This is my first post here. Please excuse my bad English, this is not my primary language.
For this Christmas I want to give me a gift for the shop: a high speed grinder.
I have make a lot of search and reading on the subject as much as possible and despite this, I still have
difficulty to choosing the righttool for my needs and especially for my bank account (I look for something
not mutch expensive than 500$, it is the maximum which my wife authorizes me)
I work mostly on mammoth ivory and mammoth bone, I already have two flex shaft Foredom with H30
handpiece but I look for something to make more detailed work and also something less heavy and tiring
because of my wrist problems. (I find that the flexshaft give a lot of vibration (harming details) and has
tendency to draw and brings resistance in movements)
According to my search, here some facts or myth about air turbine vs micromotors and some important
questions for me. Please give me your advice...
Noise (My workshop is in the basement, below the room of my daughter)
- Air turbines seem to make more noise (Is it like dentist air turbine ??).
I have also to add the compressor noise… (how long could I run a small air turbine
without starting my 25 gallons shop compressor?)
Hand behavior and freedom
-I never Used Turbine or micromotor, but the turbine seem interesting because
they seem smaller in hand and the air feed tube seems very flexible giving more
freedom and beying less heavy on the wrist… The only experiment that I have with
something like micro motor is with a dremel and I do not like this (too heavy and
lack of control)… I imagine that a real micromotor it is better?
Cutting ability and burs
- Micromotors are a lot powerfull and can use bigger shaft bits (this is not a real issue
for me because I use Foredom for the big work)
- Air turbine accept only 1/16 burs (not a problem when you have a dentist friend
- Air turbine have much less toque. (It is a real problem to work especially on details ?)
- Air turbine seem to give more clean or smooth cut with 350 000 to 400 000 rpm while
micromotors have only (?) something like 35 000 - 45 000 rpm (it is enought ?)
Does this difference in speed make a real difference ?
Roughness
-Several people say that air turbines is more fragile and more often to break.
The replacement turbine price is rather high.
Foot control
- Many air turbine come with foot control (on-off or a variable pressure foot control).
- Many micromotors accept footswith but was not sold with.
I really appreciate the possibility to control speeds with the foot. And I imagine that
decreases the air consumption for a air turbine...
Price
- Micromotors seem to be more expensive. Air turbine seem to be more accessible (but not realy if
you consider the compressor price and turbine replacement).
- With my 500$ budget I think I am in the lower range micromotor, but I can buy mid/hight
range GRS 850 or NSK Presto air turbine.
Did I forget something?
Your advice will be largely appreciated
Alain

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