Got some 5.5"x12" chunks of 1/4" and a dewalt kobalt 5/8"s drill bite and a delta drill press, wondering if anyine had some tips on drilling this. What type of cutting oil will keep my bit like new? is there a better for your money bit than the dewalt? What speed should i keep this on? really slow? Seeing how this bit was near $20 i would like to clear this up before i screw up.
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Drilling 1/4"
- Thread starter waubm
- Start date
brokexj
NAXJA Member #1165
- Location
- TIDEWATER!, VA
I just drilled some 1/2" holes in 1/4" with the same bits. I started with 1/8, 3/16, 1/4, 3/8, 1/2. I used 3-1 oil, used slow speed, steady pressure and let the bit cut.My bits still cut, though.
ECKSJAY
Water is dirty
- Location
- Covington, WA
Yup, let the bit cut for you and use plenty of oil. 
Our bits in the shop last a LONG time with this stuff.
Our bits in the shop last a LONG time with this stuff.
CanMan
NAXJA Forum User
- Location
- Lake Tapps, WA
And if they go dull, buy one of these. Its saved me tons of money on buying new bits.
BrettM
NAXJA Forum User
- Location
- michifornia
drill doctors are GREAT. go SLOW, probably as slow as your drill press will go. lots of pressure, let it cut. clamp the piece real tight. motor oil is a good coolant/lube that everyone has lying around.
FarmerMatt
NAXJA Forum User
- Location
- Down on the Farm
Rapid Tap is good stuff. I don't believe the "Drill Doctor" will sharpen 5/8" bits, but it's not hard to do it by hand on a grinding wheel.
tompatjr
NAXJA Forum User
- Location
- Hayneville,AL
I have a question, how do you know when you have enough pressure? Will you get ribbons or what?
Static-XJ
NAXJA Member #492
- Location
- Colorado Springs
The 750 models will do up to 3/4", the 500 models will if you buy the larger chuck for it.FarmerMatt said:
bigwhitey
NAXJA Forum User
- Location
- Brunswick, ME.
I had a drill doctor and it took too long to sharpen my bits. I just went back to using my bench grinder.
tealcherokee
NAXJA Forum User
- Location
- CT
the formula for rpm is
RPM = ((4 * CS) / D) * .75
for fully flooded (continous lubrication)
and
RPM = ((4 * CS) / D) * .66
for normal lubrication
the cutting speed of mild steel is about 36
D is the diameter of the drill bit
so for your application
RPM = ((4 * 36) / .625) * .66
RPM = (144 / .625) * .66
RPM = 230.4 * .66
RPM = 152.064
so around 150 RPM, as far as pressure, keep the bit cutting, with out binding up the drill press
RPM = ((4 * CS) / D) * .75
for fully flooded (continous lubrication)
and
RPM = ((4 * CS) / D) * .66
for normal lubrication
the cutting speed of mild steel is about 36
D is the diameter of the drill bit
so for your application
RPM = ((4 * 36) / .625) * .66
RPM = (144 / .625) * .66
RPM = 230.4 * .66
RPM = 152.064
so around 150 RPM, as far as pressure, keep the bit cutting, with out binding up the drill press
JAS
NAXJA Forum User
- Location
- Ann Arbor, MI
x1000
12GaugeXJ said:And if they go dull, buy one of these. Its saved me tons of money on buying new bits.
tealcherokee
NAXJA Forum User
- Location
- CT
good job on the 2 month old post to repeat what was said........
BrettM
NAXJA Forum User
- Location
- michifornia
good job on the 2 day old post to say nothing.........
CanMan
NAXJA Forum User
- Location
- Lake Tapps, WA
Way to go guys. Way to say nothing about what has already been said.
Mr.OverKill
NAXJA Forum User
- Location
- the city of El Cajon
what he said!12GaugeXJ said:
BrettM
NAXJA Forum User
- Location
- michifornia
I'll second the motion.
Jump This
Just another minion!
- Location
- Borrego Springs Ca.
All in favor of bumping this thread...say 'yep'BrettM said:
Jump This
Just another minion!
- Location
- Borrego Springs Ca.
Wait a moment....it already was on the top....
What a dead forum!
What a dead forum!
