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  1. #1
    sjensen30 is offline Aluminum
    Join Date
    Feb 2003
    Location
    Maplewood, MN USA
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    81

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    I'm kind of curious if anyone else has seen or used one of these high speed heads? It's flat belt driven with six speeds. They are,950rpm,1350,2200,3250,6500,and 12000rpm. I haven't seen any info about them and have never seen one for sale, even on Ebay. Is anyone else familiar with them?

    Steve

  2. #2
    Join Date
    Nov 2005
    Location
    Maryland
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    7,026

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    Hi Steve,

    The M head was the original offering when the BP round-ram knee mill was introduced in 1938. It had six speeds from 275 to 4250 rpm. Speeds up to 12,750 rpm were available on request.

    It's a basic head, smaller than the J, with no power downfeed. I've never used one.

    Some comparisons with the J head:

    Motor power: (M) 0.5 hp (J) 1 hp
    Quill travel: (M) 3.5" (J) 5.0"
    Spindle dia: (M) 1.437" (J) 1.875"
    Spindle taper: (M) #2MT, #7B&S, & others (J) R-8
    Max tool shank: (M) 0.50" (J) 0.875"
    Drilling cap: (M) 0.50" (J) 0.75" (in mild steel)
    Boring cap: (M) 1.5" (J) 6.0"
    Milling cap: (M) 1.0 in^3/min (J) 1.5 in^3/min

    Leigh

  3. #3
    jim rozen is offline Diamond
    Join Date
    Feb 2004
    Location
    peekskill, NY
    Posts
    21,468

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    At one time, Dave Sobel had a couple of those
    high speed, flat belt M heads. I think
    the model designation is more complicated
    than just "M" but I'm not sure on that.

    Jim

  4. #4
    sjensen30 is offline Aluminum
    Join Date
    Feb 2003
    Location
    Maplewood, MN USA
    Posts
    81

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    Thanks Leigh and Jim! I have one of these and am thinking strongly of selling it. It's an interesting piece but surplus to my needs. I've been a machinist for 30+ years and I don't remember seeing another one. I'll probably put it on Ebay along with it's knuckle and collets, hopefully someone will want it.

    Steve

  5. #5
    Crepitus is offline Plastic
    Join Date
    Oct 2010
    Location
    Chapel Hill NC USA
    Posts
    7

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    Picking up on this rather old thread - Just bought a circa 1971 BP with high-speed M head. Apparently it has sealed bearings as the nameplate says "SPINDLE BEARINGS GREASED FOR LIFE". Has a 1hp motor & flat belt / pulleys for 6 speeds, ranging 950 - 12000rpm. My guess is that maybe it was geared toward precision woodworking / pattern making. My question is, what are the pros / cons of the high-speed vs "standard" M head? (I realize there are big differences between any M head vs J / 2J heads etc.). My plan is to use this mill for gunsmithing, mostly pistols. I do plan to install a VFD for better speed control. BTW does anybody know, how rare are these high-speed M heads? Also wondering what the value might be, as I saw somebody's asking $1495 (head only) for one like mine on eBay - that's $295 more than I paid for entire mill w / AcuRite DRO & Kurt vise - anyway thanks in advance for any feedback to this post!

  6. #6
    Burton LeGeyt is offline Aluminum
    Join Date
    Mar 2011
    Location
    Boston, MA
    Posts
    50

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    I wish I had some help for you. I have been looking at these with interest lately. I have a small Johansson mill all apart and waiting to get scraped with some minor head issues and have been thinking about mounting the hi speed m head instead and using it in my guitar shop. I can think of a ton of stuff I could use it for, mostly in wood and bone/ivory.

    I would love to hear how you like yours when you get it running, there are a few heads I know of available and I am on the fence over the money. FWIW I usually see them for definitely less than that one that has been on ebay for a while.

    Burton
    Boston, MA

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