Hi Everyone - New User Bits Question

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Beej
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Hi Everyone - New User Bits Question

Post by Beej »

Hi Everyone :)
Just joined the forum today and have been dying to ask some questions, but wanted to introduce myself first but couldn't seem to find a 'Welcome' section? :)
I have been a professional sign writer, airbrush artist and designer for over 35 years now and a couple of months back, a friend and i started-up a new company. He purchased a Bear Whopper Z90 CNC machine which came with VCarve, Mach3 and lots of bits. Of course, as new users, none of us knew what any of the bits were for so I spent two weeks watching brilliant tutorials on Vectric's site and went off searching the net etc . .

Through some trial and error we managed to discover what was best for cutting MDF out of what we had in this selection (a 4mm straight flute) but have no idea what most of the other bits are for. On the images, I know that image 5 are Ball Nose bits for relief carving (they look like 3 of the same?) and pic 7 are for engraving - but will have to try them as not sure what bit is what? Practically nothing is written on the bits sides either, so makes it even more difficult!

I will post some pics of the type the things we have managed to produce in the past four weeks in the other forum of images of work done, but for now, if someone could give us some advice on what these bits are for and what material etc, I would be very grateful. I am sure I will have many more questions very soon but for now, here are the pics.

Cheers
Beej

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image9.JPG
image8.JPG
image7.JPG
image6 (2).JPG
image5 (2).JPG
image4 (2).JPG

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Beej
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Re: Hi Everyone - New User Bits Question

Post by Beej »

image3 (3).JPG
image2 (4).JPG
image1 (7).JPG
I think 9 is a huge bit for MDF, 10 is for skimming our spoil board (which we have yet to do!) and 11 is a massive 120 degree VBit (I think)?

As for the others, no idea what they are for? Guess it will all come with more use and knowledge but any help is much appreciated :)

Thanks

PS: Someone commented about the feeds and speeds elsewhere but that was down to previous owners! All the tools - complete with burns - were like that when we got them as we have only used a 6 and 4mm End Mill and the one marked 'Straight Flute', as this is the bit that seems to cut our 12mm MDF the best so far. Still learning re the Feeds n Speeds in VCarve Tool Library set-ups..

Beej

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TReischl
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Re: Hi Everyone - New User Bits Question

Post by TReischl »

In image 3 there are up and down cut spiral bits. One lifts the chips out of the cut, the other pushes them down. Hence the names.

The down cuts are used to reduce or entirely eliminate splitting on the surface of the work piece.

Pay attention to the direction of the helixes and sort them accordingly.

Same for image 2.
"If you see a good fight, get in it." Dr. Vernon Johns

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Beej
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Re: Hi Everyone - New User Bits Question

Post by Beej »

TReischl wrote:In image 3 there are up and down cut spiral bits. One lifts the chips out of the cut, the other pushes them down. Hence the names.

The down cuts are used to reduce or entirely eliminate splitting on the surface of the work piece.

Pay attention to the direction of the helixes and sort them accordingly.

Same for image 2.
Thanks, appreciated :)
So is it a stupid question to ask what material the bits are for? Or can you basically cut anything? Just try one and see?
Of course, the previous owners (as I forgot to mention in original post, we bought all the kit 2nd hand) have the Tool Library in VCarve set-up for whatever they did, so it makes it impossible (almost) to see which bit is what in there when it comes to selecting the right tool etc.

Thnks
Beej

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dealguy11
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Re: Hi Everyone - New User Bits Question

Post by dealguy11 »

My take:

Image 1 - spiral end mills appear to be for plastics. Straight bit is general purpose.
Image 2 - The second and fourth bit look like plastics bits. The rest are general purpose end mills. First bit looks like the cutting edge may be chipped off.
Image 3 - Look like general purpose spirals. 2nd and 4th bits look like down-cutters. The toasty-looking bits have probably been run hot (too high speed, too low feedrate) and may not be good.
Image 4 - Plastics bits (the word "Perspex" behind them reinforces that)
Image 5 - All ballnose bits for 3d-type work.
Image 6 - Looks like another plastics bit, but not sure.
Image 7 - Various v-cutters. The ones without tips will need to be defined with a flat on the ends or they won't cut like you want, assuming they're not just broken. If broken, throw them out.
Image 8 - Spiral end mills for general cutting/pocketing. I'd throw out the one on the right.
Image 9,10,11 - These bits all look to be in bad shape. The one on the left is a straight bit, maybe 1/2"? The one in the middle could be used to surface the table, but it looks very used. The 90-degree v-bit on the right should be thrown out. It is very toasty and the tip is broken.

