# New Fly Cutter



## 65arboc (Nov 26, 2014)

Hi,

Thanks to all for a great forum. I am fairly new on here and have learned a lot so far. I have a new Fly Cutter I want to try out and was wondering about how to grind the best shape for cutting aluminum, profile of the cutter? Thanks again and everyone have a great Holiday!

Jim in Pa


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## chucketn (Nov 26, 2014)

Your best results would be with a left hand lathe tool. At least that is my experience. Small radius on tip, maybe 1/32".


Chuck


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## Omnimill (Nov 26, 2014)

This works well for me.

http://www.homemodelenginemachinist.com/showthread.php?t=9224

I also made a tool to use round carbide inserts as well for hard materials.


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## 65arboc (Nov 26, 2014)

Ok so a small radius on the bottom where it contacts the metal. What rpm for aluminum and brass is good. Thanks Guys. I wish I had thought to get a insert type cutter like is shown.

Jim


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## canadianhorsepower (Nov 26, 2014)

65arboc said:


> Ok so a small radius on the bottom where it contacts the metal. What rpm for aluminum and brass is good.



cutting in brass or aluminium  is 2 different thing.
 your cutter rake and cutter angle are way different


 Luc


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## 65arboc (Nov 26, 2014)

canadianhorsepower said:


> cutting in brass or aluminium  is 2 different thing.
> your cutter rake and cutter angle are way different
> 
> 
> Luc



Would you have any drawings or photos to explain that please? I am really new at this so any help at all is good. Also the RPM question is still out there.

Thank you,

Jim


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## canadianhorsepower (Nov 26, 2014)

http://americanmachinist.com/turning-surface-finishes-calculator

http://its.fvtc.edu/machshop3/speedcalc/speedrpm.htm

have a look at this also


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## 65arboc (Nov 26, 2014)

canadianhorsepower said:


> http://americanmachinist.com/turning-surface-finishes-calculator
> 
> http://its.fvtc.edu/machshop3/speedcalc/speedrpm.htm
> 
> have a look at this also



Thank you. That is exactly what I was looking for! This forum is the greatest I have ever been on for my new hobby. Thanks again!

Jim


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## abby (Nov 26, 2014)

I use the same tool for brass and aluminium but apply an occasional spray of WD40 for a near mirror finish on the latter , I don't worry to much about rake but reckon around 5° works well for me .
The main thing for a good finish is for the tool to be very sharp.
I rarely take a cut of more than 15 thou and use my fly cutter for finishing large flat areas that would be a chore with an end mill as I only have hand feed on my BCA.
A fly cutter is unbalanced so speed on small machines is limited by the vibration , I go by feel but would guess an rpm of about 200 for a cutter that has a swept diameter of 2 ".
Trial and error is the best way to learn this hobby , it has very little in common with industrial machine shop practice and relies to a great degree on ingenuity and thinking "outside the box"


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## Omnimill (Nov 26, 2014)

Yes, same here. I use exactly the same flycutter for aluminium alloy and brass. I used to use the same for steel as well but the insert tool negates frequent sharpening so I use that!


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## canadianhorsepower (Nov 26, 2014)

Abby and Omnimill
 it's not because you are using the same tool for both that it's a good practice 
 I did supply the "proper information" to 65arboc
 He is starting a new hobby  and I'm helping him the best that I could. The information I give him does not
 rely only on flycutter but many other subject.
 If he ever get to do this hobby and being verry happy with the result with out hurting himself this is what matters
 in my opinion anyway:hDe:


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## Swifty (Nov 27, 2014)

Just to throw something different into the equation, the single point flycutter that I use (used it for at least the last 20 years) is a piece of carbide brazed to a mild steel shank, it has a swing of about 2 1/2" and I run it about 1500 RPM. It has no top rake, but of course some side rake. I use it for all materials, and depth of cut about .030", it has a small nose radius. But bear in mind that I do have a Bridgeport size turret mill and only use hand feed as I believe that it gives a better feedback of what's happening at the cutter tip. I am still careful not to abuse the spindle bearings, the speed and hand feed gives me a small chip, but rapid metal removal. Occasionally I might squirt some WD40 onto aluminium or copper when machining it.

