Centroid Community CNC Support Forum

I am finishing up my first project in 1018 steel. Everything worked great, but I was surprised to have issues with the simple drilling operation. I drilled a 1/4" hole pilot hole followed by a 3/8". In both cases the drills got wrapped with chips like a birds nest. The holes were drilled with YG1 jobber length 135-degree TIN coated drill bits. I used a FogBuster for MQL lubrication.

I used the G-Wizard speeds and feeds calculator to determine the rpm and feed. I tried two options:

.375 drill bit - 1 inch deep hole
s/f calculated for a TIN coated drill bit. - 978 rpm and 2.4 ipm plunge rate
s/f calculated for a non coated drill bit. - 815 rpm and 1.85 imp plunge rate

In both cases, the drill bit looked like the attached image. I tried increasing the feed rate a bit, but it did not help at all. Any suggestions as to how to avoid this?

Best... Richard

Go with the feedrates from YG1, they know there tools

for 3/8"
1100 rpm 6.6ipm in mild steel

Predrilling should not be larger than the core of the next drill, otherwise it is begging for birds nests.

I avoid predrilling unless the drill is very big and the machine is not strong.

Use peck drilling tho keep chips short and unload the flutes with deep holes.

Uwe

Thanks Uwe,

I looked high and low but could not find the chip load and surface speed recommendations from YG1. I did use a peck depth of .100" Should I use a smaller peck depth?

In comparison to the speeds and feeds that GWizard suggests, I need to push it to the most aggressive settings to come up with a feed rate of 6 ipm. Their suggested rpm is still only 897. Your Feeds and speeds seem much more aggressive... but I will give it a try.


I put a call in to YG1 to get more info.

Best... Richard

1100 rpm and 0.006 in/rev in YG1 table for a 9mm drill jobber with TIN Coating...

But mild steel is not known for good chip breaking anyway.

Uwe

Thanks so much. I was able to locate the YG1 feeds and speeds for these drills. Everything worked out great.

I think this was my first and hopefully last project with 1018 steel. While all the features machined perfectly, and I was able to machine the slot within a half thou... I just don't like working with this stuff. I will search the internet in hopes to find some other alloy that machines like aluminum with some of the strength properties of steel before I touch this stuff again

Thanks as always for your help... Richard.