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Easy answer for starters [others will surely be along with more]: A fly cutter typically has one cutting edge, and a face mill has several. … Usage is similar, but you need to consider speeds 'n' feeds.

MichaelG.

Re the roughing and finishing end mills – think here that you can get a good finish with a standard end mill but the cuts will be much less. So the cutter gets worn more quickly for a given volume of metal removed and it takes more passes, so longer time. So your choice, when it comes to it. Often the roughing and finishing route is more cost effective in terms of time and cutter replacement.

Ask yourself if you would use a felling axe to split kindling. Nope! Easier to have an axe for cutting the tree down and a small chopper for the final splitting for kindling.

I always think that flycutters and face mills are the cheap alternative to a horizontal mill. You will always finish with a dished surface unless they are trammed in absolutely perfectly. Your choice of more small ridges or fewer ridges and possibly more 'concavity'. They are an acceptable solution for those with only a vertical mill. The perfectionists who use a vertical mill will likely surface grind for a truly flat finish?!

Of course, the suppliers will encourage you to buy both – won't they!

As always the question of what will you need will depend a lot on what you intend to do.

I tend to use a flycutter on my X3 for most metals as it gives a good finish, is easily sharpened and teh HSS blanks are cheap and last a long time. However for iron castings I will use a 40mm 3 tipped cutter as it copes better with any hardspots that may be present which would take the edge straight off a flycutter.

I would say go with a flycutter first and then add a large indexable endmill or facemill if you find the need. For flycutting I have a set similar to the set of 3 with 12mm shanks that Arc sells which work fine, I also have a larger counterballanced one but don't use it much.

Rougher/ripper cutters like Mark says will remove metal at a faster rate without putting so much load on the machine so can be useful if making things from solid stock. You will need to go back and make a finishing cut as they leave a more textured surface. As most castings tend to have 3mm to come off if you are lucky, less in a lot of cases there is often not much pount in us using rippers and then a second finishing cutter, may as well just use the finishing cutter. I have 10mm and 12mm roughers. If you are doing a lot of aluminium then its worth getting the dedicated ones for that, the lack of any coating and different helix angle help a lot.

Edited By JasonB on 26/06/2016 08:11:45

A fly cutter should have a single cutting edge that can be made to cover a large surface in one pass, then if the machine is properly setup it will produce a very flat surface.

A face mill, having more than one cutting edge, will produce a more ridged surface as the cutting edges are not at all at the same height.

Unless you use a carbide insert on a fly cutter many folks struggle at first to sharpen a HSS tool correctly. Most folks that know how to use a fly cutter properly swear by them. They are cheap to run and no other tool can traverse such a large area in one pass on a small mill. You can get some pretty fancy versions these days.

https://youtu.be/FMNkPCtkM80

Edited By Vic on 26/06/2016 22:40:55

Depends on what you mean by a better finish. The finish is influenced by what ever machine and cutting tool you use. In days gone by we used to calculate feeds, speeds and cutter radius to give a particular Ra value. Having more cutting edges doesn't mean a better finish only a faster feed rate as cutting feeds are per tip. Also all tips won't be at the same height. If you have the luxury of power feed then it is easy to arrive at a decent finish, if you are doing it by hand then you are best to polish it up after cutting.

That looks pretty cool, if i had 145 notes i'd consider it.

Theres no reason why you couldn't make an indexable carbide fly cutter

Michael W

Edited By Michael Walters on 28/06/2016 12:22:22

Absolutely. Not indexable but I made this for my fly cutter.

I should have added that as these inserts wear you can not only rotate them to provide a new edge you can also sharpen them on a diamond plate.

Edited By Vic on 28/06/2016 18:30:40

Common or garden RCMT by the looks of it.

I take it you both turned down the taper that the holder normally comes with, so that the 3 jaw could hold it? Unless you bought a straight shank fly cutter to insert into a collet rather than drawbar + taper?

or, you are using one of those new fangled threaded tapers?

Edited By Michael Walters on 29/06/2016 15:41:59