Tapered ball nose cutters

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Re: Tapered ball nose cutters

Post by Leo »

Not many people are more skeptical than I am.

As an engineer I am obsessively anal retentive and I do NOT like junk. I do not cheap out on anything.

I am also a cheap yankee and I do not like spending money that I don't need to spend.

On the EBAY cutters I tested I cut brass just so I could give them a good run, and a tough test. Sure get good cutters, get the BEST you CAN get. BUT - don't spend more than you need to spend.

Not a conflict - just frugal.

I fully expected to trash the EBAY cutters and be done with it. NOPE - I was proven wrong - they performed FAR better than I would have expected. Even as I inspected the cutters under a microscope I saw minimal wear after cutting brass.

I will vouch for the EBAY cutters and I will buy them again.
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Re: Tapered ball nose cutters

Post by TReischl »

One of the things that bothers me about small tapered ball nose cutters is it is easy to break one when handling, drop it on the floor. . . . grrrrrr. Of course that is true of all small cutters. But accidentally breaking a $30+ cutter is a real pita. A $4 cutter? Not so much.

I have been having real good luck with chinese stuff lately. As I have posted before I am starting to use a lot of HSS cutters. I purchased (10) 6mm HSS end mills for $1.64 each. Cut length is about 1 inch (these are extra long). Yup, carbide cutters would "last" longer, but they are also at least twice as expensive. I can buy an Amana .25 diameter router bit for around $14. Hmmm, do I really think it will last 7 times longer? Is it really going to give that much better of a cut?
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Re: Tapered ball nose cutters

Post by Xxray »

I often see a massive difference in quality and longevity, I have a precise tapered bit I have used for dozens if not 100's of 3d projects in wood, corian and plexi still going strong, cheap bit you would be lucky to make it through half a dozen without a noticeable deterioration of quality [and yes, I have used them too of course]. Especially with lithos and plexi the results are often night and day between bits, but I guess you wouldn't notice that or be aware of it if you don't try quality bits vs cheap. Milling metals I can't speak of because I don't do it, I imagine you might have more slack here vs a bit expected to produce fine detail.

Also, they are a crap shoot if they will even fit the collet, I have more than 1 cheap ebay bit that looks pretty nice but they are unusable because the shanks are machined just a wee bit small so that they slip out of the collet they are supposed to fit and are way too big for the next collet size down. So yes IMO cheap throw away bits have a place, some are obviously better than others, I've learned to cut through the chase, avoid hassles, complications and sub par projects just to save a few $$ and use them as little as possible. I have a whole box full of cheap bits of various kinds, most are virgins and will stay that way ,,, But, they are there against the day I might need them.
Doug

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Re: Tapered ball nose cutters

Post by TReischl »

Evidently mileage varies.

I have been running the heck out of my cheap bits and I have yet to see any deterioration in quality of cut. The only time I have had shank size problems is when someone shipped me metric bits that were supposed to be imperial, but that was quite a while ago. They did fit my metric collets very nicely so I used them on my manual mill. Since then I have purchased metric collets for my cnc and all is well.

The real issue is how long they cut versus the cost. So far, mine have lasted as long as the expensive ones, so to my way of thinking I am way ahead of the game.

But like I said, mileage may vary, or at least the perception of mileage. From my experience it will be a cold day in hades before I shell out $30+ for one bit again. If the cheap bit only lasted half as long as the expensive one it would still make more sense to buy the cheap ones and toss them when they stop performing well. Another issue with expensive bits is that one tends to try to use them longer because of their cost. No one likes to toss an expensive bit in the carbide bucket, maybe just one more project. . . .and another. . . . and another.
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Re: Tapered ball nose cutters

Post by Xxray »

There are quite a few variables and considerations, if you never buy a quality USA made bit then I guess you'll never know, or care, what [if anything] you are missing. Which brings me to another consideration, supporting domestic manufacturing instead of asian sweat shops.
Doug

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Re: Tapered ball nose cutters

Post by TReischl »

Pretty much impossible to not buy goods made in the far east these days. I will let them worry about their sweat shops.
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Re: Tapered ball nose cutters

Post by Xxray »

Well, this topic I thought was about cutters, very possible not to buy from sweat shops if so inclined. For that matter, I'm anti ebay and haven't done any business with them in years, getting the same with Amazon. I'm of the opinion that we are cutting our own throats in the long run by always seeking the easiest, cheapest option, thats just me. My first consideration regardless of source is quality, I will continue to recommend more expensive domestic products over sketchy imported tools until I have a good reason not to.
Doug

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Re: Tapered ball nose cutters

Post by newmexico »

fullsizeoutput_3cd.jpeg
OK... What a wonderful discussion in this thread.

IMHO, after cutting wood with router bits for 30 years, its the V bit that is the star for complicated, detailed 2d designs.
We are especially fond of the V90 insert bit. We like those replaceable bits.

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Re: Tapered ball nose cutters

Post by TReischl »

After reading XXRay's (Doug) post I decided to look into this further.

Here are Chinese and US tapered ball nose cutters:
tbn.jpg
Then I did a little calculation. The chinese cutter starts out as a .125 diameter blank and is about 1.5 inches long. The US cutter is .25 diameter and about 2 inches long. This means that the US cutter has about 5X as much material. The length of grind is about 2X as long on the US cutter compared to the Chinese cutter. Also note that the flute depth is much, much deeper on the US cutter due to the diameter of the blank.

Now we get to where the rubber meets the road, or rather where the cutter meets the wood. Tapered ball nose cutters are by far and wide used for finishing work. A typical depth of cut would be about .03 -.04 inches deep. Stepover between .001 and about .012. Both of these cutters have no problem handling those loads.

