Need Advice About Side/Slot Milling in Steel

[Winegrower]

Not knowing the design constraints, this might be unacceptable...but I think I would use the vertical bandsaw, cut the two cross cuts to depth, then mill enough of a gap at the corner to get the bandsaw blade in position to "rip" the long side. You get to do two cuts at one time like this.

 

[MikeInOr]

I'll be honest, I've always been kind of gunshy about the AliExpress cutters/tooling. Granted I have been spoiled by working in professional machine shops with no shortage of OSG, Niagara, Harvey etc. Of course I doubt they're that good. But do you at least get your $7 worth out of them? The electric blue coating definitely raises my eyebrows .

I agree with your reluctance to buy cutting tools from AliExpress. The ones that I have bought have been specifically recommended by MrWhoopee on this forum and they have all worked out very well for my hobby uses. They have definitely been worth the ~$7 (or what ever) I spent on them.

P.S. I have never had the misfortune of being exposed to quality American made tooling.

 

[rronald]

AliExpress can have really good stuff...and really bad. I've found that the stuff from the "BB" (or "Black Blade") store is excellent.

For my homebuilt CNC, I mostly machine aluminum. Especially with MIC6, the stuff is very gummy. 4mm single flute end mills at 20K RPM snap quickly when they start to chip weld. So, I've used bits with DLC coating. Works much better than bright carbide.

For my new PM-833TV mill, I'm still learning about the right endmills to use. But, in general they are bigger (at least 8 and often 12mm). Much slower (often around 1K RPM for the 12mm). And far less likely to snap. . Haven't broken one yet. The TiN coated ones seem good.

Shipping used to be really slow, but I generally get things in about 2 weeks from AliExpress now.

 

[ChandlerJPerry]

A rougher is definitely the way to go (working within the confines of the mill anyway and not buying additional machinery). I ended up getting my hands on a 3/4" 4 flute rougher as part of a lot of cutters from an estate today and decided to throw it in the mill out of curiosity and wow! What a difference! It chews right through this tubing like it's nothing. I'll have to pick up a smaller one because there's no sense in turning 3/4" worth of material into swarf to knock out this window, but thank you everyone for the advice!

Here is a quick video of that rougher running at 560 RPM on a cutoff of the tubing I set up to test it. At this same RPM a standard 4fl 3/4" endmill was screaming for mercy trying to make this same cut.