Simple Flycutter

for the Myford ML7 (and similar lathes)

This one doesn't even need a drawing! This is, of course, another case of making a tool to make a tool. The primary tool in this case is a rear toolpost. Having rough sawn the BMS I wanted to face the sides. However, having faced blocks in the 4 jaw before I know that they will come out convex due to wear in my carriage, so I decided I needed a flycutter so I can face the block FLAT. I have other blocks that need to be made flat too, so I figured making a flycutter would be a useful diversion.

I toyed with using a piece of aluminum plate, but then decided against it and used this circle of 32mm steel plate instead. This was originally cut as a chuck back blank. I had 2 cut at the same time as each was then cheaper. I've toyed with making this one into a faceplate, but it's really too small to be an effective faceplate.

This fly cutter requires the absolute minimum of machining. Just 2 holes and some tapping. The first hole is drilling 6mm (or size to suite your cutter) leaving 4mm between it and the edge of the disk. A 3.2mm hole is then drilled radially into that hole, and tapped M4. This takes the retaining screw that holds the cutter in place.
And that's it but for grinding the cutter. I used a piece of HSS that is nearer 7.5mm wide. I ground it down till it just fits the 6mm hole, ground the end to a 'basic cutter' shape and it works fine. It has no top rake, (and too much side rake) (-:

Making a cut last night I toyed with drilling the disk for 2 more cutters to speed up the cut rate.
Sunday 27 Jun 2004 I have now added 2 more cutters to the disk and this is a real improvement. The extra cutters allow me to feed faster, and produce a much smoother finish. However, one does need to ensure that the cutters are set correctly else you will have one cutter 'high' and it will do all the work. While I was busy I turned both sides of the disk and the outside so it now 'looks nice'.

General view. The disk is just held in the 3 jaw with the cutter opposite jaw 1. Due to it's weight it has a nice flywheel effect and does not chatter or 'jump' when the cutter hits the edge of the victim. Last edited February 20 2013 09:53:03.

Close up of the cutter in it's hole. Last edited February 20 2013 09:53:04.

Sideways general view. You can see the disk was flamecut by the metal supplier and I havn't done anything to change that (the edges are HARD and I had to use a carbide cutter last time I cut one of these disks for the 4Jaw backplate project. Last edited February 20 2013 09:53:04.