Wn

"Wayne"

15/08/2005 8:13 AM

Hit brass with router bit ... is it ruined?

I am attempting to build a router table extension to my table saw. Due to a
measuring error while trimming the edge of the tabel with a 1/2 x 1" carbide
straight cut, I clipped the side off of a couple of 1/4 " brass threaded
insert screws. The bit more or less milled the brass level with the side.
There was a bit of a metalic hot smell and the bit and brass were quite warm
to the touch.

On inspection I can see nothing wrong with the router bit. There is no
discoloration from burning, no chips, and the edge feels smooth and sharp.
The project does not even seem to be ruined.

I know brass is softer than carbide, but its sure harder than wood. Is the
bit OK? Should I try touching up the carbide edge on the inside with a
diamond hone?

Wayne in Boulder CO


This topic has 15 replies

OL

"Owen Lawrence"

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 9:16 PM

"Upscale" <[email protected]> wrote in message
news:[email protected]...
> "Owen Lawrence" <[email protected]> wrote in message
>> In both cases sparks flew, but in neither case was there any difference
>> to
>> the cutting power of the bit or blade. Carbide is tough! YMMV.
>
> It's hard yes and maintains its sharpness, but it is prone to shattering
> on
> sudden impact.

Oh, man! Now you've got me wondering exactly what "sudden impact" could
possibly mean. At 20k RPM I would think almost everything happens suddenly.
:) Let's do some arithmetic: We're talking 333 RPS. Suppose I'm moving at
one inch/sec, with two blades on the bit, that's about one and a half thou
per nibble. I don't know how fast the thing really turns when it's
cutting, so let's say it goes 10k (a low estimate judging from the change in
musical pitch); that's still only 3 thou at a time.

But point well taken. I certainly wasn't happy about hitting metal with my
router bits, and except for screw ups (no pun intended) I avoid it.
Nevertheless, I don't worry so much about it when it happens. I'm glad I've
never had a carbide anything shatter.

- Owen -

MD

"Morris Dovey"

in reply to "Wayne" on 15/08/2005 8:13 AM

16/08/2005 5:13 AM

David (in [email protected]) said:

| When you want a REAL thrill, hit a steel plate with a 10" carbide
| tipped blade in a TS! I never did find the 24 carbide blade tips,
| but I sure heard them hitting the inside of the saw, the pavement,
| etc! Luckily none decided to head my way.

In the aircraft factory next door to my shop they use a miter saw for
cutting aluminum. One of the new guys tried chopping some chrome moly
steel tubing with it and stripped off all 80 teeth. I got a look at
the remains of the blade and a handful of the teeth; and saw that all
of the breaks were in the steel disk - the carbide teeth (and the
carbide-to-steel bonds) were undamaged. The teeth were still sharp and
none that I saw were chipped.

Solid carbide router bits bear a remarkable resemblence to the carbide
end mills commonly used to machine steel, brass, aluminum, etc (the
most common configuration is a spiral up-cut) and I regularly buy end
mills for use in my CNC router because they're often less expensive
and are available in more sizes than router bits.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html

SP

"Steve Peterson"

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 2:34 PM

You can machine brass with good tools, like carbide. Especially if you
can't see any damage, there probably isn't there. Of course, it almost
never hurts to hone your bits.

Steve

"Wayne" <[email protected]> wrote in message
news:[email protected]...
>I am attempting to build a router table extension to my table saw. Due to a
>measuring error while trimming the edge of the tabel with a 1/2 x 1"
>carbide straight cut, I clipped the side off of a couple of 1/4 " brass
>threaded insert screws. The bit more or less milled the brass level with
>the side. There was a bit of a metalic hot smell and the bit and brass were
>quite warm to the touch.
>
> On inspection I can see nothing wrong with the router bit. There is no
> discoloration from burning, no chips, and the edge feels smooth and sharp.
> The project does not even seem to be ruined.
>
> I know brass is softer than carbide, but its sure harder than wood. Is the
> bit OK? Should I try touching up the carbide edge on the inside with a
> diamond hone?
>
> Wayne in Boulder CO
>

Pg

Patriarch

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 3:38 PM

"Wayne" <[email protected]> wrote in
news:[email protected]:

> I am attempting to build a router table extension to my table saw. Due
> to a measuring error while trimming the edge of the tabel with a 1/2 x
> 1" carbide straight cut, I clipped the side off of a couple of 1/4 "
> brass threaded insert screws. The bit more or less milled the brass
> level with the side. There was a bit of a metalic hot smell and the
> bit and brass were quite warm to the touch.
>
> On inspection I can see nothing wrong with the router bit. There is no
> discoloration from burning, no chips, and the edge feels smooth and
> sharp. The project does not even seem to be ruined.
>
> I know brass is softer than carbide, but its sure harder than wood. Is
> the bit OK? Should I try touching up the carbide edge on the inside
> with a diamond hone?
>
> Wayne in Boulder CO
>
>

So how much would it cost to replace this bit, and forget worrying about
it?

