# What the heck am I doing wrong?



## JohnnyB60 (Jun 15, 2009)

I want a ¾” wide dado in this ¾” x 2 ½” oak board. I used a ½” Spiro router bit cutting about a ¼” off at a time and the thing nearly took my arm off. 

It grabbed the board and pulled it into itself. I thought that would be small enough of a cut. I have never used a Spiro cutter before and if this is what to expect then I don’t want these anymore. :bad:

This is a photo of my piece after two passes one on each side and the router setup.


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## JohnnyB60 (Jun 15, 2009)

*Help!*

Ok I changed the bit to a broken straight bit with only one cutter which cut much smoother, but now as each cut gets deeper the dado width gets smaller. Now I would say that the router is not square in the table, but I have no idea of how to fix that. I don’t see any adjustment for that. And I no the fence is not moving because it would be the opposite I would think. So now what? :shout:


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## JohnnyB60 (Jun 15, 2009)

I checked the Router Bit for square with the table and made sure everything is tight, but I’m baffled. I guess I’m going complete it with my Table saw. At least I know that’s square.


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## Marco (Feb 21, 2009)

Johnny my guess is taking a 1/4" of oak at one time caused the first problem and the other for the uneven cut is that your material is not flat, the side to the right of the bit is lower causing the layer effect. Try again just a little at a time keeping the material flat to the table and square to the fence,


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## bobj3 (Jan 17, 2006)

Hi

The only way this could be ,if the bit is not locked it place, if it's not it will lift up in the pass..
I would suggest you use 3/4" bit and put the slot in place with a pass or two...


==


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## JohnnyB60 (Jun 15, 2009)

Marco said:


> Johnny my guess is taking a 1/4" of oak at one time caused the first problem and the other for the uneven cut is that your material is not flat, the side to the right of the bit is lower causing the layer effect. Try again just a little at a time keeping the material flat to the table and square to the fence,


Thanks Jim, I did wounder that because after the first cut I thought the piece might be bowed so I ran it through the joiner to make sure it was flat.


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## JohnnyB60 (Jun 15, 2009)

bobj3 said:


> Hi
> 
> The only way this could be ,if the bit is not locked it place, if it's not it will lift up in the pass..
> I would suggest you use 3/4" bit and put the slot in place with a pass or two...
> ...


Thanks BJ, I do admit that the router did jump down at one point on the second cut, but I checked to see if everything was tight after that. 

I just realized that I may have been going the wrong direction because I was cutting on the inside instead of the outside although I don’t think it matters on the first cut with wood on both sides of the cutter.


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## JohnnyB60 (Jun 15, 2009)

I just noticed an adjustment for the router tightness. Maybe I should try tightening this screw up in the leaver hole and see if I can clean it up with a final cut.










I have one more question; Do I need to loosen the lever each time I fine adjust for height?


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## JohnnyB60 (Jun 15, 2009)

*Problem solved!*

I took the router out of the base and cleaned it up then tighten the screw for the leaver after putting the base back on. At first I could not budge the router in the base and had to just back off the screw until it moved. I readjusted the height for the full depth and re-cut the piece. This time it came out perfectly square and I was able to assemble the piece without any problem.

Last year the router dropped right out of the base as I was cutting a dado and I figured the only explanation was that I had forgotten to lock it even though I was sure I did. So now I think it may have been loose all this time.

So thanks BJ for the sound advice! :dance3:


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## MAFoElffen (Jun 8, 2012)

Johnny-

Coming into this late but... Am I seeing that right? 

In this photo of yours, you are using a combo-square against the straight bit.:









In the upper part of that union, you can see that the nearest carbide is broken. So you are using an off-balanced broken bit?

I didn't notice it as broken in the photo before that one... Just curious if I see that right.


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## JohnnyB60 (Jun 15, 2009)

MAFoElffen said:


> Johnny-
> 
> Coming into this late but... Am I seeing that right?
> 
> ...


Yes Mike it is broken. I dropped it off my table within a few days of purchase and I just couldn't throw it away because of how much I paid for it. The only other 1/2" bit I had was that Spiro thing I used on the first pass. I never thought about the balance thing, but surprisingly it did cut pretty good with only one cuter on top. 

