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Centering your router on a mounting plate

41967 Views 61 Replies 37 Participants Last post by  niswanger
It is very important that your router be centered on your mounting plate. Many people sweat over this for hours remeasuring before they drill their mounting holes. The quick and easy way to do this is with a centering kit from Rousseau. These kits work with all brands of mounting plates that accept Porter Cable style guide bushings and they cost $5.

Step 1. You chuck up the centering pin in your routers 1/4" collet.
Step 2. Insert the disk into the center hole of your mounting plate.
Step 3. Remove the sub base plate from your router, set it and the screws aside.
Step 4. Install the transfer screws into your routers base with the points facing out.
Step 5. place the centering pin into the disk, position your router to face the direction you want it mounted and lightly tap the edge of your router with a mallet. This marks the locations you need to drill.
Step 6. Drill the holes, flip the plate over and slightly countersink them.
Step 7. Using the new screws that came in the centering kit attach your router and it is perfectly centered.

If you are using a plate that accepts the larger Oak Park style guide bushings you can purchase a centering disk and a guide pin from them. You can purchase transfer screws from most hardware stores or tool suppliers.


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Hey, Bob; out of curiosity, are your screws conical on the underside (flat head screws) or flat on the underside (round or pan head screws). I keep seeing references and comments in books and articles suggesting replacing the existing OEM ones.
If either the countersink or the screw is conical then for sure it'll pull away from where you want it.
That's very strange, Bob.
You've obviously spent a lot of time and frustration over this, so please excuse my simplistic questions...I can't see what's actually happening.
A sideways force is being generated as the fasteners are cinched down?
Are all four (3 or 4?) screws actually centred in their baseplate holes, or are one or more maybe a little tight against a side(s) of the baseplate hole as the screw is run into the metal sub-baseplate? Can you rotate the baseplate to a different orientation, and still get exactly the same result?
Have you tried not tightening each screw down as you install it? Go around tightening down after you're sure it's actually aligned...check again after tightening each screw...trying to isolate which one's causing your problem.
Again I apologize if it seems like I'm not giving you credit for having tried those routines; just thinking out-loud what I'd be doing if it was in front of me. :)
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Perfectly clear, Bob.
I am a bit confused however, mine is like a Xmas tree...maybe specifically for plunge routers?
Bosch RA1151 Centering Pin and Cone
From their description, the brass collar is loose during the tightening process. Is it possible you've got yours tightened down, and it's actually applying sideways torque to the motor shaft/collet as you tighten the plate screws bouncing back once you remove the centring cone ?
I'm just spit-balling here; maybe someone with a lot more hands on can clarify this?


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Bob said...
"As the centerpin, shaped like a golf tee, is pressed into the brass collar installed in the center (bit) hole of the plate, the plate automatically "centers itself" as the router collet nut is tightened (like router bit)."

Sorry, Bob, but that's in conflict with the Bosch instructions that I posted. The collet nut needs to be tightened before anything else is tightened...especially the brass collar. The centering cone is the starting point for everything else being aligned (to it). The cone has to be rock solid as the starting point; not applying sideways pressure to anything.
I did see it, Bob. Never the less, there's your problem...the centering pin has to be firmly held before you can tighten anything else down.
It's the anchor for the alignment process, not the tool.
No harm in trying Bosch's technique? If that doesn't work than I'm out of ideas.
Are you talking about the accessory insert plate? The one that replaces your standard from-the-factory base plate?
If that's the one you mean, the drop in insert plate that recesses flush with your table top, the answer most often given is that if it's a good fit to the recess than the weight of the router hanging off it should be enough to keep it firmly in place.
Bill Hylton has a ton of info on baseplates etc., in his book Router Magic...look for the newest edition on .
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