Photo please!

I also had this problem. Tried running the mill in reverse but the boring head unscrewed from the morse taper shank when taking heavy cuts. My solution was to modify the cutter (see below). Ground a flat where the grub screw seats to stop tool rotating in the boring head.

Paul.

Just regrind one of the easily available HSS or brazed tipped cutters to suit running in the opposite direction. Works for me, I'll take a photo later.

You can also buy a 1/2" piece of toolsteel and grind that or make a simple steel holder to take smaller HSS bits that can be ground from old milling cutters and ctr drills.

Final option is to use a righthanded cutter and start the cut at the bottom of the work and cut upwards.

As I said you can regring an off the shelf bar, they usually have the rear angle rounded like the one on the left so just grind it straight like I have to the one on the right.

Then it can be mounted in the head like so, just take it easy as the forces are taken more by teh braze but I have not had problems using them this way. Mounted inline with teh shank it will also do external cuts.

If you don't want to grind things then just mount like this and cut upwards

Another alternative is to make a simple tool holder, drilled to take HSS toolsteel or milling cutters and a grub screw to keep it in place.

And while you are at it frill the other end at right angles so you can use it for boring smaller holes or external cuts

Or, rotate the bit so it's a left hand tool and run the spindle in reverse. I came across the same thing when I made my mini boring head.

Ed.