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Thread: 1/4" or 3/8" compression

  1. #11
    Join Date
    Jun 2009
    Location
    Thermwood Corporation, Dale IN
    Posts
    61

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    John,

    As I recall your back material is applied to the the back of the cabinet, though inset in a rabbet (full dado). As Gary indicated, you should use a 3/8" material instead of 1/4" when you design the cabinet. Since you're using 3/8" in your design, the resulting full dado or rabbet will be 3/8". If you use 1/2" material, it'll be 1/2". The machine does not know what material you layout on the table, so when it comes time to cut the backs, you just put a 1/4" on the table instead of 3/8".

    If you'll recall, I suggested that you should create a material and name it so that you know to load 1/4" material instead of the 3/8" or 1/2", that we discussed. Since the material has a different name, it will nest all the parts made with the same named material.

    With regards to setting up zero. If there are no dados or other joinery in the back, then setting up z-zero to the table surface is not necessary. They are all thru-cuts, so the retracted height is a little higher than necessary, but that's okay. It's not deeper!

    You've probably already figured this out, but if not.

    Happy New Year to all,


    Dennis L. Englert

  2. #12
    Join Date
    Dec 2008
    Location
    , Richmond Tx
    Posts
    1,086

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    Dennis,

    I don't follow you on the not cutting into the spoil board.

    If the program thinks you are cutting 1/2 inch material and you zero to the top of a piece of 1/4 inch, then you will be cutting into the spoilboard 1/4 inch.

    If you use a piece of 1/2 inch to zero the bit to the top of the material, then place the 1/4 inch in for cutting, that would work as you described.

    The easiest way is just to zero to the bed and you don't have to worry about how thick the material is.
    Kenneth

  3. #13
    Join Date
    Jun 2009
    Location
    Thermwood Corporation, Dale IN
    Posts
    61

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    Gary may need to kick in here, but we use a ZSHIFT memory variable that I believe also is used with the ShopBot Link. The ZSHIFT variable contains the material thickness from eCabinets and essentially shifts the Z0 up by that amount.

    Now that I think about it Gary's original statement is correct. I'm probably still in a fog from the holidays and the almost two week vacation.

    Anyway, set Z-zero to the surface of the table, then the ZSHIFT variable adjusts Z0 up. So while you may be using 1/4" material, but chose 1/2" material in the design, Z0 will be set 1/2" off of the table.

    Sorry for the confusion. Thanks for re-posting the question Ken. Perhaps, I'll get the brain started again in the New Year.

    Dennis

  4. #14
    Join Date
    Apr 2007
    Location
    Marquette, MI
    Posts
    3,388

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    Kenneth...

    I think I can add a little to the above. You are both correct. The difference between zero to top of mtl and Zero the bed IS the material thickness or ZSHIFT variable.

    Therefore if you zero to top of material and cut thru your depth is: negative(mtl thk + cut thru depth). I.e. bit is never deeper than cut thru depth. Zshift variable is NOT used as a Z offset.

    If you zero to bed, your depth is shifted UP the mtl thk (ZSHIFT) and then cut depth of mtl thk (same) and into the spoilboard by the cut thru depth. Again, same depth as above. Zshift IS applied as an offset(positve) to the Z axis. Same cutting depth as above.

    In my scenario above, and as Dennis confirms, with zero to bed AND outline only cuts, it doesnt matter what material thickness is on the table. The machine will cut as per its settings to a depth of the "Cut Thru Depth" setting.

    Using zero to top of mtl will cause the cut depth to be either too deep or shallow by the amout of the design vs actual thickness. This only applies to a condition setup by me above where a sheet thickness was used that was different than that input into eCabs.

    Remember: If its hardware, it made to be maintained. If its software, its made to be tricked.
    Gary Campbell
    GCnC Control
    GCnC411(at)gmail(dot)com
    Servo Controller Upgrades
    http://www.youtube.com/user/Islaww1


    "We can not solve our problems with the same level of thinking that created them"
    Albert Einstein


  5. #15
    Join Date
    Oct 2007
    Location
    Ernest Klassen Kitchens, Fenwick Ontario
    Posts
    116

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    Another consideration when chosing a router bit is the number of flutes.

    For myself I have found that I can cut faster with a single fluted compression spiral bit than a double fluted one. Probably because I have a PRT standard which has limited cutting force. With a single fluted 1/4" cutter I can cut at 5 IPS and with a double I have to slow it down to 3.5 IPS.

  6. #16
    Join Date
    Dec 2008
    Location
    Cabinetry Green, LLC, Fishers IN
    Posts
    214

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    Well at the moment all this z-zero and z-shift is confusing. I'm sure it will make more sense when I actually start up the link.. Thanks the feedback everyone!

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