4.3 mm holes, 20 mm deep

**routercnc** · 08-08-2017

Hi Chaz,

If it helps - in the line boring video I posted recently you can see 3 mm holes being peck drilled (with full retract to clear the chip) at ~12,000 rpm. Can't remember the feed - maybe 300 mm/min? Drill bit is plain HSS.

You can see the chip fly out each time, and a dab of oil keeps it running smoothly. Starts at 0:32
https://www.youtube.com/watch?v=sYhDtuqzf2I&t=6s

Been using this method for some time and it works well.

**Chaz** · 08-08-2017

Originally Posted by routercnc

Hi Chaz,

If it helps - in the line boring video I posted recently you can see 3 mm holes being peck drilled (with full retract to clear the chip) at ~12,000 rpm. Can't remember the feed - maybe 300 mm/min? Drill bit is plain HSS.

You can see the chip fly out each time, and a dab of oil keeps it running smoothly. Starts at 0:32
https://www.youtube.com/watch?v=sYhDtuqzf2I&t=6s

Been using this method for some time and it works well.

Thanks.

I did some checking last night. My VFD's current looks to be set correctly.

There is an auto compensation value for increased torque demand. Set to default of 2% but can go to 10%. That's now changed.

There are also some parameter values between PD005 and PD010 which allow different torque curves. I *think* default is a constant curve, there is an option to go for what's called high torque where it provides better torque at lower speeds. This will help a bit, Ill lower the speed and see. Clearly the feedrate of what I was doing was too slow too.

Also, what oil do people use? Anything specific or just 2 in 1 oil? Ive got big container of VG220 Mobil oil that I got with one of my ballscrew / rail orders. Would that work and is it better than trying to spray WD40?

**Chaz** · 08-08-2017

Ok, pushed up the VFD power a bit, it doesnt seem to like this but has worked.

I used a 4mm drillbit for the 4.x mm holes and the bolts fit well, no need for the slight oversize IMHO. Redid the failed 5mm holes, done.

12500 rpm, 0.25 depth, full retract, 500mm/min plunge.

I did have a problem with Thor which cost me about 2 hours, the bearing nut came loose and caused problems. I had heard something but didnt investigate it earlier, no damage done, phew.