How to keep a 1/4" shank 1/2" dovetail bit from climbing out of collet?

Thu, Feb 5, 2004, 2:14am (EST+5) [email protected] (Bay=A0Area=A0Dave)
asks:
<snip> How can I prevent this from happening in the future? <snip>

Hi Homer. I used to have that happen with my 1/4" shanks, when I
first started using a router. If they were bottomed, didn't matter how
hard I cranked them down, still moved. I started bottoming the bits,
then raising them about 1/16" to 1/8", tightening them, and viola, no
more prob. This is with the router in my table, that's the only way I
use a router.

JOAT
It's what you learn after you know it all that counts.
- Pete Maccarrone

Life just ain't life without good music. - JOAT
Web Page Update 4 Feb 2004.
Some tunes I like.
http://community-2.webtv.net/Jakofalltrades/SOMETUNESILIKE/

thank you spell checker (and my inattention): "collect" should be "collet"

Bay Area Dave wrote:

I remember tightening that sucker up in my 7518.
> I wiped out the collect with a Q-tip to remove any oil residue,

"Bay Area Dave" wrote in message
> I spoke to Charlie today who warned me about the tendency of a dovetail
> bit to climb out of the collet. Sure as hell, as prophesized, as I was
> cutting the final two pieces, I noticed AFTER the cuts that the bit had
> come out about a 1/4"! I remember tightening that sucker up in my 7518.
> I wiped out the collect with a Q-tip to remove any oil residue, of
> which there appeared to be some. And of course I wiped the shank of the
> bit with a rag. Can't think of any other preventative measures.
>
> How can I prevent this from happening in the future? The CMT bit is
> available only in a 1/4" shank. It's a 10 degree 1/2" for use with the
> Incra jig for 1/2" material and through dovetails. All my other
> dovetail bits are 1/2" shank.

Generally you would expect to see this if someone had seated the bit too
deeply in the collet before being tightening, It is not always the case, but
is a good point to be aware of. Besides, a clean collet, it is a good
practice to back the bit out of the collet an 1/8" or so before tightening.

I had this happen a couple of weeks back with a straight cut bit when
dadoing drawer sides for a bottom panel. Strangely enough, I have never
experienced it on any other router but my 7518, and that twice in the last
year or so, both times with a 1/4" collet... once is too many, however, and
I am anal about properly installing router bits so I know that was not the
problem in these instances.

In any event, all the more reason to take safety precautions and use push
blocks, even when doing blind cuts where the blade is not exposed.

--
www.e-woodshop.net
Last update: 1/31/04

Ditto here. Had the same bit climb out a 7518 in my router table. Same
job - dovetails using the Incra router fence. I couldn't stop it no matter
how tight I clamped that sucker in there.

I switched to my Keller jig with a Keller bit in my Milwaukee Bodygrip. No
problem.

Bob


"Bay Area Dave" <[email protected]> wrote in message
news:[email protected]...
> I spoke to Charlie today who warned me about the tendency of a dovetail
> bit to climb out of the collet. Sure as hell, as prophesized, as I was
> cutting the final two pieces, I noticed AFTER the cuts that the bit had
> come out about a 1/4"! I remember tightening that sucker up in my 7518.
> I wiped out the collect with a Q-tip to remove any oil residue, of
> which there appeared to be some. And of course I wiped the shank of the
> bit with a rag. Can't think of any other preventative measures.
>
> How can I prevent this from happening in the future? The CMT bit is
> available only in a 1/4" shank. It's a 10 degree 1/2" for use with the
> Incra jig for 1/2" material and through dovetails. All my other
> dovetail bits are 1/2" shank.
>
> dave
>

Hi Dave,

I use the same router (PC 7518) and have the same router lift as you (PRL),
I believe. I also have used plenty of 1/4" shank router bits in my router
table with this set-up, as well as dovetail bits (these were actually 8 mm
shank, using a 8 mm shank collet, not the adapter thingie).

