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Micromotor for woodwind repairs

Because of interest in another thread I decided to start a thread about this. For a few years now I'm using a dental micromotor for woodwind repairs.

This is a laboratory dental micromotor and is what dental technicians use. It is not what dentists use inside people's mouths, which is usually a high speed (up to around 400,000RPM) or low speed (around 200,000RPM) turbine, operated by an air compressor. There are some electric ones and other micromotors such as for surgery or endodontics (according to some makers' websites) but these are also not what is (IMO) best for woodwind repairs. The higher speed of more than 50,000RPM is not useful IMO. Plus the straight angle of the lab micromotors is better for many purposes.

There are several types of tools that are used in woodwind repairs that are similar one a lot of ways. One is a Dremel, actually brand name but there are other Dremel-like tools that are the same. I think I saw a Dremel used to grind teeth of some animals in the zoo! There are flexible shaft rotary tools, also called pendant drills. I have tried all those types significantly. There are also different types of lab dental micromotors, which I have also tried. I went to a dental equipment exhibition to try a lot of different ones and choose mine.

First, how a micromotor is different from the other "similar" tools. If repairs were a Formula 1 race, then a crude comaprison would be that the micromotor is a Ferrari race car, the flexible shaft tool is a family car and the Dremel is a bus. You can still complete the course with the bus, but it will be much slower and more cumbersome. Actually maybe there are parts you couldn't manouver with the bus at all. The family car would be better but no match for the race car. A good micromotor is significantly more expensive than the others.

The most obvious difference is that with the Dremel or pendant drill, the motor isn't micro. The Dremel has a big motor on the handpiece. This makes a very inprecise tool that is awkward to use to precision work. It also (according to Dremel's website) has a speed from 5,000RPM to 35,000RPM. Some of the uses are better with slower and faster speed than that. Some of the things I wouldn't dare to use a Dremel at all, just no enough control and accuracy. AFAIK the Dremel can also have an extension to be made into a pendant drill.

The pendant drill (aka flexible shaft rotary tool) has a motor seperate from the handpiece and they are connected with the flexible shaft. This is a cable that trasmits the rotation from motor to handpiece. In comparison with a micromotor, this is the equivilent of writing with a pencil with an apple stuck at the back end of it. Really imprecise in comparison and also lack of control. These typically have a high speed of about 20,000RPM.

The micromotor has the motor in the handpiece, but it's a 'micro' motor and doesn't have the problem of the Dremel. There's also no flexible shaft in the way. So there is a much better feel, control and precision, without the resistance from the motor or cable. The cable is just a regular one connected to a PSU which for a good micromotor is sophisticated one.

There are "cheap" micromotors, these cost around $300 or a little more here. These have a brush motor, not particularly strong (both torque and power) and just overall not as good quality, feel, etc. Cosmeticians sometimes use those on people's finger nails. I would personally avoid those for woodwind repairs.

The micromotors I recommend would have:
  • Quick change collet chuck
  • Brushless motor
  • High speed of at least 35,000RPM
  • High torque of at least 7.0Ncm (sometimes given in gfcm, in comparison it is approx 710gfcm)
  • High torque in slow speeds (a reputable company should have this, high torque in fast speeds doesn't automatically mean it will be high in slow speeds)
  • High output power of about 200w
  • Foot pedal (pretty much standard)
  • Sealed motor (to prevent dirt etc. getting there)
IMO/E the high power and torque are important for the work done in woodwind repairs. The brushless and sealed are important to logevity. Overall feel is better wiuth a higher quality tool, IME of different micromotors. The quick change collet chuck is ctritical for me to change tools in a couple of seconds. A normal shuck, especially a keyed one, would be annoying when changing several different bits in a very short time, which I do constantly.

I bought one made by NSK which is Japanese. Generally German and Japanese models are considered best. Germsn (at least here) are significantly more expensive, but I haven't found they are better. Mine has a 250w output and 8.7Ncm torque, with up to 50,000RPM, which is the strongest I found. There are cheaper models made in Korea that I found are a good value. They are significantly less expensive and have close to the same specs.

