Breaking Bits like Crazy . . . .

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avf925
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Breaking Bits like Crazy . . . .

Post by avf925 »

Morning,

I am obviously doing something wrong in the setup process of these bits - and at $20.00 a bit - I'm pretty frustrated that I have destroyed 3 of them so far just yesterday and this morning. I am in one of the steps finishing a guitar fret board. The step is cutting the fret slots out along the fret board. The bit I am using is a .56 mm End Mill - the recommended width of the slot I am trying to cut. This bit was recommended by several other gents that CNC their fret boards. When I get to this step and load my file, the CNC spins up and basically SLAMS the bit into the rosewood, instead of a smooth gradual insert.

What am I doing wrong here guys?

I have attached the info shot from my VCarve Tool Database

Thanks for your help !
EM Tool Database Info
EM Tool Database Info

Bob Reda
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Re: Breaking Bits like Crazy . . . .

Post by Bob Reda »

I am not familiar with the metric system :D but it looks to me like your depth of cut is almost twice the diameter of the bit. I would reduce the depth of cut and ramp in to the cut

Bob

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mezalick
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Re: Breaking Bits like Crazy . . . .

Post by mezalick »

I'm assuming you're using the profile toolpath ???
If so, try adding a ramp to the vector you're cutting.
And cut slower...

Michael
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Bill_L
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Re: Breaking Bits like Crazy . . . .

Post by Bill_L »

You will need to do a conversion from inch to mm but these parameters worked quite well when I had to recreate an entire neck for an expensive vintage ES-335.

If you have any specific questions send me a pm.

Bill
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ger21
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Re: Breaking Bits like Crazy . . . .

Post by ger21 »

60mm/sec is about 140ipm.
I think you need to be in the 5-10ipm range.
Gerry - http://www.thecncwoodworker.com

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Re: Breaking Bits like Crazy . . . .

Post by Leo »

I agree with GER21 - PLUS - you MUST reduce your pass depth to either 1/2 the end mill diameter or 1/4 the end mill diameter.

I would start at .15 mm pass depth and 5-10 mm/sec

I have cut corian with a 1mm mill, but you are using a mill almost half that diameter.
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Re: Breaking Bits like Crazy . . . .

Post by dwilli9013 »

Depth of cut should optimally only be half of bit diameter more so with the smaller diameter tools.
Your plunge rate is too aggresive for the size bit you are using. Cutting speed should also be taken down considerably.
Bills numbers are pretty dead on for the bit you are using. Just convert to metric and you are golden. Google is your friend on the conversion or Joshua Madisons convert software.
https://joshmadison.com/convert-for-windows/
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avf925
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Re: Breaking Bits like Crazy . . . .

Post by avf925 »

Thank you all - and Bill - I set it up like you have it laid out - cuts like butter - and the BIT LIVED ;-)
really appreciate all of you guys !

Couple things to share - since my Axiom and VCarve are setup in mm's - and I'm a MAC guy

This is an AWESOME conversion App for the MAC - and it's FREE
https://itunes.apple.com/us/app/convert ... 0061?mt=12

Attached are the converted settings in mm's
MM conversions
MM conversions

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Re: Breaking Bits like Crazy . . . .

Post by Bill_L »

Glad it worked for you. Is your fretboard bound or unbound and what radius will you use? The radius needs to be accounted for to enable the tang to seat all the way at the edges of the board.

Bill

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avf925
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Re: Breaking Bits like Crazy . . . .

Post by avf925 »

It's unbound and a 10 -16 compound - it's for a Strat

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Adrian
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Re: Breaking Bits like Crazy . . . .

Post by Adrian »

If you want to work in imperial units within VCarve and output in mm you can. There's no need to use the same units as your post processor/machine.

You can also do the direct calculations in VCarve as well so no need to use external calculators if you do want to convert from one unit to another within VCarve.

http://support.vectric.com/aspire-quest ... characters

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