Anyway, the best and only defense for not letting the bit move, other than
what you did already by cleaning the collet and bit shaft, is to really
torque down on the collet when you tighten it. You may have heard the term
"handshake tight". In practice, this means you tighten the collet down as
much as you can without needing a lot of force, and then position the two
wrenches so you can grasp them in one hand and then squeeze them together to
tighten. In my opinion, this isn't always tight enough. For dovetail bits,
I do this twice - handshake tight once, then set the wrenches apart and do
it again. Admittedly, this get's the git VERY tight and will take effort
to get the bit out. BUT, I've never had a bit slip EVER. I'm sure some
will say I'm wearing my collet out prematurely, but I'd rather have to buy
another $25 collet in a few years, than have a bit slip and screw up a
piece, or possibly throw a 22,000 rpm piece of carbide at my face.

So, my advice - TIGHTEN THAT BIT REALLY HARD!

Mike
"Bay Area Dave" <[email protected]> wrote in message
news:[email protected]...
> I spoke to Charlie today who warned me about the tendency of a dovetail
> bit to climb out of the collet. Sure as hell, as prophesized, as I was
> cutting the final two pieces, I noticed AFTER the cuts that the bit had
> come out about a 1/4"! I remember tightening that sucker up in my 7518.
> I wiped out the collect with a Q-tip to remove any oil residue, of
> which there appeared to be some. And of course I wiped the shank of the
> bit with a rag. Can't think of any other preventative measures.
>
> How can I prevent this from happening in the future? The CMT bit is
> available only in a 1/4" shank. It's a 10 degree 1/2" for use with the
> Incra jig for 1/2" material and through dovetails. All my other
> dovetail bits are 1/2" shank.
>
> dave
>

thanks Jim, I just checked the speed; it was set to 19K. I'll also feed
it slower. Hadn't thought of using a straight bit first, and that
sounds like good way to reduce the pressure on the wimpy 1/4" shanked
bit for the final dovetail cut.

dave

Jim Wilson wrote:

> Bay Area Dave wrote...
>
>
>>How can I prevent this from happening in the future?
>
>
> Might not be entirely preventable. Make sure there are no burrs in the
> collet or on the tool shank. You can try removing most of the waste with
> a straight bit. Go slow, but keep the RPM's up. Check for climb-out
> between cuts.
>
> That's about all I can think of at the moment.
>
> Jim

Bay Area Dave wrote...

> How can I prevent this from happening in the future?

Might not be entirely preventable. Make sure there are no burrs in the
collet or on the tool shank. You can try removing most of the waste with
a straight bit. Go slow, but keep the RPM's up. Check for climb-out
between cuts.

That's about all I can think of at the moment.

Jim

"Bay Area Dave" wrote in message
> thanks Jim, I just checked the speed; it was set to 19K. I'll also feed
> it slower. Hadn't thought of using a straight bit first, and that
> sounds like good way to reduce the pressure on the wimpy 1/4" shanked
> bit for the final dovetail cut.

Another suggestion ... find a used PC 690 for your dovetail jigs and bits.
Just the right size and power for the job. I picked up a refurbished 690 at
Porter Cable's outlet store here in Houston for less than $80 a couple of
years ago ... after all, one can't have too many routers. AAMOF, I keep a
dovetail bit more or less permanently mounted in a 690 for my Leigh jig.

--
www.e-woodshop.net
Last update: 1/31/04

Howdy, T. I never ever let a bit bottom. I think I just didn't crank
HARD on the wrenches. Tomorrow I'll either succeed or consider doing
dovetails with different equipment. I did quite a few dovetails before
without this problem so I think it's due to the 1/4" shank.

