Tool tedium

Let'sgoflying!

Let'sgoflying!

Touchdown! Greaser!
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Dave Taylor
Metallurgists, gather. I have a flycutter that worked really well til I loaned it out, now it won't cut worth a darn. After sharpening which I have done many times successfully in the past - now it dulls after a few rounds. I figure it was heated.
Till I can buy a new knife, think I can re-harden it? Heat then quench in water or?

Dremel tools. Do they make left handed dremels?
I own about 4 and every one turns.....the way that naturally blasts grit straight into your face! I can twist my arms into a pretzel and avoid this unpleasantness.....but I was wondering if they make one that turns the opposite direction? Or has a reversing switch.
 
Let'sgoflying! said:
Metallurgists, gather. I have a flycutter that worked really well til I loaned it out, now it won't cut worth a darn. After sharpening which I have done many times successfully in the past - now it dulls after a few rounds. I figure it was heated.
Till I can buy a new knife, think I can re-harden it? Heat then quench in water or?

Dremel tools. Do they make left handed dremels?
I own about 4 and every one turns.....the way that naturally blasts grit straight into your face! I can twist my arms into a pretzel and avoid this unpleasantness.....but I was wondering if they make one that turns the opposite direction? Or has a reversing switch.
Click to expand...

I'd be careful with any heat treating of your tool, if you do it wrong the tool could fracture the next time you use it (possibly embedding pieces in you). I'd also be surprised if you could recover the tool's ability to hold an edge with a simple quenching but I could be wrong on that.

As to the reversible Dremel, you might be able to easily rewire one to run backwards although the chuck would still have right hand threads. To make this kind of motor run backwards just swap the wires to the brushes or swap the two wires from the stator coil (but don't do both of those things).
 
if I rewire it backwards, I think the tip will loosen and fly off. Probably need one with reverse threaded tip holder
tks for input
 
Let'sgoflying! said:
if I rewire it backwards, I think the tip will loosen and fly off. Probably need one with reverse threaded tip holder
tks for input
Click to expand...

That's what I meant by the comment about right hand threads on the chuck. Theoretically the handedness of the chuck shouldn't matter much since the bits don't touch the part that rotates to tighten but if you run into the work with the chuck it might loosen then. The chuck itself might be threaded onto the motor shaft, I'd check for that before doing any rewiring.
 
Let'sgoflying! said:
Metallurgists, gather. I have a flycutter that worked really well til I loaned it out, now it won't cut worth a darn. After sharpening which I have done many times successfully in the past - now it dulls after a few rounds. I figure it was heated.
Till I can buy a new knife, think I can re-harden it? Heat then quench in water or?

Dremel tools. Do they make left handed dremels?
I own about 4 and every one turns.....the way that naturally blasts grit straight into your face! I can twist my arms into a pretzel and avoid this unpleasantness.....but I was wondering if they make one that turns the opposite direction? Or has a reversing switch.
Click to expand...

Make sure you temper the tool if you try this. Heat, quench in water, reheat and quench in 90 wt gear oil is what I usually do, and then test the tool on a machine that allows you to be in another room or behind a bullet proof shield when it makes its first cut. Personally, I wouldn't risk it. The reason I gave up being a machinist was a tool breaking in the middle of a process and sizzling by my ear sounding like a bullet. Since then I do only limited machining projects to limit my exposure, and I inspect my tools very closely.

I've never seen a backwards turning Dremmel, but I had a backwards turning Russian die grinder that I would use for some spots when doing porting and polishing on heads.
 
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Henning said:
Make sure you temper the tool if you try this. Heat, quench in water, reheat and quench in 90 wt gear oil
Click to expand...

Quenching isn't recommended if you're already starting with high-carbon steel.

If you're going to oil quench, use synthetic oil, otherwise you have the possibility of flash fire if you see white smoke after submerging the part.

My blacksmith turned me on to a super quench solution of 5 gals water, 5 lbs salt, 32 oz of Dawn dishwashing liquid and a bottle of jet dry. Stuff works great for hardening mild steel to Rockwell 42-43.
 
Dave,
What is your fly cutter made of? Is it HSS, carbide, or a brazed carbide tip?
 
What to quench it in depends on what kind of steel it is. Some get quenched in water, some in oil. The quench process makes it very hard and brittle. It is then put into a several hundred degree oven (350 - 450) for some time to temper it back to the desired hardness. There is data available for each type of steel for temperature to heat it to before quenching and tempering temperature and time to achieve a specific hardness, usuall somewhere around 60 on the Rockwell C scale. (from memory of a co-op student in a heat treat shop in Kansas City over 50 years ago).
 
