# questions about sub bases for use with PC template guides



## phillip.c (Aug 9, 2012)

Hey,

Last year sometime I got my first set of Porter-Cable style guide bushings. I also bought a new sub-base plate for use with the bushings. 

I have since tried a second base plate for two reasons. First, the plate (which was clear acrylic, which I really like) was smaller than the footprint of my router casting. Second, the hole that the guide bushing sits within was too large about about 1/32. Every time I use a bushing or need to re-tighten the nut, I need to use the centering cone. I hate this.

The first base plate was MLCS and the second was from Jasper tools. They were nearly identical. 

Question to each of you: do your guide bushings shift around in your base plate? How much slop is there? Perhaps my set of guide bushings are of lesser quality? (they are shop-fox)

I have access to a laser cutter and cnc router. Is it worth it to mill my own plate from 1/4 inch clear plastic? I would mill it so the bushing has NO slop. What do you guys think?


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## Mike (Nov 22, 2004)

Phillip, there should be no slop in the fit. Maybe take your sub base plate to a store and try the fit of a different brand of guide bushing?


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## 4DThinker (Feb 16, 2014)

If there is slop in the mounting holes of the plate then you'll need some room in the center hole to adjust the bushing using that centering cone. Or at least use the centering cone when you mount the plate and then have no slop for bushings in the center hole. If the router's base casting isn't perfect then you still may need some slop in that center hole so you CAN get the bit centered. 

4D


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## schnewj (Nov 18, 2013)

phillipdanbury said:


> Hey,
> 
> Last year sometime I got my first set of Porter-Cable style guide bushings. I also bought a new sub-base plate for use with the bushings.
> 
> ...


Do you have a "wavey" washer for the locknut? If you don't the nut will sometimes have a tendency to loosen. If your set didn't come with one, then do a search and buy a couple. It will make a world of difference.


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## Mike (Nov 22, 2004)

I think you guys are missing the point. Guide bushings are supposed to fit securely in the hole with no slop. Sub base plates are adjusted once if made that way but most are factory centered.


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## boogalee (Nov 24, 2010)

Hi Phillip

Check with Pat Warner (a member of this forum). I am sure he could help you with your problem. 

Phone number 760-747-2623 or email [email protected]


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## phillip.c (Aug 9, 2012)

Mike said:


> I think you guys are missing the point. Guide bushings are supposed to fit securely in the hole with no slop. Sub base plates are adjusted once if made that way but most are factory centered.


Yeah I'd really like to center the plate once and be done. I like the clear plastic and I plan to use this plate as my plunge base even when not using bushings. 

Is the wavy washer some sort of lock washer?


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## Stick486 (Jan 4, 2013)

they are called wavy, torsion or spring washers....
look like so...

.


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## Semipro (Mar 22, 2013)

Peachtree is one supplier of spring washers I'm sure there are others 
Mike's right, you center the base plate not the bushing


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## Stick486 (Jan 4, 2013)

Ace, Lowes and Home desperate has them...


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## phillip.c (Aug 9, 2012)

Is there anyone out there who might measure their name brand bushings with a caliper and let me know the diameter? I wonder how far off my shop-fox bushings are.

I'll definitely get some of those spring washers. Until I get a base plate that fits my bushings, though, the spring washers won't be too useful.


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## Quillman (Aug 16, 2010)

Was a PC vendor, made some of their Base Plates.
PC held the patents & was the inventor of the default 2 piece PC collar guide system.
Their flange (the max O.D. that rests in the base plate counterbore) tolerance is 1.369" - 1.374". And 1.372" is typical.
The sub base counterbore tolerances run from 1.375" - 1.379" and then some. 
Now the problem; base plates and collars today, are made world wide to all sorts of specifications.

In the worst case you could have 1.369" flange swimming in a 1.379" counterbore, .010" slop, a lot. Notwithstanding, the ring is still center-able with my ring and pin centering accessories. But the nut on the ring should be damn tight to prevent movement whilst routing. 
Appreciate that, in general, the eccentricity of the ring, counterbore and spindle is usually 1/2 the max. error. In most cases that can be tolerated but it is still advisable to do as little router rotation as possible to keep the same radians of the collar against the templet. More on the Collar guide.

And one other thing for you base plate makers. There are 3 critical diameters of a sub base. That is, they're critical if you're into symmetry and precision routing. The cutter hole & counter bore should be concentric & concentric to the sub base screw hole circle. And both the CB & SHC should be concentric to the major diameter of the plate. With a square or rectangular plate you can ignore the later but it would be nice if the cutter hole was on the length & width centerlines.


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## phillip.c (Aug 9, 2012)

Thanks for the info guys. Looks like I'll be moving forward with my sub base project.


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## Ghidrah (Oct 21, 2008)

This is what I've experienced over 20 something yrs with my PC routers and B plates regarding centering the BPs and guides.

1. Repeated removals, replacements and retightening of BP screws has modified the base's screw R/Os requiring a centering jig only when I'm setting up for template guide work. All my bits work just fine in the routers un-centered PB.

2. Regarding repeated use of guides, inlay and not, the BPs guide insert opening has modified to where the guide has room to move, miniscule. This only becomes an issue when I'm doing inlay or pattern work and requires a centering jig.

3. From repeated use, the PC brass inlay guide has been modified and has some room to move within the insert opening. This movement is miniscule but enough to cause an uneven offset within the guides ID which causes dupe error when pattern cutting.

4. I have never had a brass guide ring nut slip before during or after use, I have had the white metal ring nuts come loose, channel lock pliers took care of that, although I'm going to try out the wobbly washer thing.

As my tools got older and I notice the difference I adapted. I bought centering jigs when I began making my own BPs, they work, I blow through it fast enough not to piss me off and I'm working. Everything changes as it ages kind of like entropy.


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## Cherryville Chuck (Sep 28, 2010)

BJ used to suggest putting an o-ring under the nut. It would not only keep the nut on, it would keep the assembly from walking around if out of spec like Pat suggests.


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