60° v block

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earlgo
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60° v block

Post by earlgo » Fri Sep 14, 2018 9:19 am

How would one go about making a 60° V-block for measuring the diameter of a 3 flute milling cutter? I'm thinking of something about 1" x 1" x 1" made from cast iron. I think I know how to machine it with a slitting saw, but then how is it ground smooth? Is there any other way except dressing a less than 60° angle on a grinding wheel? I am reluctant to waste that much wheel.
I am also reluctant to spend over $100 for a 60° micrometer.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.

mikeehlert
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Re: 60° v block

Post by mikeehlert » Fri Sep 14, 2018 9:33 am

Just FYI, in a previous job we/I had a 60 degree 1" mic for a particular 3 flute job. It was a Starrett thimble 0.0001" carbide faced and when worn the cost to resurface the anvils resulted in a new mic. It was a lot more than $100 though.
Currently, this $201 is the cheapest on Amazon;
https://www.amazon.com/Fowler-52-211-14 ... micrometer

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GlennW
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Re: 60° v block

Post by GlennW » Fri Sep 14, 2018 9:39 am

I've considered doing the same and decided the way to go would be to dress a wheel that was wide enough to make a single pass to 30 degrees.

I have a sine chuck on my grinder so I would just set the chuck to 30 degrees and all would be good.

The relief groove at the bottom of the V would give you room to keep the side of the wheel from contacting the vertical side of the V during grinding.

Of course, you them flip the block 180 and finish it.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

John Hasler
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Re: 60° v block

Post by John Hasler » Fri Sep 14, 2018 11:47 am

Bolt two 60 degree blocks to a base.

earlgo
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Re: 60° v block

Post by earlgo » Fri Sep 14, 2018 12:17 pm

Yes, I considered both of those solutions, but was hoping there was some other solution I didn't think of. Oh well.
Thanks for the replies.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.

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tornitore45
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Re: 60° v block

Post by tornitore45 » Fri Sep 14, 2018 12:48 pm

Please satisfy my curiosity:
Once you have a 60 degree V block how do you determine the diameter of the 3 flute tool?
Mauro Gaetano
in Austin TX

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GlennW
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Re: 60° v block

Post by GlennW » Fri Sep 14, 2018 1:03 pm

I was going to use it to check roundness of of shafts, etc.

A 90 degree V block will not detect tri-lobed shafting.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

earlgo
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Re: 60° v block

Post by earlgo » Sat Sep 15, 2018 11:13 am

tornitore45: The attached .pdf is the way I have always done it.
V BLOCK CALCS GENERAL RULE.pdf
v-block calculations general rule
(73.69 KiB) Downloaded 36 times
Feel free to correct me if I am in error.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.

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tornitore45
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Re: 60° v block

Post by tornitore45 » Sat Sep 15, 2018 1:49 pm

Thanks, as I suspected the specialty micrometers screws are not 40 TPI but divided by the factor M to give a direct reading.
Mauro Gaetano
in Austin TX

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