# How to Route an "O" Ring Groove



## Charles Wong (Jan 5, 2009)

I currently have a "step" at the top of the flange and where the tube meet. (see pix) I want to move the "O" ring toward the thumbscrews about a 1/4" to 3/8" away from the opening of the tube for a better seal.

I have looked for a router bit to just cut a 1/4" round groove abut 1/8" -3/16" deep but nothing yet.

Anyone think of a "bit" to do this? 

I'll probably have to turn the flange upside down and "box" it in to turn it into the bit to cut the groove but I need the bit first.


tia


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## Lemuzz (Jul 25, 2008)

Have you tried an end mill?


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## bobj3 (Jan 17, 2006)

Hi Charles

I think I would use the bit(s) below

just as a side note, I would make a round fixture the same size as the OD on the ring ,then clamp it to the top of the router table, set the bit height and drop the plate on top of the bit and turn the plate in the pocket..  counter clock wise....
use a test block b/4 you do in the plastic...to get the feel of it..a light cut on the 1st. pass..
or
Put in a circle in some scrap stock the same size as the plastic ring,,stick the ring in the hole with some double sided carpet tape and use a brass guide and go around the inside of the hole with the bit and a plunge router... 


Core Box Bits or the Round Nose Bits
MLCS core box and round nose router bits

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lemonyx said:


> I currently have a "step" at the top of the flange and where the tube meet. (see pix) I want to move the "O" ring toward the thumbscrews about a 1/4" to 3/8" away from the opening of the tube for a better seal.
> 
> I have looked for a router bit to just cut a 1/4" round groove abut 1/8" -3/16" deep but nothing yet.
> 
> ...


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## Charles Wong (Jan 5, 2009)

Thanks jigs - that's exactly what I need.


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## bobj3 (Jan 17, 2006)

You're Welcome Charles

How about a snapshot once you get it done ..

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lemonyx said:


> Thanks jigs - that's exactly what I need.


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## Charles Wong (Jan 5, 2009)

Here's the groove. $10 for the bit and Free shipping, that's a deal :dance3:

I got lazy and just used some wood to box the "flange" over the bit on three sides and then just feed into the bit while turning. Worked just great and that's the shape I need for the "O" ring.

thanks again


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## bobj3 (Jan 17, 2006)

Hi Charles

Nice job and thanks for the feed back 

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lemonyx said:


> Here's the groove. $10 for the bit and Free shipping, that's a deal :dance3:
> 
> I got lazy and just used some wood to box the "flange" over the bit on three sides and then just feed into the bit while turning. Worked just great and that's the shape I need for the "O" ring.
> 
> thanks again


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## Duane867 (Oct 25, 2008)

Was that for a protein skimmer by chance ?
You are really going to want to find the correct size O-ring instead of using the old cut and glue back method. The salt will erode the glue away and you will come home to a flood if its a free standing unit thats not sitting in a sump. ( been there, done that LOL !)
I found the best and easiest thing to use to be rubber sheet. No groove cutting, no special ordering o-rings. Just lay it over, punch some holes, screw the cap on and trim the excess away. I have made many many many many many.. skimmers and that method has never failed. Its the floor side any way so you'll never see it...


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