Some of the things I do with the micromotor:
  • Debur (with setting bur) and sometimes polish (with rubber bur) metal tone holes
  • Thinning rims of tone holes that are too thick (reduces pressure needed to seal)
  • Doming materials glued to adjusting screws, or adjusting screws themselves
  • Cleaning with cup and round brushes
  • Clean or remove left over tenon cork etc.
  • Cleaning and removing rust from springs
  • Enlarging crack tops for filling
  • Removing extra glue
  • Shaping corks
  • Shaping pin holes
  • Grinding extra length of pinning wire
  • Modifying linkages to better shapes including all steps to final polish
  • Grinding key parts when necessary
  • Enlarging holes for materials
  • Reshaping spring cradles
  • Removing extra filling from wood tone holes etc.
  • Polishing wood
  • Fixing sticking wood joints
  • Cutting hinges with least damage if necessary.
  • Improving shape of flat springs
  • deburring flat springs
  • With small chuck holding pivot and rod screws for cleaning and/or polishing
  • Re-slotting stuck pivot and rod screws while still in a post, or stuck adjusting screws
  • Drilling new spring holes
  • Drilling holes for pinning broken tenons and sockets
  • Drilling holes for reinforcement pins when rebuilding an area
  • Putting a small nick before drilling for the drill to grip on
  • Shaping and rounding cork pads
  • Removing extra solder
  • Shaping joints for soldering
  • Buffing small parts with mini-buffs
I use between 2,000RPM to 40,000RPM to do these things. A lot of them would be possible, but significantly less convinient, slower, etc. with the Dremel or pendant drill. Some would be too big risk for me to even try, not enough control and precision. Some I consider impossible. I also think once you have the ability to do some things faster you do them more often. It can turn some work with tone hole deburring and linkage modifications from a couple of hours to a few minutes. It can save a stuck rod screw (sometimes including the screw itself) that otherwise might require alum, cutting a key, unsoldering, etc. and might only take a minute. Just to give a couple of examples.

A good micromotor is much more expensive than a Dremel or pendant drill. But I can say that it was worth it to me. My micromotor is one of my most important tools, after some basic hand tools and checking tools (screwdrivers, some pliers, feeler, leak light, etc). If it died beyond repair, I would go buy a new one.


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Thanks for all that information Nitai. I have heard both you and Gordon refer to the "micromotor" for years, but have never had a clear understanding of what that referred to. Would it be possible to provide a few links to sites where these are available to purchase?

Thanks for all that information Nitai. I have heard both you and Gordon refer to the "micromotor" for years, but have never had a clear understanding of what that referred to. Would it be possible to provide a few links to sites where these are available to purchase?
I can recommend the one I have which is NSK Ultimate 500D (D means Desktop style, taller PSU for less space on the table). I have the Torque model which is a slightly bigger but stronger handpiece/motor. I Googled and found it for example here http://www.denmedpro.com/Z_500_D_Electric_Lab_motor_Desk_Top_By_NSK__p3216.html
I think they have upgraded since then to the Ultimate XL model which is with a slightly stronger grip (you can see on NSK's website). Either type has what are critical features IMO like quick-change collet chuck, sealed motor, high torque, high output power, micro-processor and others.

I haven't found German models to be significantly better/different. They are excellent, but at least here they are a lot more expensive. So I can't recommend them much. They are a great option though if you want to buy one. I don't remember the brand names.

Some micromotors made in Korea are also good and a great value. Significantly less expensive than something like the NSK. The extra for the NSK was worth it to me, but these Korean ones are a very good option. One of the Brushless motor models with high torque.

For example Saeshin Forte100 OZ-Plus
or the Saeyang Handy700
BTW Foredom has a type which is I think was claimed ot be made in USA but looks suspiciously similar to the Korean Hany700 (maybe the hadpiece/motor itself is their own, with the PSU made elsewhere, maybe it just looks identical PSU, I don't know)
First post on here so Hi.

I know this is now a 10 year old post but this is such a useful thread and I am hoping for some advice on exacly this stuff. I do woodwind repair (including flutes but not so much Sax) and have a decent micromotor on the way. I want to do much of the stuff in @clarnibass list above. It will have 2.35 and 3mm chucks supplied.

Two questions it would be great to have guidance on from those that use Pendant / Micromotor setups:

1. Which size shaft has the best range of tools/ should I settle on (2.35 or 3mm)?
2. What are the most useful burrs/ bits/ mops etc to cover most bases. For example, what would you use for shaping corks?

Any help very much appreciated.
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