I've been wanting to ask if i could grind it down flat past the break, but haven't really checked it out. I need to order a new one as soon as i can because I have a few projects coming up were I will need it


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## bobj3 (Jan 17, 2006)

Hi

Just my 2 cents ,don't grind it just put it the trash can..it's the small cracks that can get you in trouble 

===


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## JohnnyB60 (Jun 15, 2009)

bobj3 said:


> Hi
> 
> Just my 2 cents ,don't grind it just put it the trash can..it's the small cracks that can get you in trouble
> 
> ===


Thanks BJ, I just ordered a new one on line, I have to say I feel a lot safer with the broken one than that Spiro bit. I still need to know what’s up with that because I may never use that one again. Could it have been the speed?


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## MEBCWD (Jan 14, 2012)

Johnny,

You did not say weather the "spiro" bit you were trying to use was an up cut or a down cut bit. If it is a down cut bit it would have a tendency to push up on the work piece when used in a router table. You need to make sure you have control over the work piece by keeping it pressed firmly against the table.

Also if the router mount was not holding the router correctly and allowing it to move around then the bit could have been jerking the router and make it hard to handle. The "spiro" bit might just cut cleanly now, just make sure you keep it push down to the table.


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## neville9999 (Jul 22, 2010)

JohnnyB60 said:


> I want a ¾” wide dado in this ¾” x 2 ½” oak board. I used a ½” Spiro router bit cutting about a ¼” off at a time and the thing nearly took my arm off.
> 
> It grabbed the board and pulled it into itself. I thought that would be small enough of a cut. I have never used a Spiro cutter before and if this is what to expect then I don’t want these anymore. :bad:
> 
> This is a photo of my piece after two passes one on each side and the router setup.


John if the cutter is grabbing the workpiece then you are going in the wrong direction, when you push in the wrong direction then the rotation of the cutter will also push it away from the fence instead of pull it into the fence and you finger board cannot hold it against the fence so you will get variation in the groove as it gets pushed away, that slightly broken cutter is out of balance but I have use a cutter with a broken tooth like that hundreds of times with out any ill effect. Of course you have to have it all tight and if anything is lose then you will get movement but if the cutter collet is tight then that movement can only be up and down, if the fence is also tight then there cannot be any side to side movement, cutter grabbing the work is always 'wrong direction' or the work piece is inside the fence and the cutter, that is that the cutter is on the opposite side if the workpiece to the fence so never work with the workpiece between the cutter and the fence as when you do that then you have to feed backwards and I never recommend that as there is no reason to do it, however the grabbing you say you got sounds like the feed is in wrong direction. set the cut shallow and test it the other way, also if the routers top bearing is shot then the router shaft may be wobbling so turn it all off and unplug it and have a look at the top bearing. NGM


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## WurliTzerwilly (Jun 9, 2013)

JohnnyB60 said:


> Thanks BJ, I do admit that the router did jump down at one point on the second cut, but I checked to see if everything was tight after that.
> 
> I just realized that I may have been going the wrong direction because I was cutting on the inside instead of the outside although I don’t think it matters on the first cut with wood on both sides of the cutter.


As you say, the first cut should not have mattered too much, but subsequent cuts on the inside were definitely taken in the wrong direction. This can be overcome by using a push block/pad and pressing quite hard on the work piece, but better to make the cut in the correct direction (L to R) in the first place.


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## JohnnyB60 (Jun 15, 2009)

MEBCWD said:


> Johnny,
> 
> You did not say weather the "spiro" bit you were trying to use was an up cut or a down cut bit. If it is a down cut bit it would have a tendency to push up on the work piece when used in a router table. You need to make sure you have control over the work piece by keeping it pressed firmly against the table.
> 
> Also if the router mount was not holding the router correctly and allowing it to move around then the bit could have been jerking the router and make it hard to handle. The "spiro" bit might just cut cleanly now, just make sure you keep it push down to the table.


Hi Mike, I bought the bit last year after breaking the straight one and I just can't remember if its up or down.
How do i know?


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## JohnnyB60 (Jun 15, 2009)

WurliTzerwilly said:


> As you say, the first cut should not have mattered too much, but subsequent cuts on the inside were definitely taken in the wrong direction. This can be overcome by using a push block/pad and pressing quite hard on the work piece, but better to make the cut in the correct direction (L to R) in the first place.


Thank you Alan, I kind of figured that but I just wasn't sure so I'm glad you replied. I did cut from the opposite direction for my final cut after I tightened up the router and it sounded much better.


