View Full Version : brushless motor drills --field data requested from SMC community
al ladd
07-11-2019, 9:51 AM
This is an appeal to the true tool-geeks out there!
One of the unsung qualities of a brushless motor drill is its high torque and ultra long battery life at very low speeds. For a demonstration, see about 6 minutes in here: https://www.youtube.com/watch?v=tPiaduBZHRU
in addition to the auto shut-off bug discussed in the video, the lowest speeds of various drills vary a lot, as does how they react to a load at low speed (or maybe at any speed). Some have lowest speeds as low as about 15 RPM, and some lowest speeds as high as 60 RPM. Some are almost unaffected by the kind of hand torque shown in the video, and others slow down considerably. Some have a very, very low speed with almost no torque.
They also all have discreet speeds as they ramp their way up --not a gradual increase, but jumps. The size of these jumps also varies considerably from model to model, so some are better than others if you're looking to dial in a particular speed in the low speed range.
I'm trying to find the best drill on the market for the purpose of powering a slow speed device requiring significant torque. I've tested quite a few, but I'm wondering if people out there would be willing to test for the lowest speed on their drill and report back about it here. It's possible to do this with a small hand screw or other clamp, or even by carefully holding down the trigger lightly by hand. The best device for finding this is something that can actually be useful for certain jobs, allowing easy use of the drill at a fixed speed other than full blast: https://www.youtube.com/watch?v=oCbRWaz2Fsw With a little care with the swiveling geometry, it's possible to build such a "switch" such that it doesn't have to fall off to reach an "off" position, so one can turn the drill on and off by simply swiveling, allowing the set speed to be returned to. The other tests that I'm interested in is whether the drill slows appreciably under minor load (like that applied by hand to the spinning chuck), and whether it has the auto shut-off "feature" at about five minutes.
I'm particularly interested in ones I haven't laid my hands on: 18 Volt Bosch brushless motor drill, which is quite costly, the Worx, Dewalt Atomic, and the super cheap ones sold on Amazon as Cacoop, but the manufacturers change model numbers frequently,(and for all I know could change even within a model number) and this is a spec that isn't mentioned in any product literature, so any report back about this on any brushless motor drill would be appreciated. The manufacturers have been unwilling to give me this information when I've written and asked.
Thanks!
David Buchhauser
07-14-2019, 11:44 PM
Hi Al,
I have Milwaukee and Ryobi 18v drills. I also have a digital tachometer. I will test for the slowest speeds and report back.
David
David Buchhauser
07-17-2019, 1:52 AM
Hi Al,
The slowest speed appears to be around 10-12 RPM for the Milwaukee drills. I do not believe that my Ryobi drills are brushless.
David
412805412806
al ladd
07-18-2019, 10:08 AM
Thanks David. The Milwaukee drill label is from a 2704, which isn't brushless . Maybe the other of the two you show is brushless. Too bad, because 10-12 RPM would be a super low speed, just about perfect.
Their Fuel brushless models are 2803 and 2804 (hammer). The 2801 is brushless too, and I've tested that one. Not so great for continuous low speed moderate torque work --it slows under load and heats up, sometimes triggering it's heat overload shut-off (as opposed to many models, which don't overheat, but simply shut-off on a timer at about 5 minutes).
Greg R Bradley
07-18-2019, 1:02 PM
My Festool T15 will run at 3rpm with enough power that I can't stop the chuck with my hand. It will run at 5rpm smoothly and with enough power I can't stop a 3.25" hole saw with my hand.
Being able to start a Zobo bit into expensive furniture by having it start the cut taking 20 seconds to make one revolution is why I bought it in the first place.
David Buchhauser
07-18-2019, 6:28 PM
Thanks David. The Milwaukee drill label is from a 2704, which isn't brushless .
Hi Al,
I own 3 of these drills. They are all brushless.
David
412869412870412873
al ladd
07-18-2019, 10:38 PM
oops, sorry David, and thanks for the clarification. I'll try to get ahold of one of these--sound great (and they'll be cheaper to find used, older model).
And the Festool sounds amazing!So maybe the higher end of the brushless drill market are the best performers for these parameters as well as the more commonly sought power at more typical use speeds.
David Buchhauser
07-18-2019, 10:59 PM
Hi Al,
The Milwaukee 2804-20 has been out for just over a year. All mechanical/electrical specs are the same. The 2804-02 is 4% lighter and just over 3/4" shorter than 2704-20. For a hammer drill, I actually prefer 2704-20 because of the heavier weight and longer drill body. When I need a smaller lighter drill, I use the Ryobi 18v. I have 3 or 4 of those as well.
David
412883
al ladd
01-29-2021, 11:58 PM
Make
Model
Lowest RPM
Autoshutoff?
comments
Ryobi
18V one+
40
no
Good budget choice if not needing very low speed
Hitachi
DS18DBFL2S
15
yes, 5 minutes
Big jump to next speed
Ridgid
860054
19
no
Sensitive switch, big jump to next speed
Porter Cable
PCC
18
yes, 5 minutes
Nice distance between many speeds on trigger.
