.

For fun, I ended up making four pins equal in both length and diameter: 1/4", 1/2", 3/4' and 1". My surface finish was an issue, but I got them to within about .0003". The surface finish was the limiting factor, and I am reluctant to use emery paper because the ways are brand spankin' new. It was good practice for turning to a diameter and facing to a length on my new lathe.

If I were to do it again, I would take down the last .0008"-.0010" with a smooth file or emery paper. I lapped one of two few faced ends, but I was in danger of going under the specified length.

Along the way, I realized that my DRO (on a PM-1030V) has a resolution of about .00020"; that is, the finest adjustment that I can dial to is .00020". So I am not able to dial in .0001" using the handwheel. I would have to use an indicator, and I don't have a test dial indicator with tenths graduations.

The 1/4" X 1/4" pin was really small in the 5" 3 jaw chuck. I don't think that I could chuck up a 1/8" X 1/8".

At one pojnt, I bumped the cross slide handwheel, dialed in for a finish cut and proceeded to scrap that pin. That scrap became the 1/2" pin. After that, I steered clear of the handwheels when measuring the part in the chuck (and kept track of my location on the DRO).

Here they are. These are the first things that I made with my first lathe.


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## f350ca (Jan 11, 2020)

Nice work.
I've never sprung for a set of gauge pins but there have been times I could use them. For standard fractional sizes dowel pins make a viable substitute.

Greg


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## erikmannie (Jan 11, 2020)

f350ca said:


> Nice work.
> I've never sprung for a set of gauge pins but there have been times I could use them. For standard fractional sizes dowel pins make a viable substitute.
> 
> Greg


I never thought of wood! I will use dowel pins until I can save up for a pin gage set.


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## f350ca (Jan 11, 2020)

I do a lot of cabinet work but I meant steel dowel pins. 



Greg


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