How to drill hole in a router adapter plate?

[Bud Brinkley]

Hello all! I bought a clear adapter plate to fit the bottom of my Ryobi router. I want to set this router up with a 5/8" guide bushing to do mortises in my new Morley mortiser jig that I just completed. None of the pre-drilled holes in the clear adapter plate fit my router so I will have to drill new ones. I have the centering cone fixture to position the plate exactly center to the router shaft, but I am at a loss as to how to precisely mark the position of the holes to drill. I can see through the plate to the router holes underneath, but I don't think I can precisely drill them very well that way. I spent a lot of effort to build my jig with very close tolerances for repeatable accuracy. I hate to lose all of that with a guide bushing that is not centered because my adapter plate holes are slightly off. The holes that I need to drill are fairly large to fit a 5/16" screw as that's what is required for the router.

Any tips or ideas would be very much appreciated. Thank You!

[Thomas McCurnin]

Remove the sub-base and using double stick tape, attach it to the acrylic base. Use it to mark screw holes with an awl, punch or the smallest vix bit that you have. While the sub-base is still on the acrylic, use a compass to mark the center of the larger hole for the Porter Cable guide bushing. Use a punch or a 1/16th inch drill bit to mark that center. I also trace the outline of the sub-base on the acrylic, Remove the sub-base.

Cut the new acrylic base to size based on your outline of the sub-base. Here, leave the line, and saw to the outside of the line. It won't fit perfect, and will look sloppy. Good, that is what you are looking for.

Now, drill the holes for the machine screws. I actually drill them slightly larger and sloppier on purpose. Countersink them.

Using a Forstner bit in a drill press, drill the bottom of the acrylic, the larger of the two Guide Bushing Holes, about half way into the plastic, so the guide bushing will sit flat. Now, use a second smaller Forstner bit to drill the through hole, using the point left behind of the larger bit as a pilot hole.

Attach your new acrylic base to the router base and leave the machine screws loose. If you did a really sloppy job drilling those machine screw holes like I suggested (I know you could do this, I have faith in you), there should be some play in the acrylic base of about 1/16th or less. Perfect.

Attach a centering cone. Now attach your Guide Bushing and a medium sized offset bushing. Raise the centering cone all the way into your new acrylic base. If you really did a sloppy job drilling those machine screw holes, your new acrylic base will self adjust to center. Tighten those machine screws.

If you were really sloppy and sawed to the outside of the outline line of the sub-base, the new acrylic base will have some run out, you know it slops over the router base by a small fraction. Sand it flush.

You're done.

The key here is to be really sloppy. Have a beer or two before starting this, and make sure that the machine screw holes are indeed sloppy and the cutting of the base outline is equally sloppy. However, when doing the cuts with the Forstner bit, I'd wait until first thing in the morning after a cup of coffee and drill those with care.

[Frederick Skelly]

Hi Bud! I don't have a solution for you, but just wanted to welcome you to the Creek.

Fred

[Bruce Wrenn]

If mounting holes open thru base of router, use a transfer punch to mark base. If they are blind holes, use either pointed set screws, or bolts with heads cut off ( and pointed) to make locations. Bill Hylton's book Router Magic covers this subject very well. You could use existing sub base and transfer punch to mark hole location. Would like to see some pictures of your Morley Mortising Jig, as it's on my ever growing bucket list.

[Bud Brinkley]

Thanks all for the really helpful tips! My new adapter plate already has a hole drilled for the guide bushings so no problem there. Unfortunately the base of the ryobi is not removable, so that complicates things a bit. I may try the pointed set screw or bolt trick and see if that works. I'll be sure to lay off the coffee while I am doing this! LOL
Thanks again!

[Thomas McCurnin]

If you sub-base is not removable (some Ryobi routers are glued on), then ....

Make a template out of poster board and punch out the approximate locations of the machine screw threads and center of of collet with an awl. Using my technique, the acrylic sub-base is supposed to be inaccurate so it moves to adjust to center.

Ryobi sub-bases, the really thin glued on types may be obtained from eBay for under $20. It actually pays to have an extra in the event your gets scratched badly or you want to make a template.

[Bob Jones 5443]

Bud, would this help?


