[kreativjustin]

I am cutting a 5/32 radius on a bunch of Alum parts. I burnt the one that I have now, which may have been slightly dull already. Tool is a .220 minor diam, .77 major diam. 4 flute HSS uncoated.

I just wanted to make sure I was running this right. I usually try to stay on the conservative sides of things, we are a tool room, not a production shop.

Heres what I'm using:

300 SFM = 1517 RPM
Feeds: .002" CPT (12 ipm)

Depths: .07, .09, 0.11, .13, .14, .145, .150 x2

Those are in inches, I only go down to .150

Any recommendations?

[Jim Dawson]

I would use a tool like this. https://www.amanatool.com/49501-carb...l?ff=1&fp=7281

Standard corner rounding end mills don't work well in aluminum, I have a couple of sets of them and never did like using them even in steel. I normally default to carbide tipped router bits for use in all metals.

Just remove the bearing, and grind off the bearing nose. I use the 1/2 shank where possible, but 1/4 inch shank will do in a pinch. Bump up the spindle speed a bit and apply plenty of coolant.

[kreativjustin]

I can borrow one of mine from home and try it tomorrow. This is the one I just ordered (similar to the last one), just got it in today: https://www.mscdirect.com/product/details/79572921 Obviously this is HSS though.

I've always used this style, I rarely do it though. I usually do chamfering.

[Jim Dawson]

In most cases router bits work just as well in metal as they do in wood, especially in aluminum. I've even used carbide tipped router bits in 304 SS with good result. They don't work well in all applications of course, but for some uses they work better than endmills.

[mactec54]

I am cutting a 5/32 radius on a bunch of Alum parts. I burnt the one that I have now, which may have been slightly dull already. Tool is a .220 minor diam, .77 major diam. 4 flute HSS uncoated.

I just wanted to make sure I was running this right. I usually try to stay on the conservative sides of things, we are a tool room, not a production shop.

Heres what I'm using:

300 SFM = 1517 RPM
Feeds: .002" CPT (12 ipm)

Depths: .07, .09, 0.11, .13, .14, .145, .150 x2

Those are in inches, I only go down to .150

Any recommendations?

What you brought don't do a great job cost a lot and don't last very long

If you do a lot of chamfers and radius cutting then buy this brand Nine9 they are magic as to how well the work, Router cutters are only good for aluminum they don't last very well on any other type of material, here is a video of the Nine9 brand cutters in action you can change an insert for a different radius chamfer and center drill and engrave can be used on a lathe as well for turning od/Id center drill and chamfer all with the same tool

These inserts last a long time so you don't need to buy more than 2 at a time which would be less than the cost you payed for the HSS cutter

https://www.youtube.com/watch?v=loeWnyxse00

[mactec54]

In most cases router bits work just as well in metal as they do in wood, especially in aluminum. I've even used carbide tipped router bits in 304 SS with good result. They don't work well in all applications of course, but for some uses they work better than endmills.

They will never work better than the right cutter designed for the job even in aluminum

They only work well for aluminum but don't last very long in steel, the cuter geometry is all wrong for steel cutting and adds stress to the material you are cutting

Part below as machined radius with nine9 cutter

[RCaffin]

Your problem may not be in the feeds and speeds area but in the material you are machining.

You see, some aluminium alloys contain fine crystals of oxide. So what? Well, aluminium oxide is what they make most grinding wheels out of, and that will rip the hell out of any HSS cutter. If what you are machining is cast aluminium that is especially likely. Some cast aluminium is as hard as 'mild steel'.

You may need to use good carbide, with a coating, and then to fine tune what sort of cutter angle you use as well. Softer alloys or CP will like the sharp tools designated for aluminium, but hard alloys will need a cutter closer to what you use for steel. You don't need flood coolant these days, but you will need MQL.

Cheers
Roger

[Jim Dawson]

They will never work better than the right cutter designed for the job even in aluminum

I agree to a point. If I am doing a production run I may buy exactly the correct tool for the job. Clearly for the OPs application the standard corner rounders are not working, but yes, there are other bits that would work well. A really cheap tool for this job and cutting conditions is a standard carbide tipped router bit. I also use solid carbide router bits in all metals.

They only work well for aluminum but don't last very long in steel, the cuter geometry is all wrong for steel cutting and adds stress to the material you are cutting

I have found that they last just as long in steel as any other bit. Agreed that the geometry is all wrong for steel. Would I even concider them in a high production setting? No, but for toolroom use and very low volume production they work well in many applications. You do have to adjust the cutting parameters because router bits do not generally have the core strength of an endmill.

[kreativjustin]

I forgot my router bit.. *grr*

Well I will try my router bit when I can remember it, then look into that Nine9 Cutter. We are a small tool room, and budget is ALWAYS an issue. I have to condone even small stuff at times. The carbide version was literally $90, and I don't do a crap ton of radius on the mills. We are doing a collaborative robot cell that isn't allowed to have even a tiny edge on it, must be at least 5/32 radius on all edges that are exposed. Just trying to keep my cutters from dulling so quick.

[kreativjustin]

I looked into the Nine9 tool, pretty cool stuff. https://www.mscdirect.com/product/details/56910821

However, I couldn't find any inserts that would provide a radius for the outside of the part.

[mactec54]

I looked into the Nine9 tool, pretty cool stuff. https://www.mscdirect.com/product/details/56910821

However, I couldn't find any inserts that would provide a radius for the outside of the part.

Here is a snip of the Radius insert it does more than just a radius as well, if you scroll down on the link I posted you will see these inserts

Travers tool Have better prices than MSC

[kreativjustin]

Very awesome. I'll have to look into getting this. I just gotta find a way to condone it to the boss.

[RCaffin]

Just tell him it will do a better job and be cheaper in the long run. Then hope.

Cheers
Roger

[kreativjustin]

Awesome news! I got approved for 2 of them However, I only ordered the regular inserts because I was having trouble finding these on an American seller: N9MT11T3RC 1/8 or N9MT1704RC40 (.157")

So I'll have to figure out what to do about that, but it's a start!

I really appreciate all of your help, keep making chips!

[mactec54]

Awesome news! I got approved for 2 of them However, I only ordered the regular inserts because I was having trouble finding these on an American seller: N9MT11T3RC 1/8 or N9MT1704RC40 (.157")

So I'll have to figure out what to do about that, but it's a start!

I really appreciate all of your help, keep making chips!

The seller you used will order them from index.html and they will drop ship them to you, if the supplier does not have them, call Everede 331 871 5214 and get the part numbers you want, you may be able to buy them direct

Just make sure you get the correct inserts for the tool holders you brought

[kreativjustin]

My company actually gets a really good discount from MSC Direct, that's why I ordered it from there. I ended up paying like $130 for each bar, and like $22 for each insert, and overnight shipping is free. I'll contact MSC and Travers and see if they can get me the desired insert. Thanks again!

[mactec54]

My company actually gets a really good discount from MSC Direct, that's why I ordered it from there. I ended up paying like $130 for each bar, and like $22 for each insert, and overnight shipping is free. I'll contact MSC and Travers and see if they can get me the desired insert. Thanks again!

Because MSC sells them they can get you anything you need for that tooling, in most cases you will have to give them the insert part number you want, that is why I said to call the importer to get the right inserts for the tool holders you have

That's a good deal you getting from MSC