Fixed router to plunge router?

[csa3d]

Hey all,

When I purchased a router, I went with an inexpensive Ryobi fixed base router from the home depot (it's probably the one 1 1/2 HP one listed on ryobi's site) I am now wishing I had bought a plunge combo router of some sort.  Are there kits or bases one can purchase to turn a fixed based router into a plunge router?



Ultimately, I need to cut an interior circle, and don't have any idea how one does this with a fixed based router.  I've seen jigs for exterior circle cuts, but am looking to knock out the middle instead.  Any ideas?

Thanks
-csa

[fixedpigs]

if ryobi makes a plunge base for that...then you can most certainly use that motor with it...

how big of an internal circle do you need to make...?

[csa3d]

Looking to make something like 18-20" likely.  They do make 2-in-1's, and they make plunge routers.. I have not been able to find anyplace that sells a kit just for that though.   

-csa

[sstorkel]

Unfortunately, you're probably out of luck on this one. Best bet is to call a Ryobi service center and see if there's a plunge base that fits your motor. If you don't care about quality and only need to make a few cuts, you can probably buy an entire plunge router from Harbor Freight for $40 or so.

Luckily, you can use a fixed-base router to make a circle. You just attach your router to your circle cutting jig, then drill a pilot hole for the bit. Position the router so that the bit is in the hole, but not touching the sides. Fire it up and cut away!

[csa3d]

Luckily, you can use a fixed-base router to make a circle. You just attach your router to your circle cutting jig, then drill a pilot hole for the bit. Position the router so that the bit is in the hole, but not touching the sides. Fire it up and cut away!

Hmm.. So this means that

   1.)  My pilot hole should probably be a few sizes larger diameter then the router bit
   2.)  One side of the pilot hole will need to touch the edge of the interior circle (otherwise you will have an bump in the final cut)

Which makes we ask then how I would turn on the router, having no sides touching wood.  If it's just touching in 1 place inside the pilot hole, very minimally, will I be safe assuming all is clamped down tight?  Do I need to cut some sort of adjustment slot with a wingnut lockdown mechanism in order to turn on the router having the bit touch zero wood surfaces, then slide it up to the circles edge, then tighten the jig's pivot wingnut?  Either way, I feel like I'm going to turn on the router, and then risk being mulled somehow

Thanks again!
-csa

[csa3d]

While we're asking questions here, if I was cutting plexiglass and not wood, would this change the answers to any of the above questions.

Thanks
-csa

[ChadTower]

   2.)  One side of the pilot hole will need to touch the edge of the interior circle (otherwise you will have an bump in the final cut)

Not really.  You can just make it close - nothing you do for that is going to be 100% dead perfect at the first cut.  Get it close and finish that spot with a good chisel.

[csa3d]

   2.)  One side of the pilot hole will need to touch the edge of the interior circle (otherwise you will have an bump in the final cut)

Not really.  You can just make it close - nothing you do for that is going to be 100% dead perfect at the first cut.  Get it close and finish that spot with a good chisel.

Guess I'm a woodshop bonehead.. I see how that works if I was cutting out a disk, and I wanted to keep the Disk, but I want to discard the disk, and keep the hole and the wood surrounding the hole.  Are you saying therefore, to cut the hole a tad shy of my desired diameter, and sand it to touch the desired circle diameter?  Sorry if this sounds stupid..

-csa

[jhabers]

The way i did it before I had a plunge router is to put the router on a circle jig, set the blade above the cutting surface, turn on the router, then lower the blade into the wood and go! Plunge it manually. I have done this dozens of times before getting a plunge router and always worked for me. Make sure you have a firm grip on the router while lowering it into the wood

Jon

[ChadTower]

Guess I'm a woodshop bonehead.. I see how that works if I was cutting out a disk, and I wanted to keep the Disk, but I want to discard the disk, and keep the hole and the wood surrounding the hole.  Are you saying therefore, to cut the hole a tad shy of my desired diameter, and sand it to touch the desired circle diameter?  Sorry if this sounds stupid..

Here's another way, probably a bit simpler.  Drill a pilot hole a third of an inch in and use a jigsaw to cut out the inner circle a third of an inch in all the way around.  Then use the router to flush trim the edge.