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## JohnnyB60 (Jun 15, 2009)

neville9999 said:


> John if the cutter is grabbing the workpiece then you are going in the wrong direction, when you push in the wrong direction then the rotation of the cutter will also push it away from the fence instead of pull it into the fence and you finger board cannot hold it against the fence so you will get variation in the groove as it gets pushed away, that slightly broken cutter is out of balance but I have use a cutter with a broken tooth like that hundreds of times with out any ill effect. Of course you have to have it all tight and if anything is lose then you will get movement but if the cutter collet is tight then that movement can only be up and down, if the fence is also tight then there cannot be any side to side movement, cutter grabbing the work is always 'wrong direction' or the work piece is inside the fence and the cutter, that is that the cutter is on the opposite side if the workpiece to the fence so never work with the workpiece between the cutter and the fence as when you do that then you have to feed backwards and I never recommend that as there is no reason to do it, however the grabbing you say you got sounds like the feed is in wrong direction. set the cut shallow and test it the other way, also if the routers top bearing is shot then the router shaft may be wobbling so turn it all off and unplug it and have a look at the top bearing. NGM


Hi Neville, sorry I somehow missed this post, but thanks so much for replying with so much great information.


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## MAFoElffen (Jun 8, 2012)

JohnnyB60 said:


> Hi Mike, I bought the bit last year after breaking the straight one and I just can't remember if its up or down.
> How do i know?


First look at the photo of your bit and the twist...

Then look at your diagram:








As you look down at the cutter in your table, the bit turns clockwise. The twist on your bit is counter-clockwise. It is a down-cut spiral cutter. 

There are two cautions with a down-cut spiral bit. One- it is "made" to push the material away from the router as it cuts... so you have to have good control of the stock and push it down into the bit as you cut. You found out what happens if not. The second caution is that if you are using it to trench/groove/dado, that you need to ensure that you have good dust control to keep the groove clear of sawdust. If not, the packed sawdust will keep in heat around the bit.

Like I said, a down-spiral bit is designed to push into the material, so that if you are cutting material that has a laminant or veneer. it pushes that layer into the stock as it cut instead of pulling, lifting and tearing that layer. It is usually used in free-hand routing where the weight of the router helps push the two together...

Broken carbide. Carbide is very hard, but very brittle. Broken with a large piece off the tip of one side, you don't know what other cracks or fissures it has in the carbide... Will be out of balance. Spinning at 20,000 to 22,000 rpm. 1/4" shank... At the tip. May be a recipe for disaster, causing another piece to come off or breaking the shank. Have to admit, that when I was younger, was guilty of finishing up with a broke bit, which then became more broke. The shank broke, luckily didn't hit anyone... as it flew and went through a wall. No. Not smart. Not safe. Even if it doesn't break, the full cutter will finish the cut of the missing piece, but it doesn't turn out as good a quality as it could be. Some cutters only have one cutter surface or carbide, but they are balanced for that. At the tip. hard on the top bearing. If any wear in the top bearing already, will be more out.

Good decision to replace it. // Caution to others who will read this later... Most don't have a wet-stone tool grinder to keep the bit cool "while" grinding. The carbide is only brazed on. Visualization of grinding, red hot... breaking the brazed bond on the carbide cutter to the tool... loosing the carbide as it it used...//

Have to agree with Neville, in that feeding the opposite way pulls from the fence, creates a bad quality cut and is not generally safe... as along with being unsupported, then the material tends to get pulled by the bit instead of getting pushed against it as it cuts.
-----
With learning this, all on this in one project, I am really happy that you posted. I am happier that you didn't get hurt! We are here to learn and to share experience. Hopefully we can do that safely so we can enjoy what we do.


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## JohnnyB60 (Jun 15, 2009)

MAFoElffen said:


> First look at the photo of your bit and the twist...
> 
> Then look at your diagram:
> 
> ...


Thanks Mike, I need to get a sharpie and write all this stuff down right on my table so I don’t forget. 
I’m still not that proficient with a router even though I’ve had one for 30 years. I always forget which way to go and have to look it up each time. I guess it would be different if I used it all the time like my table saw, I never have to think much with that.:laugh:


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## JohnnyB60 (Jun 15, 2009)

I just found one of my other threads when the router actually fell out of the base into my cabinet and it looks like this bit was not the only one I broke. :sarcastic:

http://www.routerforums.com/general-routing/35377-how-do-i-cut-3-dia-hole-2.html


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## JohnnyB60 (Jun 15, 2009)

*Please Another Question?*

I need to make a couple of plunge dado cuts and I’m running out of bits. The only thing I have small enough right now is the ½” down-cut spiral cutter that I spoke about earlier and just want to be sure that I understand it correctly. Mike said it pushes the sawdust downward if I understand it correctly and I’m just wondering if that’s a good idea for plunge routing. 
My board is only 2” wide and 55” long but I’m only making two or three mortises and not going the whole distance. This was an afterthought and I cannot use the router table at this time because of a couple of end pieces already glued on. I’m a little worried about keeping control over the router if this thing pulls me into it with my plunge router.


