# Upcut or Downcut for Box Joint? Bran Name?



## RJM (Apr 11, 2010)

I made a version of the jig shown below but I need a better bit. I'm thinking I want a spiral downcut but I want to make sure before I buy it.

Also, I found this bit at Amazon but I don't know if this is a good quality bit: Onsrud Down-Cut Spiral Bit

Any advice would be appreciated. Thanks.

Box joint jig:


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## bobj3 (Jan 17, 2006)

Hi Bob

That bit will work fine but you don't need to use a high end spiral bit a normal bit will do the job just fine because you are not plunging the bit into the stock just a strait clean pass into it..


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RJM60 said:


> I made a version of the jig shown below but I need a better bit. I'm thinking I want a spiral downcut but I want to make sure before I buy it.
> 
> Also, I found this bit at Amazon but I don't know if this is a good quality bit: Onsrud Down-Cut Spiral Bit
> 
> ...


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## RJM (Apr 11, 2010)

Right now, I only have some cheap bits. They're okay but (for various reasons) I want to start buying bits specific to current projects; however, I don't want to skimp if it will make a difference.

I do some plunge cuts and I want to try making box joints in plywood. I also think a spiral bit would be a little easier to setup but if a straight Katana, MLCS, or other brand name bit will give me better results (especially in plywood) then I'll upgrade to a better straight bit.

Does any of this change your answer?


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## jschaben (Jun 21, 2009)

RJM60 said:


> I made a version of the jig shown below but I need a better bit. I'm thinking I want a spiral downcut but I want to make sure before I buy it.
> 
> Also, I found this bit at Amazon but I don't know if this is a good quality bit: Onsrud Down-Cut Spiral Bit
> 
> ...


Well, dunno about the box joints,,, but I think that's kinda pricey for a HSS bit. Also, I personally prefer an upcut bit unless it is a through cut, just helps get the chips out. 
Here's a pretty decent bit for the $$:
cripedistributing.com : BOSCH 85913M 3/8" x 1-1 1/4" Up Spiral Router Bit [85913m] - $14.00
I would stick with carbide whenever possible.


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## RJM (Apr 11, 2010)

jschaben said:


> Well, dunno about the box joints,,, but I think that's kinda pricey for a HSS bit. Also, I personally prefer an upcut bit unless it is a through cut, just helps get the chips out.
> Here's a pretty decent bit for the $$:
> cripedistributing.com : BOSCH 85913M 3/8" x 1-1 1/4" Up Spiral Router Bit [85913m] - $14.00
> I would stick with carbide whenever possible.


 
Thanks for that. I didn't realize it was just HSS. I do want a carbide bit.

I'm not so concerned with getting the chips out; I'm thinking that the downcut might reduce tearouts.


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## TWheels (May 26, 2006)

One of the first projects I tried involved making many box joints with the O-P ig very similar to yours. I used a downcut spiral bit. The chips accumulated and got so hot they caught fire and almost ignited the chips on the wooden deck! Fortunately I had water with me and was able to extinguish the burning chips. The bit itself was burned and retired from use. 

There is an ancient thread with a title something along the lines of "This may be stupid but don't do it " that describes this incident in more detail which you might find helpful.


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## Hamlin (Dec 25, 2005)

If you intend on using a spiral bit for box joints, use the upcut not the downcut. Downcut is better suited for working with ply. 

If you're looking for top quality bits, look at Whiteside. Expensive, but worth the cost.


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## AxlMyk (Jun 13, 2006)

I agree with the upcut bit. That's what I use. Does a great job.
When installed in a table router, it becomes a downcut bit.


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## BigJimAK (Mar 13, 2009)

Tom "Fire Starter" mftha... Were you once a Boy Scout?  :jester:


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## TWheels (May 26, 2006)

BigJimAK said:


> Tom "Fire Starter" mftha... Were you once a Boy Scout?  :jester:


Actually I was, and I won a fire starter contest!


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## TWheels (May 26, 2006)

The method I used to win the contest has ingrained in me the necessity for keeping steel wool far, far away from any possible source of ignition


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## TWheels (May 26, 2006)

BigJimAK said:


> Tom "Fire Starter" mftha... Were you once a Boy Scout?  :jester:


BigJim, what made you suspect that I had once been a Boy Scout?


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## BigJimAK (Mar 13, 2009)

"The chips accumulated and got so hot they caught fire" I was just being a smart-:jester:


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## Rob1 (Mar 6, 2009)

Up cut means the chips are pulled twarts the router. Down cut means away from the router. A table mounted router with an up cut bits pulls the chips down and away from the material.


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## TWheels (May 26, 2006)

mftha said:


> One of the first projects I tried involved making many box joints with the O-P ig very similar to yours. I used a downcut spiral bit. The chips accumulated and got so hot they caught fire and almost ignited the chips on the wooden deck! Fortunately I had water with me and was able to extinguish the burning chips. The bit itself was burned and retired from use.
> 
> There is an ancient thread with a title something along the lines of "This may be stupid but don't do it " that describes this incident in more detail which you might find helpful.


 I did get the name of the thread almost correct. The name was "This may be dumb but do not do it". It dates to Sept. 2006 and describes the incident, and several forum members gave some very useful information about safety issues. Searching for it requires using "mftha" because the words in the title are too common to be included in the community search.


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## Cochese (Jan 12, 2010)

I made my daughter a very nice jewelry box with a straight bit. Very little if any tearout.


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## distrbd (Oct 8, 2009)

AxlMyk said:


> I agree with the upcut bit. That's what I use. Does a great job.
> When installed in a table router, it becomes a downcut bit.


Please don't take this the wrong way I know you don't mean to confuse any one but an up cut spiral bit does not change its characteristic if used in a router table as rob1 said it best:

Up cut means the chips are pulled twarts the router. Down cut means away from the router.* A table mounted router with an up cut bits pulls the chips down and away from the material*.


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## Hamlin (Dec 25, 2005)

distrbd said:


> Please don't take this the wrong way I know you don't mean to confuse any one but an up cut spiral bit does not change its characteristic if used in a router table as rob1 said it best:
> 
> Up cut means the chips are pulled twarts the router. Down cut means away from the router.* A table mounted router with an up cut bits pulls the chips down and away from the material*.


Technically, you're both right!!


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## TwoSkies57 (Feb 23, 2009)

don't cha just hate when that happens...:dance3:


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## RJM (Apr 11, 2010)

distrbd said:


> Please don't take this the wrong way I know you don't mean to confuse any one but an up cut spiral bit does not change its characteristic if used in a router table as rob1 said it best:
> 
> Up cut means the chips are pulled twarts the router. Down cut means away from the router.* A table mounted router with an up cut bits pulls the chips down and away from the material*.


 
Actually - downcut means toward the work piece, or down, for a handheld router. Upcut means away from the work piece, or up, for a hand held router.   :big_boss:


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