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#1
Posted to rec.woodworking
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Lesson learned...
Never use a zero-clearance insert while cutting tapers on a table saw.
Reason? The tapered offcut can wedge between the blade and the ZCI, pushing the blade into the workpiece. Makes a helluva noise, too. DAMHIKT. Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? S**t. S**t, s**t, s**t. S**T!! |
#2
Posted to rec.woodworking
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Lesson learned...
On 8/20/14, 10:32 PM, Doug Miller wrote:
Never use a zero-clearance insert while cutting tapers on a table saw. Reason? The tapered offcut can wedge between the blade and the ZCI, pushing the blade into the workpiece. Makes a helluva noise, too. DAMHIKT. Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? S**t. S**t, s**t, s**t. S**T!! Are you cutting the waste side against the fence or something? Seems to me the waste on the taper should just fall down and away from the blade. What am I missing? -- -MIKE- "Playing is not something I do at night, it's my function in life" --Elvin Jones (1927-2004) -- http://mikedrums.com ---remove "DOT" ^^^^ to reply |
#3
Posted to rec.woodworking
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Lesson learned...
-MIKE- wrote:
On 8/20/14, 10:32 PM, Doug Miller wrote: Never use a zero-clearance insert while cutting tapers on a table saw. Reason? The tapered offcut can wedge between the blade and the ZCI, pushing the blade into the workpiece. Makes a helluva noise, too. DAMHIKT. Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? S**t. S**t, s**t, s**t. S**T!! Are you cutting the waste side against the fence or something? Seems to me the waste on the taper should just fall down and away from the blade. What am I missing? It must be the possibility that the waste piece falls into the blade (and it even upended as a result). |
#4
Posted to rec.woodworking
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Lesson learned...
On Thursday, August 21, 2014 1:02:50 AM UTC-5, Bill wrote:
Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? I didn't notice it, until you mentioned it. It must be the possibility that the waste piece falls into the blade (and it even upended as a result). I guess one would have to anticipate that the sharp edged piece would fall into the narrow space. In that anticipated case, glue a scrap piece to that cutoff edge, which would prevent the problem. Somewhat similarly, scrap pieces are glued to mitered corners, to facilitate clamping, then cut off, sanded off, after the job is done |
#5
Posted to rec.woodworking
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Lesson learned...
-MIKE- wrote in :
Are you cutting the waste side against the fence or something? No, of course not. I know better than that. The fence was a good six, eight inches away. Seems to me the waste on the taper should just fall down and away from the blade. Seemed to me, too, that it should just fall down and away from the blade. And, in fact, that is exactly what happened on the first 13 tapers I cut (of 16 total). What am I missing? A "zero clearance" insert is actually zero clearance *only* at the tips of the teeth. Because a saw kerf is necessarily wider than the plate of the blade, there is a gap of some 15 or 20 thousandths of an inch between the plate and the insert everywhere except at the ends. If the tapered offcut should chance to drop straight down, the tip of it goes right into that gap -- where friction with the spinning blade pulls it in farther. |
#6
Posted to rec.woodworking
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Lesson learned...
Sonny wrote in
: On Thursday, August 21, 2014 1:02:50 AM UTC-5, Bill wrote: Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? I didn't notice it, until you mentioned it. It must be the possibility that the waste piece falls into the blade (and it even upended as a result). I guess one would have to anticipate that the sharp edged piece would fall into the narrow space. Which I clearly failed to do -- a mistake I won't make again. In that anticipated case, glue a scrap piece to that cutoff edge, which would prevent the problem. Easier to replace the zero-clearance insert with the factory insert, so that the offcuts drop all the way through. In fact, since I cut all my tapers using a sled that rides in one of the miter slots (see my post a couple years ago titled The Ultimate Taper Sled) there's no need for any insert in the saw throat at all. Might even improve dust collection. |
#7
Posted to rec.woodworking
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Lesson learned...
