Measuring the diameter of 3-flute/sided tooll

Stick the cutter in your mill, start the cutter turning, and edge it up to a piece of stock of known length. Make note of the digital read out's X (or Y depending on which way you decide to traverse) position. Then traverse the mill to the other side of the stock and edge the mill up to it. Some simple addition or subtraction should give you the cutter's diameter. Dave

Do a cut across a piece of scrap.

PV:

If you're going to be doing a lot of measuring of 3 flute end mills you might invest in an anvil micrometer:

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Otherwise, you can use a V-Block and a height gage. Set zero on the shank, then measure the flute diameter (rotating the cutter to get the highest reading. Calculate from there.

The suggestion by Tid Bit , to just take a pass in a piece of scrap (use the same material you're going to machine your part out of) is quick, easy, and accurate.

See, this is what happens when you sit around goddamm pyooters'n's*it all day--you lose yer common sense!

Great idear! Which can be used to determine the multiplier for caliper-measuring as well. Actually, I thought of this this morning, and was going to post it, but not after frittering away boucou time yesterday on an effing spreadsheet, thinking I was a shop bad-ass.

PV:

Or how about putting a gage pin in a V block and comparing the endmill with an indicator.

Best, Steve

BottleBob wrote in news: snipped-for-privacy@earthlink.net:

It's actually more accurate, since you can measure what the cutter actually _cuts_ instead of it's diameter.....there can be a considerable difference in the two.

They sell v-anvil micrometers designed for the measuring of 3- and 5- fluted tooling.

A drill sizing plate - an array of holes - would size it.

A draftsman circle template is the say concept.

Rather than milling a block of Al or steel - how about wax.

Mart> See, this is what happens when you sit around goddamm pyooters'n's*it all

Read what it says on the shank

Bob

Along the same lines...Drill an undersize hole and bore with the endmill then measure the hole diameter? Randy

But if it's been sharpened............. Randy

But if it's been sharpened _properly_.........

LLoyd

I meant to say re-sharpened. Randy

I meant to say "re-sharpened properly".

LLoyd

Bob is a good example of why I have to work alone.

LOL

I trusted a resharpened endmill (1) time. It was .01 smaller than the etching on the shank. So it had been resharpened at least twice.

Now I measure.

Gunner

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How about reading what is written on the shank?

Bob

According to woodworker88 :

Yes -- the one for three-flute (and also six-flute if you want to measure other than across two opposite flutes) has a V of 120 degrees, while the one for five-flute tooling is 72 degrees. I've got an example of each -- from eBay auctions over the years.

Enjoy, DoN.