Micro Motor vs Air Turbine

Beathard

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I have a GRS 850 that gets lots if use. I have one friend that has an NSK micromotor and another with a Foredom micromotor. They keep trying to get me to switch or add the micromotor.

I'm interested in what others think about the micromotor vs the 850. Is there enough difference to justify the cost? If yes, what is the selling point?
 

monk

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air turbines should be used with a very good coalescing filter. else wise, the moisture can ruin the unit. don't dare ask how i know, but be assured i found out the expensive way. seems to me the micro motors are fatter and somewhat heavier.
my air turbine unit is about the size of a sharpie pen. no load speed-- around 400k rpm. it cuts at a very slow rate compared to a micro motor. but can be far more forgiving if a skip should happen.
 

Tira

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I second the forgiving thing by Monk. If your hand misses slightly with the fast turbine hand piece the metal is erased. This works very well for the background removal, etc., but if you miss it usually isn't pretty. With the slower micromotors the "slip" would not be as complete.

I like the micromotors because the burs do not wear out nearly as fast. Not as much heat builds up due to the slower speed. I have even had luck on titanium where the burrs last a lot longer. Just a factor and it depends on how you like to work.
 

GTJC460

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The aforementioned benefits are all true. I will continue on with one other benefit.

The micro motor is actuated by a foot pedal. The 850 runs continuously. If the bur grabs and tries to skid out of control the 850 keeps running at full bore. Your natural instinct with a foot pedal will be to let off and stop the spinning.

So realistically there are multiple advantages of a micro motor over an 850 for background removal.
 

diandwill

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On the other side...First, all the things said before are probably 100% right and true, but, on the otherhand...you already have the 850 and use it well. If you don't need to throw another $400+ after another tool, don't.

When the 850 dies, try the microtool and make the change then, or not.

Just my 25 cents (inflation) worth.
 

Skylineski

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I have a SCM air turbine and it runs on a variable speed foot pedal and i can slow it way down by not pushing as hard on the pedal. if you want the control you could incorporate a foot pedal into your 850 for around $80 and it would counteract all the before mentioned problems and you can still run it at high speed when you need to. just a thought.

Doug
 

Aurifex

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I use a Saeshin Oz Black for jewellery work and stone setting. You can use foot pedal or just the hand piece by control of the main unit. Also forward and reverse direction. Hardly use a flex shaft now. 1 to 50K speed. Sorry not tried air turbine. Hope this helps.
 

Big-Un

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I have one of the cheap Russian dental drills and it has been working fine for several years now. My air pressure to the drill is not so great that it turns at its maximum, but it's fast enough for me and I think any faster and I might cause serious damage to the engraving should I slip. Concentration is paramount with any tool running that fast.

Bill
 

Sam

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For me it's a question of feedback provided by the handpiece. The 850 is so bloody fast that you can't feel the cutting action. The metal just disappears. The NSK is slower and you can feel its grinding action, and you can grind and shape metal with it. I have both but use the NSK on my and my student's benches.
 

LVVP

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I have both and I am using 850 or NSK depends on situation, but love both of them
 

scott99

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Hi, I use both a 40,000 rpm micro motor ands a 400,000 rpm SCM. I find both have their uses but the super high speed air driven SCM seems to disitagrate material rather than cut it, in some cases this can be disconcerting. I find the 40,000 rpm micro motor gives a bit more control an still leaves a good finish.


scott99
 

bram ramon

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I don't use it but i know for these high speed pencil air grinders like the nsk the smallest carbide bur is 0.5mm for me that's big.. While those who have a 2.35mm shank you can buy carbide burs starting at 0.2mm. I use them in my flex shaft and buy Komet burs good quality for a good price!
 

tim halloran

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Betahard: I use an old Fordam ultra high speed hand piece and I have no trouble with it .If you know how to use it ,it's the best thing you can use if you want to move a lot of metal fast. Sam has an excellent DVD on jewelry engraving which gives you a good tutorial on how to use one . I think he touches on it in his other video engraving scroll work start to finish. I think that the best thing a budding engraver can do is take a class with an experienced engraver, or at least buy some of the videos available today. Steve Lindsay has over 11 hours of free videos available on his webb site. Sam also has them available on his site also. There are also a lot of them on U-Tube. As far as the size of the one sixteenth shank burrs, GRS has some that go down to .020" and Gesswien also has them. As far as the cost of the burrs you have to weigh how much time you spend on the job, as time is money, so you need to calculate the cost of the burs into the job. Ann the old adage is, nothing lasts for ever. Also you can hand grind burrs down really small to get into really tight places.
 

Sam

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There was a NSK complete set on eBay recently that went for around $700. I would have bought if I hadn't recently gotten a second one.
 
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