[SCzEngrgGroup]

Sorry, but your logic seems to me a bit convoluted. Your concept of "effective RPM" is simply not a useful quantity. RPM is nothing more than a means to achieve a particular SFPM, so the tool will operate efficiently. Increasing, or decreasing, the number of flutes on the tool does not change SFPM in the slightest, but will directly change the chipload per tooth.

I could just as well use the same logic to come up with:

#teeth = Ipm / (rpm * chipload)

and then conclude that increasing RPM reduces the "effective #teeth", which makes about as much sense.

Regards,
Ray L.

[BobWarfield]

Edit:
You know, I can see your flawed logic, 1.5*2=3, in the ipm equation you multiply the right side by 1.5, and you then say it increases the spindle speed by 1.5. But by that logic you could say it effectively increases the chipload by 1.5. Continuing, if you sub in the equation for RPM we get, ipm=(12*sfm*chipload*#teeth)/(tooldiameter*pi)
Now following your logic this says that increasing the number of teeth effectively decreases the tool diameter or the value of pi.

I'm really beginning to grow a distaste for this forum. Everyone is so quick to undermine anyone else's opinion without backing their own statements up yet at the same time ironically demanding that of others questioning them, or trying to brush them off because god forbid, you know everything and are always right. Prove me wrong. This is almost as golden as gridleysomething in another thread trying to tell me that on any given day 304 is more cost effective than 303.

Denis, I can see from the quote above you finally did figure out that increasing flutes is tantamount to increasing spindle speed, though you're struggling mightily not to accept it. The good news is you don't have to accept it. Others will understand what it means and take advantage.

Here is some extra credit that I'm sure will have you up in arms all over again:

Fewer flutes can be thought of as decreasing spindle speed. This is important to the router folk, who often can't turn the spindle slowly enough with harder materials. Hence the one flute endmill was created for just such an audience.

As for fuming about how quick everyone is to undermine someone else's opinion, consider that it was you who leaped in to dispute whether using more flutes could possibly be a substitute for more spindle speed. You even responded to your own post before anyone else could just now.

I don't think that's a bad thing either, especially now that you've kindly made my point for me. Heck, I've even learned from you that I can change the value of Pi--Priceless!

I am annoyed though, that you have stolen my thunder about being able to change the diameter of the cutter. That's the whole point of interpolated holes, don't you know.

Cheers,

BW

[SirDenisNayland]

Sorry, but your logic seems to me a bit convoluted. Your concept of "effective RPM" is simply not a useful quantity. RPM is nothing more than a means to achieve a particular SFPM, so the tool will operate efficiently. Increasing, or decreasing, the number of flutes on the tool does not change SFPM in the slightest, but will directly change the chipload per tooth.

I could just as well use the same logic to come up with:

#teeth = Ipm / (rpm * chipload)

and then conclude that increasing RPM reduces the "effective #teeth", which makes about as much sense.

Regards,
Ray L.

Exactly, the whole concept of the entire logic is convoluted and flawed that I am trying to impress upon BW. Changing any of those variables cannot be thought of as effectively changing any of the other variables. However strictly mathematically speaking, like you noticed, if you want to keep the equation constant then changing of one variable necessitates the change of another, pick and choose, but that's not how it works in the real world. I am glad someone understands where I am coming from.

Bob:

They made the one flute for high rates of chip evacuation in softer materials like plastics etc which you pound the living **** out of where even two flutes can jam up. Applications mostly include routers like you mentioned, which, more often than not cannot achieve the feedrates necessary to carry a proper chipload which would otherwise cause excess rubbing, in the case of plastics even melting, and doubly like I said, that increased chipload can lead to flute jamming, so the single flute does well to alleviate two major problems with plastics and other soft synthetic materials.

One flute, two flute, a thousand flutes, your "effective" rpm and SFM still remains the same. As I said before, and what the poster I quoted echoed is the only thing that allows you to do is use a faster or slower feed as well as increase or decrease the chipload.

Though I see you chose to beat around the bit about SFM because clearly you don't understand the concept and how important it is.

[SirDenisNayland]

Let's follow you in the last statement which has gotten me oh so up in arms, decreasing teeth decreases the RPM.

