Rotary tools in support of electronics, Dremel and more ..

[StubbornGreek]

I use a Dremel with a flex shaft attached but I've been eye-balling a proxxon for a while - I just can't justify the purchase as I use other tools for precision work (like a drill press, etc.) and my little Dremel (ok, I have a few) does everything I need it to.

[robrenz]

EDIT:  posted my negative thoughts on this thing above.

 :DI just found this milwaukee unit.  If it the same quality as all the other milwaukee stuff I have it will be a winner.  The reviews are very positive. I know it is battery powered.  If you dont like that hook up to your PS at 12V.  Milwaukee manual/parts list shows no guts so cant see internals.

I dont like the typical "plastic shell at resonant frequency" sound in the video but that is a big disk and probably running at its top 32000 rpm.  I do like the electronic overload protection that kicked in in the video, very nice.  I know my M12 drill and my M12 driver also do a forced shut off at the low battery level, also very nice.

 The kit is better buy than the bare tool without battery. For $20.00 more you get a $45.00 battery and a charger

Milwaukee press release
http://www.milwaukeetool.com/news/press-releases/1146


You tube review. 

[saturation]

I concur, I give their design the benefit of the doubt, but Amazon users review suggest the design can have issues particularly if the motor is overloaded or even run for extended periods,  the geared connection is a source of heat generation, and transfer loss probably caps the upper speed to 20krpm.

The Dremel design is a more reliable direct drive, and far less parts.

Eyeballing Proxxon reviews on Amazon.com, for 115/E and IB/E units, ~ 25% complain [ 3 star or less reviews] of early failures with motors smoking as a fairly common symptom.  Anyone experience this?

The parts listing on thier website shows a geared drive.  That is why the spindle is offset from the body.  It does not look like it would be very robust.

[saturation]

Brushes wear proportionate to use.  If they are cheaply made and wear, which I haven't found to be the case, they are easy to get a hold of, and worse can you can get any brush that is sized like it.  I used to find them generic in Asia, and kept a box I never used I paid a $1 for 10 or so, just find the right size and shape.

The Dremels rotary tool has its faults, but the core design is simple, little can go wrong.  Its basically unchanged for 50 years, and the current series 100,200 is identical to the Mototool series of 1992, and the 3000 is a just a 300 in a new body.  Its principal advantage over Black and Decker or Chinese nameless clones, is the older technology is easy to fix DIY,  modify if needed, its 'schematic' and part are 'open', and easily available.  Its like the VW bug of cars, if you don't mind a VW bug.


It will pay for owners to disassemble and understand how it works, and were it can fail.

I've seen other people's problems with it most due to job sizes that were better off with a die grinder, or often misused: applying pressure to the wheel/bits to speed up a work, then complain of rapid wheel wear or the motor bog down, both tasks accelerates wear on the drive system, overheat the chassis, and premature fail any electronics.

Worse case the parts are fairly cheap and easy to acquire in the USA, the Mexican parts, particularly the rotor and stator are reliable, but like others before it, unsealed [ so it can get fatally dirty when grit enters the motor]; its basically a universal brushed motor with a on/off switch or a light dimmer [ variable control], it can easily be bypassed with wires and solder, then later add an external light dimmer to provide continuously variable control.

Thus, the cheapest basic 275 or 100 model kept clean and given a supply of brushes, will most likely die from mileage related use, and far less than quality defects.

I only know dremels suffer from premature brush failure, fake or not.

[T4P]

Or it can be due to stress from incorrect brush tuning- Actually, i mean positioning

[robrenz]

I have a Dremel Professional model #398 that has served me well for the last 8 years with no problems. It is better constructed than the cheaper models.  But it is a retired model.

Like saturation says these have real motors in them. 
http://www.ereplacementparts.com/dremel-398-f013039807-corded-multitool-parts-c-15440_15456_15477.html

[saturation]

Yes, you are right. 

I've seen it on factory new boxed models too or poorly reassembled by users: the cap isn't screwed on correctly so as the brushes age the tension of the spring isn't what it should be, causing it to loose contact prematurely or provide uneven pressure on the commutator,  so the brush errodes unevenly.

