Milling ... feeds, speed and DOC

[Janger]

Zoom to minute 15:30.

You can see here Abom is milling with a DOC of 0.090" (3/32") with what would be a fast feed rate on my mill. This is much faster and deeper and quieter than I can do on my mill. Maybe I have some problems like loose Gibs or other issues?

Comments?

 

[kevin.decelles]

I suspect everything in that video has an impact, from the non-banggood end-mills, to the mist-coolant, to the 3 ton heavy machinery he is running......to the fact that he knows his trade. But yes, I hear ya, I had so much harmonics going the other night cutting slots (and ultimately destroying a couple of end-mills) that I sometimes question the videos I watch to wonder what I'm doing wrong.

I did some tapping the other night...... long story short, snapped 2 separate 1/4-20 taps from my 'bought on sale master craft premium titanium maximum blah blah set'. Switched to a set of taps I pulled out of a barn this spring (snap-on brand that looks like the case was made in the '70s). Cut like a hot-knife through butter. Found an individually wrapped 'Hanson' tap, opened that, tapped another 15 holes with ease. Sometimes the technique isn't the issue, it's the tooling....

Sorry, just musing here, nothing concrete to add.

 

[PeterT]

I think the machine mass + power + tightness all collectively help with these big boy cuts. Interesting to me is he plunks in a 3/8 (0.375") EM in there then gets 0.374" width on a the single pass confirmed with gage block stack. I usually always get increased width over the nominal cutter diameter, like 1-2 thou depending on material. feed, phase of the moon. Usually when guys shoot for a fit they run a smaller end mill on either side of center & that also benefits the finish pass (climb milling). Traversing in one direction like that to full depth, one side is ploughing the other climb milling.

I'm not that familiar with that 4-flute Niagra EM or its diameter tolerance but a) looks like a nice carbide b) has that funky varying asymmetrical geometry that seems to be a thing. I've been meaning to try one, but I will probably experiment from Asia vendors I've had good luck with. I haven't priced out a Niagra in a while, they are a very good name but also spendy. I had a corn cob roughing EM that was just awesome... till I broke it on what I now recognize was an iffy setup. Live & learn.

http://www.niagaracutter.com/news-stabilizer-2
The Stabilizer 2.0 family of end mills raises the bar in high performance milling by incorporating a patented continuously varying asymmetrical geometry which helps create a smooth chatter free milling condition. This configuration, along with a specially engineered flute shape, allow for feed rates twice that of the current Stabilizer.

 

[PeterT]

Another technique observation - he kind of worked the slot from the end first, establishing the entry track as a setup to the big single pass? I have done very few keyways but I have also seen others do them in full depth pass mode. Maybe any ridge lines resulting from multi-depth passes don't play well with keyway fitting. Not sure but makes sense. I've done similar work with a roughing EM up the middle to take say 80% material away & leave 20% to a clean up pass on your good EM. But when you do this for a living, time is money, so likely different techniques & tools come into play vs hobbyists.

I'm sure if you posted a question, he would answer.

 

[Downwindtracker2]

I bought a RF-45 that had been CNCed , and I put it back to manual use. After milling some slots for a motor mount, I'm getting little tired of the drama. The combination of a powerful motor and a gearhead exposes the center wear on the X-axis and the backlash on the feed screw nut. There are no belts to slip. I've adjusted the gib so it's tight, almost too tight at the ends. I was making a .020 DOC with a 3/8" two flute slot drill end mill. I now refer to the mill as the Drama Queen. Time to fix. I didn't even measure the slots, wider is better on a motor mount. You can twist the motor for belt alignment.

 

[Janger]

I think the machine mass + power + tightness all collectively help with these big boy cuts. Interesting to me is he plunks in a 3/8 (0.375") EM in there then gets 0.374" width on a the single pass confirmed with gage block stack. I usually always get increased width over the nominal cutter diameter, like 1-2 thou depending on material. feed, phase of the moon. Usually when guys shoot for a fit they run a smaller end mill on either side of center & that also benefits the finish pass (climb milling). Traversing in one direction like that to full depth, one side is ploughing the other climb milling.

I'm not that familiar with that 4-flute Niagra EM or its diameter tolerance but a) looks like a nice carbide b) has that funky varying asymmetrical geometry that seems to be a thing. I've been meaning to try one, but I will probably experiment from Asia vendors I've had good luck with. I haven't priced out a Niagra in a while, they are a very good name but also spendy. I had a corn cob roughing EM that was just awesome... till I broke it on what I now recognize was an iffy setup. Live & learn.

http://www.niagaracutter.com/news-stabilizer-2
The Stabilizer 2.0 family of end mills raises the bar in high performance milling by incorporating a patented continuously varying asymmetrical geometry which helps create a smooth chatter free milling condition. This configuration, along with a specially engineered flute shape, allow for feed rates twice that of the current Stabilizer.

https://www.kbctools.ca/products/CUTTING TOOLS/END MILLS/CORNER RADIUS END MILLS/10200.aspx

!

 

[Tom Kitta]

I don't exactly know the diameter of the end mill but I am guessing something like 1/2 cutting 0.09 is a piece of cake on my machine. I think he is actually going slow - I would go faster with my carbide especially if new in something mild.

This also has a lot to do with what metal he is cutting with what end mill - I can tell you there is quite a difference between mild steel and 4140 and a huge difference between mild steel and 4330.

End mill quality and how new it is - carbide can be "forced" but the finish and machine will feel it. Fresh end mill cuts much more smoothly.

Finally we all know a rougher end mill can remove far more.

Rigidness of setup and of the machine table / head plays a role. A horizontal mill can remove more metal than a vertical - having your cutting head in the main body of the machine helps a lot.

Personally I was never able to get even close to the awesome videos of people taking some huge cuts with their BP clones. I think a lot of these are done with aluminium. My usual max with BP clone is around 0.08 depth at I think 3 or 4 IPM with a dull carbide end mill in 1" size cutting 4140 steel, touch less with 4330. Coolant is just a spray bottle with water based oil. I can easily get far more with fresh carbide EM & mild steel with better coolant.

I also think the HP ratings in a lot of machines are total overkill - remember original BP had like 1hp and then they moved to 2hp. 1hp should be good enough to supposedly remove 1 cubic inch of mild steel (more or less).

 

[Tom Kitta]

I suspect everything in that video has an impact, from the non-banggood end-mills, to the mist-coolant, to the 3 ton heavy machinery he is running......to the fact that he knows his trade. But yes, I hear ya, I had so much harmonics going the other night cutting slots (and ultimately destroying a couple of end-mills) that I sometimes question the videos I watch to wonder what I'm doing wrong.

I did some tapping the other night...... long story short, snapped 2 separate 1/4-20 taps from my 'bought on sale master craft premium titanium maximum blah blah set'. Switched to a set of taps I pulled out of a barn this spring (snap-on brand that looks like the case was made in the '70s). Cut like a hot-knife through butter. Found an individually wrapped 'Hanson' tap, opened that, tapped another 15 holes with ease. Sometimes the technique isn't the issue, it's the tooling....

Sorry, just musing here, nothing concrete to add.

Certainly tooling plays huge role - you can get taps that only cut part of the thread. You can change the drills you use for less thread engagement. You can use premium cutting fluid. Generally found that tapping hard stuff like 4330 is at the edge of what can actually be tapped with standard thread tapping taps in HSS.