# Prevent Bottoming out of Router Bit



## Adarus (Jul 31, 2014)

Long time listener - first time caller 

I have read many people say not to bottom out the router bit when putting it in the router. I am not sure why, but I will heed that advice. 

I also read about people having small rubber washers placed in the bottom of the collet that will prevent the bottoming out. Have others done this and if so, where would I buy such a washer.

Thanks in advance


----------



## RainMan 2.0 (May 6, 2014)

Welcome to the forum . I can't help you with your query but I'm sure the experts will chime in soon


----------



## Cherryville Chuck (Sep 28, 2010)

Welcome to the forum Adarus. You don't want to bottom out router bits or drill bits and for the same reason. As the bits get hot, the metal stretches. If the bits are bottomed out they can't expand in that direction. Therefore the bits push outwards which can loosen them in the collet or chuck. Anything that can absorb some stress will work. Wooden dowel, o-rings, rubber grommets, compressed paper, whatever. It just has to keep the bit from bottoming out in the shaft recess. Drill bits you bottom out then pull back a little when you tighten.

While I'm at it I might as well point out that nothing is gained in holding power once 100% of the length of the collet is being used. If you only stick your bits in far enough to do this you will have a little more height adjustment available.


----------



## Semipro (Mar 22, 2013)

Hello, glad you found us, it's great to have you as a member of the community, welcome to Router Forums.
You can buy 1/2" rubber grommets at any hardware store


----------



## old55 (Aug 11, 2013)

Welcome to the forum.


----------



## IBUILD2 (Mar 27, 2014)

The big box store"s have them in the hardware section.


----------



## Stick486 (Jan 4, 2013)

Adarus said:


> Long time listener - first time caller
> 
> I have read many people say not to bottom out the router bit when putting it in the router. I am not sure why, but I will heed that advice.
> 
> ...


thick "O" rings of the correct OD and small ID...


----------



## Willway (Aug 16, 2012)

Try Sommerfeld tools.

Grommets

Dick


----------



## RainMan 2.0 (May 6, 2014)

Semipro said:


> Hello, glad you found us, it's great to have you as a member of the community, welcome to Router Forums.
> You can buy 1/2" rubber grommets at any hardware store


My vote is for the grommets . I wasn't aware of this so I'm going to get some ASAP . I guess now my question would be what is the least amount the bit should be in the collet ? 
I have needed more cutting depth and had less than half in , mind you that was with a 1/4" straight bit as I wouldn't do that with a large diameter bit


----------



## Stick486 (Jan 4, 2013)

big boxes..

Shop rubber grommets at Lowes.com: Search Results!

Search Results for rubber grommets at The Home Depot


----------



## Adarus (Jul 31, 2014)

Thanks for the comments everyone - grommets from big box stores seem the way to go...off I go for a solution that should work out well and keep me from bottoming out by accident.


----------



## Stick486 (Jan 4, 2013)

you there is a depth line on the shank of some of the better router bits...
also if you extend the bit out as far as you can get away with that encourages run out...


----------



## Bigjet747 (Mar 9, 2011)

Try Marc Sommerfeld tools. Big user of this method. Works well


----------



## RainMan 2.0 (May 6, 2014)

Stick486 said:


> you there is a depth line on the shank of some of the better router bits...
> also if you extend the bit out as far as you can get away with that encourages run out...


Well I had about a third of the 1/4" straight bit in my collet trying to cut that extra little depth and things went south . The bit came out completely . Oh well now I know lol


----------



## Cherryville Chuck (Sep 28, 2010)

RainMan1 said:


> Well I had about a third of the 1/4" straight bit in my collet trying to cut that extra little depth and things went south . The bit came out completely . Oh well now I know lol


In general you should stay at 100% of the length of the collet. Once in a while if it is really necessary maybe go to 90%. I wouldn't go much less than that ever. You risk damaging the collet, having the bit fly off into local space, excessive runout, and damaging your work. Look for a longer bit for those jobs or redesign the job.


----------



## Murtu01 (Mar 9, 2014)

Semipro said:


> Hello, glad you found us, it's great to have you as a member of the community, welcome to Router Forums.
> You can buy 1/2" rubber grommets at any hardware store


Welcome to the forum, this is exactly what I use and it works perfectly.

Regards

Rudi


----------



## N'awlins77 (Feb 25, 2011)

I use 1/4 and 1/2" I.D. O-rings. Keep 3 each in my router bit drawer.


----------



## RainMan 2.0 (May 6, 2014)

Cherryville Chuck said:


> In general you should stay at 100% of the length of the collet. Once in a while if it is really necessary maybe go to 90%. I wouldn't go much less than that ever. You risk damaging the collet, having the bit fly off into local space, excessive runout, and damaging your work. Look for a longer bit for those jobs or redesign the job.


Yes I wish they made a longer straight bit in 1/4" as I wanted the tight radius in the corners . I had to flip it over and route from the other side . It was much safer that way but kind of a pain lining it up properly . I should have just made a better template and it would have gone better . I'll know better next time :sad:

Charles I'm not sure if I'm reading this right . Your saying in general you should stay at 100% of the length of the collet . I thought the discussion here was to not have it all the way in the collet because of heat expansion? Or am I misunderstanding as usual?


----------



## Cherryville Chuck (Sep 28, 2010)

RainMan1 said:


> Yes I wish they made a longer straight bit in 1/4" as I wanted the tight radius in the corners . I had to flip it over and route from the other side . It was much safer that way but kind of a pain lining it up properly . I should have just made a better template and it would have gone better . I'll know better next time :sad:
> 
> Charles I'm not sure if I'm reading this right . Your saying in general you should stay at 100% of the length of the collet . I thought the discussion here was to not have it all the way in the collet because of heat expansion? Or am I misunderstanding as usual?


You should have the bit all the way in the collet but not all the way through and bottomed out against the end of the recess in the router arbor shaft. The distance from the bottom of the collet to the end of the recess varies from maker to maker. On some routers it is impossible to have bits with short shanks bottom out. There was another thread on this subject a while back. http://www.routerforums.com/general-routing/43339-answer-how-far-insert-bit.html


----------



## shuja.shaher (Oct 18, 2014)

Yes, I would like to know how much minimum shank length should be used for gaining cutting depth? Will the collet length be enough?


----------