Dewalt
DCD777
20
yes, 5 minutes
Bosch
DDS182
20
no
Makita
XFD131
10
yes, 5 minutes
Slows much under load, then holds that speed
Dewalt
DCD996
20
yes, 5 minutes
Craftsman
CMCD7202
26
yes, 5 minutes
Metabo
36 VHPT DV36DA
14
yes, 5 minutes
Can run on optional AC adapter
Above drills recommended over below drills as power source for low speed/high torque
Milwaukee Fuel
2704
8
no
Generates heat, sometimes enough to shut off**
Milwaukee
2902
21
no
Generates heat, sometimes enough to shut off**
Milwaukee
2801
19
no
Generates heat, sometimes enough to shut off**
Makita
XPH07
15
yes, 3 minutes
Ridgid
Octane
60
yes, 5 minutes
Kobalt
20V
50
no
Above drills adequate but with limitations. Below drill inadequate.
Skil
PWRCore 12V
23
no
#Insufficient power --shut down
**all 3 Milwaukee drills shut down at irregular intervals, sometimes after short run times (3 minutes), others after long run times (20+ minutes), unlike any others. All brushless motor drills have over heat protection, but most, unlike the Milwaukees, generated no perceptible heat.
If anyone can add to this chart, I'd appreciate it. Please PM me for incentive.
Bruce King
01-30-2021, 12:39 AM
What is the application?
Sounds like you will wear out the variable speed trigger running at low rpm.
Why can’t you use this:
https://www.amazon.com/BEMONOC-Electric-DC-Reversible-Torque/dp/B01EY6SOEE
David Buchhauser
01-30-2021, 3:20 AM
For Al's application - small power feeder for router table/band saw/table saw - it is nice to have the variable speed feature. Plus his power feeder kit is designed to use a hand drill. I have owned and used Al's power feeder (built from kit) for about a year now and it works great. I particularly like it for my router table.
David
450758
al ladd
01-30-2021, 9:21 AM
The torque of an inexpensive brushless motor drill is much greater than that of most DC motors, like the one Bruce linked to. Those motors can be controlled to be variable speed through a fairly inexpensive electronic speed control, but the useful speed range is from 1/10th up to rated speed, as compared to a brushless motor drill , where the maximum speed is around 2000 rpm's, and as my chart shows, minimum varies from about 10 RPM (Greg says 3 rpm for Festool!) to about 60, 3 to 20X the range of the DC motor with speed control --with much more torque. When you consider the cost and work of assembly of a DC motor, a speed control, and an inverter, the drill shows itself as an amazing bargain. Now that batteries are more powerful, with power-left indicator lights, and fast charge times, a drill is a viable power source for low speed applications.
I hope Bruce is wrong about wearing out the variable speed trigger at low RPM. Do you have experience with this happening? In my months of using brushless motor drills for extended periods at low speed I've seen no degradation. Anyone know what it would take to hack the trigger into a dial knob?
When you consider how easy (and inexpensive) it is to just pop on a brushless motor drill as a variable speed power source with lots of torque even at super low speeds, I'm sure there are many more potential uses, both in and out of the shop. But the relevant specs to determine which is best for a very specific use aren't available from the manufacturer, even through direct inquiry. Hence my table, and desire to have it expanded from user gathered data.
Ronald Blue
01-30-2021, 10:16 AM
Have you looked at something like this Al? I know it would require some redesign but thought it might allow more flexibility and adjustability in the end.
surpluscenter.com/Gear-Reducers/Right-Angle-Gear-Reducers/Aluminum-Worm-Gear-Reducers/10-1-Gearbox-LH-13-1574.axd
After looking closer this one is likely to large physically but something along this line might work.
al ladd
01-30-2021, 10:40 AM
Thanks Ron, yes I looked at things like that. For one thing, it's heavy. 24 pounds. My power feeder, with the drill, weighs about 16 pounds, and low weight is an advantage in many uses.
Everything I looked at (lots!) came back to the conclusion that the humble ugly-ducking drill is unbeatable. Cheap, useful for other things, powerful, wide speed range.... So much engineering and mass production efficiency.
David Buchhauser
01-30-2021, 4:28 PM
I agree Al - the drill motor is the way to go. Plus most folks already have a suitable hand drill for this application, and so definitely a cost savings for those on a budget.
David
Douglas Mosman
01-30-2021, 10:18 PM
Interesting workup Al. Could you add the actual model number of the Ryobi that you used, like P251, P252, etc.? Ryobi has been iterating through model numbers pretty rapidly as they moved into brushless and also might have the bare drill, the bare hammer drill, a bare 1/2 in drill and/or a different model drill for their kits (saw this one with their impact drivers).
Rod Sheridan
01-31-2021, 4:54 PM
If I understand this, the application is for a stock feeder?
Does a cordless drill have speed regulation?
A stock feeder with an induction motor has limited motor slip so the shaft rpm is almost independent of load.
Regards, Rod
al ladd
02-02-2021, 9:17 PM
Douglas Mosman--the Ryobi I tested is model P252. I am curious whether these qualities (lowest speed, auto-shut-off) might be different as similar drills
undergo different iterations....
Rod Sheridan, I guess I think the answer is "yes" --brushless motor cordless drills do have speed regulation. See below video.
One of the unsung qualities of a brushless motor drill is its high torque and ultra long battery life at very low speeds. For a demonstration, see about 6 minutes in here: https://www.youtube.com/watch?v=tPiaduBZHRU
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