# Bit/bushing centering



## jeepered (Nov 8, 2013)

Hi All,
This may not be the best category in which to ask this question but I'm going to ask it anyway. i have a Porter Cable 690 router and I'm having a very difficult time setting it to "perfect center" in my "Fast-Joing Precision Joinery System" bushing. Is there a more accurate brand router out there that sets up to "perfect center" faster and without a lot of tweeking? I'm using a Rockler router table without any bells and whistles on it for micro adjustments. All I want to do is mount the router to the inset plate on the table, have it center perfectly in the bushing and start routing. Any suggestions regarding which router centers best that I should check out?
Thanks,
ED


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## Dmeadows (Jun 28, 2011)

Try one of these, or similar...

Bosch RA1151 Router Subbase Centering Pin and Cone - Amazon.com


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## Cherryville Chuck (Sep 28, 2010)

If you can't find that one there is this type also. One of my Hitachis came with one. Google Image Result for http://www.ptreeusa.com/Peach%20Graphics/bushing_center_pin_200.jpg


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## MAFoElffen (Jun 8, 2012)

Didn't I answer this for you last week in another thread... when you were having problems with that MLCS fast joining system? You didn't comment on that post then and now it seems that post was either ignored or overlooked. If not you, then I did see your posts in that thread... There does seem to be a lot of questions on this joining jig lately.

Recap on what I said-
Router tables are not usually held to having the router motors to be accurately centered in the router insert plate... to use a guide bushing in the router plate. That is normally a hand router concern when using a guide bushing with such. But this joining jig does, so now it "IS" a concern if you use that jig.

There are router insert plates with center inserts that are made more accurately with guide bushings in mind... where I recommended/mentioned the ROUSSEAU Deluxe Router insert plate...

Rousseau also sells 6 different centering kits for their router insert plates, tailored to different routers that you might be using.

I also said that a "router lift" would have too much side-play for that joining system. That I recommended using a fixed router base, connected to that Rousseau Insert plate. With that kind of plate "locked down" and not adjusted after centering the router base to the router table insert plate... there then should be no side movement from that centered setting. Again, I thought a plunge router base or a router lift would have too much side-play for that joining jig. 

I also mention that there is a thread in the "guides and bushings" section of this forum that is specifically on guide bushing/router base centering kits. I mentioned that the one I liked the best was like the one mentioned in that thread- consisting on a cone and a centering bit that fits in the router Colette.

That is a summary of my past post. I believe I went into more detail and had other recommendations in that post... I also mentioned that I didn't think any of my router table inserts here would work with that joining system. (LOL)


Things I did not mention (yet)-

A more expensive alternative would be to have an insert plate made just for that jig... Meaning make one up from acrylic or aluminum, with an opening machined specifically for that guide bushing. That way it would take the possibility of there being any side-play from a router table table bushing (that that router guide bushing mounts to) of having any play with the router table insert plate. Instead of there being 2 pieces to the insert plate, there would be just one. You could cut that cost down by making your own, but then the accuracy of that is in your hands. 

Another tip I learned from PC guide bushings... that sometimes adding a spring washer on the guide bushing will help prevent it from loosening up or shifting... so that is stays where you put it.

The drawback to that is if you wanted to use a larger bit than that opening or a smaller bit where you wanted less clearance in that hole... Then you might want to go back to your more generic router table insert plate.


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## jeepered (Nov 8, 2013)

MIKE,
THANKS A HUNDRED TIMES OVER for you in depth reply. I've tried several of your suggestions and what I found to be most successful to date is shimming the router motor inside the router's base . For example, if the cutter is off center to the left (greater space between the bushing and the cutter at 3 o'clock) I shim the router motor with aluminum tape at the 9 o'clock. in my case it took 3 layers of tape to center the cutter in the bushing. As it turned out I was able to cut some respectable joints for decorative boxes.
Thanks again for your help Mike,
ED


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## jeepered (Nov 8, 2013)

Duane,
MIKE,
THANKS for you in reply. I've tried several of the suggestions that I have received and what I found to be most successful to date is shimming the router motor inside the router's base . For example, if the cutter is off center to the left (greater space between the bushing and the cutter at 3 o'clock) I shim the router motor with aluminum tape at the 9 o'clock. in my case it took 3 layers of tape to center the cutter in the bushing. As it turned out I was able to cut some respectable joints for decorative boxes.
Thanks,
ED


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## jeepered (Nov 8, 2013)

Thanks Charles. I'll look into it.
ED


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## jw2170 (Jan 24, 2008)

I would use the Rousseau type plate or make your own from 3/8" acrylic.

I made a square plate for one of my small routers. It would be easy to increase the outside dimensions to have it fit into the table cut out.

http://www.routerforums.com/guide-bushings-templates/39218-new-base-plate.html

There is also a sticky, Mike made on this subject.

http://www.routerforums.com/table-mounted-routing/14985-centering-your-router-mounting-plate.html

The important thing to keep in mind is that the router does not have to be exactly centered on the plate. Once referencing off a fence or bearing it does not make any difference.