The older models with stiffer plastic or even metal screw caps were more reliable, but the new soft plastic caps can be screwed in improperly.  The good news is the cost cutting by Dremel can't go any further since the chassis needs to be rigid enough to support the bearings, so the chassis is pretty much that from the 1992 version, and similar quality.

On bad thing Dremel did in the 1990s was use a Bosch "safety" feature, a plastic clutch connecting the motor to the drive shaft.  With overloading, this 'flex coupler' would break severing the shaft from the motor.   Alas, with just age all these coupling meant guaranteed failure!  As it wore with use, it would slip, reducing speed! Its easy to repair, just insert a new one or until it arrives, use a piece of aquarium air pump tubing, but you have to be comfortable opening the unit, like we all do on eevblog, "take it apart". 



If you send those older Dremels in for service, they will give you free of charge add the new motor assembly, about $20, which does away with the coupling, or you can have a supply of couplings, $2@.

IIRC, all Dremel rotary tools use the same proven old motor design, what's been unfortunate is cost cutting in some parts harmed their reputation, and so did using the dreaded coupler.

The Dremel 4000 seems like a good unit, but only time will tell.  But I think the simpler 275 aka 100  is a better deal for reliability and expected performance of a Dremel rotary tool.

Or it can be due to stress from incorrect brush tuning- Actually, i mean positioning

[robrenz]

Went to home depot to try out the Milwaukee unit I mentioned previously in the thread.  Very disappointing, with nothing in the collet it has that sick resonating sound at all speeds. It may be gear noise but it even feels bad in the hand. The spindle can be flexed laterally at least .020" in the housing with mild pressure. I could not find a position where the "ergonomic shape" at the nose could be held pencil style.  I am sure the motor and electronics will hold up in typical Milwaukee style but I think this is a total FAIL!

[Kremmen]

Well, since the question included the word _quality_, my vote has to go to Kress. (please copy the link into your browser; Kress has stupidly included characters in the URL that this forum misinterprets: http://www.kress-elektrik.com/Power-tools.71+M561855e446b.0.html?&tx_commerce_pi1[catUid]=17 )
While i am not familiar with all the brands mentioned, those that i do recognize and own, do not come anywhere near Kress quality. The models i linked are quite popular in CNC circles as spindles for mini mills for wood and aluminium, as well as PCB work - drilling, isolation routing, v-grooving etc etc. High quality collets are available for all popular shaft diameters making a Kress a good allround tool. If only it could do 60 000 rpm as well...

[T4P]

60,000  You might as well use a mini jet engine 

[G7PSK]

Some model makers use dentist drills as they are lighter and give greater accuracy,they tend to be a bit pricey and you have to be able to stand the noise as well.
One of these is the best compromise very light runs cool (too cool they freeze up) are these units, they are also very cheap.

http://www.ebay.co.uk/itm/Pro-Micro-Air-Die-Grinder-Kit-56-000RPM-Pencil-1-4-NPT-Water-Oil-Separator-/280805025684?pt=Motors_Automotive_Tools&hash=item416148a7

[M. András]

Well, since the question included the word _quality_, my vote has to go to Kress. (please copy the link into your browser; Kress has stupidly included characters in the URL that this forum misinterprets: http://www.kress-elektrik.com/Power-tools.71+M561855e446b.0.html?&tx_commerce_pi1[catUid]=17 )
While i am not familiar with all the brands mentioned, those that i do recognize and own, do not come anywhere near Kress quality. The models i linked are quite popular in CNC circles as spindles for mini mills for wood and aluminium, as well as PCB work - drilling, isolation routing, v-grooving etc etc. High quality collets are available for all popular shaft diameters making a Kress a good allround tool. If only it could do 60 000 rpm as well...

we have a kress drill here at home the thing is more then 20 years old and the only problem of this the bearing and the shaft is resonating a bit, you cant make nice holes with this anymore, but apart from this its running fine with original brushes. it wasnt treated gently during its life.


as for the dremels these are intented for hobby/modelling work right? how can it contain any plastic parts for the internals? at those speeds just waiting to an accident...
for the 4k series dremel tools anyone used 1 of it, does it different from the others or just a "new" look and a stronger motor?

