From: Joe and Cass Leone <leone@xxxxxxxx> Date: June 28, 2009 11:10:23 PM EDT To: Vern Smith <jevern@xxxxxxx> Subject: Re: [Harp-L] Re: tuning reeds...motors
On Jun 28, 2009, at 5:33 PM, Vern Smith wrote:
Even if you can control the speed, a Dremel motor is inconveniently large and heavy for tuning. DC nail filing spindles are, IMO, better.
A Dremel 'type' tool (I have a Craftsman) weighs about a pound and has a cord that winds up under your forearm, over your forearm, around your forearm. It also has .142 hp when figured using the voltage/amperage formulae. That's about 1/7th hp. I dunno, if you extrapolate a horse at 1050 lbs, that means the tool is about equiv to a 150 pound goat. I think it's a little large for the job.
The manicurists tool is 5 ozs, has no cord, and at .042 hp is around equiv to a 31 lb wombat. That should be plenty of power.
Most Dremel motors have a little dial on the side for controlling speed (5000-30,000 rpm) so that a separate speed control may not be necessary.
Notice that there is no way to get the tool BELOW a certain speed. This is because all motors have a 'tickling current' requirement. You need to put in enough current to get the armature to activate. THEN, once it is running smoothly, you can dial back the power a little bit. But once you reach a certain point, the armature will again cease to activate. These motors are high speed and so have a ratio of 1 to 6. Most motors won;t want to run at less than 1/3rd their designed top speed. It's the way they were designed and wound.
If I were determined to use a Dremel motor, I would get a Dremel flexible shaft that has a small-diameter and light-weight handpiece. However, the stiffness of a drive cable is a minor inconvenience.
Woodcarvers are fond of the hand fixtures. As are dentists. Now if I were to have a use for one of these tools other than harmonica, I would certainly have one..and I do, but if the writer doesn't already have this tool, there really is no justification to buy one JUST to do reed work.
An induction motor's speed depends on the line frequency and not the applied voltage. Without special starting features, they cannot deliver enough torque to start under load.
Right, so some have capacitors. Most motors won't start even without a load at less than 1/3 their power requisite. Example: A 1 hp motor requires 746 watts to run. But it needs more like 1120 watts to tickle it to life. THEN, it will scroll back. But, cut it back to 250 watts, and it will likely stop. Especially if any load at all is applied. You can test this by grabbing the shaft while holding a heavy rag.
Thus any motor that can run faster than 1800 rpm almost certainly has a commutator (brushes) to switch the currents faster than 60 Hz. Commutator motors can be slowed down by reducing the applied voltage. I cannot imagine a Dremel tool with an induction motor.
Right, single speed motors are designed for 1750 rpm no load. double speed at 3500. I cannot imagine a high speed motor with induction motor windings.
Certain motors have solid-state commutators that function as brushes. These are better because the solid state commutators don't wear as do brushes. High speed appliances and tools that use commutators include vacuum cleaners, blenders, Dremel tools, and almost all plug-in hand tools.
Most larger power tools are around 10.5 amps (1.625 hp). Drills are more like 3.2-4.8 amps (.5 to .75 hp)
I have used a 2KW light dimmer to slow down a vacuum cleaner to use as an air pump for vibrating harmonica reeds. A 200 watt light dimmer should work for a Dremel (1.15A x 115V = 132 watts) Modern light dimmers reduce the voltage by altering the wave form. At low speeds, a dimmer-slowed motor's speed will be highly variable with load. That is, you will set a speed but the tool will slow down a lot as you start to grind. A better, but much more expensive, alternative is a variable transformer ("Variac").
Right, and when using a battery or plug in low voltage tool, an HO gage train transformer works well.
smo-joe
Vern
----- Original Message ----- From: "Dane Paul" <Monsterharp@xxxxxxxxxxx>
To: "Michael Easton" <diachrome@xxxxxxxxxxx>; <harp-l@xxxxxxxxxx>
Sent: Sunday, June 28, 2009 1:16 PM
Subject: Re: [Harp-L] Re: tuning reeds
I have concacted Dremel...............they said if you use a non inductive
Dremel (the one with the brushes) you can use a reostat to slow your speed
down. I had an old sewing machine pedal which I repurposed for the dremel.
You can also use a ceiling fan speed switch, or a high amperage light switch
switch to make a desktop version.......KNOW YOUR AMPERAGE
Although I have made both, there is switches avalible through woodcraft and
other companies to acheive the same result. AGAIN MAKE SURE AMPERAGE IS
COMPATIBLE
DISCLAMER....................................
DONT ELECTR-O-CUTE YOURSELF IF YOUR NOT FAMILLIAR WITH ELECTRIC ........DONT<<<<<<(no not yelling just being enphatic)
----- Original Message ----- From: "Michael Easton" <diachrome@xxxxxxxxxxx>
To: <harp-l@xxxxxxxxxx>
Sent: Saturday, June 27, 2009 6:52 AM
Subject: [Harp-L] Re: tuning reeds
Vern is correct about Dremels but there is a way to tame the beast. I use a multi speed Dremel and even on the lowest setting it is too strong.
I've been using 'hand pieces" at work for over 30 years and the key to using them correctly is learning how to control the speed for the task at hand.
Since I don't have a grand to blow on the type I use at my day job I improvised. Anyone that already owns a Dremel can do this as well. I purchased one of
those outlets for use with Christmas trees that allow you to turn the lights on and off without crawling under the tree to get to the wall outlet.
They have a big red button on them that you control with your foot. I attached my Dremel to that and can press it down enough with my foot without clicking it on.
This way I can create a pulse to get the dremel working but not enough to bring it up to full speed. I pump the foot switch while working the reed never allowing it to
go to full speed. What you are doing is working on the reed when the spindle is decelerating rather then revving up.
Good tool stores carry on/off foot pedals. Try to get one that allows you to turn it on momentary rather then having to click it on every time. That way it will be easier to pump the switch. The only time I actually leave it on is when I'm retuning the reed to another note.
Coast to Coast use to sell Brownies. If they don't carry them contact me offlist. One Brownie should last you for years if you only use it on reeds.
I use them in combination with files and sanding wands.
On Jun 26, 2009, at 11:10 PM, harp-l-request@xxxxxxxxxx wrote:
Hello,
Any recommendations for tools for tuning reeds and where to get them. I like the idea of a dremel like rotary tool and the shofu brownee attachment. But don´t know specific model numbers or places to purchase them. Any advice on those or any better methods greatly appreciated.
Thanks! Rich
Michael Easton www.harmonicarepair.com
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