Paul.


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## Omnimill (Nov 27, 2014)

I use the same flycutter tool on all metals simply because it works. If I'd had any problems with specific materials then I'd do what I normally do and try something different. I suppose I originally expected the same tool to work on everything though because I'd never seen end mills or slot drills ground specifically for different metals. The main thing I've found is to keep the cutter very sharp to get the best finish.


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## Tin Falcon (Nov 27, 2014)

Guys relax. 
CHP that is very good  info you posted. 

As far as using the same angle for brass steel and aluminum as long as one does not push speeds feeds or depth of cut should not be a problem. 

the published angles for each material are the best angle for performance and tool life found after much research over the years. 
If you are setting up to cut one material all day you would be wise to use ideal angles.  but if you are going to cut a piece of brass and then  one in aluminum and another in steel, then by all means there is nothing wrong with a general purpose bit. 
As far as carbide IMHO not the best idea unless really needed. carbide does not like interrupted cuts and a fly cutter is not usually in constant contact with the work. 
This is a hobby it should be fun  no need to argue to try to impress the new guy. 
It is Thanksgiving have a glass or mug  of your favorite beverage and relax. 
Tin


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## BaronJ (Nov 27, 2014)

Hi Guys,

Some pictures of my fly cutter and a couple of the toolbit that I use for aluminium.  The tool is about 65 mm diameter and 20 mm thick with a 15 mm shaft.  I tend to run this at about 800 to 1000 rpm for alloy and 500 / 600 for steel.  The toolbit is sharpened with one end for alloy and the other for steel.
I find that due to the bulk I can take advantage of the inertia and lower deflection on heavy cuts. 1 mm in aluminium is no problem, though that would depend upon your mill's capability.


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## abby (Nov 27, 2014)

As I pointed out this is hobby engineering not industrial production , we do not have to follow convention , we all find the way that works best for us , this does not mean that one is correct and another is wrong.
The availability of machinery , tooling and materials , and not the least money , will be different for everyone and the techniques used will vary to suit , what is important is that we get the enjoyment and satisfaction that we hoped for from the hobby.
Luc I did not intend to gainsay your reply , and I certainly don't doubt your ability , but I feel that newcomers to the hobby can often be given more information than they need and can be put off by over complication.
If I offended you then I apologise.
Dan.


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## canadianhorsepower (Nov 27, 2014)

.
Luc I did not intend to gainsay your reply  said:
			
		

> Hi Dan
> maybe It's anatural thing for me to give more info then needed:fan:
> But I teach this stuff all year long, can it be called a proffesional sickness
> 
> ...


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## Tin Falcon (Nov 27, 2014)

> we do not have to follow convention



We should follow convention. For safety and productivity. 
But you are right in that home shop machining requirements are different than a production environment or maintenance shop. More like a job shop but no need to meet deadlines.  Lots of room for creativity as long as we follow the rules.
Tin


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## Omnimill (Nov 28, 2014)

Just in case the OP is thoroughly confused this is a good article on the subject.
I should have posted the link earlier as John is an experienced machinist who really knows his stuff. He's also a thoroughly nice bloke who used to post on here a lot but that's another story!

http://start-model-engineering.co.uk/begin-with-bogs/fly-cutting/


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## chrsbrbnk (Nov 28, 2014)

Just a note , you may need to increase the cutter relief to accommodate the radius of the cutter


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## TorontoBuilder (Nov 28, 2014)

abby said:


> I feel that newcomers to the hobby can often be given more information than they need and can be put off by over complication.
> If I offended you then I apologise.
> Dan.