Let's say you have
A spindle which only turns at 1000rpm
A piece of material which requires 100sfm
A 10 insert, 3.82" facemill.

You realize you are spinning way too fast, ten times too fast in fact. So by your logic you decide to decrease the number of teeth by a factor of 10 to decrease the spindle speed by a factor of 10, leaving you with one insert in the facemill.

Go try that out and get back to me with how well that works for you.

Cheers

[Spinnetti]

Man, you guys need to chill.. its not worth acromony.

What I'd say, is that additional cutter flutes allow a greater feedrate at a given chipload rather than having any effect on spindle speed... maybe you guys are just hung up on semantics. We aren't saving the world here, just making chips.

Whatever. As long as I can make parts that meet my needs, I'm good :boxing:

[BobWarfield]

Man, you guys need to chill.. its not worth acromony.

What I'd say, additional cutter flutes is allow a greater feedrate at a given chipload rather than spindle speed... maybe you guys are just hung up on semantics.

Whatever. As long as I can make parts that meet my needs, I'm good :boxing:

I agree. Time to quit feeding the Troll.

Cheers,

BW

[SirDenisNayland]

I agree. Time to quit feeding the Troll.

Cheers,

BW

You're the only troll here.

You ignore logic and spout off false information as fact. Your cluelessness only shows you've never done much more than hobby work in materials where SFM really doesn't matter at all.

People like you are hilarious Bob, and whats worse is people actually take you seriously. You can't for a single second even contemplate the fact you may just be wrong.

It's sad that this industry is so secretive, and I am happy to see people willing to share information which will only lead to the resurgence of manufacturing in North America. But the information you share only serves to keep work being sent to China.

Seriously, go try that experiment. Take a 4" facemill with ten teeth, a block of M4, let's say .05doc, set the spindle to 1000rpm and use whatever feedrate you want. Remove all the teeth but one to "effectively" reduce you rpm to one appropriate for the SFM required and hit the start button with the door open and tell me what happens. Dont bother wearing glasses, they won't save you from the chunk of material that will bury itself into your skull.

I can only hope you do this experiment to "validate" your claims.

[cadcam]

To make these parts as I have many times little ones like this. Not sure how many you have to make. I take double sided tape and a 8" x 8" pc of the 1/8 stock and tape to a alum plate. I would program this using the tab option leaving no bigger then a .01 thick tab max width of .1 in 3 to 4 places on the part. I would lay then out nested accounting for the tool and tabs.cut it dry with air. get a Destiny Viper 3flt 1/8 mill. That is my place to start.

[SirDenisNayland]

Man, you guys need to chill.. its not worth acromony.

What I'd say, additional cutter flutes is allow a greater feedrate at a given chipload rather than spindle speed... maybe you guys are just hung up on semantics.

Whatever. As long as I can make parts that meet my needs, I'm good :boxing:

No, he firmly believes changing the number of teeth is an equal substitute for changing the spindle speed.
He has not changed that claim at all, he even rehashed it again with his patronizing comment "here's one for you to get you up in arms, decreasing the number of flutes decreases the effective rpm!1!" As if even if he were correct I, nor anyone else would have been able to deduce that if an increase leads to an increase that a decrease should lead to a decrease.

You are correct about what Bob is trying to say, but his notions completely ignore the importance of SFM. Have you noticed he has not once commented on the notion of SFM? I wonder why.

If you wish to alter the IPR chipload for a given IPM then yes, increasing/decreasing the spindle speed is akin to increasing/decreasing the number of teeth on your cutter, the theoretical surface finish will remain the same, the "gaps" between cuts remain constant which hey hey, is question that started this whole thread.

I'm simply trying to say that you cannot just blindly change one for the other because the speed at which the tooth cuts into a given material DOES matter, is completely independant of the number of teeth and is especially more so important when you get into tougher materials.

Bob will never admit this though.

[Spinnetti]

To make these parts as I have many times little ones like this. Not sure how many you have to make. I take double sided tape and a 8" x 8" pc of the 1/8 stock and tape to a alum plate. I would program this using the tab option leaving no bigger then a .01 thick tab max width of .1 in 3 to 4 places on the part. I would lay then out nested accounting for the tool and tabs.cut it dry with air. get a Destiny Viper 3flt 1/8 mill. That is my place to start.