For all the time I messed around with power equipment a REAL woodworker
could have cut dovetails by hand for several projects! oh well,
tomorrow's another day...

dave

T. wrote:

> Thu, Feb 5, 2004, 2:14am (EST+5) [email protected] (Bay Area Dave)
> asks:
> <snip> How can I prevent this from happening in the future? <snip>
>
> Hi Homer. I used to have that happen with my 1/4" shanks, when I
> first started using a router. If they were bottomed, didn't matter how
> hard I cranked them down, still moved. I started bottoming the bits,
> then raising them about 1/16" to 1/8", tightening them, and viola, no
> more prob. This is with the router in my table, that's the only way I
> use a router.
>
> JOAT
> It's what you learn after you know it all that counts.
> - Pete Maccarrone
>
> Life just ain't life without good music. - JOAT
> Web Page Update 4 Feb 2004.
> Some tunes I like.
> http://community-2.webtv.net/Jakofalltrades/SOMETUNESILIKE/
>

Try to wipe your collet and bit shank with some lacquer thinner then crank
it down Dave. Works for me, but I don't have the same router as you do. Hope
it works.
"Bay Area Dave" <[email protected]> wrote in message
news:[email protected]...
> I spoke to Charlie today who warned me about the tendency of a dovetail
> bit to climb out of the collet. Sure as hell, as prophesized, as I was
> cutting the final two pieces, I noticed AFTER the cuts that the bit had
> come out about a 1/4"! I remember tightening that sucker up in my 7518.
> I wiped out the collect with a Q-tip to remove any oil residue, of
> which there appeared to be some. And of course I wiped the shank of the
> bit with a rag. Can't think of any other preventative measures.
>
> How can I prevent this from happening in the future? The CMT bit is
> available only in a 1/4" shank. It's a 10 degree 1/2" for use with the
> Incra jig for 1/2" material and through dovetails. All my other
> dovetail bits are 1/2" shank.
>
> dave
>

Well, Mike, in preparation for tomorrow when I TRY to redo the project
(essentially from scratch), I torqued the living daylights out of the
collet. I couldn't get it any tighter than I did tonight. Usually, I
just tighten it snugly, like I do the TS blades. If tomorrow ends up
like today, want to buy a bunch of tools cheap?? ( I didn't mention yet
what ELSE went wrong today in the shop... <g>)

dave

Mike in Mystic wrote:

> Hi Dave,
>
> I use the same router (PC 7518) and have the same router lift as you (PRL),
> I believe. I also have used plenty of 1/4" shank router bits in my router
> table with this set-up, as well as dovetail bits (these were actually 8 mm
> shank, using a 8 mm shank collet, not the adapter thingie).
>
> Anyway, the best and only defense for not letting the bit move, other than
> what you did already by cleaning the collet and bit shaft, is to really
> torque down on the collet when you tighten it. You may have heard the term
> "handshake tight". In practice, this means you tighten the collet down as
> much as you can without needing a lot of force, and then position the two
> wrenches so you can grasp them in one hand and then squeeze them together to
> tighten. In my opinion, this isn't always tight enough. For dovetail bits,
> I do this twice - handshake tight once, then set the wrenches apart and do
> it again. Admittedly, this get's the git VERY tight and will take effort
> to get the bit out. BUT, I've never had a bit slip EVER. I'm sure some
> will say I'm wearing my collet out prematurely, but I'd rather have to buy
> another $25 collet in a few years, than have a bit slip and screw up a
> piece, or possibly throw a 22,000 rpm piece of carbide at my face.
>
> So, my advice - TIGHTEN THAT BIT REALLY HARD!
>
> Mike
> "Bay Area Dave" <[email protected]> wrote in message
> news:[email protected]...
>
>>I spoke to Charlie today who warned me about the tendency of a dovetail
>>bit to climb out of the collet. Sure as hell, as prophesized, as I was
>>cutting the final two pieces, I noticed AFTER the cuts that the bit had
>>come out about a 1/4"! I remember tightening that sucker up in my 7518.
>> I wiped out the collect with a Q-tip to remove any oil residue, of
>>which there appeared to be some. And of course I wiped the shank of the
>>bit with a rag. Can't think of any other preventative measures.
>>
>>How can I prevent this from happening in the future? The CMT bit is
>>available only in a 1/4" shank. It's a 10 degree 1/2" for use with the
>>Incra jig for 1/2" material and through dovetails. All my other
>>dovetail bits are 1/2" shank.
>>
>>dave
>>
>
>
>

FOW wrote:
> Try to wipe your collet and bit shank with some lacquer thinner then crank
> it down Dave. Works for me, but I don't have the same router as you do. Hope
> it works.


