5/8” diameter, 3 flute end mill, cutting hole

[Firstgear]

I needed to drill a 5/8” diameter hole through 1-1/4” thick 6061 aluminum. I didn’t have a 5/8” drill, but had a 3 flute end mill. I had the mill speed at around 1300rpm. The three flutes at the end were fine initially, but the deeper I got they would load up in the flutes near the tip. When this happened the end mill didn’t really want to cut any more.

I would stop the mill and use a small screw driver to flick out the loaded up aluminum.

Is there something I can do to avoid the flutes loading up or is this just something that comes with the territory?

 

[mmcmdl]

End mills load up . Use a smaller size drill first and then send the end mill thru . Use some type of lubricant such as wd-40 .

 

[Firstgear]

End mills load up . Use a smaller size drill first and then send the end mill thru . Use some type of lubricant such as wd-40 .

I should have added that I was using WD40.... I have 1/2” drills, I can use one of those. Speed ok?

 

[mmcmdl]

1/2" is fine . Even though center cutting end mills " cut in the center " , the surface speed is virtually zero , thus they load up . Pre-drill it and you'll only be using .062 of the flutes and chips will clear .

 

[petertha]

I would recommend investing in some annulur cutters. You can buy them onsey-twosey as you need certain sizes or graduated sets. They come in 1, 2 and 3" flute length. You will need an arbor like R8 or MT3 (or both if that is your mill & lathe respectively). Anyways they do a very efficient job of cutting clean, accurate bigger diameter holes with little fuss. Plus you get the leftover core slug for another project instead of making a pile of swarf.

1" Depth Cutter 8pcs HSS Annular Cutters Set, 7/16", 9/16", 11/16", 13/16", 15/16", 1-1/16", HSS1-0000

The annular cutter is typically for the following tools and solutions: annular cutter, core drill, core cutter, broach cutter, trepanning drill, hole saw, cup-type cutter, annular cutter 1/2, annular cutter 5/8, annular cutter adapter, annular cutter 3/4, annular cutter drill adapter, annular...

www.accusizetools.com

 

[Firstgear]

I would recommend investing in some annulur cutters. You can buy them onsey-twosey as you need certain sizes or graduated sets. They come in 1, 2 and 3" flute length. You will need an arbor like R8 or MT3 (or both if that is your mill & lathe respectively). Anyways they do a very efficient job of cutting clean, accurate bigger diameter holes with little fuss. Plus you get the leftover core slug for another project instead of making a pile of swarf.

1" Depth Cutter 8pcs HSS Annular Cutters Set, 7/16", 9/16", 11/16", 13/16", 15/16", 1-1/16", HSS1-0000

The annular cutter is typically for the following tools and solutions: annular cutter, core drill, core cutter, broach cutter, trepanning drill, hole saw, cup-type cutter, annular cutter 1/2, annular cutter 5/8, annular cutter adapter, annular cutter 3/4, annular cutter drill adapter, annular...

www.accusizetools.com

I thought about using one of those. I have a couple of sets, so I will try that next.

 

[projectnut]

I would recommend investing in some annulur cutters. You can buy them onsey-twosey as you need certain sizes or graduated sets. They come in 1, 2 and 3" flute length. You will need an arbor like R8 or MT3 (or both if that is your mill & lathe respectively). Anyways they do a very efficient job of cutting clean, accurate bigger diameter holes with little fuss. Plus you get the leftover core slug for another project instead of making a pile of swarf.

1" Depth Cutter 8pcs HSS Annular Cutters Set, 7/16", 9/16", 11/16", 13/16", 15/16", 1-1/16", HSS1-0000

The annular cutter is typically for the following tools and solutions: annular cutter, core drill, core cutter, broach cutter, trepanning drill, hole saw, cup-type cutter, annular cutter 1/2, annular cutter 5/8, annular cutter adapter, annular cutter 3/4, annular cutter drill adapter, annular...

www.accusizetools.com

Annular cutters are good, but they can be expensive. The ones you linked only have a cutting depth of 1". In this case the OP needs to cur 1 1/4" material. He'll need a little more expensive set like these

13 Pc/Set, 7/16" to 1-1/16" HSS Annular Cutters, 2" Cutting Depth with 2 Pilot Pins in Strong Plastic Box, #N2

The Accusize annular cutter is commonly used as the following tools (and solutions): annular cutter, core drill, core cutter, broach cutter, trepanning drill, hole saw, cup-type cutter, annular cutter 1/2, annular cutter 5/8, annular cutter adapter, annular cutter 3/4, annular cutter drill...

www.accusizetools.com

I've often thought about purchasing a set, but due to the cost, (and limited use) so far slightly undersized hole saws and finishing with a boring head or end mill.

 

[petertha]

Yeah sorry. I just included a generic picture of a 1" set but I did mention they can be purchased in 1,2,3" cutting length and purchased individually. They are more expensive because they more complex to manufacture. You also have to factor the cost of R8/MT3 toolholder. Like any tool, one has to assess the pros & cons & usage in your own applications vs. expense. That's why I still don't have a TIG welder - but ONE DAY! lol

 

[C-Bag]

Maybe it's just me, but 1300rpm?!?! IMHO that way too fast and the bigger the bit, the slower the rpm. I'd be around 3-400rpm no matter a drill or end mill.

 

[Toolmaker51]

I would recommend investing in some annulur cutters. You can buy them onsey-twosey as you need certain sizes or graduated sets. They come in 1, 2 and 3" flute length. You will need an arbor like R8 or MT3 (or both if that is your mill & lathe respectively). Anyways they do a very efficient job of cutting clean, accurate bigger diameter holes with little fuss. Plus you get the leftover core slug for another project instead of making a pile of swarf.

And solid remnants beat chips any day of the week. Just be certain to paint mark accordingly the material. Don't be afraid of cataloging them in one of a 100 methods. It further saves material and time for a project, because we often design according to sizes on hand.