Cutting a square pocket in aluminum. Test your skills on where this stuff came from.

[rons]

Designing a square pocket into a 3/8" thick 6061. I was told it is 6061. Anyway is this stuff imported? Numbering system used?

Real question is making a square pocket into the 6061. Like the thickness of a door hinge.
I made this tool for plastics from 3/4" stainless by recommendation of a machinist. He was working at a tool supply after having been laid off after 9/11.
It works good for plastic. Square two sides and grind a bevel on the bottom. Apply force downward. What can be done better for aluminum or harder stuff?

 

[sfriedberg]

Anyway is this stuff imported? Numbering system used?

Can't tell you from a photo if it's imported. All three of those printed labels are ASME or SAE (i.e, " 'Murican") material specs applicable to 6061 alloy, although you may see B209 for the ASTM spec instead of SB209 for the ASME spec. IIRC, 4027 is specific to 6061, while the other two specs apply to multiple alloys. FWIW, the unsuffixed AMSQQA250 spec was updated in 2012 to 250A and again in 2018 to 250B, but I don't know if that's significant or not.

 

[Limy Sami]

Designing a square pocket into a 3/8" thick 6061. I was told it is 6061. Anyway is this stuff imported? Numbering system used?

Real question is making a square pocket into the 6061. Like the thickness of a door hinge.
I made this tool for plastics from 3/4" stainless by recommendation of a machinist. He was working at a tool supply after having been laid off after 9/11.
It works good for plastic. Square two sides and grind a bevel on the bottom. Apply force downward. What can be done better for aluminum or harder stuff?

View attachment 391352

View attachment 391353

Make the same tool from a HSS drill blank or high carbon drill rod and heat treat yourself, and keep it as short and still as possible (said the porn star to the bishop)

 

[DavidScott]

My solution was to make a bar to hold a square carbide insert so I could have an easily replaceable cutting edge with proper rake.

 

[Bill D]

Rotary broach?
Bill D

 

[sfriedberg]

Not really a good application for a rotary broach, in my opinion. You can synchronize a rotary broach to surface features (like the edges of the recess), but that doesn't come for free. The part has to spin, and you'd need to set up for all four corners, so that's a pretty good sized faceplate or 4-jaw chuck. (Recess may not be that large, but they aren't going to be centered on the part, either.)

The real difficulty with any broaching technique, rotary or otherwise, into a blind hole is "Where is that chip going?" The shallow flat-bottomed recess does not lend itself to a relief groove, which is usually considered mandatory on a vertical shaper/slotter for non-through broaching.

 

[rons]

A video for making a through hole pocket.
Start in center and travel to one edge minus .010. Traverse circumference. Then widen your travel by .010.

I need a partial depth pocket off the edge. Long edge is X. In X the length is 6". In Y the length is 4". Depth is .185. Plate is .385 thick.
What is a good size cutter and pattern to do this? I have seen some awful cut stuff with spirals all over the place.

What path would a CNC machine make?

 

[kustomizer]

I would drill a small hole near each corner leaving as little material as possible, mill the prifile of the pocket with as small an endmill as you can then use a rotary broach bit held static to nibble out the corners likely 2 or 3 bites at each corner. Plunge straight down to a couple thousandths off the bottom of the pocket, move away from the corner .005 or so at a 45 degree angle, back up aid into the corner about .005 farther than the last bite also at a 45 degree angle, then move on to the next corner. I use polygon solutions 3/8 square broach as it seems very economical for this type of work, through holes or pockets it works well just don't hit the bottom of the pocket with it. These happen to be through but the same process.