# why is centering cone needed?



## sofasurfer (May 30, 2009)

I don't have one yet but I am just trying to learn a little. 
Why is a centering cone needed? Why isn't the base plate just MADE TO BE CENTERED instead of being made to be inacurate? Seems like a very easy thing to do.


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## Ghidrah (Oct 21, 2008)

Its helpful for centering "new" base plates for screw holes, and when using template guides. some bit diameter to inside guide diameters can be very tight, an offset of 1/128" can mean disaster.

I can't speak for all 2nd party plate manufacturers but all the extra non (OEM) plates I ever bought don't come with alignment ribs like the PC default plates do. As tight as the (default) plates fit even they need to be checked when tight tolerances are in effect.


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## bobj3 (Jan 17, 2006)

Hi 

You don't need to buy a cone you can make your own very easy and it 's a must thing you must do on all routers and mounting plates.. 
You can use plastic or some scrap stock from the shop.

They stamp out the base plates and most are not dead on the norm.

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sofasurfer said:


> I don't have one yet but I am just trying to learn a little.
> Why is a centering cone needed? Why isn't the base plate just MADE TO BE CENTERED instead of being made to be inacurate? Seems like a very easy thing to do.


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## Noob (Apr 18, 2009)

bobj3 said:


> Hi
> 
> You don't need to buy a cone you can make your own very easy and it 's a must thing you must do on all routers and mounting plates..
> You can use plastic or some scrap stock from the shop.
> ...



That is one of them "That is so simple, why didn't I think of that" little jigs, thanks for the tip... because I was wondering how do you make one without a lathe.


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## sofasurfer (May 30, 2009)

Ok, either I am having a "duh" moment or I'm just not that smart, but how the heck do you make those little centering guides. A hole saw? Cut out the disk and try to make a centered hole? Make the center hole and cut a circle around it? Come on, don't assume I get it cause I don't:help:


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## bobj3 (Jan 17, 2006)

Hi

I use the hole saw to puch them out but I do cheat a little bit, I use the jig below to get them just right and on dead center, in about 2 min. job.

Note ::you can clamp the jig on the other side of the sander as well ( the round disk side with the flat plate) 
Plus it's neat and easy way to make wheels for toys or the offset rings for the brass guides..


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sofasurfer said:


> Ok, either I am having a "duh" moment or I'm just not that smart, but how the heck do you make those little centering guides. A hole saw? Cut out the disk and try to make a centered hole? Make the center hole and cut a circle around it? Come on, don't assume I get it cause I don't:help:


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## sofasurfer (May 30, 2009)

Aaaa-haaaa!!
You guys sure do know your way around the shop, don't you?
I see what your trying to tell me. Very clever. Thanks.


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## Noob (Apr 18, 2009)

sofasurfer said:


> Ok, either I am having a "duh" moment or I'm just not that smart, but how the heck do you make those little centering guides. A hole saw? Cut out the disk and try to make a centered hole? Make the center hole and cut a circle around it? Come on, don't assume I get it cause I don't:help:


I'm glad you asked soda. :sold:


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## bobj3 (Jan 17, 2006)

You're Welcome *sofasurfe

It's great little jig and can do many jobs..I use it all the time.
Try it with two dowel pins in place, a easy way to get a radius just right  
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sofasurfer said:


> Aaaa-haaaa!!
> You guys sure do know your way around the shop, don't you?
> I see what your trying to tell me. Very clever. Thanks.


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## Mike Wingate (Apr 26, 2009)

Hole saw. Mount disc blank on its shank/mandrel. Chuck in drill press or lathe, abrade to shape with tool of choice until it fits. No jigs to make. Somewhere I have seen a really neat and simple disc sander jig. Back to the books. Nice one Bob.


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