446973

https://www.rockler.com/spring-tool-set?country=US&sid=V91040&promo=shopping&utm_source=google&utm_medium=cpc&utm_term=&utm_content=&utm_campaign=PL&gclid=Cj0KCQiA8dH-BRD_ARIsAC24umbe8l5sVa_9T_Cdyw8oMmK2jHybx7TsrwCiWx 31wsCZDgDN8_OAv9gaApgNEALw_wcB

[lowell holmes]

You might check this site.

https://www.homedepot.com/b/Tools-Power-Tool-Accessories-Woodworking-Tool-Accessories-Router-Bits/N-5yc1vZc8y9/Ntk-EnrichedProductInfo/Ntt-router+bit+set?Ntx=mode+matchpartialmax&NCNI-5

[Charlie Velasquez]

....... I have the centering cone fixture to position the plate exactly center to the router shaft, but I am at a loss as to how to precisely mark the position of the holes to drill. I can see through the plate to the router holes underneath, but .....
I hate to lose all of that with a guide bushing that is not centered because my adapter plate holes are slightly off. The holes that I need to drill are fairly large to fit a 5/16" screw as that's what is required for the router.

Any tips or ideas would be very much appreciated. Thank You!

The issue, then is keeping the holes concentric to your already established hole. Once the goal is established the method is the same as marking any other concentric point.

Use your centering cone as the fixed center of your preexisting hole.
Measure the distance as accurately as you can from center to a screw hole.
Make a trammel beam from a piece of wood (paint stick maybe?)
Make a dot that will drilled to fit the router centering bit and one for the screw hole
Drill the center hole. Drill the screw hole for a pin, or drill bit or something
Place the base on centering jig and use the trammel to mark a spot on the back of the base. Check it to see if it is in fact the correct distance by placing it on your router. If not, adjust the drilled screw hole in you trammel with a needle file ($2 for a set of 12 at Harbor Freight) or similar and repeat. (Aha, it would make sense to drill the screw hole the same diameter as your needle file)

When your trammel is the correct distance you can mark the circumference, or parts of it, by scratching the back of the base plate. Check again.
You can make holes anywhere on the scratch; the scratch will help the bit from wandering.

Your first hole will always be in the correct spot. The second and third holes will be the correct distance for concentricity but may be off left or right a hair. No matter. As long as you elongate the hole carefully along the scratch it will stay concentric. As long as the one hole, the first one, has no play, the other holes will have no play even if you elongated them as long as it is along the circumference scratch.

[Melvin Feng]

I can't fully visualize what you are trying to do, but if you need to transfer holes from the bottom of your router and can't remove it, could you use a piece a paper and a crayon on its side to trace out the positions of everything on the base plate? Imagine what kids do with butcher paper and leaves in elementary school to get the veins and the outline of the leaves.

If you can get a good tracing, then you should be able to use that as a template.

[Bud Brinkley]

A quick follow-up to my conundrum. I figured out that my adapter plate actually fit another one of my routers using their pre-drilled holes. So I just kept that one and ordered another one that actually fit my Ryobi router very nicely. Here it is installed. I want to use this router just for this mortising jig and leave it setup for that purpose. I have started another thread in the homemade jigs section describing my Morley Mortiser.

Thanks again for all those who gave me some very good suggestions and help!
447093447094

[Carl Crout]

Transfer punches. Very useful around the shop...........

https://www.harborfreight.com/28-piece-transfer-punch-set-3577.html?cid=paid_google|||3577&utm_source=google&utm_medium=cpc&utm_campaign=&utm_content=&gclid=Cj0KCQiA2uH-BRCCARIsAEeef3nt-oFRPhZveSEuM0ePzPlAReWE23I3tCLm2ofQcFeERyM1tjpunAE aAvDPEALw_wcB (https://www.harborfreight.com/28-piece-transfer-punch-set-3577.html?cid=paid_google|||3577&utm_source=google&utm_medium=cpc&utm_campaign=&utm_content=&gclid=Cj0KCQiA2uH-BRCCARIsAEeef3nt-oFRPhZveSEuM0ePzPlAReWE23I3tCLm2ofQcFeERyM1tjpunAE aAvDPEALw_wcB)