# Run bit beyond cutting height?

**URL:** <https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962>\
**Category:** Uncategorized\
**Created:** [September 28, 2021, 11:49pm UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962 "2021-09-28T23:49:11Z")\
**Posts on this page:** 11\
**Page:** 1

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**Author:** ![Watkins](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/watkins/32/3188_2.png) [@Watkins](https://forum.onefinitycnc.com/u/Watkins)\
**Post date:** [September 28, 2021, 11:49pm UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/1 "2021-09-28T23:49:11Z")

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So, the Amana 46170-k has a cut depth of 7/8”. Let’s say my depth per pass is .25”, how far down can I run this bit? What if I run the bit beyond the flutes?

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**Author:** ![pootaholic](https://avatars.discourse-cdn.com/v4/letter/p/8e7dd6/32.png) [@pootaholic](https://forum.onefinitycnc.com/u/pootaholic)\
**Post date:** [September 29, 2021, 12:05am UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/2 "2021-09-29T00:05:17Z")

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You could safely run it to the depth of the cutting flutes (7/8") after that the top portion of the bit would start rubbing against the workpiece possibly causing burning.

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**Author:** ![Dr-Al](https://avatars.discourse-cdn.com/v4/letter/d/cc9497/32.png) [@Dr-Al](https://forum.onefinitycnc.com/u/Dr-Al)\
**Post date:** [September 29, 2021, 4:52pm UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/3 "2021-09-29T16:52:56Z")

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It depends on how wide of a cut you are trying to make. Since it’s a 1/4" bit if you were trying to make a 1/2" groove the chips would have plenty of room. But if just doing 1/4" wide you’ll run into the chips getting packed into the cut which isn’t ideal. If the chips fill up the cut to the point where they will need to be removed by the smooth part of the bit it could put too much load on the bit and break it.

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**Author:** ![Watkins](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/watkins/32/3188_2.png) [@Watkins](https://forum.onefinitycnc.com/u/Watkins)\
**Post date:** [September 29, 2021, 7:39pm UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/4 "2021-09-29T19:39:30Z")

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Hmm, that makes sense. What I’m trying to figure out is how to cut through two pieces of 3/4" plywood glued/laminated together with a total thickness of 1.4".

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**Author:** ![Kneepit](https://avatars.discourse-cdn.com/v4/letter/k/ebca7d/32.png) [@Kneepit](https://forum.onefinitycnc.com/u/Kneepit)\
**Post date:** [September 29, 2021, 9:35pm UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/5 "2021-09-29T21:35:48Z")

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Can you drop the bit a little lower from the collett?

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**Author:** ![Dustoff00](https://avatars.discourse-cdn.com/v4/letter/d/34f0e0/32.png) [@Dustoff00](https://forum.onefinitycnc.com/u/Dustoff00)\
**Post date:** [September 29, 2021, 9:36pm UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/6 "2021-09-29T21:36:53Z")

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To support Dr Al’s point, could you do two tool paths, say Outside the line for the first with a depth of 3/4" and then the one on or inside the line that goes the full 1.4. That should give room for the chips to be evacuated on the one side as the final few passes happen in the last .7 down. You may also have to account for a smaller chip load factor when computing feeds speeds. (Assuming that you are cutting all the way through, that you have some waste to work with on either the inside or outside of the path).

Another possible solution is to use two sided and use some pins, similar to tiling for alignment.

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**Author:** ![TMToronto](https://avatars.discourse-cdn.com/v4/letter/t/7ea924/32.png) [@TMToronto](https://forum.onefinitycnc.com/u/TMToronto)\
**Post date:** [September 29, 2021, 10:33pm UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/7 "2021-09-29T22:33:32Z")

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I had looked at options for deeper cuts a while ago and found a few options. Here is a link to one such manufacturer that offers end mills with both extra long overall length as well as and flute cut length:  
[https://www.kodiakcuttingtools.com/viewseries/carbide-end-mills/extra-extra-long-carbide-end-mills/](https://www.kodiakcuttingtools.com/viewseries/carbide-end-mills/extra-extra-long-carbide-end-mills/)

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**Author:** ![Dr-Al](https://avatars.discourse-cdn.com/v4/letter/d/cc9497/32.png) [@Dr-Al](https://forum.onefinitycnc.com/u/Dr-Al)\
**Post date:** [September 29, 2021, 10:47pm UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/8 "2021-09-29T22:47:22Z")

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Could you cut each sheet individually and then glue them together?

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**Author:** ![Bear](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/bear/32/30015_2.png) [@Bear](https://forum.onefinitycnc.com/u/Bear)\
**Post date:** [September 30, 2021, 12:48am UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/9 "2021-09-30T00:48:51Z")

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I use a 1/4" x 2.5 inch with the 7/8" flue to cut though 2 inch hardwood material all the time. Slow down the feed rate (between 40 and 60), and you will avoid burning and stressing out the machine… it just takes longer… oh well.  
😁

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<div class="post-metadata">

**Author:** ![Watkins](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/watkins/32/3188_2.png) [@Watkins](https://forum.onefinitycnc.com/u/Watkins)\
**Post date:** [September 30, 2021, 12:59am UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/10 "2021-09-30T00:59:49Z")

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Yes, that’s what I’ve been doing, just wondering if there was a more efficient process.

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<div class="post-metadata">

**Author:** ![Bear](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.onefinitycnc.com/bear/32/30015_2.png) [@Bear](https://forum.onefinitycnc.com/u/Bear)\
**Post date:** [September 30, 2021, 1:10am UTC](https://forum.onefinitycnc.com/t/run-bit-beyond-cutting-height/7962/11 "2021-09-30T01:10:02Z")

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@Watkins  
The only thing I can think of is longer bits. They are out there… But I haven’t found the need… YET! I have an extension bit holder that allows me to dig down 3" + with larger bits… but you have to be mindful of the shaft… I use it with 1" and larger.
