Help, please: Problem with handpiece rotary nsk presto

Dani Girl

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Hey everyone. Does anyone know what's wrong with my handpiece? It's an NSK presto (refer photo)... and over the last couple of days it's been not feeling quite right, sounds like it's slowing down and speeding up without me applying drag by removing background.

Today I took it apart and did a maintainence job as per the instructions on here.

http://www.treelineusa.com/learn-how-to-maintain-an-nsk-presto-engraving-tool.html

Then I went back into the shed and plugged it back into the air. Ran it for like thirty seconds in it's stand upright and then it stopped spinning. I had to wind the air right up to thirty psi before it started spinning. It usually works down to like 15 or 10psi.

I am worried.
 

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Dani Girl

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One of the things I noticed is that without any reason i seemed to be feeling more air than usual blowing back onto my hand which would normally have been blowing through the handpiece to make the tool spin. Probably part of it...
 

Gemsetterchris

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Sounds like a leak in the air hose?
Either It's worked loose or has a hole somewhere..check that first.
 
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Barry Lee Hands

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When mine has done that, i replace the entire turbine, and it fixes it. I would say they last around 200 hours.
 

rodsta

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I have this similar problem and bought the new turbine which helped a little but didn't fix it. I've looked for a detailed blow up of the housing to see what could be the problem but have not come up with anything. As you apply air it speeds up to speed but if you turn the air up a bit more it fades on speed and you can back it off and it will climb but nothing consistent. I'm hoping someone has some info on this also.
Rod
 

Dani Girl

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Moisture.... Hmmm... I did mention to my electrical engineer father that something was wrong with it and he stick the back.end in his mouth and blew before I could say nooooo.
 

Dave London

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Do you have a foot control, or running it straight off the regulator. Is it still under warranty . For most air tools clean dry air is required. Good luck
 

Dani Girl

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My handpiece is set up just like the picture... with the filter and the switch. It has another filter between it and the compressor though because I split the air between it and my palm control.

I didn't realize any cleaning was necessary... I've just always been careful to clean the bur before I slipped it in the chuck. I thought it was a sealed system.

There are no leaks in the air hose which could have explained the issue... but close inspection of the airhose shows some tiny rust like spots on the inside of the air hose. Odd.
 

Eugene Carkoski

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Rusty spots inside the air hose could indicate water from the compressor tank, make sure your tank is drained every couple of weeks. This is for both safety and to prevent water getting in your system.
 

monk

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could it be the regulator ? they will sometimes give one fits. is yours the one that came with the hand piece ? as mentioned, dark spots in the hose is a sign something's gone astray. i've got compressors from a jun-air all the way to a giant 7.5hp w 80 gallon tank. the big one "eats" cheap harbor freight regulators. have had it for 10 years or so. it's now on the fifth replacement regulator. the cheap regulators are ( at least for me) difficult to fine-tune the pressure settings.
cheap diaphragm compressors usually have no problem with oil. they can deliver erratic pressure if the tank is not drained as a routine procedure. if gunk builds in the tank, some can go out to cause problems. the filters should be cleaned to make sure the air flow is unobstructed. if washed in petroleum based solvents, wash again a few times with 91% isopropyl. allow to completely dry before re-installing.
 

DDBright

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Aug 3, 2012
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See if you have a dental hand piece repair technician in your area. (ask your Dentist) They are experts at diagnosing and repairing this type of equipment. I have one about 2 miles from my house.

David
 

RDP

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Danae, the easiest way of finding out if is an air problem or a turbine problem is to unscrew the turbine off, and run air to the hand piece the normal way,( as a precaution keep your thumb on the opening, there is a small O ring there that you don't want flying any where), if you are getting a constant air flow through it then the problem most likely is with the turbine, if you hold the black plastic little fan with your fingers, the nozzle should spin around freely, from your description it sounds like it could still have some dirt in it that may be slowing it down, my suggestion is to carefully clean it again, and see what happens, good luck,

Richard.
 

Dani Girl

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Rdp

Thanks Richard.

Took you advice. Looks like the bearing's not in top shape. Without the front end on the tool sounds fine.

The place i bought it from says $100 to fix it...

Or $150 for a new turbine.

Does anyone know of dental handpiece repairers in Australia?

Danae.
 

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