# Dealing with depth when changing bits



## uOpt (Dec 18, 2008)

Hello again 

When you are working on something where the bottom of the route will remain visible - how do you deal with router marks that are left from the slight changes in depth?

Long story:

Got my Bosch Colt, thanks again for the recommendation. I did my first test routings in old shelves without killing myself or setting the house on fire. So far so good.

I have one thing that puzzles me: I am doing letters (later 
for a shop sign) and the smaller bits are, of course, making the better corners. But the larger bits make much nicer straights.

I have been unsuccessful in keeping a precise enough depth when changing the bit to have no visible marks on the bottom of the routes. I guess this isn't really possible.

How do people deal with this? Do you just use the small bit for everything? Use the small bit for as few surface as possible and live with the mark on the bottom near the finer parts? Sand out the marks on the bottom?


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## woodshopdemos (Oct 13, 2008)

Look for a "mortising" bit. It has two cutting surfaces on the bottom that are to leave a smooth bottom. Otherwise t hey look like a two flute straight bit. They do not plunge as aggressively but they do leave a smooth bottom.


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## bobj3 (Jan 17, 2006)

Hi uOpt

Here's one that works very well for the job 

Dado Clean Out Router Bits
#5382 1/2" 1/4" $13.95
http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_dado.html


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uOpt said:


> Hello again
> 
> When you are working on something where the bottom of the route will remain visible - how do you deal with router marks that are left from the slight changes in depth?
> 
> ...


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## uOpt (Dec 18, 2008)

Thanks, guys. You are the best.

In general, what do you prefer: to use fewer different size bits for one job? Or change often to do each corner with the most suitable one?


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## Mike (Nov 22, 2004)

Use a piece of scrap as a set up block. Make a cut with your small bit at the depth needed, and be sure it is large enough for your bigger bit to fit into. Unplug, change the bit and use the set up block to set the depth of the larger bit. This should be right on the money.


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## uOpt (Dec 18, 2008)

Thanks.

Turns out that my Bosch Colt actually changes depth by about a millimeter if you use it long enough. I'll look into that, it's quite annoying. Maybe there's dust buildup where it shouldn't.


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## bobj3 (Jan 17, 2006)

Hi uOpt

I ran into the same error, and I don't like the metric setting  , so I made a stop block that just sits in the opening under the motor and the base, I know how deep I want to go and when I pull the motor down to the stop block it's set just right..I also use the brass setup bars, to setup the bit(s) from the get go..

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uOpt said:


> Thanks.
> 
> Turns out that my Bosch Colt actually changes depth by about a millimeter if you use it long enough. I'll look into that, it's quite annoying. Maybe there's dust buildup where it shouldn't.


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