It is very apparent why the chinese cutters are so much cheaper than US cutters. They use much less material and remove much less material in the manufacturing process. I did some more research on how these cutters are made. My cutters are manufactured by Jerray (a registered trade name). Here is a blurb about them:

"Shenzhen Jerray CNC Tools Co. Ltd, is specialized in R&D, manufacture, sale and technology service of CNC tools. We have the" JERRAY" Trademark registered in United States. Our products are widely used in automobile, machinery, electronics, metallurgy, metal, mining, aviation and other fields.

JERRAY Tools, the spirit of craftsman. The company introduces advanced manufacturing equipment and technology from Germany and Australia, using highest quality materials to produce the high quality products such as CNC Carbide End Mills, molding end mills and CNC tools holder ect. Meanwhile customize non-standard tools according to the customer's request. Our highest quality products are welcomed in home and abroad.
"

What is important in this blurb is that they use cnc grinding equipment from Australia and Germany. Those countries make some of the best cnc grinding equipment in the world. If you would like to see some of this equipment in operation:

https://www.youtube.com/watch?v=_NwP8O2E7JM

Given the above information it is apparent why the chinese tools are so much cheaper, less material, less grinding and using quality machinery for production. And yes, their cost of labor is much less but labor is not one of the major contributors to the cost of manufacturing. It is very typical for these type of companies to have one employee overseeing 5 or more machines at a time. Pretty much the same thing as the old bar stock feeder machines in terms of labor.

The only other factor I can think of right now is the material used. Companies of that size are not buying unknown grades of carbide and feeding it to millions of dollars worth of cnc controlled grinders. It would not make sense.

If a US cutter grinder wants to compete then they should look at reducing material usage. Sure, those bigger cutters can be useful, but not for shallow finishing work, it just does not make sense to pay for material and grinding that is never used.
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Re: Tapered ball nose cutters

Post by newmexico »

Tapered ball nose cutters are by far and wide used for finishing work.
2d or 3d finish work?
Wood or metal?

(Great info above by TReischl. Thanks!)

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Re: Tapered ball nose cutters

Post by TReischl »

newmexico wrote:
Tapered ball nose cutters are by far and wide used for finishing work.
2d or 3d finish work?
Wood or metal?

(Great info above by TReischl. Thanks!)
I am thinking mostly 3D work. Frankly, I cannot see much use for them on regular 2D work, maybe the real fine tips (like the .25 mm) for engraving. In my past life the only time I saw a ball nose cutter of any type being used was in mold work. If the surface was flat a regular end mill was used. I also remember guys sitting on top of large automotive injection molds removing all the tiny cusps created by the ball nose mill and then polishing the surfaces.

The thing to remember is that these cutters are designed for metal work, that is the huge majority of work being done by cutters in general. Woodworking is a very small subset of the cutter world. The problem a lot of us have with using them for metal work is that our machines are not really designed for metal working (think rigid as all get out) and many of us use routers for a spindle, we cannot slow them down enough to use them effectively on metal.

I have a small mini mill and it is amazing how well these cutters work on that machine. The max rpm is 2500. My minimum on the router is 16,000.
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Re: Tapered ball nose cutters

Post by SteveNelson46 »

I have certainly purchased a lot of cheap crap from China. On the other hand, I have also purchased a lot of cheap crap made here in the U.S. My point here is that all countries have different manufacturers with a range of quality. Just because a product is manufactured in the U.S doesn't mean that it is high quality. JMTCW.
Steve

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Re: Tapered ball nose cutters

Post by martin54 »

I would say mostly 3D same as Ted, but in the small sizes like 0.5mm diameter then they would probably do a pretty good job with a lot of vcave jobs, don't do a lot of vcarving so never experimented but it would be easy enough to toolpath a vcave job with one & then have a look at the toolpath preview :lol: :lol:

They wouldn't be best for all vcarve jobs as you are not going to get sharp corners as you would with a V bit or engraving bit but not all vcarve jobs call for sharp corners :lol: :lol:
The advantage over a straight ball nose bit of the same size would be he strength of the bit, a 0.5mm straight shank bit is extremely fraile :lol: :lol:

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Re: Tapered ball nose cutters

Post by Xxray »

SteveNelson46 wrote:I have certainly purchased a lot of cheap crap from China. On the other hand, I have also purchased a lot of cheap crap made here in the U.S. My point here is that all countries have different manufacturers with a range of quality. Just because a product is manufactured in the U.S doesn't mean that it is high quality. JMTCW.
The particular, specific link I posted means exactly that.

Good critique TR, I don't begrudge anyone the perfect right to buy and use whatever they see fit. We are all products of our yesterdays and have lots of different experiences. I use top grade cutters because of my experiences, could not in good conscience recommend anything else, though I think everyone should have a small box full of cheap foreign tooling for experimentation and redundancy on the cheap.
I don't know if they use top end German production tooling our not, certainly would not believe it just on the basis of them saying so. They reverse engineer and copy anything they get their hands on, don't see why they'd make exceptions for production tooling. And they could rather easily be feeding sub par material into their machines, it would take a metallurgist to find out for sure.
Doug

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Re: Tapered ball nose cutters

Post by TReischl »

My point was pretty clear, when a company is using 1/5 of the material and doing 50% less grinding their product is going to cost less, way less.

Did some more research and found out these chinese "sweatshops" are anything but that. Moreover, they are running machines like Walter grinders. Anyone who has been around precision grinding shops knows the name Walter. German made, ultra precise.

Here are some pics, all of this stuff is available on the internet with a little bit of research.
walther grinder.JPG
walter 2.JPG
Capture.JPG
It only makes sense that the chinese have shops like these. They are heavy into manufacturing, their own companies cannot be competitive relying on junky tooling, it doesn't work for anyone, including them.
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