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Thread: Large End Mill for Bridgeport

  1. #21
    Join Date
    Apr 2012
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    Medford Oregon USA
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    132

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    I ended up purchasing a used 2" R8 Valenite facemill that uses SEET 42 inserts. I think it may fit the SEHT1204 inserts that are popular now too. If not I will make do with what ever works. I thought about shars, I have had good luck and bad with some of their stuff so this time I tried made in the USA for about the same price.

  2. #22
    Join Date
    Dec 2009
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    Stevens Point, WI
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    You will be happy. I use mine quite a bit.

    If you don't have one yet a boring head is a nice thing to have for the mill too. Can set them up for fly cutting as well.
    Andy

  3. #23
    Join Date
    Apr 2017
    Location
    Kelowna BC
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    Quote Originally Posted by wdtom44 View Post
    Quote Originally Posted by wdtom44 View Post
    Sounds like a job for a shaper....

    Does not help the guy solve his problem.
    -D

    Doozer, You are right I didn't help him with the problem at hand except for the way he might save the end mills he smoked. However if someone was not familiar with a shaper I might have planted the idea of a shaper that might help in the future and might help save another shaper form being melted down.
    Using the flycutter with cheap regrindable tooling is very similar to the cheap tooling aspect of a shaper.

  4. #24
    Join Date
    Jul 2007
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    West Michigan
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    2,992

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    Quote Originally Posted by Doozer View Post
    Also does not help the guy solve his problem.

    -D
    What I'm hearing is that he has a couple of HSS end mills that are dull and he is planning on replacing them. He can probably get a facemill with carbide inserts for less than the price of a couple of large endmills with smaller shafts but the carbide will outlast the HSS ones by multiples. So I stick by my advice. But the carbide facemill and skip the HSS.

    Does anybody use HSS router bits anymore. Not that I know of. If we buy carbide to cut wood why would we continue to use HSS for all steel cutting?

    Brian
    OPEN EYES, OPEN EARS, OPEN MIND

    THINK HARDER

    BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

    MY NAME IS BRIAN AND I AM A TOOLOHOLIC

  5. #25
    Join Date
    Nov 2017
    Location
    Shingletown, CA
    Posts
    114

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    To repeat what 754 said:

    Cutting Speed x 4 / diameter=RPM

    Memorize it! You don't need somebody's table, you can do it in your head (well I can anyway).

    I realize you've already made your purchase, but I'm +1 for a fly cutter. Cheap to buy, cheap to tool, easy to resharpen.
    It's all mind over matter.
    If you don't mind, it don't matter.

  6. #26
    Join Date
    Dec 2015
    Location
    Chilliwack, BC, Canada
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    5,392

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    I'm not a human calculator. I'd rather look at the chart on SFM values for materials and then at the SFM vs diameter chart next to it and skip the higher brain functions.

  7. #27
    Join Date
    Apr 2017
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    Kelowna BC
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    It's not hard for high speed steel. Drill or end mill 1 inch is 400 rpm.
    -1 /2 inch is 800 rpm. 1/4 inch is 1600 rpm.

  8. #28
    Join Date
    May 2013
    Location
    UK, near London
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    1,228

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    I remember 625 is the speed for 5/8 (that's .625 inch)

  9. #29
    Join Date
    Oct 2015
    Location
    Wyoming
    Posts
    106

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    In your first posting, you mentioned mill scale. If you were taking a shallow cut on hot-rolled steel and cutting in the outer layer of mill scale, you probably took the edge off the end mills.

    Mill scale is some rather abrasive stuff, and it takes the edge off HSS end mills pretty quickly. As I see it, there are three options to clean the scale off hot-rolled steel:

    1. Use a HSS end mill, but make your depth of cut deep enough that you're fully under the scale, and the scale is just peeling up with the chip you're taking under the scale. Keep your HSS end mills down, fully cutting in the steel instead of doing most of your cutting in the layer with the scale. When you get under the scale, you'll often find that your HSS end mills last longer.

    2. As many have suggested, you could get yourself a face mill that uses carbide inserts. This is my solution to getting rid of mill scale most of the time.

    3. As others have also suggested, you could use a fly cutter. A single-point HSS toolbit could be used, or you could use a cemented carbide tool bit. Be careful to tram in your mill closely, or set it up for "tailing", where the leading arc of a fly cutter is cutting a thou or so higher than the rear arc. If you tram a mill for tailing, you can run your work in only one direction to get a good finish.

  10. #30
    Join Date
    Dec 2009
    Location
    Stevens Point, WI
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    Quote Originally Posted by MrWhoopee View Post
    To repeat what 754 said:

    Cutting Speed x 4 / diameter=RPM
    Quote Originally Posted by 754 View Post
    It's not hard for high speed steel. Drill or end mill 1 inch is 400 rpm.
    -1 /2 inch is 800 rpm. 1/4 inch is 1600 rpm.

    I never put much thought into sfpm or cut speeds, I just kind of know what sounds and feels right.

    But to get to know this math anyhow, what number are you starting with all the time to figure out rpms? "cut speed" is mentioned to be multiplied by 4 then divided by the tool diameter. What is "cut speed"?
    Andy

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