HILDA 400 watt drill die grinder low speed issue

I take another look at this popular unit.

Camera: Nikon L820

[Xynudu]

I found a PWM speed reduction module in the workshop and ran the Hilda unit through it to see what happens at an even slower armature speed. It did not cause pulsing as can happen, so it does do the job reasonably smoothly on that brushed motor.

Basically there's no advantage/point using one as the torque just evaporates below 17, 000 rpm (minimum speed as supplied). The motor will only run above 10K and the power is useless until 17K. So basically they have reduced the speed (as supplied) to the minimum practical amount.

I played around with the unit and tried drilling at various speeds. Interestingly while the no load minimum speed may be 17K, once you start drilling (I used 1/8") into hard steel, the speed drops drastically to a level you would normally use, so drill burn isn't an issue provided you apply sufficient pressure.

As cutting load will increase with drill diameter, I expect you could even increase drill speed/torque and once it starts cutting the same thing will happen.

Not ideal, but certainly it appeared to do the job with smallish drills. I have drilled brass and alloy with it on the lathe with no problem when I made the Stirling engine, but not steel.

So it can do drilling, but not in a controlled fashion like a proper geared drill.

Cheers Rob

[fun_ghoul]

Interesting to note that the sticker on the unit itself doesn't even make a claim as to the low speed, it just says "no:25000/min".

[cheztaylor]

Agreed, the Hilda is really a die grinder and too fast for drilling most materials.
Because it has a chuck, people assume it’s a drill.

Air die grinders typically come with a collet and nobody thinks they’re a drill. ;-)

[glennfelpel]

Rob, this is very helpful.  Over here we see motors rated in horsepower mostly.  According to Jeremy Fielding's channel 1 hp = 746 watts.   That puts this grinder just over 1/2 hp in our terms or what I can relate to.  That is a quite strong little grinder.  Thanks for the video.  :-)

[RetroSteamTech]

Thanks for posting this Rob. After watching this i did a few tests on my own Hilda. On the lowest setting it tops out at about 16000, so similar to yours. I then connected it up to my meaty variac and dropped the voltage a bit. Even a small reduction in rpm results in almost no torque. Which, having now read the other comments i see you discovered. I use it for cross drilling on the lathe but only up to 3mm in drill bit size. As you said, if you use a fairly heavy feed rate the speed drops right down anyway. I will keep a look out for a suitable geared motor that i can use with the flexidrive for more control. Cheers, Alan.

[keldsor]

Hi Rob !
I've had one from Dremel and it never sounded good when running - low or high speed doesm't matter and now it's dead !
I think the speed control was killing it because when run on reduced speed it got very very hot and in the end I think it simply
tousted the speed control.
Now I'm trying to convert a Broun Food blender using the parts from the tousted Dremel ;-))

[nigelp]

It's a bit rattly, but good for wire brushing and using up worn down cutting discs. Really doesn't like high loads though!

[pierresgarage]

This is one place where getting more isn't seen as a better deal... lol

[Telectronics]

This should give a proper milling device at those speeds.

[ChrisB]

Have come to same conclusions Rob... drill burnout potential.
Still got those darned pigeons then :-)

[glennfelpel]

Thank you Rob.  Some of my power tools for example will say they are a 10 amp or a 7 amp motor or so. They sometimes don't give anything else.   How is this converted into Watts to get an idea of its strength?  I really do appreciate your channel.  Thanks

[iTeerRex]

humm, Looked and looked but didn't find the 110v version for use in the states, but the reviews are all very good about it.

[jonnafry]

At low rev setting the torque probably fades away as would the revs

[duser]

Does that even have a CE mark/RCM mark? Dodgey.
I wouldn't use that chuck at 27k RPM personally :)

[GG-odtr]

Hi Rob I have watched some of your videos and I would like to get into lathe work I am looking at the lathe you recommended best bang for buck METAL LATHE & STAND - 610MM BC would you still recommend this lathe for someone with no experience and best value in Australia? I am in QLD and would really appreciate your advice thanks m8.

[fun_ghoul]

The only thing you'd drill with that thing is your wallet, for the cost of new bits!

[howder]

Did you check the speed under load? I'd wonder what it works out to.

[navaho]

Stuff that would shut thoughts pidgins up, defiantly a tool to respect cheers.

[vmitchinson]

If you live in NA do not buy this thing. I did and 120 V does not work. 0 to 3 the top speed is 0 RPM 3 to 6 it runs but I do not have a meter to measure the speed but I suspect that it runs at half the top speed. If any one knows how to rewire it to run on 120V I would love to know.