Cutters

Is there any reason why the cutting tool on a flycutter is usually a small square section like 1/4" or 5/16" ? Why not a 1/2" or 12mm cutting tool?

Also what is the reason for the main block, that the cutting tool is fastened to, at such a high angle?

Is there an optimum size that the flycutter should be made to? If so what criteria is used to determine this size?

Tool size really comes down to head size eg I have a small flycutter with a 3/4" dia head - not much point putting a 1/2" bit into that same with my largest flycutter wich takes a 10mm bit fine but a 4mm sq tool would be lost.

Size would really be based on the size of your mill and area that you want to sweep. Though I have seen 6" disc type flycutters used on quite modest size mills and lathes

Not sure on angle but would have thought any shallower would make it harder to sharpen the tool unless you used a cranked one.

I have one I made some years ago that uses a left hand cranked tool ...

... Home made fly cutter

Having an MT3 taper it doesn't fit my WM16 now but I have a new one so its not a problem so maybe will alter this for another use.

George.

The front face of the toolbit is on the centreline so it has limits unless you want a huge unit.

The angle is to give clearance on a square toolbit. You can have flat ones if you use a lathe tool. I have also made one using just a flat disc and two round toolbits held vertically with pinch screws.

Overall diameter will be limited by the torque and minimum speed of your mill.

Don't make things too heavy on a flycutter. It will be hard on the drivetrain, particularly belts, the heavier it is, when the motor is trying to get things turning.

They're a simple inexpensive tool and when set up right, nothing makes a nicer finish, with less effort then other methods. JD

I have tried the conventional types of fly cutter as described above, but the noise in the drive train due to the intermittent cut was unbearable. I have had much more success when the fly cutter is heavier.

I tend to make mine out of a large steel disc, and insert a round HSS or carbide tipped tool bit through a hole in the face near the outer edge, I secure it with a couple of grub screws.

The whole cutter acts as a flywheel, and damps out the intermittent cuts very nicely.

Phil

If You want to grind down a 1/2" tool bit when a 1/4" would do, it's Your choice. Takes longer to grind.

If You want to grind down a 1/2" tool bit when a 1/4" would do, it's Your choice. Takes longer to grind

Perhaps you are correct but my dumpy little fingers find it difficult to hold a 1/4" tool.

Thank you everyone for your input. I will make one and see how it goes, if it goes well I may post a picture of it, when I have sussed out how to.

My bought one takes 3/8" bits. I've also made an insert holder for it as well for tough materials.

Have just been on internet and found this.http://www.ebay.co.uk/itm/3-piece-Fly-Cutter-Set-1-2-034-Shank-/360413450905?_trksid=p2054897.l4275 Is it a misprint, if not what is so special about it?

Common practice on e-bay when an item is out of stock to save having to relist it.

I've had a set of those for years and they are what I tend to use for most of my flycutting.

J