[saturation]

Wow.  I've never heard of this tool, but its schematic and the support provided by the linked website suggests this is the best one so far listed, based on specs listed below.  Now that's a rotary tool with all the features I've idealized:

handheld field usable
The power and reliability of old style brushed universal motors, direct drive
self resetting electronics protecting it from overheating and overloading while providing variable control
isolation of the electronics for protection against dust and dirt
higher precision

Alas, a quick google shows one reason we don't hear much of it here is its primarily an EU/UK product. 


Pricewise for USA, it competes with the Foredom, which has a similar reputation for reliability, albeit its not
transportable given its mounting style and size.

http://www.ebay.com/itm/Kress-1050-FME-Milling-Grinding-Spindle-CNC-Router-10-year-warranty-/310393277059#vi-content

Well, since the question included the word _quality_, my vote has to go to Kress. (please copy the link into your browser; Kress has stupidly included characters in the URL that this forum misinterprets: http://www.kress-elektrik.com/Power-tools.71+M561855e446b.0.html?&tx_commerce_pi1[catUid]=17 )
While i am not familiar with all the brands mentioned, those that i do recognize and own, do not come anywhere near Kress quality. The models i linked are quite popular in CNC circles as spindles for mini mills for wood and aluminium, as well as PCB work - drilling, isolation routing, v-grooving etc etc. High quality collets are available for all popular shaft diameters making a Kress a good allround tool. If only it could do 60 000 rpm as well...

[saturation]

I've added Kress to the poll list. 

With age bearings and motor to wear, its vital to have spares as wear is expected, but they have to be far cheaper than buying a new tool.

I've dissected and owned Dremels for some time, and the plastic casing is fairly durable, but its not a precision device.  The bearing mounts will wear with use, so it maybe good for limited precision work when new, but not as it ages, but it won't wear to the point its useless as a general purpose handheld grinder/drill.

FWIW, Dremel plastic housings in the 100, 200, 300 series have proven durability simply because its unchanged from a design of 20 years ago [called multipro, a rehashed 1980s mototool], using the same material.  The original cases were metal back in the 1940s. 

The newer tools, 4000 & 3000, still have to prove themselves, but the material looks to be of similar composite as the 100 series.

The 3000 is just a rehoused 300.

The 4000 is a "new" and in my eyes still unproven but the reviews on Amazon are very good, 3+ or less star review account for less than 5% of total responders, compared to 25% with Proxxon. 

The electronics now include feedback control to maintain rotational speed, but how well it works under load has not been tested well, reviews suggest it works but rapidly overheats when overloaded.  The  overload protection is just a fuse, it blows, the unit dies, unlike the Kress design which allows feedback to the motor to reduce output until the overload is resolved.  The Dremel electronics are not sealed, and also exposed to the inside housing,  thus it can get fouled and shorted by metal debris.  It is also larger, I cannot hold it like a pen as the Dremel 100 series, so they sell an accessory so you can grip it better 

I think the 4000 addresses complaints of users that fled to the Black and Decker RTX series tool.  Basically, its used as an electric handheld die grinder.  But unlike pneumatic die grinders, air keeps the unit cool and pushes out dirt, whereas the electric grinders suck in air, and thus suck in dust caused by grinding; it causes a lot of premature unit failures if its not protected from dust.

I personally do not use such tools for home repair routinely.  It mainly in my bench to cut PCBs, casings, etc., in support of electronics. The small 100 series works better and is a tested design, and can do double duty for occasional home repairs.

we have a kress drill here at home the thing is more then 20 years old and the only problem of this the bearing and the shaft is resonating a bit, you cant make nice holes with this anymore, but apart from this its running fine with original brushes. it wasnt treated gently during its life.


as for the dremels these are intented for hobby/modelling work right? how can it contain any plastic parts for the internals? at those speeds just waiting to an accident...
for the does it different from the others or just a "new" look and a stronger motor?

[saturation]

Thanks for checking, I was about to do this later this week.  The Amazon reviews rate it 4 stars, but bring up the issues you raised too, mainly noise, then more vibration under load, and battery life.    It sounds like some motors are not well balanced, and bearing mounts have too much free play.

Those problems plague all rotary tools but you can get some from the cheapos like Harbor Freight that are well done.  I think it shows quality control for low cost tools cannot be slackened, because such a small difference in bearing mount clearances, straightness of shafts or accessories, collets etc., can make a big difference at difference speeds.  Rotor balancing is another, if its not done correctly as found in quality tools, it won't do at all even for cheap tools.

