Milling with small endmills

[Wolfie]

OK, I'm trying to cut a slot in a 4mm round piece of bar about 1.5" from the end to an open end. Now I wanted it to be 2mm wide but as the smallest endmill I have is 3mm, then 3mm it was. However after drilling a 3mm hole into the bar, I simply couldn't keep the endmill on line, it was too springy (for want of a better word) and wandered all over. I broke at least one 3mm endmill in trying this.

So is there a better way of cutting a 2mm slot into the end of some round bar. ie splitting it down the middle.

 

[Terry - Somerset]

OK, I'm trying to cut a slot in a 4mm round piece of bar about 1.5" from the end to an open end. Now I wanted it to be 2mm wide but as the smallest endmill I have is 3mm, then 3mm it was. However after drilling a 3mm hole into the bar, I simply couldn't keep the endmill on line, it was too springy (for want of a better word) and wandered all over. I broke at least one 3mm endmill in trying this.

So is there a better way of cutting a 2mm slot into the end of some round bar. ie splitting it down the middle.

Could the end of the bar be set in some clear resin which would hold it rigidly, removed after the slot is cut.

Another thought - cut the bar too long, mill the slot in the middle of the bar which will allow both ends of the slot to be held rigidly. Then cut the bar to reveal the open end.

 

[Daniel2]

I would use a slitting saw.

 

[clogs]

crank up the speed, it will help as in maximum the machine will go.....

 

[Dee J]

If it's only one item needed then a hacksaw and a warding file would get you there quick enough.

 

[highwood122]

OK, I'm trying to cut a slot in a 4mm round piece of bar about 1.5" from the end to an open end. Now I wanted it to be 2mm wide but as the smallest endmill I have is 3mm, then 3mm it was. However after drilling a 3mm hole into the bar, I simply couldn't keep the endmill on line, it was too springy (for want of a better word) and wandered all over. I broke at least one 3mm endmill in trying this.

So is there a better way of cutting a 2mm slot into the end of some round bar. ie splitting it down the middle.

slitting disc in angle grinder then file

 

[Woody Alan]

woodruff cutter

 

[sawtooth-9]

OK, I'm trying to cut a slot in a 4mm round piece of bar about 1.5" from the end to an open end. Now I wanted it to be 2mm wide but as the smallest endmill I have is 3mm, then 3mm it was. However after drilling a 3mm hole into the bar, I simply couldn't keep the endmill on line, it was too springy (for want of a better word) and wandered all over. I broke at least one 3mm endmill in trying this.

So is there a better way of cutting a 2mm slot into the end of some round bar. ie splitting it down the middle.

I would start at the open end and keep the speed of the tool high and take MANY shallow cuts.
I assume your bar is steel but if you take very shallow cuts with a SLOW feed, your tool should survive. I have cut 3 mm slots into stainless steel bar this way without coolant, with no problems.

 

[sploo]

I would use a slitting saw.

This.

It's a job for a slitting saw.

 

[Fergie 307]

Sawtooths advice if you are going to mill it, but I agree with Sploo and Daniel, really a job for a slitting saw.

 

[flh801978]

I actually cant think of a good way of doing this…cutting a 2mm slot in a 4mm dia doesn’t leave much…1mm thick at the thickest 3mm even worse leaving just 0.5.
I think placing your 4mm inside a 10mm bar with a 4mm hole and using a slitting saw or a 1mm cutting disc might do it…then remove the 10mm tube

Ian

 

[paulrbarnard]

It’s a remarkably high precision operation. Your going to need a pretty good mill with no runout.