• Still More Metal Working - Bench Top Belt Grinders - 1x30 vs 1x40

    From Bob La Londe@21:1/5 to All on Mon Nov 15 11:26:14 2021
    When it comes to 1 inch belt grinders is there any inherent benefit of
    one over another? The two common sizes appear to be 1x30 and 1x42.

    I think a 1x30 can be built to be more compact and a 1x42 would run
    cooler and have more media and therefor more belt life. Of course
    compactness can be largely dependent on form. A 3 wheel isn't going to
    be that much different I think. A two wheel design maybe depending on
    wheel size would show more difference.

    The 1x30s seem to be offered by "manufacturers" in nearly identical configurations in a variety of prices, but not much real difference in
    form.

    Is one more common? Does one have more belt options than the other?




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  • From Jim Wilkins@21:1/5 to All on Mon Nov 15 17:59:08 2021
    "Bob La Londe" wrote in message news:smu8o7$2bh$1@gioia.aioe.org...

    When it comes to 1 inch belt grinders is there any inherent benefit of
    one over another? The two common sizes appear to be 1x30 and 1x42.

    I think a 1x30 can be built to be more compact and a 1x42 would run
    cooler and have more media and therefor more belt life. Of course
    compactness can be largely dependent on form. A 3 wheel isn't going to
    be that much different I think. A two wheel design maybe depending on
    wheel size would show more difference.

    The 1x30s seem to be offered by "manufacturers" in nearly identical configurations in a variety of prices, but not much real difference in
    form.

    Is one more common? Does one have more belt options than the other?

    -------------------

    Googling for knife grinders might give you ideas. You could design it to
    accept a range of belt lengths and widths. Home Depot sells telescoping perforated square tubing that might help. https://www.homedepot.com/b/Hardware-Metal-Stock-Metal-Tubes/Square/N-5yc1vZ2fkos9vZ1z1czmv

    I began the design of my bandsaw mill with the item I couldn't make, the wheels. The frame between them wasn't particularly hard to design and
    fabricate from square and rectangular tubing.

    The shop made new drive wheel for the 1/2" x 12" belt sander has a straight taper on both ends, blended into the cylindrical center with a file, and fortunately that was good enough to track straight since there is no adjustment. The outer end roller is cylindrical.

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  • From Bob La Londe@21:1/5 to Jim Wilkins on Mon Nov 15 16:58:05 2021
    On 11/15/2021 3:59 PM, Jim Wilkins wrote:
    "Bob La Londe"  wrote in message news:smu8o7$2bh$1@gioia.aioe.org...

    When it comes to 1 inch belt grinders is there any inherent benefit of
    one over another?  The two common sizes appear to be 1x30 and 1x42.

    I think a 1x30 can be built to be more compact and a 1x42 would run
    cooler and have more media and therefor more belt life.  Of course compactness can be largely dependent on form.  A 3 wheel isn't going to
    be that much different I think.  A two wheel design maybe depending on
    wheel size would show more difference.

    The 1x30s seem to be offered by "manufacturers" in nearly identical configurations in a variety of prices, but not much real difference in
    form.

    Is one more common?  Does one have more belt options than the other?

    -------------------

    Googling for knife grinders might give you ideas. You could design it to accept a range of belt lengths and widths. Home Depot sells telescoping perforated square tubing that might help. https://www.homedepot.com/b/Hardware-Metal-Stock-Metal-Tubes/Square/N-5yc1vZ2fkos9vZ1z1czmv


    I began the design of my bandsaw mill with the item I couldn't make, the wheels. The frame between them wasn't particularly hard to design and fabricate from square and rectangular tubing.

    The shop made new drive wheel for the 1/2" x 12" belt sander has a
    straight taper on both ends, blended into the cylindrical center with a
    file, and fortunately that was good enough to track straight since there
    is no adjustment. The outer end roller is cylindrical.



    I have a lathe, a drawer full of misc bearings, and I am a moldmaker*.
    I can make wheels. LOL. Yeah, I get it. For something the size of
    band saw wheels it is a different animal. Actually wheels is really not
    a big deal for me for this size machine. I can machine hard caster
    wheels, cast wheels out of various resins or rubbers, or machine solid
    wheels. I can static balance as well as the next guy with a couple
    angle plates or parallels on the surface plate.

    There are generally two decent ways to get useable belt tracking. With
    an adjustable (tilting) tracking wheel or with crowned wheels. Some
    grinder designs use both. The 2 x 72 is the quintessential knifemaker's grinder, but if you look on YouTube there are plenty of guys who started
    out with a 1x30.

    I've probably watched 30 videos** on belt grinder builds over the last
    several years. While I am certainly no expert on how to build one I'm
    probably as knowledgeable as I can be without breaking out the hacksaw
    and the grinder to cut one out of a rutabaga.

    *I am a niche mold maker. I do not claim to be capable of the level of precision and high tolerance as some "real" mold makers.

    **Part of my morning routine is to catch up on news and emails, have my
    morning coffee, and put some builder's YouTube video up on the big
    screen TV in the living room.

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  • From Jim Wilkins@21:1/5 to All on Tue Nov 16 10:00:39 2021
    "Bob La Londe" wrote in message news:smus6c$kbs$1@gioia.aioe.org...

    I have a lathe, a drawer full of misc bearings, and I am a moldmaker*.
    I can make wheels. LOL. Yeah, I get it. For something the size of
    band saw wheels it is a different animal. Actually wheels is really not
    a big deal for me for this size machine. I can machine hard caster
    wheels, cast wheels out of various resins or rubbers, or machine solid
    wheels. I can static balance as well as the next guy with a couple
    angle plates or parallels on the surface plate.

    There are generally two decent ways to get useable belt tracking. With
    an adjustable (tilting) tracking wheel or with crowned wheels. Some
    grinder designs use both. The 2 x 72 is the quintessential knifemaker's grinder, but if you look on YouTube there are plenty of guys who started
    out with a 1x30.

    I've probably watched 30 videos** on belt grinder builds over the last
    several years. While I am certainly no expert on how to build one I'm
    probably as knowledgeable as I can be without breaking out the hacksaw
    and the grinder to cut one out of a rutabaga.

    *I am a niche mold maker. I do not claim to be capable of the level of precision and high tolerance as some "real" mold makers.

    **Part of my morning routine is to catch up on news and emails, have my
    morning coffee, and put some builder's YouTube video up on the big
    screen TV in the living room.
    -----------------------

    Between building the sawmill and a bucket loader for my tractor, and fixing/modifying belt sanders I think I've done all the operations for
    making a large knife grinder, just not all on the same project. The
    'precision' of a carefully squared 4" x 6" horizontal bandsaw and a stick welder were generally enough, after straightening bent stock and correcting welding distortion to eyeball accuracy with a hydraulic jack. 2" square
    tubing isn't stiff enough to resist weld bead shrinkage. I can adjust the
    saw to cut square within about 0.005" per inch.

    I had to make weldments that are critical to accuracy small enough to trim
    on the mill and then match-drill and bolt them to the frame, and provide
    enough adjusting setscrews for the main wheel axle supports which have to withstand >1000 lbs of blade tension and thus were welded to the frame,
    which is much too large and heavy to mill. The axle ends are in small rectangular blocks which could be milled to adjust the axles (or test rods) parallel, though I didn't have to. The mounting bolt hole or slot
    perpendicular to the axle crosses through the other end of the block, and
    the tracking setscrews bear against the ends. This axle mount is quick and simple to make and can be finely tuned. It also comes apart easily and
    returns to exact position when reassembled, which is important for storing
    the bulky sawmill and would be if you have to change clogged wheel bearings.
    My blade guide roller bearings are exposed to a 60MPH blast of sawdust and
    need fairly frequent cleaning and replacement. The trick to disassemble shielded bearings is to find and pry out the beveled end of the snap ring.
    The rubber just pops out of sealed bearings.

    On the sawmill the drive wheel axle is rigidly located and the other axle slides in a subframe to adjust blade tension, so the tension and tracking
    don't interact. You could tension with an idler wheel to preserve the
    tracking adjustment. My sawmill drive belt clutch/tensioner is a crank arm
    with a stop just past top dead center that pulls or releases the idler
    through a spring, whose length and stiffness provide the adjustment. Simple.

    Setscrews bearing on the ends hold the alignment of the the pillow blocks in the transmission against belt and chain tension. You may not need them for
    3HP or less but I felt them necessary when designing for 10HP. The 4HP motor
    on my air compressor appears to be near the limit of relying on mounting
    bolt friction.

    For simplicity I like using cone pulleys and a hinged motor mount to vary speed, as a compromise between ease of changing speed and time spent on construction. Then any spare one-speed motor will do, and swapping in a
    larger one is easy.

    The job is much simpler if all frame parts are within your mill's work envelope, but not impossible if they aren't. I've drilled and reamed
    parallel holes for bearings in the outer ends of frame members somewhat
    longer than my Clausing mill's 24" table by clamping them in two drill press vises located to put either end under the spindle and both vises on the
    table. You can walk the vises down the stock at some risk to accuracy. A
    spacer block the exact height of the vise helps a lot if you don't have two identical ones to clamp long stock. My spacer block is a rejected prototype
    of the Segway Lean Steer mechanism.

    Good luck with it.
    jsw

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