Milling 37 degree chamfer around a circular piece...

[blksmith]

can you put the part in the mill collet and clamp a lathe tool in the vise?

[widgitmaster]

ok, grab a broken 1/2" endmill, take it over to a pedestal or bench grinder along with a cup of water!

Grind a flat that is .25 deep, so the broken end is now a half-moon!

Take a small protractor, and grind one side to a 37° angle.
Then remove all the rest of material that would be behind the cutting edge!

this is what's called a single lip cutter!
They are quick and dirty way of doing simple tasks, and you will not be the first to need one or make one! Or burn your fingers while trying! (that's what the water is for)

Give it a try, it will make a machinist out of you!

They work exceptionally well, and best used in climb milling!

Eric

Oh yea, I forgot to mention you need to put it in a boring head and adjust it to the required part OD!

[JPMach]

Originally Posted by widgitmaster Oh yea, I forgot to mention you need to put it in a boring head and adjust it to the required part OD!

That is exactly what i was thinking should be done. You could mount it in an endmill holder and interpolate but nothing will be faster than in a boring head.

My problem is any broken endmills I have are all solid carbide, and no carbide grinder!

JP

[widgitmaster]

Originally Posted by JPMach That is exactly what i was thinking should be done. You could mount it in an endmill holder and interpolate but nothing will be faster than in a boring head. My problem is any broken endmills I have are all solid carbide, and no carbide grinder! JP

So use a .500 gage pin, then buy a new one later!

[Kiwi]

If you grind a cutter out of 1/2in HSS like attached pic this can be feed directly down the axis of your part. No interpolation or boring head adjusting.

[peter.blais]

Hmm. hehe, might take me some doing to get that ground right... Seems like the way to go though... I could make a large one that way that can handle the different sizes I need, which are mostly between 1/4" and 3/4"... Seems like the hardest part will be getting it really close to 37 degrees as that is a bit critical for the application.

They are for low pressure AN fittings carrying oil, there really isn't any pressure in the application but it still needs to not seep any oil. They seal on the 37 degree, so I think going straight down the axis is better then interpolating around anyways because it won't leave any small machine marks... Since its raw 6061 they tend to deform and seal up ok anyways though becuase most of these decent sized threads generate a healthy clamp.

Just going to have to start grinding some tools and do some bench testing to make sure i'm getting a workable seal out of the finished product.

[Kiwi]

You may have some chatter problems if the face gets too wide.
As this is a fitting to carry oil I presume it has a hole through the centre. If part of the cutter can enter the hole and also cut a small radius on the hole-edge this will help to prevent chatter.
Are the holes different sizes and is the hole already bored before you machine the 37deg face?

[peter.blais]

There are a bunch of different sizes I will need to cut. The hole could be bored, before, after, whatever.

The 37 degree face is like .125" wide even on the large fittings. Pretty small.

[mxtras]

http://www.internationalscrew.com/pa...tor/metcut.htm

Or more specifically:
http://www.kennametalipg.com/brands/...ourcutters.pdf

An SAE countersink - is this what you are looking to duplicate? These tools ream the hole for threading, cut the o-ring chamfer to spec and create the proper spot-face for SAE, JIC (or whatever) fittings.

I don't know if this is what you are working with, but it sounded like this might be what you are attempting to create.



Scott

[peter.blais]

Those are handy, for cutting the internal thread... Thats for an O ring boss style fitting correct? I might end up buying some of those as well because I am siiick of pipe thread stuff.

Here is what i'm trying to do- essentially mill a male -4, and -10 (different parts) on the outside of a part. The HSS chamfer above will work well I think, i'm trying to do ~20 of these at a time from sheet.

like this: