Quote Originally Posted by Jonathan View Post
The alternative is you use a bigger cutter to start with for a roughing pass and leave just 1mm (or so) for the finishing pass with the 1.5mm cutter. That will put a lot less force on the cutter, may mean you can use a short a cutter resulting in a better finish. There's more to it than just slowing the feed down...
This is exactly the way I to do it.!
I use a 6mm carbide ballnose slot cutter to rough the bulk away leaving an offset from surface (could use straight bit and z level roughing pass's but prefer this way), the amount of offset depends on job and amount of detailed required. I will use cutters as small as 0.4mm but amount of offset is tiny at this dia.
Often with the smaller Dia cutters I'll do rest machining pass's that just remove any material that the larger cutter couldn't remove this helps speed the job up because it doesn't re-cut the whole job.
For really detailed work usually I'll use 3 pass's. 1st full pass roughing 6mm BN leaving 0.75-1mm offset, 2nd full pass 1.5mmBN finished surface 3rd 0.5mmBN Rest machining clean up pass.
Doing it this way means you can use standard length cutters, but be aware you'll often find the really small cutter have short length below shank(LBS) and tiny length of cut(LOC), IE: Dia 0.4mm = 0.75mm LOC & 2mm LBS these are only used for the most detailed work and can be restrictive in tight/deep places plus if you so much look at them in a funny way they snap.