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## MEBCWD (Jan 14, 2012)

Johnny you can use the downcut bit to make the plunge dado cuts.

Just remember to keep your hand held router pushed down and under control while making the cut, it will have a tendency to push the router up from the work.

Make sure you use a fence or guide on your router.


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## JohnnyB60 (Jun 15, 2009)

MEBCWD said:


> Johnny you can use the downcut bit to make the plunge dado cuts.
> 
> Just remember to keep your hand held router pushed down and under control while making the cut, it will have a tendency to push the router up from the work.
> 
> Make sure you use a fence or guide on your router.


Thanks Mike, I'm going to do a practice run before i tempt it and have a fence on both sides just to see how it fells.


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## MEBCWD (Jan 14, 2012)

Sounds good! 

Practice is always good. Even with my years of woodworking I will make test cut for new situations.


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## JohnnyB60 (Jun 15, 2009)

*I've decided I never use the Spiro Bit again*

I guess I’m just not getting it with the Spiro Router bit. I tried to make a simple rabbet cut today ant it just chattered, jumped and just made a really bad cut. 

I give up on it for good because it not only damages the wood, but it tearing up my router. I ordered a new ½” straight bit last weekend and everything went as smooth as pie after changing to it, So the Spiro is done and I’ll never buy or recommend another.


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## harrysin (Jan 15, 2007)

Just a couple of points, this is a good example of why I advocate the use of PLUNGE routers, they are quick to adjust and can't fall out of the table. Second, I can't see any means that you used to keep downward pressure on the wood, a GRR-Ripper is perfect for this purpose.
As an aside, years ago I had a big Bosch router under the table and it took me a while to figure out why my joints suddenly became imperfect, it turned out that there was slight play in the pillars of the new router and when pressure was applied the bit tilted slightly backwards. I fitted shims to tilt it a fraction forward so that applied pressure sent the bit vertical. It didn't take me long to replace the Bosch for a Makita and then A Triton.


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## WurliTzerwilly (Jun 9, 2013)

harrysin said:


> Just a couple of points, this is a good example of why I advocate the use of PLUNGE routers, they are quick to adjust and can't fall out of the table. Second, I can't see any means that you used to keep downward pressure on the wood, a GRR-Ripper is perfect for this purpose.
> As an aside, years ago I had a big Bosch router under the table and it took me a while to figure out why my joints suddenly became imperfect, it turned out that there was slight play in the pillars of the new router and when pressure was applied the bit tilted slightly backwards. I fitted shims to tilt it a fraction forward so that applied pressure sent the bit vertical. It didn't take me long to replace the Bosch for a Makita and then A Triton.


I agree about the Grrr-Ripper. I just cut some raised panel door frames and I didn't feel especially safe using a push-block and push stick, so decided to try out the Grrr-Ripper. Easy to setup and no chance of the workpiece getting away from me. It will now be my preferred method for raised panel frames.

Speaking of Triton, I've been trying to get a price for their TTS1400 plunge saw, but there doesn't seem to be a dealer in the UK that has one in stock. Even the Triton website doesn't show much of it, although their catalog has it. My local supplier was supposed to call me back last week and did not, so I don't think much of them either. Does anyone know how the Triton plunge saw might compare in price to (say) the Bosch or Sheppach?


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## JohnnyB60 (Jun 15, 2009)

harrysin said:


> Just a couple of points, this is a good example of why I advocate the use of PLUNGE routers, they are quick to adjust and can't fall out of the table. Second, I can't see any means that you used to keep downward pressure on the wood, a GRR-Ripper is perfect for this purpose.
> As an aside, years ago I had a big Bosch router under the table and it took me a while to figure out why my joints suddenly became imperfect, it turned out that there was slight play in the pillars of the new router and when pressure was applied the bit tilted slightly backwards. I fitted shims to tilt it a fraction forward so that applied pressure sent the bit vertical. It didn't take me long to replace the Bosch for a Makita and then A Triton.


Thanks Harry, I did remember the advice on this thread to use a lot of downward force so I used one of these Push Blocks and I was practically on top of the table. I’m starting to suspect that there may be something wrong with the bit itself. 









Anyway I ordered some plunge router bits and I’m just going to use them from now on, because this Spiro doesn’t even cut a smooth edge. My table saw does a better job than this in half the time.
Now I haven’t tried to use it yet in my plunge router and maybe I should at least try before getting rid of it.


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