Let'sgoflying! said:
if I rewire it backwards, I think the tip will loosen and fly off. Probably need one with reverse threaded tip holder
tks for input
Click to expand...

Beside the bits won't cut either. They are made to go in one direction.
Dave G.:blueplane:
 
Shipoke said:
Beside the bits won't cut either. They are made to go in one direction.
Dave G.:blueplane:
Click to expand...

You're correct about the metal bits and drills but the grinding bits that look like sandstone on a rod should work fine in either direction.

All fun and games aside, maybe write to the company asking for a reversible motor...some companies listen to their customers and make product changes based on feedback.
 
Most fly cuters use high speed steel or a cheap tool steel, depends on how high of a quality the tool is. My recomendation would be to heat the blade with a torch until it's an even cherry red color, then oil quench it. Then reheat with a lower flame starting at the non-cutting end. you don't want it to get red but you will start seeing a color transformation start to take place and travel towards the tip, almost a bluish color. when it reaches the tip stop and let it air-cool. Agan it depends on the type of steel but this should let it releive internal stress and still hold an edge.
 
Buy a new damned tool, before you put out your eye or something.
 
I wouldn't think that a tool that cuts FLYS would have to be hardened!!!

Are you using this FLY-cutter in a drill press or Vertical Mill? What material are you cutting? I was a tool and die maker (machinist) in my prior 13yr career and there are many different types of fly cutters. Some you would replace the toolsteel tool bit and sharpen. Others you would change the carbide tip. If you bought it at Sears you throw it away
 
dogman said:
I wouldn't think that a tool that cuts FLYS would have to be hardened!!!

Are you using this FLY-cutter in a drill press or Vertical Mill? What material are you cutting? I was a tool and die maker (machinist) in my prior 13yr career and there are many different types of fly cutters. Some you would replace the toolsteel tool bit and sharpen. Others you would change the carbide tip. If you bought it at Sears you throw it away
Click to expand...

Agreed you really need to know what type of it is and how it's used to offer real advice, I was thinking of the type used in a drill press to cut cirles out of wood.

Buy a new damned tool, before you put out your eye or something.
Click to expand...

Not knowing how to do something is no reason to be scared of it or to think that starting over is the only way to fix it. Thats why the OP asked the question, to find out his options. Yes he should be extra careful for a while if he choses to fix it. But he should be wearing safety glasses and the like anyways. It's just a s possible to get hurt when a new fly cutter comes apart as it is when a cutting bit shatters.
 
roebuck85 said:
Agreed you really need to know what type of it is and how it's used to offer real advice, I was thinking of the type used in a drill press to cut cirles out of wood.



Not knowing how to do something is no reason to be scared of it or to think that starting over is the only way to fix it. Thats why the OP asked the question, to find out his options. Yes he should be extra careful for a while if he choses to fix it. But he should be wearing safety glasses and the like anyways. It's just a s possible to get hurt when a new fly cutter comes apart as it is when a cutting bit shatters.
Click to expand...

You gotta know him. He's a real goober with tools, and he talks funny.

---

Edit:

Fair disclosure: See that avatar picture? Dave took it from his wooden wonder. He's actually not terribly likely to harm himself. Much.
 
Dave, I have to admit I first thought these
p001094hz07.jpg

when you said "fly cutter" ... from the fly-tying department at Cabela's
 
gkainz said:
Dave, I have to admit I first thought these

when you said "fly cutter" ... from the fly-tying department at Cabela's
Click to expand...

No - he is talking about the kind you chuck up in your hand drill and see how close you can come to taking off a couple fingers...
 
gismo said:
To make this kind of motor run backwards just swap the wires to the brushes or swap the two wires from the stator coil (but don't do both of those things).
Click to expand...


I assume dremel uses a standard 120v, AC motor and if this is correct then I don't think this would work. AC motors spin in the same direction even if you swap the hot and neutral (single phase motors anyway).

OTOH, three phase motors and DC motors will reverse direction when leads are swapped.
 
timwinters said:
I assume dremel uses a standard 120v, AC motor and if this is correct then I don't think this would work. AC motors spin in the same direction even if you swap the hot and neutral (single phase motors anyway).

OTOH, three phase motors and DC motors will reverse direction when leads are swapped.
Click to expand...

Dremel tools (and virtually all other AC motors with brushes) are series wound "universal" motors consisting of a stationary field winding (stator) and a rotating winding (armature) wired in series with the connection to the armature made via a "commutator" which routes the current to the armature so that the magnetic poles are about 90 degrees out of phase producing maximum torque in one direction. Reversing the connections to the commutator or stator rotates the phase 180 degrees causing the torque to reverse direction.

The "AC" motors you are thinking of are induction motors, many of which can be reversed as well but they operate quite differently.
 
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