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Thread: New 1/8" cutting bit causing serious overheating problem

  1. #1

    Default New 1/8" cutting bit causing serious overheating problem

    I've cut dozens of these gears in the past, and never had a problem like this until today. The project board is 1/4" Baltic birch on a 1/2" sled. The cuts are made in one pass. I've run the same project with the same material and sled a dozen times. I did switch to Designer 2, and also used a brand-new bit that I just got from LHR. The new bit is seriously overheating to the point of starting a fire. I had smouldering sawdust in my dust collection system. Scary.
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    Since I changed both software (machine code) and bits, I compared predicted cut time for the project with both Designer 1 and Designer 2, and they were identical, so I don't think the feed rate has changed. However, comparing the new bit (right) to the old (left), the spiral flutes are tighter on the new bit. I believe sawdust is not being ejected from the cut as well with the new bit. This causes overheating to the point of heavy charring and near fire. This is not a fluke; it happened twice. Like I said, nothing like this has happened before, same project, same wood.

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    I am making another run with the old bit. Of course I will be keeping a close eye on this.

  2. #2
    Join Date
    Oct 2009
    Location
    Ohio
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    1,691

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    Think maybe the rpm's for the tool has changed? Don't know how to check the speed with out using a tack or a special instrument for rpms. Looks like it cut ok at first but then loaded up or something. Keep us posted on what you find out. Thanks
    CarverJerry

    ver. 1.188 Win 7- 64b with 6 GB ram @ 2.8Ghz and dual 1Tb hard drives. Rock Chuck & Ringneck vacuum system hooked up to a Harbor Freight large vacuum. Center line text, conforming vectors.

  3. #3
    Join Date
    Dec 2011
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    Spring Arbor Michigan
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    That looks bad. Glad there was no major fire trouble.

  4. #4
    Join Date
    Aug 2009
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    Whidbey Island, WA
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    Glad you are all right... scary indeed

    Was there any damage to your machine?

    Lawrence

  5. #5

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    No damage to my machine, but my dust pickup which is half wood was charred.

    I just finished a rerun of the project with my old bit with no incident (top left). Still using Designer 2 software and firmware. Don't know about the RPMs. Comparing the two results, the new bit does seem to load up the cut more, but it's not a dramatic difference. It is clearly running hotter. I wonder if I could get temperature readings with my non-contact thermometer? Not anxious to use that new bit again though.

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    I have to conclude it is the bit. I would like to know the reason for the bit change. I would also like to know how I can get replacements identical to my old one before it gets completely dulled or broken. As it stands, the new style are no good for this.

  6. #6
    Join Date
    Aug 2008
    Location
    Bangor, ME
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    614

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    Any chance the bit and/or holder are not 100% straight?

  7. #7

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    Quote Originally Posted by brdad View Post
    Any chance the bit and/or holder are not 100% straight?
    Two different new bits, same results.

  8. #8
    Join Date
    Aug 2009
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    Quote Originally Posted by DickB View Post
    Two different new bits, same results.
    Do you think the bits are damaged/prematurely dulled now from excessive heat?

    Lawrence

  9. #9

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    Don't know. They definitely got blackened, but feel sharp as I rub my thumb over them. I may get brave tomorrow and try to get temperature readings.

  10. #10
    Join Date
    Dec 2012
    Location
    Fruitport, Michigan
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    I would like to hear from the Carvewright staff to find out if they changed suppliers. Like most manufacturers, I would assume they are always on the lookout for suppliers who will provide them with parts and bits at a lower cost. They supply the specs and then the suppliers bid on the RFPs. Could be a new supplier. I am sure LHR will do their very best to get to the bottom of this for us. And they cant begin to check things out until they know there could be a problem. Hope this gets resolved for you very soon.

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