On 8/20/2014 10:32 PM, Doug Miller wrote:
Never use a zero-clearance insert while cutting tapers on a table saw. Reason? The tapered offcut can wedge between the blade and the ZCI, pushing the blade into the workpiece. Makes a helluva noise, too. DAMHIKT. Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? S**t. S**t, s**t, s**t. S**T!! Actually I have had that happen often even when doing normal ripping, WHEN ripping off 1/16" or less. Not using a zero clearance insert makes matters worse. Put the odd leg in the back. ;~) |
#8
Posted to rec.woodworking
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Lesson learned...
On 8/20/2014 11:40 PM, -MIKE- wrote:
On 8/20/14, 10:32 PM, Doug Miller wrote: Never use a zero-clearance insert while cutting tapers on a table saw. Reason? The tapered offcut can wedge between the blade and the ZCI, pushing the blade into the workpiece. Makes a helluva noise, too. DAMHIKT. Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? S**t. S**t, s**t, s**t. S**T!! Are you cutting the waste side against the fence or something? Seems to me the waste on the taper should just fall down and away from the blade. What am I missing? With any wood, especially case hardened or that which is not perfectly flat, the pointed end of the taper, the leading end, can bend down and wedge between the slot and the blade after being cut. |
#9
Posted to rec.woodworking
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Lesson learned...
On 8/20/2014 11:32 PM, Doug Miller wrote:
Never use a zero-clearance insert while cutting tapers on a table saw. Reason? The tapered offcut can wedge between the blade and the ZCI, pushing the blade into the workpiece. Makes a helluva noise, too. DAMHIKT. Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? S**t. S**t, s**t, s**t. S**T!! While I did not loose the finger I have a significant scar on the end of my finger from an "Oh s**t" accident, that I should have foreseen and done some thing different |
#10
Posted to rec.woodworking
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Lesson learned...
Keith Nuttle wrote in
: On 8/20/2014 11:32 PM, Doug Miller wrote: Never use a zero-clearance insert while cutting tapers on a table saw. Reason? The tapered offcut can wedge between the blade and the ZCI, pushing the blade into the workpiece. Makes a helluva noise, too. DAMHIKT. Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? S**t. S**t, s**t, s**t. S**T!! While I did not loose the finger I have a significant scar on the end of my finger from an "Oh s**t" accident, that I should have foreseen and done some thing different Ouch. Underscores the need to always think one or two steps ahead of our actions. In this case, there was no danger to any of my body parts, only the workpiece. As you might remember from a post I made a couple years ago, I cut tapers using a sled that rides in the left miter slot, so I'm standing at the left end of the saw, well out of the path of the blade. The stop blocks on the sled double as handles, so my hands don't come within half a foot of the blade. The risk of personal injury in this setup is as close to zero as any table saw operation can be. |
#11
Posted to rec.woodworking
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Lesson learned...
On 8/21/14, 7:49 AM, Doug Miller wrote:
-MIKE- wrote in : Are you cutting the waste side against the fence or something? No, of course not. I know better than that. The fence was a good six, eight inches away. Seems to me the waste on the taper should just fall down and away from the blade. Seemed to me, too, that it should just fall down and away from the blade. And, in fact, that is exactly what happened on the first 13 tapers I cut (of 16 total). What am I missing? A "zero clearance" insert is actually zero clearance *only* at the tips of the teeth. Because a saw kerf is necessarily wider than the plate of the blade, there is a gap of some 15 or 20 thousandths of an inch between the plate and the insert everywhere except at the ends. If the tapered offcut should chance to drop straight down, the tip of it goes right into that gap -- where friction with the spinning blade pulls it in farther. Ok, I'm picturing that fine and understand what you're describing. I guess what I'm having trouble picturing is how that wedge can fall into the blade when it's still connected to the longer stock. I know that tension in many woods can make for some really strange movement in freshly cut wood. I can see where the cut off sliver might start to bow down into the ZCI slot. But wouldn't that sliver then catch the front of the slot and stop the stock from moving any further forward? Or is that exactly what happened, only after the damamge was done? -- -MIKE- "Playing is not something I do at night, it's my function in life" --Elvin Jones (1927-2004) -- http://mikedrums.com ---remove "DOT" ^^^^ to reply |
#12
Posted to rec.woodworking
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Lesson learned...