Patriarch

Pg

Patriarch

in reply to "Wayne" on 15/08/2005 8:13 AM

16/08/2005 12:07 AM

David <[email protected]> wrote in
news:[email protected]:

<snip>
>> So how much would it cost to replace this bit, and forget worrying
>> about it?
>>
>> Patriarch
> You and I both know his bit is fine so why put doubts in his mind? If
> he had any remaining doubts all he needs to do is USE the bit and see
> that it cuts properly and requires no more effort to cut with than it
> did before the non-event of milling some brass.
>
> Dave
>

His bit MAY be fine, or maybe not. I can't tell from here. The question
was more one of economics: How much money is it worth to put the question
to rest? Is it a $15 blue wonder from Rockler, or an expensive spiral
cutter from a leading industrial supplier?

He had the doubts, made a post asking a question, without any prompting
from me.

Patriarch,
with reasonable certainty regarding a few things, none of which involve
spinning metal at 20k+ rpm...

Uu

"Upscale"

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 9:30 PM

"Owen Lawrence" <[email protected]> wrote in message
>
> Oh, man! Now you've got me wondering exactly what "sudden impact" could
> possibly mean. At 20k RPM I would think almost everything happens
suddenly.

The carbide on router bits can break when they're accidentally dropped on
the floor. That's the type of sudden impact that I had in mind. Carbide is
extremely hard in one respect, but it has some weaknesses in other respects.

MD

"Morris Dovey"

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 9:34 AM

Wayne (in [email protected]) said:

| I am attempting to build a router table extension to my table saw.
| Due to a measuring error while trimming the edge of the tabel with
| a 1/2 x 1" carbide straight cut, I clipped the side off of a couple
| of 1/4 " brass threaded insert screws. The bit more or less milled
| the brass level with the side. There was a bit of a metalic hot
| smell and the bit and brass were quite warm to the touch.
|
| On inspection I can see nothing wrong with the router bit. There is
| no discoloration from burning, no chips, and the edge feels smooth
| and sharp. The project does not even seem to be ruined.
|
| I know brass is softer than carbide, but its sure harder than wood.
| Is the bit OK? Should I try touching up the carbide edge on the
| inside with a diamond hone?

Probably a good idea to check the bit with a magnifying lens. A touch
up with an extra fine hone probably wouldn't hurt.

Next time slow the router and use coolant. Don't forget safety
glasses. :-)

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html

Uu

"Upscale"

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 5:21 PM

"Owen Lawrence" <[email protected]> wrote in message
> In both cases sparks flew, but in neither case was there any difference to
> the cutting power of the bit or blade. Carbide is tough! YMMV.

It's hard yes and maintains its sharpness, but it is prone to shattering on
sudden impact.

JT

John T

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 10:38 AM

About the only thing I'd look for is any chips in the carbide. The
carbide is WAY harder than the fairly soft brass. I don't think you'll
have a problem.

John

OL

"Owen Lawrence"

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 4:00 PM

>I am attempting to build a router table extension to my table saw. Due to a
>measuring error while trimming the edge of the tabel with a 1/2 x 1"
>carbide straight cut, I clipped the side off of a couple of 1/4 " brass
>threaded insert screws. The bit more or less milled the brass level with
>the side. There was a bit of a metalic hot smell and the bit and brass were
>quite warm to the touch.
>
> On inspection I can see nothing wrong with the router bit. There is no
> discoloration from burning, no chips, and the edge feels smooth and sharp.
> The project does not even seem to be ruined.
>
> I know brass is softer than carbide, but its sure harder than wood. Is the
> bit OK? Should I try touching up the carbide edge on the inside with a
> diamond hone?

I did the same sort of thing building my router table. I was routing for
the fence T-slot and ran into a steel hinge screw. I have no concern about
the bit since it's clear that it "cut" the screw, rather than mashed it.
The same thing happened once or twice on the table saw when I hit a nail.
The nail was just as long as it was when I started, but only half as wide.
In both cases sparks flew, but in neither case was there any difference to
the cutting power of the bit or blade. Carbide is tough! YMMV.

- Owen -

Wn

"Wayne"

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 7:58 PM

Thanks to everyone for the replies. The valium goes back on the shelf! :-)

Back to work on the table. I will post a picture when its done.