I'm an adult tech educator in the building science field, while I concur that during a training sessions there are limits to how much students can absorb at any one time, permanent online resources are just that, permanent resources that can be accessed once or as often as necessary until the student grasps the lesson. Therefore its beneficial to have the lesson include machining best practices.

Therefore, I find that its far preferable to provide detailed best practice references. How ppl structure their posts and how you link to material is what will keep it interesting and on a level that all forum participants can enjoy... 

So Luc, thanks for the detailed fly cutting angles... I'll make use of them


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## abby (Nov 28, 2014)

Ah well , think I'll go back in the workshop and make some swarf !


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## Tin Falcon (Nov 28, 2014)

> I'm an adult tech educator in the building science field, while I concur that during a training sessions there are limits to how much students can absorb at any one time, permanent online resources are just that, permanent resources that can be accessed once or as often as necessary until the student grasps the lesson. Therefore its beneficial to have the lesson include machining best practices.
> 
> Therefore, I find that its far preferable to provide detailed best practice references. How ppl structure their posts and how you link to material is what will keep it interesting and on a level that all forum participants can enjoy...
> 
> So Luc, thanks for the detailed fly cutting angles... I'll make use of them


Very well put.  While not currently a professional teacher I too have had training as an instructor and have held instructor ratings in the past as well as helping run the place here for 7 years.  I too believe in giving the basics and then giving resources to find more info when it is needed  and or desired. 

So there is a place for the technical references and the KISS methods. 


What I do feel is a distraction to learning here is the petty arguing, one upmanship attitudes, and the childish my way is better than you way attitudes exhibited by certain members. There is nothing wrong with book data or this is the way that works for me. As long as the methods procedures and info are safe. there is room for varied perspectives. let the new guy try things and find what works for him or her. Show respect for other views. 
People want clear answers not a debate between a couple of seemingly old people full of smelly air.
Tin


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## abby (Nov 28, 2014)

I would hardly describe some one having a different approach to a topic as "one up man ship" or having an argument simply because they post what they think.
Make up your minds Do you want members to post or not ? I do not post often because if someone has answered the question to it's fullest I have nothing to add, unlike many who insist on repeating what has already been said or starting with "well I don't really know but "
If I think that a post can be expanded then I will do just that , as did the other guys , if that is argumentive then what are we allowed to post.
Quite frankly I find your "it's my ball" attitude very typical from your side of the atlantic , and for all the guys who claim to be college lecturers , teachers or training officers of other description, we have a saying here "those who can do ! those who can't teach!".
I have better things to do with my time than waste it here.


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## canadianhorsepower (Nov 28, 2014)

I have better things to do with my time than waste it here.[/QUOTE said:
			
		

> with all due respect enjoy it  where you want to
> but respect other's opinion
> 
> :fan:


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## Swifty (Nov 28, 2014)

I must have missed something on this topic, I haven't seen any petty arguing at all, just different ideas. That's what I find good about this forum, members can post their ideas without fear of being shot down.

Theory and charts for clearance angles are great, thanks Luc, but there comes a time where the end user is confident in their approach to be able to grind tools freehand without resorting to using protractors etc to check angles. Of course, the novice is nervous and needs all the help they can get, which they do get here.

Paul.


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## Omnimill (Nov 29, 2014)

It's a shame this thread has degenerated but it's by no means unusual on Internet forums. There are many "experts" out there but readers would be wise to treat any information given with some scepticism until they can confirm safety or suitability for their own particular purpose. This should go without saying but there you go, I've said it anyway just to be clear.

Much of the "data" for the tools we hobbyists use today and repeated ad nauseam even in new publications comes from books written in the late 1800's or early 1900's. This "data" came from practical experimentation by machinists. Anything that worked well was noted and passed by word of mouth or written up in the journals or books of the time.

I have a number of old engineering books in digital format and by far the most information about tool bits is centred (pun intended) around Lathe tools and to a lesser degree tool bits for Shaping machines. There is precious little about fly cutters for Milling machines. I'm sure I could find the odd page or two if I looked long enough but I'm sure you'll forgive me for not wanting to spend the time trying.
If I missed something really good out there though please let me know.

