End mills

Talk about all things CNC
Enraged
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Re: End mills

Post by Enraged » Sun Apr 15, 2012 3:10 pm

I'll start a new thread once I talk to him and work out the details.

alpha
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Re: End mills

Post by alpha » Sun Apr 15, 2012 4:57 pm

I'm a total endmill noob, I just finshed reading the Wikipedia article about endmills but I still don't understand what type is used with what material? I also searched the ShapeOko wiki but I was not able to find any list ether. Is there a good resource out there? If someone puts a kit together please explain for what the bits are good and how to use them without damaging it.

Thanks,
Markus

PS: I'm interested in the kit too
PPS: looks like this article is better: http://en.wikipedia.org/wiki/Milling_cutter then the endmill article - I think this answered most of my questions... here is a quote:
]Selecting a milling cutter

Selecting a milling cutter is not a simple task. There are many variables, opinions and lore to consider, but essentially the machinist is trying to choose a tool which will cut the material to the required specification for the least cost. The cost of the job is a combination of the price of the tool, the time taken by the milling machine, and the time taken by the machinist. Often, for jobs of a large number of parts, and days of machining time, the cost of the tool is lowest of the three costs.
Material: High speed steel (HSS) cutters are the least-expensive and shortest-lived cutters. Cobalt steel is an improvement on HSS and generally can be run 10% faster. Carbide tools are more expensive than steel, but last longer, and can be run much faster, so prove more economical in the long run. HSS tools are perfectly adequate for many applications. The progression from HSS to cobalt steel to carbide could be viewed as very good, even better, and the best.
Diameter: Larger tools can remove material faster than small ones, therefore the largest possible cutter that will fit in the job is usually chosen. When milling an internal contour, or concave external contours, the diameter is limited by the size of internal curves. The radius of the cutter must be less than or equal to the radius of the smallest arc.
Flutes: More flutes allows a higher feed rate, because there is less material removed per flute. But because the core diameter increases, there is less room for swarf, so a balance must be chosen.
Coating: Coatings, such as titanium nitride, also increase initial cost but reduce wear and increase tool life.
Helix angle: High helix angles are typically best for soft metals, and low helix angles for hard or tough metals.

kargofab
Posts: 12
Joined: Tue Apr 10, 2012 12:30 am

Re: End mills

Post by kargofab » Sun Apr 15, 2012 5:46 pm

Enraged wrote:If anyone is interested, I contact that seller about making a custom Shapeoko set of end mills. If we can get about 10 or more people interested, he would be willing to offer some discounts. If anyone is interested in doing this, we would need to work out what types of end mills to put in the set, and we can go from there.

I ordered five 1/8" 4 flute end mills (for $18.75, so $3.75 per end mill) to check out the quality, but for a Shapeoko set I would suggest a few different sizes, as well as maybe a ballnose and a v-groove cutter as well. That way we could have one kit that has all the end mills you would need to do a variety of first projects, for a reasonable amount of money, that would fit in the standard 1/8" collet in a dremel.
I'd be in, but I'd want an end mill for aluminium to be included....

-m

Enraged
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Re: End mills

Post by Enraged » Sun Apr 15, 2012 7:55 pm

discussion on the group discount moved here: http://www.shapeoko.com/forum/viewtopic.php?f=7&t=47

edwardrford
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Re: End mills

Post by edwardrford » Sun Apr 15, 2012 8:14 pm

@alpha - That excerpt you posted from wikipedia is a wonderful 20,000ft overview of end mill selection in relation to material. That was a great find!

Here's another that I ran across a while ago which really gave me some insight into the science behind choosing end mills. http://www.cncathome.com/spindles.html the interesting bit starts just below the picture of the spindle with the last word indicator mounted to it (about 1/3 down the page). However, the whole page is worth a read. That guy really knows what he's talking about.

After reading through the page you'll realize why having a variable speed spindle (a true variable speed that doesn't lose torque as you reduce the speed!) is so important. With our dremels, we don't really have that luxury. Regardless, it's good information to know.

-Edward
Shapeoko 1 #0 - a couple of upgrades.
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alpha
Posts: 174
Joined: Thu Apr 12, 2012 2:49 pm

Re: End mills

Post by alpha » Mon Apr 16, 2012 12:38 am

Thanks for this link:
edwardrford wrote:Here's another that I ran across a while ago which really gave me some insight into the science behind choosing end mills. http://www.cncathome.com/spindles.html the interesting bit starts just below the picture of the spindle with the last word indicator mounted to it (about 1/3 down the page). However, the whole page is worth a read. That guy really knows what he's talking about.
I found this page on the same server:
http://www.cncathome.com/speedsnfeeds.html
I guess this is very helpful information... I think it would be good to create a wiki page that showcases different endmills with there settings on a standard ShapeOko setup(I guess a with a Dremel like router). This should also include the material that can be worked on and all the settings and the Dremel rpm setting as well...

Regards,
Markus

AtomSoft
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Re: End mills

Post by AtomSoft » Mon Apr 16, 2012 8:45 pm

WOW SO MANY POST. How come i dont get email confirmations? Ill have to check my settings.

But yeah. Ithanks. I plan to do both Plastic and Wood and some Metal work.
I will be using a Dremel 4000 for now. but plan to use a custom spindle stronger.

Im about to read and post in : End Mill Group Discount thread... thanks again!
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AtomSoft
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Re: End mills

Post by AtomSoft » Mon Apr 16, 2012 8:51 pm

Just noticed the links and wow this is some awesome stuff. Perhaps Edward can make a sticky of some USEFUL LINKS

:) Thanks for all the info ... got to say i already love the community here :D
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