Where can I get precisely ground cylindrical tool steel rods for metrology ?

[maxime.levesque]

A lot of measuring techniques involve the use of cylindrical rods, for ex, to measure dove tail with a micrometer, one can place rods at both ends, measure the distance between the rods, subtract the diameters.

I'm not equipped to turn rods as accurately as I'd like (unfortunately), so I'd like to buy a few,

McMaster Carr sells with a somewhat decent accuracy, I've also looked at end mill blanks that can be had with an accuracy of "0.0002,
end mill blanks have the advantage that they should last given the hard alloys.

I'd like to get suggestions of sources for buying precisely ground cylindrical blanks, at reasonable prices.

a few pairs of length of "3 would be ideal, of widths, 1/8, 1/4, 1/2, 3/4.

 

[jwmay]

Most just use dowel pins.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[RaisedByWolves]

Do well pins work but may require extra math thought processes.

Thompson rod is ground on size and would be what I would use if I was making up tooling I was wanting to keep for future use.

You will need carbide or a cutoff saw to work with this.

 

[ChazzC]

Drill Blanks

 

[jwmay]

There’s a pretty big gap between mating dovetails. A big enough gap for a gib strip held firm with gib screws. Unless it’s paid work with tolerances called out, there’s not much excuse to worry about .0002” on the diameter.

 

[Flyinfool]

You can buy plug gauges in any diameter you want with tolerance down to .0001.

 

[MrWhoopee]

Individual gage pins can be had very cheaply
All the way at the bottom.

Gauge Blocks & Clamps | Zoro

We offer a wide selection of gauge blocks and clamps, from elaborate sets to simple designs. Get the precision and calibration you need with these quality tools.

www.zoro.com

 

[Ulma Doctor]

Carbide blanks are readily available on ebay, relatively inexpensive too
I can’t say for certain what the tolerances would be, but I’m sure they are worthy of investigating.

Gauge pins are relatively inexpensive for single sizes and are excellent for the purpose of measuring

Dowel pins are very precisely ground usually within .0005”
Carbide endmills are usually within .0005” too

 

[aliva]

Fastenal.ca carries drill rod which has pretty tight tolerances

 

[Janderso]

Plus 1 on gauge pins. I use my sets quite frequently for many projects. Joe Pie uses them to locate a visual center on model castings. I use them to check hole sizes while machining. They come in handy on the mill for many reasons
The import sets are very reasonable.
This set is from Meyer. I paid $200 for both. No pins missing