On 8/21/14, 8:13 AM, Leon wrote:
On 8/20/2014 11:40 PM, -MIKE- wrote: On 8/20/14, 10:32 PM, Doug Miller wrote: Never use a zero-clearance insert while cutting tapers on a table saw. Reason? The tapered offcut can wedge between the blade and the ZCI, pushing the blade into the workpiece. Makes a helluva noise, too. DAMHIKT. Think anybody will notice that one of the four legs on an end table is about 1/16" narrower than the other three? S**t. S**t, s**t, s**t. S**T!! Are you cutting the waste side against the fence or something? Seems to me the waste on the taper should just fall down and away from the blade. What am I missing? With any wood, especially case hardened or that which is not perfectly flat, the pointed end of the taper, the leading end, can bend down and wedge between the slot and the blade after being cut. After thinking about it some more, that's what I thought might have happened. Especially after he said he had cut a bunch of them with no problem. -- -MIKE- "Playing is not something I do at night, it's my function in life" --Elvin Jones (1927-2004) -- http://mikedrums.com ---remove "DOT" ^^^^ to reply |
#13
Posted to rec.woodworking
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Lesson learned...
On Thu, 21 Aug 2014 08:13:57 -0500, Leon wrote:
With any wood, especially case hardened or that which is not perfectly flat, the pointed end of the taper, the leading end, can bend down and wedge between the slot and the blade after being cut. Seems like lately most wood I buy is either case hardened or the reverse thereof. The bean counters strike again? |
#14
Posted to rec.woodworking
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Lesson learned...
-MIKE- wrote in :
Ok, I'm picturing that fine and understand what you're describing. I guess what I'm having trouble picturing is how that wedge can fall into the blade when it's still connected to the longer stock. I cut tapers with the blade entering the stock at the end and exiting on the side. I've found that cutting the other way, entering on the side and exiting at the end, can produce some deflection of the blade at entry. |
#15
Posted to rec.woodworking
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Lesson learned...
On 8/23/14, 12:12 PM, Doug Miller wrote:
-MIKE- wrote in : Ok, I'm picturing that fine and understand what you're describing. I guess what I'm having trouble picturing is how that wedge can fall into the blade when it's still connected to the longer stock. I cut tapers with the blade entering the stock at the end and exiting on the side. I've found that cutting the other way, entering on the side and exiting at the end, can produce some deflection of the blade at entry. Good point! When tapering table legs I always need to square up the top of the taper with a hand plane. Only problem I see is most of the leg would be hanging off the saw table before the cut begins (nothing a longer jig wouldn't cure) -BR --- news://freenews.netfront.net/ - complaints: --- |
#16
Posted to rec.woodworking
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Lesson learned...
Brewster wrote in
: On 8/23/14, 12:12 PM, Doug Miller wrote: -MIKE- wrote in : Ok, I'm picturing that fine and understand what you're describing. I guess what I'm having trouble picturing is how that wedge can fall into the blade when it's still connected to the longer stock. I cut tapers with the blade entering the stock at the end and exiting on the side. I've found that cutting the other way, entering on the side and exiting at the end, can produce some deflection of the blade at entry. Good point! When tapering table legs I always need to square up the top of the taper with a hand plane. Only problem I see is most of the leg would be hanging off the saw table before the cut begins (nothing a longer jig wouldn't cure) My jig is about a meter long. |
#17
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Lesson learned...
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#18
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Lesson learned...
On Mon, 25 Aug 2014 16:09:24 -0400, "Mike Marlow"
wrote: Doug Miller wrote: My jig is about a meter long. Bragger... Beat me to it. ;-) |
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