Looks like you'll need to invest in bits sometime soon. This is a very well-used set.
Steve Godding
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Beej
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Re: Hi Everyone - New User Bits Question

Post by Beej »

dealguy11 wrote:My take:

Image 1 - spiral end mills appear to be for plastics. Straight bit is general purpose.
Image 2 - The second and fourth bit look like plastics bits. The rest are general purpose end mills. First bit looks like the cutting edge may be chipped off.
Image 3 - Look like general purpose spirals. 2nd and 4th bits look like down-cutters. The toasty-looking bits have probably been run hot (too high speed, too low feedrate) and may not be good.
Image 4 - Plastics bits (the word "Perspex" behind them reinforces that)
Image 5 - All ballnose bits for 3d-type work.
Image 6 - Looks like another plastics bit, but not sure.
Image 7 - Various v-cutters. The ones without tips will need to be defined with a flat on the ends or they won't cut like you want, assuming they're not just broken. If broken, throw them out.
Image 8 - Spiral end mills for general cutting/pocketing. I'd throw out the one on the right.
Image 9,10,11 - These bits all look to be in bad shape. The one on the left is a straight bit, maybe 1/2"? The one in the middle could be used to surface the table, but it looks very used. The 90-degree v-bit on the right should be thrown out. It is very toasty and the tip is broken.

Looks like you'll need to invest in bits sometime soon. This is a very well-used set.
Thanks bud, SO much appreciate your post :) And have to agree, reckon it's time to simply start over with a few! At least that way we can the right advice from the CNC tool suppliers

All the best..

Beej

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highpockets
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Re: Hi Everyone - New User Bits Question

Post by highpockets »

Beej,

Welcome to the forum and the joys of CNCing. There are no stupid questions except the ones not asked.

Reading your background I see why your art work and painting skills are so great.

Looking forward to seeing more of your projects in the future.
John
Maker of Chips

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Re: Hi Everyone - New User Bits Question

Post by TSmith88 »

Feedrates and speedrates are very important when calculating the proper chipload. Chipload is the size of the chips being produced by the cutter, it is determined by many factors including the speedrate, the feedrate, the material being cut, the diameter of the bit, how many teeth/flutes the bit has etc. To high of a chipload will cause the bit to "tear" the material instead of cutting it, and to small of a chipload will cause the bit to burn because the chips aren't extracted properly. It's always a little bit of trial and error to figure exactly what is best for your machine and the materials/tooling you use but there are many calculators online that can help you find a good starting point.

https://www.guhdo.com/chipload-calculator
Here is a chipload calculator from GDP Guhdo that I have used many times over the years. Guhdo is a good company to buy bits from and they are very knowledgeable about their products so you can call them up and tell them what you want to cut, and they can help you find the tooling that would best suit your needs.

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TReischl
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Re: Hi Everyone - New User Bits Question

Post by TReischl »

We all know that Steve Godding has more money than the Lord Almighty, so he just tosses bits out the door. ::::snicker:::: I hang around outside his back door for the freebies.

Seriously, one thing you should do is locate a tool sharpener near you. Especially for large bits. Large bits are pricey bits. Especially ones like a big honking V bit. Sharpening works wonders and saves big bucks.

I do not bother getting smaller bits sharpened, like 1/4, 3/8 and 1/2. These days I run a lot of cheapo chinese HSS bits so sharpening does not make sense. I am also known to buy their el cheapo tapered ball nose bits. I have had really good luck with them.
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dealguy11
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Re: Hi Everyone - New User Bits Question

Post by dealguy11 »

Ouch, that hurt! I've had mixed luck with resharpening, but if it works for you, go for it. There's a point where it doesn't make sense, though. When the tip is gone from a v-bit then it won't cut the same. Once a bit gets toasty, the temper of the metal can change and it may not hold an edge.

