# Centering guide bushings...fail



## Bikeworks (Oct 24, 2012)

Hi forum, it's my first attempt to use guide bushings.

I am not able to center my Woodcraft Guide Bushings (brass) in my PC 693 or Craftsman 320.27683. Both routers have their original base plates and are designed for bushings. I have followed some suggestions from youtube about centering the bushing on the bit by rotating the base plate one mounting screw at a time until the bushing is centered. No matter what I do the bushing is not near center. I can only get it down to about 1/16" off center.

The bushings are sloppy in the base plate. Actually, when measuring the outside diameter of each guide bushing they vary quite a bit. Is this common? I paid $35 for this set. Should I have expected tighter tolerances?

Is there any remedy for keeping them from slopping around? I have resorted to wrenching on the bushing locknut which makes it tight, but, I cannot get them adjusted close to center while wrenching on them. I don't have time to order a centering cone/pin. Can I make one on the wood lathe? If I make one do I mount the cone in the chuck first, then mount the base plate and bushing in that order?

Thanks, Tim


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## Quillman (Aug 16, 2010)

This Masi rider can get you within a few mils of center.


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## Bikeworks (Oct 24, 2012)

Thanks, I found this post reply (below) by "curious george" that explains the procedure well. Thought I would have to create some type of cone shaped thing to get center. I will give this a try. Thanks curious george

1. Remove the base plate from your router.
2. Mount a 1/4" ID bushing on the base plate.
3. Insert a 1/4" straight bit, drill rod or drill bit in your router collet and tighten it in.
4. Replace the base plate on your router with the bit or rod through the bushing and tighten the screws.
Your base plate and bushing should now be centered. If not you will need to enlarge the mounting screw holes slightly to allow the base plate to align itself with the bushing and bit.
__________________
George
Fort Worth, Texas
City where the west begins.


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## jschaben (Jun 21, 2009)

Bikeworks said:


> Hi forum, it's my first attempt to use guide bushings.
> 
> I am not able to center my Woodcraft Guide Bushings (brass) in my PC 693 or Craftsman 320.27683. Both routers have their original base plates and are designed for bushings. I have followed some suggestions from youtube about centering the bushing on the bit by rotating the base plate one mounting screw at a time until the bushing is centered. No matter what I do the bushing is not near center. I can only get it down to about 1/16" off center.
> 
> ...


Hi Tim - First off, are the screws that hold the base plate on tapered (flat head) screws or pan heads. If they are flat heads with the taper on the bottom of the base, use a forstner bit to flatten the tapered screw holes. Not much, just enough to hide the heads of a pan head screw. Switch out the flat heads for pan heads, that should give you some adjustment of the base plate. OK, a 5/16 OD guide bushing usually has a 1/4" ID so you can use that and a 1/4" bit chucked in the router to tighten your base plate on center. 
I'd recommend you go ahead and pick up a centering cone and make or buy another base plate but this should get you out of a bind.


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## Bikeworks (Oct 24, 2012)

Thanks John. Looks like I will have to use your advice to flatten out the mounting holes. The counter sunk screw holes force the base back to out of center every time. Thanks for the advice.


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## jschaben (Jun 21, 2009)

Bikeworks said:


> Thanks John. Looks like I will have to use your advice to flatten out the mounting holes. The counter sunk screw holes force the base back to out of center every time. Thanks for the advice.


Hi Tim - yeah, I was thinking the 893 used tapered seats. I still recommend you make a new base as soon as able. Not sure how much plastic you have left under those screws and it may be susceptible to cracking around them. Should work OK for awhile, the long term is what I was thinking of. 
Base plates are pretty easy, no lathe required. I start with a blank and double face tape the existing base plate to it. The old one doesn't need to be perfectly centered on the blank, just close. I use the existing plate as a template to drill the mounting holes and then put counter bores around those. I then attach the blank to the router base and install a 1/8" bit in the router (Just a note, a 1/4" bit will work just as well but it does need to be a spiral). I plunge the bit through the blank to mark the exact center. Remove the new plate from the router and use the router mounting holes to screw it to a piece of scrap that can be clamped to the drill press table. Use a 1/8" bit in the drill press to align the base plate to the drill press and clamp in place. Now use forstner bits to drill the bushing hole and counterbore. 
This method pretty well insures a centered plate, or at least one that requires very little adjustment.


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## Bill B (Jan 17, 2013)

*Bit is off center*



jschaben said:


> Hi Tim - yeah, I was thinking the 893 used tapered seats. I still recommend you make a new base as soon as able. Not sure how much plastic you have left under those screws and it may be susceptible to cracking around them. Should work OK for awhile, the long term is what I was thinking of.
> Base plates are pretty easy, no lathe required. I start with a blank and double face tape the existing base plate to it. The old one doesn't need to be perfectly centered on the blank, just close. I use the existing plate as a template to drill the mounting holes and then put counter bores around those. I then attach the blank to the router base and install a 1/8" bit in the router (Just a note, a 1/4" bit will work just as well but it does need to be a spiral). I plunge the bit through the blank to mark the exact center. Remove the new plate from the router and use the router mounting holes to screw it to a piece of scrap that can be clamped to the drill press table. Use a 1/8" bit in the drill press to align the base plate to the drill press and clamp in place. Now use forstner bits to drill the bushing hole and counterbore.
> This method pretty well insures a centered plate, or at least one that requires very little adjustment.


Thanks everyone. I just registered and this nicely answers my first question. cheers, bill.


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## jw2170 (Jan 24, 2008)

Bill B said:


> Thanks everyone. I just registered and this nicely answers my first question. cheers, bill.


Your welcome, Bill.

Glad you could join us.


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## Mike (Nov 22, 2004)

You can purchase a centering cone for $8 on Amazon. I think this is the easiest way to adjust your routers sub base plate. This can also be used for installing a mounting plate.


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## Cherryville Chuck (Sep 28, 2010)

I think I remember BJ recommending adding an o-ring between the two halves to keep the assembly from loosening up. A 1/4" or 1/2 drill bit can also be used to center with in the short term.


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