Engraving cutters

[So not a Guru]

We've got an aluminum job that requires a serrated pattern on a flat surface. The grooves are 0.017" deep 60° walls & 0.003" fillets roots.

A quick search found uncoated engraving cutters with 0.005" radius 120° included angle. Anyone know of a resource that has 0.003" radius cutters with ZrN or similar coating? I'm afraid of galling in the aluminum, without some form of coated tool.

[AHarrison1]

I would go with what you have found with the .005" rad, unless they have actually put a tolerance no the rad. The difference between the 2 rads is very minute

and will be very difficult to check.

[So not a Guru]

8 minutes ago, AHarrison1 said:

I would go with what you have found with the .005" rad, unless they have actually put a tolerance no the rad. The difference between the 2 rads is very minute

and will be very difficult to check.

The flats at the top are 0.0045", I don't know if they are meant to mate together, but if they are the 0.005" radius might be an issue. Also, that still leaves me with an uncoated tool.

[nickbe10]

49 minutes ago, So not a Guru said:

A quick search found uncoated engraving cutters with 0.005" radius 120° included angle.

Try Harvey, they have tip radii down to 0.0025.

[Matthew Hajicek - Singularity]

If you need a custom, Maritool will do them at a good price.  They take a couple weeks though.

[crazy^millman]

Can you kick the part over and get to the area with a slitting saw or an endmill with a .003R?

[So not a Guru]

1 hour ago, crazy^millman said:

Can you kick the part over and get to the area with a slitting saw or an endmill with a .003R?

Possibly, I'll look at it tomorrow.

 

[PAnderson]

Regardless of the root radius, shouldn't the driving dimension be the pitch between each 120 degr. groove? To me, the bottom radius should be irrelevant. Purpose? Like a thread roo, serves no real purpose dimensionally.

 

Paul