Is the hdm rigid enough to make .5 inch endmills worth while?

Im wondering if anyone has tried using half inch endmills for roughing/finishing givin they are more rigid then .25 inch ones. Im not sure if the hdm is rigid enough to take advantage of that extra girth or not.

Mine has the 1.5kw. I have found the sweet spot is 0.375" cutters. But my machine stalls the spindle before rigidity is effected. I do like 0.5" cutters for facing and I have a 1.0" surfacing bit with a 0.5" shank I like.

The 2.2kw may change that dynamic.


The machine is plenty rigid for this, hands down. Most likely you’ll stall your spindle before rigidity becomes even close to being in play.


A further consideration is that in my experience, reducing tool deflection leads towards better surface finishes and more accurate part dimensions.


Yes similar issues with stalling, but the right tool paths and they work great! I too use a lot of bits that are .375”

1 Like

I run a 10mm end mill all the time. I don’t take more than 20mm DOC and ramp.

I’ve never tried slotting.

This is in oak and a few other common hard woods.


I’m new here. Is there a link to have the definition of all the words you’re using ?
slotting, DOC, ramp, tool deflection, etc


If you feel like reading, you may want to go through the ebook, and then you’ll know everything about all the lingo


A half inch endmill in wood is fine.

But half inch cutter in aluminum isn’t a great experience. You need to run at a lower RPM, and because of that have less torque. 1/4" to 3/8" would be the sweet spot IMO.


Running 1/2" and above endmills actually requires a lot more spindle torque than most people think. I mostly use my HDM for aluminum and I do use 1/2" endmills, but really only for facing operations. Otherwise 3/8" and 1/4" are the workhorses. :slight_smile: