# Bit centering



## oldrusty (Mar 31, 2011)

Hi members I am new to routing and was trying to set up my " not cheap " router with a template guide and a dovetail bit. I was amazed to find that the bit was not centered in the guide. The bit even rubbed one side of the guide when raised but had a fair amount of clearance the other side. Is this a common occurrence for a tool as accurate as a router seems to be and what's the solution to this problem ?


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## bobj3 (Jan 17, 2006)

Hi 

The easy way is to replace the base plate, with one you can adjust easy to get it on dead center, it's true you can buy a high end and high price one from Pat but why not get one that can do it all at the right price...the real key for me is how easy you can put the brass guides in place and get them tight at the same time.
By the way it comes with a center tool right in the kit to make the job easy.
Amazon.com: Milescraft 1211 Base Plate Metal-Nose Bushing Set for Routers: Home Improvement

You will be amazed how easy it can be with the MilesCraft plate,you can also use your brass guides that you now have on hand..

The big one comes in the 1211 kit
http://www.amazon.com/Milescraft-12...ref=sr_1_8?s=hi&ie=UTF8&qid=1307633747&sr=1-8
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oldrusty said:


> Hi members I am new to routing and was trying to set up my " not cheap " router with a template guide and a dovetail bit. I was amazed to find that the bit was not centered in the guide. The bit even rubbed one side of the guide when raised but had a fair amount of clearance the other side. Is this a common occurrence for a tool as accurate as a router seems to be and what's the solution to this problem ?


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## CharleyL (Feb 28, 2009)

This is a common problem with many routers. So much so that many new routers are coming with a centering tool. It's a straight shaft of the size to fit the collet, with a plastic cone that fits tightly on the shaft, but can be slid along the shaft with some effort. You place the shaft into the collet as you would a router bit and secure the collet. Then you slide the cone down the shaft until the narrow end goes through the base plate or router bushing, pushing it to be centered with the shaft and the collet. You then tighten the mounting screws on the base plate or the nut on the router bushing. Make one more check to be sure that everything is still centered and then loosen the collet and remove the centering tool.

Some routers will hold this alignment fairly well during depth adjustments, but other routers require re-centering after each change. 

Charley


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## Phil P (Jul 25, 2010)

oldrusty said:


> Hi members I am new to routing and was trying to set up my " not cheap " router with a template guide and a dovetail bit. I was amazed to find that the bit was not centered in the guide. The bit even rubbed one side of the guide when raised but had a fair amount of clearance the other side. Is this a common occurrence for a tool as accurate as a router seems to be and what's the solution to this problem ?


Is this common? Well yes it is IMHO. What's the solution? Generally I find that there's a wee bit of slop in the mounting of a guide bush which I use to my advantage. I sometimes use guide bushes on both Elu/deWalt and Festool plunge routers and in order to center guide bushes precisely I centre the guide bush using a Festool centring mandrel (#492-187 or "ZD-OF/D 6,35+8" as the snappily call it in the catalogues) before fixing in position using cheese head machine screws rather than router manufacturers' countersunk head ones which tend to pull the guide bush back into the "wrong" place. The Festool mandrel can be used with both 1/4in and 8mm collets.

Whilst my approach works well with plunge routers but I'm not sure about how well it would work with fixed base models unless they have rack and pinnion depth adjustment. 

Regards

Phil


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