PC 690 Plunge Router Sub-base

[Corvin Alstot]

Short story - I am trying to cut a few mortise joints for a work bench leg. I bought a guide bushing to run around the sides of my shop made mortise jig which is base on a FWW magazine jig.

<O:p</O:pAfter attaching the guide bushing to the router sub base, I realized that the router would not center in the subbase opening even after loosening the adjustment screws and twisting. It is only off by 1/16" of an inch but this will not give a precise center in the bushing or make a precise cut in the jig. Part of the problem is the sub-base adjustment screws what to re-center in the screw countersink opening.

<O:p</O:pDo I just buy a new sub-base (I see Rockler has a clear base for $8), enlarge the openings in the plastic subbase template to limit the countersunk openings and force it into place, or is there a solution I am missing.<O:p</O:p

<O:p</O:pDid I say that it’s frustrating working with equipment that is not made with precision? It must be getting late and I am tired of working on the equipment rather than wood- excuse the rant.<O:p</O:p

[Curt Harms]

Hi Corvin

I feel your pain, I've run into the same thing. I've used 2 solutions. One was to make my own subbase out of 3/8" thick acrylic. I clamped a p-c subbase over the chunk of acrylic and drilled a pilot hole using a vix bit. I then drilled a countersink using a 1/2"(I think) forstner bit. The screws on the p-c subbase are 3/16". I drilled the thru hole oversize, 1/4" or more. I then used screws whose heads were flat top & bottom. Insert a 1/4" bit and install a 1/4" I.D. bushing. Rousseau also sells centering kit for $6 or so. Once the base is centered, tighten the sub base screws. This isn't a perfect solution, but it seems to work.

I think it was Pat Warner who observed that bushings are not precision solutions. I've started using pattern cutting bits with a bearing on the shaft above the cutter and bearing O.D. matches the cutter size. That bit will cut precisely and I don't have to do any template math. Easy, and no monkeying with bushings.

I've read about a 3rd solution that seems like a good idea but I haven't tried. Make a sub base with a 2 bearings equidistant from the bit opening and 2" or so from the opening on the bottom of the sub base. Place the bearings on either side of the piece to be mortised and twist the router. The bearings will ride along either side of the work and the bit will always be centered on the work. You could use a couple sticks to extend the edges if the bearing wanted to run off the edge of the work. To offset, put a spacer stick on one side. Seems like an interesting jig, anybody ever try it? (yeah, it'd be easier to draw it than to try to explain it :(


Curt

[Jim Dunn]

I had the same problem with my 690 Portercable router and called customer service. They determined, after I prompted them, that the base is drilled wrong. They sent me a new base, no charge. That's good customer service!!

[Corvin Alstot]

Looks like I am not the only one with this problem. You would think that their designers/engineers would create a sub-base that could be adjusted so as to be re-centered. Probably would not even cost any additional dollars to have this feature on the router.
Jim/ I will contact PorterCable but my router is at least 5 years old.
Curt/ I will look into pattern cutting bits with a bearing on the shaft above the cutter. Sounds like a simple solution.

[Jim Dunn]

Corvin, Porter Cable sent me a base that uses "cap screws" having counter-bores for the screw heads. The base it replaces has counter-sinks. At least with the counter-bores there is some adjustability of the base on the router.

I was trying to use it with a Whitesides inlay kit and couldn't get the bushing to line up with the center-line of the bit. That took care of my problem.

[pat warner]

Not sure of the Kosher-ability of this but do see the pin/ring link (http://www.patwarner.com/sundries.html)for some insight.

[Jim Dunn]

Very nice Pat. I've drooled over your web site a lot. My wife thinks I'm looking at something I'm not supposed too:)

[Andrew Ault]

I have the Pat Warner pin and ring used to center the guide bushings. They work perfectly and allow me to get the bushing exactly concentric with the collet.

The ring is slightly tapered and goes into the hole in the subbase. With the subbase attached loosly to the router, the 1/2" pin goes in the collet and through a 1/2" hole in the ring. At this point, the subbase is aligned with the collet and the subbase is tightened to the router and the pin and ring removed.

This requires that the router base be manufactured correctly, of course. It allows for the subbase to be attached very precisely.

As with everything Pat makes, the quality and design are first class.

- Andy

[john whittaker]

Corvin, all advice given is good (IMHO)

In woodworking there are often more than a few ways to skin the cat. When I use the router for making just a few mortises, I find it quick and easy to use my edge guide with a spiral bit without any jig. At first I balked at buying a quality edge guide with fine adjustment. But after using it one time realized how much value it offered. (I'm talking about a guide that is sold for your specific router, not the $$$$$micro guide)
If you have a bunch to make, a jig might be the ticket but for just a few, routing by hand using the fence works for me just fine. And eliminates the need for template guides.

Now...back to work:mad:

[Norman Hitt]

Corvin, you don't have to make a new subbase, just take the screws out, use an inlay setup to center the plate, then rotate the sub base to a new location, and use the Rousso marking kit, (small pointed studs) and drill new holes.

If you can find it, I made a post, or maybe a reply, (long) several months ago giving the step by step procedure to tune your router sub base to exact dead center, you can probably find it with the search function. Once you have your sub base tuned to Dead Center, All your router work will be easier and more enjoyable. I have never had a router, (any brand) that was "Dead on" out of the box.

For Curt Harms; The baseplate you are talking about with the two bearings on it, is used all time by the Router Workshop guys, and can be purchased from them. I've used it and it works great. Like you said, there are always more than one way to skin a cat. :D

Note: Sorry, but I went back and looked and can't find the post for the step by step, so I must have posted it on the "Other" Forum I used to hang out on, (Wood) if you care to look it up there. ( I sure thought it was on this one). :o