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Thread: Help on Speeds and Feeds 1/2 Ball nose

  1. #1
    Join Date
    Feb 2019
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    Cary, NC
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    Default Help on Speeds and Feeds 1/2 Ball nose

    Can anyone give me a starting point on speeds and feeds for 1/2" Ball nose, 4 flute end mill? I have a 1hp spindle on a Desktop. I have only used 1/4" end mills thus far, but have a project that needs a 1/2 inch ball. It's not a 2.5d, I just need a round bottom on a pocketing tool path. I'm going to do a first cut in pine and if all goes well I probably use maple for the finished project. Thanks

  2. #2
    Join Date
    Dec 2008
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    Diamond Lake, WA
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    Last time I used a 1/2" ballnose was on alder. I was running a 2.2HP spindle on a PRSAlpha 96x60. My spindle speed was around 14K. My feed rate was around 6IPS. I was taking a 1/8" on each pass. Prior to that, I also used it on some seat bottoms to create a contoured seats in hickory. My spindle speed was 14K and feed rate was around 4IPS. I was taking 3/32" on each pass. Haven't used the bit in about 6 years so my numbers might not work with you machine.
    Don
    Diamond Lake Custom Woodworks, LLC
    www.dlwoodworks.com
    ***********************************
    Life is not a journey to the grave with the intention of arriving safely in one pretty and well preserved piece; But to skid in broadside, thoroughly used up, worn out, bank accounts empty, credit cards maxed out, defiantly shouting "Geronimo"!

    If you make something idiot proof, all they do is create a better idiot.

  3. #3
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    Feb 2019
    Location
    Cary, NC
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    Thanks Don, There are many differences in our machines. My machine tops out at 4ips, but thanks for your help.

  4. #4
    Join Date
    Apr 2013
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    Kennebunkport, Maine
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    I pretty much only use 2F .5" ballnose with the Fluting toolpath(and sometimes 3D) for bowl shapes and troughs...and not production by any means.
    Generally my lines for Fluting toolpath approximate a stepover of 6-8%
    Very conservative pass depth of 1/2Diameter.
    Generally run 15-17K, and depending on wood and results 1-2IPS, and .3-.5 IPS on Plunge(3D it's usually 1.5,1.5,17K)
    Should get you in the ballpark, but Pine won't be a good comparison to Sugar Maple.
    Attached Images Attached Images
    Scott P.
    2013 Desktop/spindle/VCP 10
    Maine

  5. #5
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    Feb 2019
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    Cary, NC
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    Thanks Scott. I was hoping you might read my ad. If anyone knows anything about a Desktop with a spindle it's you. Thanks again, you've given me a good starting point.
    Mike

  6. #6
    Join Date
    Apr 2013
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    Kennebunkport, Maine
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    No problem Mike.
    Best finish(almost no sand like shown) for a pocket seems to be one final finish pass(just adjust pass depth to leave the amount) is between .002-.005".
    You could use the pocket allowance and a slightly shallower cut toolpath and much bigger stepover to hog it out....
    And then a second full depth skim cut with no allowance and then actual depth, if doing quantities and didn't want to change bits....That worked for me on one item we made.

    Only 4 flute I have is a .125", 1" CEL made for Carvewright by Drillman1 that I used when doing tight Nesting. It liked doing the cutouts at 1/2D pass depth at 2.4-2.6, .5, 9.5K
    and REALLY preferred a conventional cut! And those setting worked fine for cutting out from Cherry to Cocobolo.
    4F drove me half crazy trying to keep it cool until I kept dropping rpms, and she settled down.
    Don't use that often now, but using that bit for .8-.95" material for 5+ yrs.
    Scott P.
    2013 Desktop/spindle/VCP 10
    Maine

  7. #7
    Join Date
    Feb 2019
    Location
    Cary, NC
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    Thanks Scott. I'll take your advice on the pocketing and watch the RPMs on the 4 flute.

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