wobble while drilling

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This topic contains 1 reply, has 2 voices, and was last updated by Profile photo of Barry Barry 5 months ago.

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    Profile photo of Jeffeb3

    I’m pretty sure I know what’s happening here, but in case there is a simple fix I haven’t thought of, I thought I should post it here.

    I’m cutting 1/4″ MDF, 1/8″ downcut bit, and I have the old version of the MPCNC. When drilling the holes, 1/25 or so has gone crazy, after cutting most of the way through, and ends up wobbling and making a big hole. I’m using EstlCAM, and it’s cutting 1mm deep, then backing all the way up, until it reaches the full 6mm depth.

    So my thoughts were:
    – Downcut bit for drilling is not great. I have an upcut bit, but I really like the contours the downcut bit makes. So maybe a bit change?
    – I thought it was maybe a dull bit, but I switched to a brand new one, and it failed on about the 6th hole. Then finished another 20 with no issues.
    – The 525 version is more rigid, so maybe I should just bite the bullet and update my MPCNC, maybe take the chance to switch to stainless 1″ tubes while I’m at it. I’m trying to hold off until I finish this MP3DP.
    – The bit isn’t perfectly perpendicular to the board, so as it goes deeper, it’s getting slightly jammed against the side. The DW660 mount is another thing that I’m trying to just kick the can a little further until I update to 525.

    So my conclusion is, this MDF is cheap, just cut it again, and if I really want to ensure success, either do a tool change, or just do 2mm deep drill holes, and finish with the drill press. Anyone have any other thoughts on what I could be doing wrong?

    • This topic was modified 2 weeks, 4 days ago by Profile photo of Ryan Ryan. Reason: Moved
    Profile photo of Barry

    Downcut bits should never be used to drill holes. You can actually start a fire doing that. Think about it. They push the cut chips down through what you’re cutting. If you’re cutting a slot, it’s not a big deal as the chips get thrown out the slot. If you’re just drilling a hole they get compressed into the bottom of the hole. You’d get the same result by chucking a wooden dowel into your router. You can use them if you do a spiral hole cut, but the bit needs to be smaller than the hole.

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