Thanks. I'm only making a dozen or so of lots of little parts like this. I'll try that cutter... where do you get em? How many rpm and ipm would you run with that cutter?

Thanks..

[mike sr1]

Easy boys, we're all friends here.. please take any misunderstandings to the telephone... we're talking surface finishes, and the parts they are for here!

I agree!
I am just reading the posts now as I dont like the personal attacks, mud slinging etc. as it serves no useful purpose related to the topic at hand.

[tbaker2500]

Yikes. Is there a block poster function here? Dennis is clearly trying to make a point he feels is important, but the manner in which he is trying to make this point removes any desire for me to read it.

Back to the topic at hand, I've found double-sided tape to sometimes be too weak for such a small part, but I've never tried super glue. For my future knowledge, does the super glue residue come off the aluminum?

[mike sr1]

Yikes. Is there a block poster function here? Dennis is clearly trying to make a point he feels is important, but the manner in which he is trying to make this point removes any desire for me to read it.

Back to the topic at hand, I've found double-sided tape to sometimes be too weak for such a small part, but I've never tried super glue. For my future knowledge, does the super glue residue come off the aluminum?

superglue can be removed with acetone, heat it a bit and it will come off the jig then acetone to remove the residue. I am going to try it in the future just to see what happpens, I havent tried it on a machine part.

[cadcam]

I use the 3m tape about 2" wide stuff started way back in 1986 to flatten stock on a bridgport mill to make sides 1 and 2 parallel with a fly cutter the best way to make a flat plate. but as for the small parts this why I stated using the tabs then they do not lift and you can cut the out with a exacto knife.

[cadcam]

Thanks. I'm only making a dozen or so of lots of little parts like this. I'll try that cutter... where do you get em? How many rpm and ipm would you run with that cutter?

Thanks..

You can get the info from the manufacture, but I would start at 5348 rpm and 20 to 22 ipm
Do about .025 deep cuts leave .015 to .01 tabs.
Let me know if you need me to right you a program for it.

[Dylwad]

Super glue works great, I hate tabs....ill do batches if 40-100 small parts at a time and dont want to deal with them afterwards.

The trick with superglue us to use accelerator to make sure the glue in the middle if the sheet hardens. I spread glue on the sacrificial board, spray the aluminum with kicker and press tgem together hard.

Aluminum gets superglued down, delrin gets epoxied (pops right off after cutting), carbon sheet gets stuck with tape, cut under water and soaked in rubbing alcohol to release after suctioning the nasty water out and rinsing the sheet. Most of my carbon is .8mm thick with 1.25mm wall thickness, tabs would be a pain!

I only use tabs on small ABS parts, cut with a .8mm bit.

[SirDenisNayland]

Yikes. Is there a block poster function here? Dennis is clearly trying to make a point he feels is important, but the manner in which he is trying to make this point removes any desire for me to read it.

Go ahead, block one of the only critically thinking posters in this entire thread.

I never started this to cause a ruckus, I simply disagreed with bobs statement:

+1 on the 3 flutes--they effectively multiply spindle speed by 1.5 vs a 2 flute. BTW, when profiling and there's plenty of chip clearance, you could even try a 4 flute (yep, even with aluminum)

Then he says this little gem, not in direct response to my post, but in a passive aggressive manner:

PS Dennis will also tell you (as he did in another thread) to reduce chipload as much as possible to minimize work hardening. He and I are destined to disagree about a lot of things at this rate, LOL. (chair)

Here Bob creates a completely imaginary previous scenario where I supposedly told someone to lower their chipload as much as possible to prevent work hardening. Why would he do this? Why not just address me and prove my disagreement to be wrong? I'll tell you why, because he knows he is wrong and he has customers to elicit from this website. Who would want to buy product from a man who cannot properly understand such an elementary concept? He makes up a totally audacious comment and puts it in my mouth in order to dismiss me and 'prove' to everyone that I have no idea what I am talking about. This is where I "get all up in arms", this is where Bob begins the mud slinging.

Being me, I try to see it from his point of view and attempt to follow his train of thought on the matter and I post this:

You know, I can see your flawed logic, 1.5*2=3, in the ipm equation you multiply the right side by 1.5, and you then say it increases the spindle speed by 1.5.