Went to home depot to try out the Milwaukee unit I mentioned previously in the thread.  Very disappointing, with nothing in the collet it has that sick resonating sound at all speeds. It may be gear noise but it even feels bad in the hand. The spindle can be flexed laterally at least .020" in the housing with mild pressure. I could not find a position where the "ergonomic shape" at the nose could be held pencil style.  I am sure the motor and electronics will hold up in typical Milwaukee style but I think this is a total FAIL!

[siliconmix]

my old no brand name  tool just packed in  .so just bought a dremel 300 ..it's ok but i do find it a little heavy 480g .

[robrenz]

I've added Kress to the poll list. 

I don't think the Kress items are in the "dremel style" range. I think they fit into the rotozip, mini router or die grinder category.  I think of dremel style as something you can hold pencil style reasonably well.  I think latest versions shown in your history photo are departing from that comfortable pencil style like the 398 I have and is shown in that list.  Just my 2 cents.

[siliconmix]

like a pencil .mine weighs half a kilo

[saturation]

You are right, robrenz, but it also has options for a flexible shaft, making it more like the Foredom, which clearly one cannot work with without the shaft.  A price for heavy duty use and higher precision cuts is greater bulk it seems, but at least the Kress can be hand carried, all 3-4 lbs of it!

I found this dissection of the Proxxon Micromot and a Dremel clone used as mill.  Not many side by side discussions on the net.

http://reprap.org/wiki/Milling_and_Drilling_Head#Inspiration_for_Own_Designs

 

I've added Kress to the poll list. 

I don't think the Kress items are in the "dremel style" range. I think they fit into the rotozip, mini router or die grinder category.  I think of dremel style as something you can hold pencil style reasonably well.  I think latest versions shown in your history photo are departing from that comfortable pencil style like the 398 I have and is shown in that list.  Just my 2 cents.

[Dawn]

Over the years, I've seen several flexible shaft accessories added to dremel-like tools, even the motor shaft of a Pace soldering/desoldering rework station. None even came close to the suppleness of a real, jewelry grade flexible shaft. Most of the add-ons are very stiff or fight with you at every move. There's no comparison either to a real handchuck. These tools are in a class by themselves, but like mentioned above, they aren't multipurpose tools. Back in the 80's, Dremel sold a flex shaft attachment as part of a desktop workstation that was a round carousel that held the bits with a pivot mount to hold the motor in the center and a collet style handpiece. It was near impossible to work with with mounted on the round tray or hung because of the rigid shaft. Maybe the current ones are much better. Nothing like a smooth foot lever to control the speed either.

[robrenz]

I have often considered using a brushless inrunner helicopter motor and its corresponding controller to do a awesome high power mini die grinder/ bore grinder using an ER8 collet milling extension as the spindle shaft. I would use a preloaded ball sleeve bearing at the nose to keep the diameter small and a preloaded angular contact pair at the back to control the axial motion. My real job is designing and building high precision spindles. Material costs would be about $300.00 so not a real practical thing but it might still happen.

[nukie]

rob, have a look at this, I have a earlier version made out of ceramic bearing spindle and it has amazing precision.

http://www.ebay.ca/itm/All-New-1-8-12V-TB-650-Package-Deal-CNC-Router-Spindle-/170877195518?pt=LH_DefaultDomain_0&hash=item27c91314fe#ht_2047wt_1396

It works very well with R/C brushless motor. It actually heats up after while even when it's doing nothing due to the bearings, it's ceramic so heat don't really expand it so it stays precise.

I have this model

[robrenz]

Very nice video.  He's not making much money on that spindle setup if any.

[Carrington]

Some images of the PROXXON FBS 240/E (superb machine):

[Carrington]

The Proxxon FBS240/E uses a triac and then the waveform (AC) is rectified with a diode bridge (DC).
So it is much more eficiciente than one AC motor with the same power, and is less noisy.
I've had two dremel, both burned, his AC motor only makes noise... And its design and construction compared to PROXXON is garbage.

I can't understand why Dremel and Proxxon have a matching percent in this poll.