The router has to be centered on the counter bored hole to take your guide bushing.

The way I centered mine was straight forward and uncomplicated.

1. I used the sub base plate to align the centre of the base plate roughly with the new base plate/insert plate and marked the position of the screw holes. Drilled the screw holes and attached the router to the plate.

2. using a small v-bit cutter, plunge the router until the cutter is just touching the base plate and turn by hand until a small pin hole marks the spot. This pin hole will be exactly centered on the router.

3. Detach the router and take base plate to drill press. Insert the correct correct size Forstner bit into the drill press and centre the forstner bit on the pin hole in the plate.

4. Clamp the base plate to the drill press table in that position. Drill the through hole and counter bore hole on the drill press without moving the plate. This hole will now be exactly centered on the router.

5. Re-attach router to insert plate.

I also bobj3 made a post some time ago on using this method.


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## Mike (Nov 22, 2004)

The Rousseau centering kit is the least expensive method for getting it right the first time. Infinity cutting tools also sells a similar kit. A centering cone will do the same job and most inlay kits come with a centering pin because this type of work requires precision.

Shimming is not the answer because your bit is not cutting straight. All the mentioned solutions are under $10 except the inlay kit. Do yourself a favor and get which ever makes the most sense to you.


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## oldrusty (Mar 31, 2011)

I'm a bit confused as to how you can centre a router to a plate using tapered countersunk screws.. Wouldn't the taper pull the plate back to its original position? I would have thought flat bottomed countersinks and flat bottomed screws would be needed ( in U.K. we called them cheese head ) . I just checked my Triton and it has exactly this set up. Oldrusty


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## Dmeadows (Jun 28, 2011)

oldrusty said:


> I'm a bit confused as to how you can centre a router to a plate using tapered countersunk screws.. Wouldn't the taper pull the plate back to its original position? I would have thought flat bottomed countersinks and flat bottomed screws would be needed ( in U.K. we called them cheese head ) . I just checked my Triton and it has exactly this set up. Oldrusty


Al, you are absolutely correct!


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## jw2170 (Jan 24, 2008)

Using my method, the hole is centered to the router, not the other way around.

It does not matter what screws are used.


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## Dmeadows (Jun 28, 2011)

jw2170 said:


> Using my method, the hole is centered to the router, not the other way around.
> 
> It does not matter what screws are used.


If you remove that sub base plate, and get it turned by even one mounting hole when reinstalling, you can be off center a few thousandth of an inch. The kind of jig the OP is using will double that error.

Marking the base so it always goes on in the same direction will help, but check centering every time for joinery use with a guide bush. If there is any play between the guide and the sub base, that will cause the same problem!

I still think the centering cone is as accurate a way to setup as anything.

Al is right about the screws and plates that come with many routers. Counter boring the mounting holes flat and using flat screws will allow adjust for centering. 

I would center the guide bush when installing every time for that type of joinery.

As usual... YMMV:yes4:


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## jeepered (Nov 8, 2013)

James,
I just dropped a line to Mike in Detroit. Here is what I told him and how I solved the problem in my situation,
"Thanks Mike,
I've come to conclude that my router motor is not properly lined up with its base. That is why I had to shim the router motor's housing in its base to make the collet line up perfectly with the 1/4' bushing that is fastened to the insert plate in the router table. Now everything is working pretty well.
Thanks,
ED"

I, like yourself, could not understand how conic flathead screws would not pull the router and its base back to the original position in relation to the insert plate in the router table.
Again, Thanks,
ED
Thanks,
ED


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## jeepered (Nov 8, 2013)

Opps, James, I almost forgot, I will look into the Rouesseau insert plate that you mentioned.
TTFN,
ED


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## jeepered (Nov 8, 2013)

Sorry Mike,
I'm new to the Forum and haven't yet learned how to operate it properly in order to get where I want to go in it. I plead ignorance and not intent. I was able to get back to another Mike (in Detroit and James in Australia, however, and like you they mentioned the ROUSSEAU Deluxe Router insert plate which I will look into.
Sorry and Thanks,
ED


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## Mike (Nov 22, 2004)

Ed, the Grizzly T10432047 plate costs $13 and is almost identical to the Rousseau plate; the difference is the Grizzly plate is flat and the Rousseau has the patented slightly convex design. I have used both ways but if you plan on using any jigs on top of the plate I think the flat option is the best.


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## jeepered (Nov 8, 2013)

Too all of you out there who responded to my plea regarding cutter centering: THANK YOU ALL! Because of you I now have an arsenal of options I can try out to conquer centering with my "Fast-Joint Precision Joinery System". In return, the latest strategy that I'd like to share with you is I used a shim of two (2) layers of masking tape between the router base and the router table's inset plate on the long side of "off-center". This approach was simple and worked perfectly. You can be sure, however, that I"m going to keep all the ideas and references you all shared with me in my bag of tricks.
ED


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