I saw the Milling Cutters Store 3 Flute Slot Drill on Instagram and as I was in need of some new 6mm slot drills I ordered some. Previously I’ve been buying Rennie tools 2 flute carbide cutters. They work really well, but it was time to try something new.
The cutters arrive in the normal packaging used by many suppliers
This particular cutter is: 3 flute 35 degree helix cutters for use in general steel and materials of a hardness up to 55HRC. 0.6 Micrograin carbide. TiXco coated.
These carbide slot drills work superbly, cutting through mild steel really easily. The three flute design means they actually work well as an end mill as well. A real bonus to have a slot drill and end mill in one.
The cutting edges on the end are very asymmetric, with one long edge that goes from the centre to the diameter. Then two shorter cutting edges that don’t extend to the centre.
I’ve happily run this bit at maximum speed in my Sieg SX2.7 manual milling machine with no issues. I use a small amount of cutting oil applied with a brush and this is normally enough.
Then I went and broke the tip of one of the cutting edges. My stupid fault as I moved the cutter into contact with the surface of the part when it wasn’t rotating. This was to find the surface height. I then stupidly moved the table in X or Y (cannot remember which), I heard the crack as the tip of the carbide tool fractured.
Normally I would throw the cutter away at this point. However I had some more machining to do and so put it back in and carried on. Interestingly it’s still cutting better than most of my other slot drills. So good in fact that I’m still using it several weeks later.
So, the conclusion is the Milling Cutters Store 3 Flute Slot Drill is fabulous and I would highly recommend them.
You can purchase these direct from MillingCutter.store