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

--- Quote from: Kremmen on July 14, 2012, 06:36:05 am ---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...

--- End quote ---
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



--- Quote from: Kremmen on July 14, 2012, 06:36:05 am ---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...

--- End quote ---
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  :o

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.



--- Quote from: M. András on July 14, 2012, 12:39:05 pm ---
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?

--- End quote ---
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.


--- Quote from: robrenz on July 14, 2012, 02:35:11 am ---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!

--- End quote ---
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