New Fly Cutter

[65arboc]

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

 

[chucketn]

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

 

[Omnimill]

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.

 

[65arboc]

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

 

[canadianhorsepower]

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

 

[65arboc]

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

 

[canadianhorsepower]

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

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

have a look at this also

 

[65arboc]

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

 

[abby]

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"

 

[Omnimill]

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!

 

[canadianhorsepower]

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:

 

[Swifty]

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.

 

[Omnimill]

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.

 

[Tin Falcon]

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

 

[BaronJ]

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.

 

[abby]

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.

 

[canadianhorsepower]

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

no bad feeling safety and fun is the objective here Thm:Thm:
Luc

 

[Tin Falcon]

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

 

[Omnimill]

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/

 

[chrsbrbnk]

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