Wayne

"David" <[email protected]> wrote in message
news:[email protected]...
> Wayne wrote:
>
>> I am attempting to build a router table extension to my table saw. Due to
>> a measuring error while trimming the edge of the tabel with a 1/2 x 1"
>> carbide straight cut, I clipped the side off of a couple of 1/4 " brass
>> threaded insert screws. The bit more or less milled the brass level with
>> the side. There was a bit of a metalic hot smell and the bit and brass
>> were quite warm to the touch.
>>
>> On inspection I can see nothing wrong with the router bit. There is no
>> discoloration from burning, no chips, and the edge feels smooth and
>> sharp. The project does not even seem to be ruined.
>>
>> I know brass is softer than carbide, but its sure harder than wood. Is
>> the bit OK? Should I try touching up the carbide edge on the inside with
>> a diamond hone?
>>
>> Wayne in Boulder CO
> Not to worry, Wayne. Your bit is fine judging from the soft metal you
> said it encountered and your visual inspection bears that out.
>
> Dave

On

Obfuscated

in reply to "Wayne" on 15/08/2005 8:13 AM

20/08/2005 5:40 PM

Yes. The brass is shot. Send the router bit to me.

;-)

DD

David

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 7:10 PM

Owen Lawrence wrote:

> "Upscale" <[email protected]> wrote in message
> news:[email protected]...
>
>>"Owen Lawrence" <[email protected]> wrote in message
>>
>>>In both cases sparks flew, but in neither case was there any difference
>>>to
>>>the cutting power of the bit or blade. Carbide is tough! YMMV.
>>
>>It's hard yes and maintains its sharpness, but it is prone to shattering
>>on
>>sudden impact.
>
>
> Oh, man! Now you've got me wondering exactly what "sudden impact" could
> possibly mean. At 20k RPM I would think almost everything happens suddenly.
> :) Let's do some arithmetic: We're talking 333 RPS. Suppose I'm moving at
> one inch/sec, with two blades on the bit, that's about one and a half thou
> per nibble. I don't know how fast the thing really turns when it's
> cutting, so let's say it goes 10k (a low estimate judging from the change in
> musical pitch); that's still only 3 thou at a time.
>
> But point well taken. I certainly wasn't happy about hitting metal with my
> router bits, and except for screw ups (no pun intended) I avoid it.
> Nevertheless, I don't worry so much about it when it happens. I'm glad I've
> never had a carbide anything shatter.
>
> - Owen -
>
>
When you want a REAL thrill, hit a steel plate with a 10" carbide tipped
blade in a TS! I never did find the 24 carbide blade tips, but I sure
heard them hitting the inside of the saw, the pavement, etc! Luckily
none decided to head my way.

Dave

DD

David

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 1:41 PM

Wayne wrote:

> I am attempting to build a router table extension to my table saw. Due to a
> measuring error while trimming the edge of the tabel with a 1/2 x 1" carbide
> straight cut, I clipped the side off of a couple of 1/4 " brass threaded
> insert screws. The bit more or less milled the brass level with the side.
> There was a bit of a metalic hot smell and the bit and brass were quite warm
> to the touch.
>
> On inspection I can see nothing wrong with the router bit. There is no
> discoloration from burning, no chips, and the edge feels smooth and sharp.
> The project does not even seem to be ruined.
>
> I know brass is softer than carbide, but its sure harder than wood. Is the
> bit OK? Should I try touching up the carbide edge on the inside with a
> diamond hone?
>
> Wayne in Boulder CO
>
>
Not to worry, Wayne. Your bit is fine judging from the soft metal you
said it encountered and your visual inspection bears that out.

Dave

DD

David

in reply to "Wayne" on 15/08/2005 8:13 AM

15/08/2005 1:45 PM

Patriarch wrote:

> "Wayne" <[email protected]> wrote in
> news:[email protected]:
>
>
>>I am attempting to build a router table extension to my table saw. Due
>>to a measuring error while trimming the edge of the tabel with a 1/2 x
>>1" carbide straight cut, I clipped the side off of a couple of 1/4 "
>>brass threaded insert screws. The bit more or less milled the brass
>>level with the side. There was a bit of a metalic hot smell and the
>>bit and brass were quite warm to the touch.
>>
>>On inspection I can see nothing wrong with the router bit. There is no
>>discoloration from burning, no chips, and the edge feels smooth and
>>sharp. The project does not even seem to be ruined.
>>
>>I know brass is softer than carbide, but its sure harder than wood. Is
>>the bit OK? Should I try touching up the carbide edge on the inside
>>with a diamond hone?
>>
>>Wayne in Boulder CO
>>
>>
>
>
> So how much would it cost to replace this bit, and forget worrying about
> it?
>
> Patriarch
You and I both know his bit is fine so why put doubts in his mind? If
he had any remaining doubts all he needs to do is USE the bit and see
that it cuts properly and requires no more effort to cut with than it
did before the non-event of milling some brass.

Dave


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