[csa3d]

Guess I'm a woodshop bonehead.. I see how that works if I was cutting out a disk, and I wanted to keep the Disk, but I want to discard the disk, and keep the hole and the wood surrounding the hole.  Are you saying therefore, to cut the hole a tad shy of my desired diameter, and sand it to touch the desired circle diameter?  Sorry if this sounds stupid..

Here's another way, probably a bit simpler.  Drill a pilot hole a third of an inch in and use a jigsaw to cut out the inner circle a third of an inch in all the way around.  Then use the router to flush trim the edge.

With this technique, I'd still use a center pivot router jig like this one


Then, I'll need to make sure I have a piece of wood of the same thickness under the pivot bolt so that the jig rests level.. then rip away?  I'll still have to turn on the router with it touching the wood, no?

Or are you suggesting to first cut out a circle, the size I want the hole.. then use IT as a guild to flush trim with?  This seems like more work then purchasing a ?plunge bit? and manually plunging like jhabers  is saying, no?

-csa

[csa3d]

The way i did it before I had a plunge router is to put the router on a circle jig, set the blade above the cutting surface, turn on the router, then lower the blade into the wood and go! Plunge it manually. I have done this dozens of times before getting a plunge router and always worked for me. Make sure you have a firm grip on the router while lowering it into the wood

Jon

What kind of bit would i need to do this?  Something longer, with teeth on the bottom like a drill bit, right?
Thanks!

-csa

[DaOld Man]

Hey CAS3D,
You can probably use that router the same way I did mine.
Just make sure the bit you use has cutting shanks as long as the wood is thick, then take it slow while routing through the whole thickness of the wood (1 pass).

Home depot sells this one:

Click

Just make sure the cutting part is as long as the wood you are using is thick, so you can make the cut in one pass.
You will have to drill a 1/4" hole first, to fit the router bit in. If you drill the same diameter as the router bit, you wont have a "bump" in the wood.

[ChadTower]

Which piece are you intending to keep?  The circle or the piece you cut the circle from?  That method is for cutting and keeping the circle.

[csa3d]

Which piece are you intending to keep?  The circle or the piece you cut the circle from?  That method is for cutting and keeping the circle.

Ahh.. gotchya.  Well, I need to do two cuts total.  One will be to keep the circle (which will be larger, and mounted to a monitor as a back bezel), the other I'll be needing to keep the wood from which a smaller circle was cut (acting as the top bezel).  Together, these bezels will allow a clean bezel mask for monitor rotation.  I'm currently trying to figure out the top bezel, where you keep the wood the disk was removed from.

AT this point, I'm leaning towards manual plunging, unless there is a much better trick..

-csa

[jhabers]

Guess I'm a woodshop bonehead.. I see how that works if I was cutting out a disk, and I wanted to keep the Disk, but I want to discard the disk, and keep the hole and the wood surrounding the hole.  Are you saying therefore, to cut the hole a tad shy of my desired diameter, and sand it to touch the desired circle diameter?  Sorry if this sounds stupid..

Here's another way, probably a bit simpler.  Drill a pilot hole a third of an inch in and use a jigsaw to cut out the inner circle a third of an inch in all the way around.  Then use the router to flush trim the edge.

With this technique, I'd still use a center pivot router jig like this one


Then, I'll need to make sure I have a piece of wood of the same thickness under the pivot bolt so that the jig rests level.. then rip away?  I'll still have to turn on the router with it touching the wood, no?

Or are you suggesting to first cut out a circle, the size I want the hole.. then use IT as a guild to flush trim with?  This seems like more work then purchasing a ?plunge bit? and manually plunging like jhabers  is saying, no?

-csa

you wont want to cut the whole depth in one pass, use the jig, lower the blade about 1/8", lift the router just off the wood but keep the pivit point tight, turn on the router and plunge it in, make a ful circle, keep the router running and lower it another 1/4" and make another pass and proceed till you get all the way through

[csa3d]

Thanks all!  The manual plunge and lowing the blade in tiny increments worked pretty well.  Next time, I'll keep the jig moving while the blades on and not let it sit in on position.. I got a few nicks on the side at the places I stopped.  Good thing I screwed up the diameter math, and can cut a new one now!

Much appreciated on all this help
-csa

[csa3d]

The self plunging technique worked out really well!  Here's what all your help led up to.  Thanks again!

-csa