But then again, it may. Try it and see.

I generally run bits until they either break or I start getting ragged edges. You're welcome to them TReischl! If it's a big custom profile, I may have it resharpened. Maybe we should resharpen more stuff, but it changes the geometry of the bit, which can be an annoyance when precision counts.
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Re: Hi Everyone - New User Bits Question

Post by scottp55 »

I agree with Steve on most of that breakdown....a few look like they've been smoked and heat damaged.
They really need a good cleaning and brushing.

Beej..Welcome!
But looks like you have a spindle..and one of the first things I would do is clean the spindle cone!!
Then check all collets and your collet nuts and clean them...IF worn or damaged replace asap....damage to the spindle cone is pretty much non repairable,and WAY more expensive than the the collets or nuts which are consumables.
IF shank is corroded or burred....do NOT use in the new collets as they'll mar the surface and eventually mar your brand new bits.

If available on your side of the pond BladeCote is good for cleaning bits with a brass brush, and preventing buildup?
I'm fussy, BUT clean my bits after every use...that way when I'm rushing, I KNOW I'll always be grabbing a clean bit.

I'd also skim your spoilboard as soon as you can.

You do wonderful work!
But with clean,sharp bits..and a flat spoilboard...it will save you a bunch of time having clean sharp cuts:)

Again..Welcome Beej :D
I've learned my lesson well. You can't please everyone,so you have to please yourself
R.N.

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TReischl
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Re: Hi Everyone - New User Bits Question

Post by TReischl »

dealguy11 wrote:Ouch, that hurt! I've had mixed luck with resharpening, but if it works for you, go for it. There's a point where it doesn't make sense, though. When the tip is gone from a v-bit then it won't cut the same. Once a bit gets toasty, the temper of the metal can change and it may not hold an edge.

That temper thing is really true for HSS bits. If they turn blue they are done for. Carbide is a whole different animal, getting it too hot and then cooling it rapidly cause micro fractures. If I recall correctly carbide is not heat treated, could be wrong about that. I think a lot of what we see when a bit looks like that V bit in his photo is material (resin) that has caked up on the bit and of course it starts rubbing and getting hot. Which is not good.

But then again, it may. Try it and see.

I generally run bits until they either break or I start getting ragged edges. You're welcome to them TReischl! If it's a big custom profile, I may have it resharpened. Maybe we should resharpen more stuff, but it changes the geometry of the bit, which can be an annoyance when precision counts.

Yup, I do not get end mills sharpened, too much hassle with the size changes. I suppose I could have a section in my tool storage for "roughing only" or something, but these days I just use cheap chinese end mills for roughing and finishing dimensional work.

I have not found a good sharpening service where I live now. My last place I had a really good sharpening service close by. They knew what grinds to use for different materials. They were also very reasonable when it came to pricing. And quick. Drop off in morning, pick up the same late in the afternoon. They really took the pain out of buying large ball nose cutters because they did a great job resharpening them.

Edit: That bit #10 (looks like a large dado bit) is pretty obvious, someone tried plunging it into the material and of course it is not center cutting so it smoked the material and caked up the bit. Wonder how hot that got before someone hit the Panic button? Beej, if you are going to use a bit like that for the spoil board make sure you use a ramp in so that you avoid doing the same thing.

Scotty, you were posting while I was writing, feel the same about cleaning the bits.
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Re: Hi Everyone - New User Bits Question

Post by tomgardiner »

I'm lucky to have an excellent sharpening service (Goldsmith in Prescott Ontario) and get end mills, compression bits resharpened twice. If I get them done just as they lose performance then the diameter loss is .005-.010" so now I have five "3/8" compression bits with an actual diameter of. 365" that is in my database. The bit's stay in their plastic cases with the diameter marked. Performance is as good as new. Price to sharpen is $8 I think as opposed to $40 new.
I have heard of cryogenic treatment to improve the performance of carbide.

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