To which he replies:

Denis, I can see from the quote above you finally did figure out that increasing flutes is tantamount to increasing spindle speed, though you're struggling mightily not to accept it. The good news is you don't have to accept it. Others will understand what it means and take advantage.

Here is some extra credit that I'm sure will have you up in arms all over again:

Fewer flutes can be thought of as decreasing spindle speed. This is important to the router folk, who often can't turn the spindle slowly enough with harder materials. Hence the one flute endmill was created for just such an audience.

So I finally did figure out that "increasing the number of teeth is tantamount of increasing the spindle speed", which means that he agrees with my (false) methodology and logic in that particular post. I finally get it right?

So now that I figured out his "correct" logic, I continue to apply it to other variables in the equation:

But by that logic you could say it effectively increases the chipload by 1.5. Continuing, if you sub in the equation for RPM we get, ipm=(12*sfm*chipload*#teeth)/(tooldiameter*pi)
Now following your logic this says that increasing the number of teeth effectively decreases the tool diameter or the value of pi.

As for fuming about how quick everyone is to undermine someone else's opinion, consider that it was you who leaped in to dispute whether using more flutes could possibly be a substitute for more spindle speed. You even responded to your own post before anyone else could just now.
Heck, I've even learned from you that I can change the value of Pi--Priceless!

If changing the # of flutes is tantamount to changing a fixed value like the spindle speed, how is it any different for any other fixed variable in the equation? be it the chipload, the tool diameter, the number of inches in a foot, or yes even the value of pi?
Even more priceless, he makes up some more complete and utter BS with his example of the one flute endmill being designed purposely to effectively lower spindle speeds. Let me tell you, it was not for router folks who needed to work with harder materials. Harder materials means a lower SFM is necessary, and changing the number of flutes does NOT change that. I wont go into why they were designed and for what purposes because I already explained it, and it was completely ignored.

So, putting his logic to the test again I post:

Let's follow you in the last statement which has gotten me oh so up in arms, decreasing teeth decreases the RPM.
Let's say you have
A spindle which only turns at 1000rpm
A piece of material which requires 100sfm
A 10 insert, 3.82" facemill.

You realize you are spinning way too fast, ten times too fast in fact. So by your logic you decide to decrease the number of teeth by a factor of 10 to effectively decrease the spindle speed by a factor of 10, leaving you with one insert in the facemill.

Go try that out and get back to me with how well that works for you.

Cheers

Which anyone with half a brain can see is just absolutely and utterly absurd, but is exactly what Bob is saying. Notice he fails to address this post and yet again dismisses me by calling me a troll? Funny.

I did not start any of this as a personal attack to Bob, I simply disagreed and detailed why I disagreed with him. He went from there straight into a personal attack on me. Notice how he completely ignores all of my valid points, and then only chooses to acknowledge me when I am talking on his convoluted terms? But even then he picks and chooses what of his own words are true. All he has done is make personal attacks and belittling comments, and has not once backed up his position and why he believes it to be true, he has simply just said it over and over again, as if his reputation and the number of times he says it makes it right. So yes, in addition to actually posting detailed responses of my thought process I have thrown in my own little jabs.

How ANYONE could think increasing or decreasing the number of flutes is a substitute for increasing or decreasing the spindle speed is well beyond my comprehension. Bob completely ignores the notion and importance of SFM and never chooses to address my direct questions towards him on that subject for some reason. Its quite strange to me because Bob seems like a relatively smart guy from a quick glancing at his website, so I cant even comprehend how he believes any of this to be true.

Good luck with everything Spinnetti. I hope everything works out well for you and you've taken some good information from this thread - just hopefully not the notion that if you need to increase or decrease your spindle speed but cannot directly, that you can simply add or remove flutes as necessary without any repercussions.

Cheers

[latenorgreat]

Dennis is the one making more sense, albeit in a more aggressive manner.

You can plug the numbers into the equation however you like, it's a simple equation, and the numbers coming out don't lie.

Bob's statement that adding flutes increases the "effective" spindle speed doesn't make much sense, I don't know what he means by "effective" in this context. Assuming you keep SFPM and chip load the same, increasing the number of flutes would require a decrease in spindle speed. Removing flutes would require an increase in spindle speed.

