I feel honored to get the opportunity to comment on one of your videos for a change. You can use that 2 flute at 1950 RPM if you wish, but get ready to kiss it goodbye after about 3 seconds. I would cut the RPM to at least half of your current setting and take full depth side cuts with the 4 flute to remove that boss. Logic being.....If you take multiple, centered, shallow cuts to remove that rib, you risk wearing out the lower sides of the cutter and just generating more heat. Plus, you'll never get a true vertical wall on any other piece because you wore out the bottom 1/16" of the cutter. Since you probably cut the outer channels that way, I'd take a good look at the original cutter to see if this has taken place already. Good luck.
Thanks a bunch Mr P. I am an oldest guy just picking up the trade as a hobby. I appreciate all your videos many of which are way above my head, but I still find them damned interesting. You’re a good man for sharing.
@@kimber1958 I was just going to recommend you get on Pies channel and then I seen his comment. He has a lot of videos covering just about everything including end mills. Email him and ask for some videos and he will send you something Im sure that will address what your're doing.
A 2 flute will work fine. I'd run it at 685 and use a bit of oil or coolant. As mentioned before me, you can also just side mill with the 4 flute. make sure you conventional mill!
for rpm, high speed steel cutter you want 60-120 surface feet per minute. 80 being good middle ground to start at. then use this formula. SFM*3.82/(Diameter of cutter) so for .5 inch hss end mill 80*3.82/.5 = 687 RPM it works for all diameters even turning. flutes matter for feed rate and chip load per tooth and that gets funky as you side mill. Run the .75 end mill at 450 or so. 2 flute just cant feed as fast.
Without knowing the carbon content of the steel I would run it between 500, and 700 rpm with a 3/4" end mill. A 4 fluted end mill is preferred in steel. two fluted are for aluminum and plastics. Use coolant to extend the cutter life. I just made a single aloris styled tool holder last week. Keep up the good work!
Those 4 flute carbide end mills are nice but they are also costly so save them for other things. Buy a 1/2" or 5/8" Tin coated 4 flute Fine Tooth Roughing end mill Run at 60FPM with some coolant. With those you can take 2 diameters depth of cut and feed them at .001 per tooth. Maybe time to get some coolant installed on your mill.
Coolant is in the future a friend of mine just gave me two roughing windmills and a finishing Enville. I think they’re either fine what they’re either 5/8 or three-quarter.
The slot drill (2 flute) is better for roughing and it will cut size, the problem is it will deflect from the centre line but it will rough the depth in one cut. The endmill (4 flute) is designed to machine on the side not the full width you will get even more deflection through the pressure of the cut. There are two ways to finish your slot. 1. open each side up with the endmill or 2. Obtain a straight flute slot drill (2 flue) and finish both sides in one cut. The straight flute end mill won't deflect from the centre. Regarding tolerances on slot drills is size - h7, the endmill is always a plus on diameter.
*_Why don't you finish with the 4 flute you've been using? No idea what to say on the speeds and feeds. I tend to go slower RPMs on speeds and easy does it on feeds. If I were doing it in my shop, Id use the 4 flute roughing end mills to hog it all out, then go back and finish pass with a 4 flute spiral, I guess a 2 flute would work for a finish pass but not sure on using the 2 flute to hog that last bit out. BUT--- I'm not really qualified to advise because I'm not a machinist. I'm a mechanic cosplaying as a machinist.._* 🤣😆👣👣👣👣
Kimber do you have an indexable cutter that will fit in that space? It looks like maybe 3/4”-1”? Two flute is not the most ideal way to cut that….do you have a carbide endmill?
