ned
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 posted on 7/6/06 at 07:28 AM |
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drill speeds reference
Was wondering if anyone has a link to a site that has a guide as to what speeds you should run certain size drill bits at?
ie i know that smaller drill bits can run at higher speeds and larger drill bits should be run at lower speeds but i wondered if there is some sort of
reference or guide out there? Tried a google but nothing useful came up.
cheers,
Ned.
beware, I've got yellow skin
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flak monkey
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| posted on 7/6/06 at 07:36 AM |
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The RPM is also linked to the tool material (I assume you are using HSS drills) and also the feedrate.
You calculate the RPM from the feedrate.
RPM = (k*feed)/diameter.
k=0.32 for metres/min or 0.4 for feet/minute. Diameter in metres too, to keep units homogenous.
Feedrate tables are fairly easy to find. Heres a quick guide:
Material type metres/min (feet/min)
Steel 15 - 18 (50 - 60)
Mild steel 30-38 (100-125)
Cast iron 18-24 (60-80)
Bronzes 24-45 (80-150)
Brass 45-60 (150-200)
Aluminium 75-105 (250-350)
David
I should add that there are several different formulae for feed and speed calculations and they are all approximations, and should all give you
roughly the same answer. A lot of it is experimentation around the suggested speed to find the best speed for the job. There is no single
'optimum' as such.
[Edited on 7/6/06 by flak monkey]
Sera
http://www.motosera.com
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donut
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| posted on 7/6/06 at 07:54 AM |
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Mr Monkey
Is there anything you don't know about?
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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flak monkey
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| posted on 7/6/06 at 07:57 AM |
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Wikipedia is your friend for things like this! We also covered tooling last year, couldn't remember the forumla though! Mind like a sieve!
David
Sera
http://www.motosera.com
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ned
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| posted on 7/6/06 at 07:57 AM |
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I remember back at college some pillar drills had charts on for wood, metal or plastic and suggested speeds for drill size in each. Just after
something simple and idiot proof to be honest - not getting my calculator out. Doubt I'd ever be drilling into mega hard steels so are there
suggested one size fits all on the side of caution rpm's for say drill sizes 2-13mm at 1mm increments?
cheers,
Ned.
ps yes hss drills.
beware, I've got yellow skin
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flak monkey
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| posted on 7/6/06 at 08:00 AM |
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Something like this do you?
http://www.ibiblio.org/twa/info/drillSpeedChart.pdf
Or this:
http://www.auto-ware.com/techref/drillspeed.htm
1mm increments is really too fine. All the suggested speeds arent 'optimum' anyway. Saying there is an 'optimum' when it comes
to feed and speeds on cutting tools is rather misleading, as for example there are 3 'optimums' i can think off straight away - tool life,
finish or production rate. Lots of things to consider!
David
[Edited on 7/6/06 by flak monkey]
Sera
http://www.motosera.com
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John P
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| posted on 7/6/06 at 08:09 AM |
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Speeds and Feeds
Have a look at this.
http://www.tapdie.com/html/tapping_drills_for_taps.html
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donut
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| posted on 7/6/06 at 09:33 AM |
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quote:
Wikipedia is your friend for things like this!
And theres me thinking you were clever!!
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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tks
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| posted on 7/6/06 at 09:33 AM |
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mhh
the drill speed is an optium speed just because its a per material based number wich says the cutting speed.
to apply the right cutting speed you should increment rotating speed with a small drill, and decrement with a bigger drill..
the problem often is that you have gearing choices on the machines (lathe,drill)
sow thats where all the calc stuff is wasted.
from drill 1 to 3mm i would use 1800rpm..
(max.)
for more than 3 to 6 i would use 1000
6 - 8 for me i guess its 800
bigger then 8 i would do it with 500..
from 13 onwards i would do it with 200..
depending on your machine offcourse you could have better choices....
when using a home drill the trick done over here is that they "give gas" and let go..and then give gas and let go..
give gas = press the run button...
anyway for your drills life, i would go lower then higher..
this is as far i can remember from my mech. engineering study
Tks
The above comments are always meant to be from the above persons perspective.
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ned
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| posted on 7/6/06 at 10:26 AM |
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thanks guys just what i was after. looking at pillar drills again and wanted to find what the advertised speeds can actually drill. I appreciate you
can go quicker but are more likely to damage something, I was of the understanding that going slower is normally safer/better practise?
cheers,
Ned.
beware, I've got yellow skin
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MikeR
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| posted on 7/6/06 at 03:23 PM |
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i just run mine on the slowest setting all the time 
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paulf
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| posted on 7/6/06 at 09:30 PM |
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Recommended cutting speeds are only a guide anyway, there are so many variables that it is impossible to be specific.
On a small diy drill it is usually a case of having to go slower as the machine is not rigid and wont have the power to drive larger drills at the
correct speed. Just remember fast speeds for ally and brass , slower for bronze and plastics and mild steel and slower still for cast iron and
stainless steel .
When you have drilled a few holes in differnt materials you will get a feel for the machine etc.
Always remember to use a vice and or clamp the work correctly as drillpresses are one of the most dangerous and misused machines in a workshop and
likely to catch you out if not treated with respect, i have seen a number of accidents when misused
Paul
quote:
Originally posted by ned
thanks guys just what i was after. looking at pillar drills again and wanted to find what the advertised speeds can actually drill. I appreciate you
can go quicker but are more likely to damage something, I was of the understanding that going slower is normally safer/better practise?
cheers,
Ned.
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MikeR
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| posted on 7/6/06 at 10:10 PM |
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and always wear eye protection.
I know of someone who has sight in one eye. drilling away, perfectly normally and the drill bit shattered (no idea why). Only when he took his goggles
off did he notice the lump embedded in the goggles infront of his good eye.
for 5 seconds hassle its not worth the risk. I keep mind on the handle to remind me.
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Coose
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| posted on 8/6/06 at 11:13 AM |
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Right, take the cutting speed (cs) in metres per minute from flak's chart on page 1 and the drill diameter (d) in mm and insert it into this
formula: -
{(cs x 1000) / (3.14 x d)} / 3.
If you're turning or milling, don't divide by 3. Job's a carrot!
Spin 'er off Well...
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MikeR
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| posted on 8/6/06 at 05:34 PM |
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ok, but how fast should you be drilling?
i mean if i'm drilling a bit of 3mm steel, how fast should i be pushing that drill into the material, i'd guess it would be 1cm a minute?
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