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Marvel

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20 minutes ago, Edgar said:

 

Maybe they've gone up significantly in price. I haven't had to buy any in a while.

Well it seemed like it if it's replaced when it gets dull, also with so many already I hated to buy a new one. On wood they last a good while on metal not as much of a life span at all.

 

Never had a sharpener before, it's the reason I had so many dull drills bits. 

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37 minutes ago, Edgar said:

You know, my father left me a whole drawer full of high-speed steel bits when he died ... every last one of them too dull to even drill cream cheese. Maybe one of those sharpeners might be a good idea after all.

I'll bet your father's bits are made of better material than most of the new ones.

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1 hour ago, dtel said:

On wood they last a good while on metal not as much of a life span at all.

You might already know, but...for those who don't know, and wants to know about what speed to drill into mild steel:

 

N = 12 * V / Pi * D

Where

N = desired RPM
V = Velocity in feet per minute
Pi = 3.141592....
D = Diameter (of either the drill bit, mill cutter, work piece chucked in the lathe, etc)

HSS = ~  72 fpm (cutting into mild steel that is not so thin that it can't carry the heat away (Ex: sheet metal) 
Carbide can safely stand 3x that speed

EX: What speed to turn for machining mild steel using 1/2" HSS bit (0.500")?
N = 12 * 72 / 3.14 * .5
N = 550 RPM

^^^^^^^Now, don't worry about remembering ANY of that ^^^^^^^^^^
Put in your pocket that 1/2" HSS bit (0.500") can, generally, turn 500 RPM in mild steel (.500 = 500)
Doubling the diameter, drop the RPM in half (Ex: 1" bit = 250 RPM, 2" = 125 RPM, etc...)
Double the RPM for what's half the diameter (Ex: 1/4" bit = 1,000 RPM, 1/8" = 2,000 RPM, etc...)
 

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18 minutes ago, Woofers and Tweeters said:

HSS = ~  72 fpm (cutting into mild steel that is not so thin that it can't carry the heat away (Ex: sheet metal) 
Carbide can safely stand 3x that speed

 

Is that with or without coolant? I always use light oil when drilling steel.

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4 minutes ago, Edgar said:

 

Is that with or without coolant? I always use light oil when drilling steel.

without

Types of coolant, chip load, different metals, etc changes everything... sometime small changes, sometimes large changes. Most don't need to know much more than the easy rule of 500 = 500 because it's easy to use for whatever size...3/8, 3/4, etc

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2 hours ago, Edgar said:

You know, my father left me a whole drawer full of high-speed steel bits when he died ... every last one of them too dull to even drill cream cheese. Maybe one of those sharpeners might be a good idea after all.

That's exactly how I ended up with so many, but when I went to use one I would pick out 3 the same size hoping to get one to work. The sharpener works quick adjust the bit in the holder, put in machine and spin until it stops making a sharpening/ grinding sound, less than 30 seconds, just a guess, probably way less.

 

1 hour ago, Woofers and Tweeters said:

You might already know

NO I didn't, I knew there was proper speed but had no idea what it was or how to figure it out. 

 

Probably why my drill press has 4 different pulleys....duh, I left it where my dad had it 

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48 minutes ago, DizRotus said:

He might be one of those blind persons who uses echo location.

 

I'd like to say he probably just uses his stick to find his way around. There is the long one for walking and a smaller one for up close use. He may also have some limited vision. My ex without her corrective lenses she was certified blind. With her glasses on she could read a license plate out on the highway when I could not even see if there was a front plate on the car at all and back then I had just better than 20/20 vision. Just happy for the guy in that photo being able to enjoy his limited vision.

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