I'm sure you'll agree that pressing a fixed tool against a rotating, largely cylindrical object is slightly different to traversing a rotating tool against a fixed flat object.

It was said earlier "I did supply the "proper information". And someone else called it "published" (data), "book data" and "we should follow convention". Good idea, I'd agree with that. I had a look to find this "proper information". Even now 99% of the information on fly cutters seems to be on forums so it's not surprising I found this link which shows where the Fly cutter drawing posted earlier on here appears to originate, post #7:

http://bbs.homeshopmachinist.net/threads/40978-Fly-Cutter-Cutting-Tool-Bit-Geometry

As the guys says: "Here's an image I *edited* from one on Wikepedia". And "I edited the surface names in the image to make it* more appropriate for a flycutter".*

He then gives a link to the original Wikepedia page where he got the image:

http://en.m.wikipedia.org/wiki/File:Tool_Bit_Geometry.JPG

I tried to find the other image listing rake angles for different materials but failed to find it. I suspect though it's just one of many charts used over the years for *Turning* tools.

Anyone can cut and paste "data" from the internet, it doesn't mean it's valid.

Abby, Swifty and I all appear to be using very modest angles on our fly cutters with what seems to be complete safety. I've certainly not had any safety issues like chipped cutters etc and the finish I get is very good - have a look at my Tangential tool on here so many have said they like.

I would be very careful using some of the rake angles suggested by the chart posted earlier. Judging by the comments I've seen on some other forums greater angles can cause the tool bit to move down during the cut damaging the workpiece. In the worst case scenario the cutter could come out of the machine. 

Abby, Swifty and myself have all been told we're doing it the wrong way. Which is fair enough, everyone is entitled to their own opinion. It's a shame though that some have resorted to mild verbal abuse to make their point. I'm sorry you have so many "seemingly old people full of smelly air" over there. It's not a problem we seem to suffer from here though. That was meant in jest in case you were wondering...

I'm in the middle of refurbishing my old bench drill and only posted on this thread originally while I was waiting for the paint to dry on some of the parts. I won't be spending any more time on this thread though so if you want to abuse me further you best do it by PM. Don't expect a reply soon though as I'm near to the exciting part of putting my drill back together. Can't wait to see how quiet it is with the new bearings! I'll post pictures on the "other" site if folks want to see it.


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## TorontoBuilder (Nov 29, 2014)

please Austin add an option to dislike posts as well as like. when people feel the need to denigrate the sharing of info it turns people off more than having to read what may be old info to some...


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## Blogwitch (Nov 29, 2014)

A lot of people have mentioned the flycutter shape that I showed many years ago.
Even though I am now coming to the end of my model engineering life, I have still not found anything that can beat it for performance and quality of finish, and I use it even when I should be using normal cutters for mass material removal, all because the surface finish it leaves behind is fantastic and I can very easily machine with it to a tolerance of a couple of 10ths.
One thing that must be done, and not just for flycutting, is that the spindle should ALWAYS be in perfect tram with the table, and so the piece part. Without the machine being in perfect tram, you may as well use a hacksaw to attempt to shape your piece part.
This tool cuts so smoothly, even at depth, I have never had the tool lift more than a couple of 10ths while in action and have never had it dig in or move in it's holder.

Here is a slow motion video of my cutter in action, showing even at this cutting depth, the surface finish left behind was a lot better than most people can obtain when trying for a good surface finish.

http://youtu.be/FipAdIUr5OE

BTW, about 50 years ago, as I was breaking in my first pair of safety boots, I worked with an old codger, with wrinkles all over his face and skin on his hands that could be used to make a crocodile handbag. 
Well one of the first things he told me was to disregard all those know it alls who blow formula out of their rear ends (tidied up to make it internet safe) and listen to the people who actually work on the machines, they have already tried and discarded everything they have had to say or show and come up with methods to get the job done quicker and safer than they (ass blowers) could ever dream or come up with.
It was a man like that who first showed me the flycutter shape that I use, and it has never failed me yet.

