# Help with finding bit



## HiloDB1 (Jun 2, 2011)

Hello,

I am in search of a special router bit. I dont know what it is called exactly but have heard it referred to as an "expanding template bit". It basically looks like the opposite of a rabbit bit. The guide bearing is larger than the cutting bit itself. Its used to make a larger sized piece of a template or whatever you shape you want. I dont know who makes it but I would like to find out where I can get one or get in touch with someone who can get it.

Here is a picture I found of the bit.










Any help would be appreciated.

Thanks!


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## Semipro (Mar 22, 2013)

Tad
Just buy a bearing kit they come in multiple sizes up to an inch and a quarter and then just install them on a regular flush trim bit to to increases size of pattern


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## Cherryville Chuck (Sep 28, 2010)

The largest of the collars in these sets might be close to what you want. Insert Superabbet Jr.-17 Piece Collar Kit (Flush-15/32") - Toolstoday.com 

Industrial Quality Bearings | Rub Collars | Router Bit Bearings | Shaper Rub Collars

Amana and Eagle aren't the only companies that have them. I think most of the major bit makers have some like them and they have online, downloadable catalogs you can look them up in. You may be also be able to use shaper rub collars with a 3/4" ID if you can find a bearing with that OD and then you can probably get a much larger diameter.


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## jw2170 (Jan 24, 2008)

I would make a 'doughnut' to fit over a 1/2" bearing.

You could make this any reasonable size.


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## jw2170 (Jan 24, 2008)

Good link, Charles.

Those 'rub collars' look just the part......


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## Cherryville Chuck (Sep 28, 2010)

jw2170 said:


> I would make a 'doughnut' to fit over a 1/2 bearing.
> 
> You could make this any reasonable size.


That's a good idea too James. If you poked a hole through a piece of 1/4" thick mdf, plastic, or aluminum the size of your router bit bearing OD and then filled it with a bearing that has an ID the size of the pin on this circle cutter Precision Circle Jig - Lee Valley Tools then you could make rub collars any size you want.


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## HiloDB1 (Jun 2, 2011)

Thank you all for your suggestions and help. I think I have found what I'm looking for with the rub collars and different size bearing to fit my current flush trim bits. Only fear I have is that the rub collars must have a nice press fit to them. Wouldnt want one flying off in the middle of a pass.


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## Cherryville Chuck (Sep 28, 2010)

If that is a problem I would put a little bit of rubber cement between them, something like Goop. That should hold them together but still allow dis assembly.


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## MAFoElffen (Jun 8, 2012)

HiloDB1 said:


> Thank you all for your suggestions and help. I think I have found what I'm looking for with the rub collars and different size bearing to fit my current flush trim bits. Only fear I have is that the rub collars must have a nice press fit to them. Wouldnt want one flying off in the middle of a pass.


I think that fit, being true/round... and being in balance. 20,000 rpm puts some forces at work...


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## Cherryville Chuck (Sep 28, 2010)

I am just thinking that the rub collar probably will only be turning a few revolutions a minute as it follows the template, the inner bearing will be the one turning 20,000 rpm.


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## malb (Sep 15, 2008)

Cherryville Chuck said:


> I am just thinking that the rub collar probably will only be turning a few revolutions a minute as it follows the template, the inner bearing will be the one turning 20,000 rpm.


Only while in contact with the pattern, when off the pattern it will rapidly accelerate to bit speed, then be required to decelerate once it contacts the pattern. This applies to all bearings on bits.

Also, if you are building out a bearing, the added material needs to be perfectly concentric with the bearing to avoid getting a scalloped edge as the added disk rotates while working along the pattern.


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