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Jason Magruder

Jason Magruder

Joined
Mar 27, 2004
Messages
570
When you are using those little sanding bands in your foredom or dremel GO SLOW If you spin it fast you will just knock the grit off of it. I was trying to shape some titanium last night and I went through 3 of them using my normal full speed cutting method. I tried going really slow like 1000-2000 rpm and the thing not only lasted about 10 times as long but it removed material alot faster too. I then trid it on steel and carbon fiber with the same results. fast wore it out and burned stuff and slowjust kept on cutting and cutting faster and cleaner too.
 
I have found the same thing with the mini cut off wheels

It made me really mad because i couldnt figure out why it was hapining
 
As a jeweler,I can attest that "faster ain't always better" .When any glued or bonded grit product is used at a high speed,the resulting heat breaks the bond and the grit flies off.The same applies to rubber bonded wheels like cratex,they will disintegrate at high speed.1000-2000 is a good speed for most.
 
Good thoughts gentlemen. The first I heard of this phenomon was from
Bob Loveless in his video. Finer grits work much bette and longer at slower speeds, this was my first hint at the desirable aspects of the variable speed grinders.
 
I guess I'll have to get a variable speed Dremel. Mine has only one speed FAST :D I've found the bands do wear out right quick.
Scott
 
A hardware store lamp dimmer will vary the speed of series-wound ( brush) motors. Wire one up in a little box and you can use it on shop-vacs and other brush motored gadgets
 
Go to the thrift store and find an old used sewing machine. Buy a busted one that has a foot pedal reostat. With a little creative wiring you can make a foot operated speed control for your dremel or any other small motorized hand tool.
So easy you wouldn't believe it!
Some thrift stores have bins full fo transformers, patch cords, and often these foot pedals get chunked in there. They can usually be had for a couple of bucks.
Beats a fan/light reostat all to heck and will handle the amperage load just fine.
Great for "pulse drilling" stone and glass with diamond bits and water.
CREX
 
Guys, don't try the old rheostat trick on even small AC motors. They are designed to pull a constant 110 Volts ( unless there is something I don't know about the Dremel)

if you decrease the voltage, it will call for a corresponding increase in amperage to balance the operating wattage. The windings are not designed for that and will die at an early age.

Get a speed controller. They only cost a couple bucks at HF and reduce the speed by changing the frequency of the AC.
 
Don't know Pete, I've been running a fixed speed dremel with a flex shaft attachment off the old Singer foot pedal control for close to 6 years. I'm not what you'd call a light user either. I use it just about eveyday in the shop for something even if it's not knife or lapidary related.

I agree on the light reostat not being good but the foot pedal control is made for heavy use on a sewing machine motor (not much different from a dremel, just a little more power and torque). The thing allows me to run the fixed speed dremel from 0 to top end quite smoothly with no apparent loss in torque, which is very important in lapidary work.

CRx
 
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