John


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## Swifty (Nov 29, 2014)

I went back and reread all the posts, strange thing, the brazed tip cutter that I have been using for years has zero top rake, exactly as shown in the chart (bar one with negative rake), this was without reference to charts.

Another thing that no one has mentioned, some of the angles will vary depending on the angle that the toolbit is held in the cutter body.

When running my toolmaking business, when we tried out a new style of facing cutter, of course we had to use all speeds and feeds that were recommended, eventually we either stuck with the data or altered it to suit ourselves.

Maybe I'm one of the old farts, but it comes from many years of practical experience in a toolroom, and I certainly was hands on all the time. I have trained about a dozen apprentices, and some even won awards at trade school for their practical and theoretical work, that ability was not solely gained by their one day attendance at trade school per week, but by being trained by experienced tradesmen at work.

Paul.


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## Tin Falcon (Nov 29, 2014)

Swifty  you are correct there is value in book learning and reference material and hands on experience. Best practice is going to vary based on the tool the machine , material being cut , lubricate or lack thereof.  
Tin


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## canadianhorsepower (Nov 29, 2014)

> I'll post pictures on the "other" site if folks want to see it.


 

 Thats the best news today.:fan:


 Now remember that LONG LONG LONG.... LONG time ago machinist were using granite to cut steel......................................practice have change..............how about reading books of 2014 

 stuff have change like it or not:wall::wall::wall:
 I just hope that some older peoples attitude want get new members to go away  My answer did please the person asking for help
 like it or not


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## Swifty (Nov 29, 2014)

Quite right Luc, I employed several tradesmen over the age of 60. They had the experience, which was fine, but I made it quite clear that I didn't want to hear "I'm my day, we did it like this". I was in business to make money, so modern materials and methods were critical.

Paul.


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## Blogwitch (Nov 30, 2014)

Swifty said:


> Quite right Luc, I employed several tradesmen over the age of 60. They had the experience, which was fine, but I made it quite clear that I didn't want to hear "I'm my day, we did it like this". I was in business to make money, so modern materials and methods were critical.
> 
> Paul.



Unfortunately, this and many other sites are beginner orientated, who in the most part can't afford the latest wizz bang, blow it out of your a** bits and pieces that keep the wolf from the door when in a production environment. 
All they require is good first class information to make good results within their reach and budget, and showing them the latest trade catalogues will do them no good at all.
I am one of those old pharts who try to pass on good information to the great unwashed masses in the model engineering fraternity, but not only did I look to the past for info, but also to the modern day, which in my view, when it comes to affordable machining in a small workshop, most of the modern stuff just wasn't relevent purely because of cost. What was needed could be done with very small budgets.
I also ran a small production environment, and converted my shop to contain all the latest gizmos and gadgets, purely because it was required to remain competitive. The workshop was onto a winner and large profits were being made, unfortunately the weak link (my own health) wasn't able to keep up, so my high precision workshop reverted back to a hobby shop. 
99.9% of all those expensive bits were never used again, purely because they were not needed, I could do everything that was now needed in my shop with old fashioned technology and materials. All those expensive bits are now sitting under the benches gathering dust.

I would suggest to all you beginners, is to go onto the free book download sites and get a few of the many machining books available (usually pre first world war) and you will learn how they did things in the past, and you will also find, most of it is perfectly relevent to what you are doing in your small shops now, and it will hardly cost you anything at all, as in those days it was usually make it yourself for pennies.
Or, if you can, search out an old phart and he/she will overload you with good info to use in your home shop.

John


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## Tin Falcon (Nov 30, 2014)

I am locking this thread . It has turned from a new member asking a question to a debate over book learning published  data and off the cuff machining.  
Tin


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