Here are your options when choosing a tool with more flutes (increasing total # of flutes), in order to balance out the other side of the equation, so to speak.

1. Keep SFPM and chip load constant = increased feed rate. This is very common, as noted by both Bob and Dennis. Bob noted the case where even in aluminum you can get away with more flutes in a profiling operation where there is enough space for chip evacuation. Dennis brought up the example of the 8 flute finishing cutters where you can maintain proper SFPM and chip load without having to deal with slow feeds.

2. Keep SFPM and feed rate constant = decreased chip load. As per the previous example, maybe you want a decreased chip load for a finishing or spring pass.

3. Keep feed rate and chip load constant = decreased spindle speed/SFPM. This combo doesn't make much sense, but it's remaining combination of outcomes. Maybe if your machine has a low spindle speed limit?

In reality, chip load and SFPM are the more important parameters. Feed rate is normally just going to be the result of properly choosing/setting the proper SFPM and chip load for the operation. Of course proper cutting tool selection should come first/be informed by the parameters. Of course you can also modify multiple/all parameters at the same time, but keeping two of them constant simplifies the explanation.

Whatever the combination, adding flutes and keeping everything else the same requires a reduction in spindle speed/SFPM, and removing flutes requires increasing spindle speed/SFPM.

Maybe if Bob explains what he means by "effective spindle speed", it would bring a simple conclusion to this topic, because as far as I see, the opposite of what he's saying is true

[SCzEngrgGroup]

Dennis is the one making more sense, albeit in a more aggressive manner.

You can plug the numbers into the equation however you like, it's a simple equation, and the numbers coming out don't lie.

Bob's statement that adding flutes increases the "effective" spindle speed doesn't make much sense, I don't know what he means by "effective" in this context. Assuming you keep SFPM and chip load the same, increasing the number of flutes would require a decrease in spindle speed. Removing flutes would require an increase in spindle speed.

Here are your options when choosing a tool with more flutes (increasing total # of flutes), in order to balance out the other side of the equation, so to speak.

1. Keep SFPM and chip load constant = increased feed rate. This is very common, as noted by both Bob and Dennis. Bob noted the case where even in aluminum you can get away with more flutes in a profiling operation where there is enough space for chip evacuation. Dennis brought up the example of the 8 flute finishing cutters where you can maintain proper SFPM and chip load without having to deal with slow feeds.

2. Keep SFPM and feed rate constant = decreased chip load. As per the previous example, maybe you want a decreased chip load for a finishing or spring pass.

3. Keep feed rate and chip load constant = decreased spindle speed/SFPM. This combo doesn't make much sense, but it's remaining combination of outcomes. Maybe if your machine has a low spindle speed limit?

In reality, chip load and SFPM are the more important parameters. Feed rate is normally just going to be the result of properly choosing/setting the proper SFPM and chip load for the operation. Of course proper cutting tool selection should come first/be informed by the parameters. Of course you can also modify multiple/all parameters at the same time, but keeping two of them constant simplifies the explanation.

Whatever the combination, adding flutes and keeping everything else the same requires a reduction in spindle speed/SFPM, and removing flutes requires increasing spindle speed/SFPM.

Maybe if Bob explains what he means by "effective spindle speed", it would bring a simple conclusion to this topic, because as far as I see, the opposite of what he's saying is true

Ummmm.... No. There is NO dependant relationship between either spindle speed or SPFM and the number of flutes. Ideal SFPM is a function of the material the tool is made of, and the material being cut, NOT the number of flutes. RPM is calculated based on desired SFPM and the tool diameter. The number of flutes is not a factor AT ALL. For a given tool material, and a given work material, and a given cutter geometry, ideal SFPM is constant, regardless of the number of flutes. ONLY feedrate changes as a function of the number of flutes. SFPM and chipload are independant parameters, while RPM is the sole dependant parameter. You can re-arrange the equations to make it appear otherwise, but you will be fooling yourself, and will not end up with ideal cut parameters, while will result in decreased tool life, and/or reduced MRR and/or reduced cut quality.

Regards,
Ray L.

[thefu]

idk what all the fuss is about...just make chips