How to make a sharp corner on a mill?

[zaebis]

Vertical mill, rectangular poket bt 3x4" 1" deep need to mill it with sharp corners. How?

[PoiToi]

How sharp is "sharp"??

You can use progressively smaller endmills to get to the corner radius you need (no matter what you do, there is ALWAYS gonna be a radius. even if it's .00001, it's still there)
Or use small drills at the corners first, and then mill the pocket.

You can rough it out and file down the corners by hand...

I think if you tell us more info there are many namy members who will have great ideas.

[Switcher]

Can you cut pockets in the corners?

http://www.omwcorp.com/img/cutawayco...ket600x514.jpg

[zaebis]

Originally Posted by Switcher Can you cut pockets in the corners? http://www.omwcorp.com/img/cutawayco...ket600x514.jpg

ya that is what I thought. Thanks will have to settle for this workaround.

[DareBee]

It is an EDM job if you can't pocket the corners.

[zaebis]

Originally Posted by DareBee It is an EDM job if you can't pocket the corners.

can EDM cut a pocket? e.g. carve 0.5" deep of 1" thick stock? not through !!!

[beege]

Ram EDM

[DareBee]

Of course.
I do it all the time.

I also have tapping rig, amazing how many people need tapped holes in hard material.

[palenn]

Making a square broach to fit in the mill spindle might be a way to approach the square corners. A piece of 1/2" drill rod, for example, milled to a square shape on one end and then hardened could be used in the mill spindle as a broaching tool moving the spindle up and down by hand while feeding the X and Y axis in small increments. This method is sometimes used in lathes for making blind keyways.
An alternative to making your broach out of round stock would be to use one of these sleeves to hold a square HSS lathe tool http://http://www.sturdybroach.com/products.nxg

[Charlie Gary]

Originally Posted by palenn Making a square broach to fit in the mill spindle might be a way to approach the square corners. A piece of 1/2" drill rod, for example, milled to a square shape on one end and then hardened could be used in the mill spindle as a broaching tool moving the spindle up and down by hand while feeding the X and Y axis in small increments. This method is sometimes used in lathes for making blind keyways. An alternative to making your broach out of round stock would be to use one of these sleeves to hold a square HSS lathe tool http://http://www.sturdybroach.com/products.nxg

Be sure to ask your boss if it's ok to use the spindle bearings as a press. Most will freak out.

[DareBee]

Originally Posted by palenn Making a square broach to fit in the mill spindle might be a way to approach the square corners. A piece of 1/2" drill rod, for example, milled to a square shape on one end and then hardened could be used in the mill spindle as a broaching tool moving the spindle up and down by hand while feeding the X and Y axis in small increments. This method is sometimes used in lathes for making blind keyways. An alternative to making your broach out of round stock would be to use one of these sleeves to hold a square HSS lathe tool http://http://www.sturdybroach.com/products.nxg

This method works, but you will not get a good bottom.
For lack of not wanting to type big explanation for many variables, you will end up with a material pile under the broach that will not shear (remember this is a blind pocket). This could be as much as 1/4" considering you are working a 1" deep pocket and envisioning normal cutters and cutting practices for the initial milled pocket.

[RICHARD ZASTROW]

Try "googling" cherrying or cherrying head.

Dick Z