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Preferred bit for 5mm line bore, in melamine4/4
Suddenly we are having some chipping issues when line boring melamine (3/4"). It's mostly in white melamine but doesn't seem to matter what brand.
For drilling line bore all the way through (2 sided partitions, for example), we have used a V point 5mm bit rather than a brad point, since the brad points tend to chip the underside. Lately, even the two brands of V-point I have tried are chipping the UP side. The down side still cuts clean.
I've had this happen with brand new bits, and I have also swapped tool holders and collets to rule out a damaged holder.
The one thing I haven't tested yet is the rotation and feed speed (9000rpm, I don't recall the feed speed) but historically these have worked pretty well.
What bits are you guys having good results with, for full through line bore?
I recently made the switch to solid carbide bits.
4500 RPM 75 IPM
No more chipping.
Try changing the feed speed (faster).
vortex makes some nice bits,,,,
keep in mind, ,,most cnc boring blocks (not independent boring machines) have a limit of 2.3-3.77HP mechanically, more often than none the plc limit is 4k rpm,,some newer machines you can push to 6k because of linear motor/drives ,,,keep it steady(slow and steady wins the race) ,,the drive and boring block assembly drive all your vertical and horizontal spindles and your grooving saw, with on one belt/ or cam,,if you are pushing that drive past what the manufacturer sets it at leads to a headache (7k service job) the boring block case is not easy to dissemble/reassembly(correctly)
4000rpm with some nice carbide bits
-Some words from Chev
Brad point are designed to chip the bottom not the top, v point to chip the top not the bottom.
Why not both? Drill 1/2 way with a brad point finish with a v point. No chip out on either side (provided you're using sharp tools). No bit is going to not chip one or the other, that's not how drill bits are designed.
weather brad or vpoint ,,pierce into the spoil board 1/16" will clear the melamine egg shell/plywood veneer, ,,if your concerned about protecting your spoil board,, the fishtail(reverse) type drill bits give you that 1/16" threshold ,,
I've had good luck using brad point and not going all the way through within a few thousands.Leave just a hair of material on the on the other side that either falls out or brush over it with your hand during assembly to remove.