The easiest and best way to get rid of oil residue that I know is brake cleaner
spray, available from any auto parts store. It'll be absolutely bone dry after
that.



--
Mortimer Schnerd, RN

[email protected]
http://www.mortimerschnerd.com

good point; I used to use that as a mechanic. fabulous degreaser.

dave

Mortimer Schnerd, RN wrote:

> FOW wrote:
>
>>Try to wipe your collet and bit shank with some lacquer thinner then crank
>>it down Dave. Works for me, but I don't have the same router as you do. Hope
>>it works.
>
>
>
> The easiest and best way to get rid of oil residue that I know is brake cleaner
> spray, available from any auto parts store. It'll be absolutely bone dry after
> that.
>
>
>

The weird thing was that Charlie mentioned the possibility of this
happening to a dovetail bit, due to it's geometry. About an hour after
discussing it, my first bit to "lose it's grip" was a dovetail! I must
confess I didn't reef on it; I've been just "snugging" the collets. No
more of that! I also hadn't checked for oil residue in the collet before...

At least these kinds of mishaps are the kinds you never forget.

dave

Swingman wrote:

> "Bay Area Dave" wrote in message
>
>>I spoke to Charlie today who warned me about the tendency of a dovetail
>>bit to climb out of the collet. Sure as hell, as prophesized, as I was
>>cutting the final two pieces, I noticed AFTER the cuts that the bit had
>>come out about a 1/4"! I remember tightening that sucker up in my 7518.
>> I wiped out the collect with a Q-tip to remove any oil residue, of
>>which there appeared to be some. And of course I wiped the shank of the
>>bit with a rag. Can't think of any other preventative measures.
>>
>>How can I prevent this from happening in the future? The CMT bit is
>>available only in a 1/4" shank. It's a 10 degree 1/2" for use with the
>>Incra jig for 1/2" material and through dovetails. All my other
>>dovetail bits are 1/2" shank.
>
>
> Generally you would expect to see this if someone had seated the bit too
> deeply in the collet before being tightening, It is not always the case, but
> is a good point to be aware of. Besides, a clean collet, it is a good
> practice to back the bit out of the collet an 1/8" or so before tightening.
>
> I had this happen a couple of weeks back with a straight cut bit when
> dadoing drawer sides for a bottom panel. Strangely enough, I have never
> experienced it on any other router but my 7518, and that twice in the last
> year or so, both times with a 1/4" collet... once is too many, however, and
> I am anal about properly installing router bits so I know that was not the
> problem in these instances.
>
> In any event, all the more reason to take safety precautions and use push
> blocks, even when doing blind cuts where the blade is not exposed.
>

Hey, how you doing?? I'll give it a try. When I woke up this morning I
started thinking about that loose bit again and wondered if I should use
a solvent to get ALL traces of oil off. I'll follow your suggestion
this morning. Thanks!

How's everything going? I got a new email and don't think I gave it to
you yet: dave1812dave1234 "at" yahoo "dot" com

unlike hotmail, this email service works! :)

remove ONLY "1234"

dave

FOW wrote:

> Try to wipe your collet and bit shank with some lacquer thinner then crank
> it down Dave. Works for me, but I don't have the same router as you do. Hope
> it works.
> "Bay Area Dave" <[email protected]> wrote in message
> news:[email protected]...
>
>>I spoke to Charlie today who warned me about the tendency of a dovetail
>>bit to climb out of the collet. Sure as hell, as prophesized, as I was
>>cutting the final two pieces, I noticed AFTER the cuts that the bit had
>>come out about a 1/4"! I remember tightening that sucker up in my 7518.
>> I wiped out the collect with a Q-tip to remove any oil residue, of
>>which there appeared to be some. And of course I wiped the shank of the
>>bit with a rag. Can't think of any other preventative measures.
>>
>>How can I prevent this from happening in the future? The CMT bit is
>>available only in a 1/4" shank. It's a 10 degree 1/2" for use with the
>>Incra jig for 1/2" material and through dovetails. All my other
>>dovetail bits are 1/2" shank.
>>
>>dave
>>
>
>
>