Routing Circular Holes

[workboy]

Hello:

What do I need in order to route a circular hole? I already have a template. I was thinking of clamping the new piece on top of the template and do the following:
1) drill a hole in the place to be routed out
2) use a fixed base router (fitted with a top bearing trim bit) to follow the curve
Is this the correct way of doing things? A local HD person told me I should get a template guide but then the template would have to be at the top and the cutting bit would start cutting into my table.

[Dave Arbuckle]

For a circle, a flush trim or pattern bit is a better choice than a template guide, because the bearing is concentric to the cutter. A template guide won't be, without an extreme effort to align it.

I would use a saw to rough cut reasonably close to the line, this will save a lot of wear on the router bit. A jigsaw will do this well, as would a coping saw.

When you use a guide on top, you elevate the workpiece in a convenient fashion (scrap pieces of 2x4s usually do it for me), and clamp. If possible, clamping the workpiece will really increase your ease in routing.

Dave

[workboy]

Hello:

There are different diameters of bits. Is there a general rule for let say a larger diameter give a smoother finish? Are there differences between different fixed base routers if all I do is to route out circles?

Thanks

[Dave Arbuckle]

Larger bits experience less tearout than smaller ones. In general, the largest bit that will do a job is best.

"Are there differences between different fixed base routers if all I do is to route out circles?" Tricky question.

There are big routers and small routers, wouldn't make much difference for this application.
Some have much better bit extension mechanisms than others, again not in this application.
Some run faster than others. Here's a difference, as a faster router gives a better finish for a given feed.
Some routers are simply of, shall we say, less than stellar quality. This I avoid at all cost, not only because I like high quality gear that lasts a long time, but because a machine that spins a heavy cutter at over twenty thousand r.p.m. should be of good quality.

The two fixed base routers I use are the Porter-Cable 690 and the Bosch 1617. Out of the box, the PC is a better machine, due to a bad design on the Bosch's baseplate. With a replacement baseplate, the Bosch is a joy.

But for this application only? Any quality router will do just fine. But are you really only going to cut holes?

Dave

[workboy]

Hey yo:

Yes I just cut holes and bullnose edges. What's the typical speed range available for routers? Home Depot has a Ryobi fixed base model R160 8Amp 25,000 rpm for $88 CAD. I bought it. You think have anything wrong with it?

[JSchnarre]

Hey Thanks for all the good info Dave. Routers are a bit out of my area of expertise. (pun intended)

Jake

[larliz]

I was wondering what you found bad about the bosch base plate. I just bought that router and it seems really good. Upon researching it I only heard really good reviews. This s a first. Tell me more.

<BLOCKQUOTE>quote:</font><HR>Originally posted by Dave Arbuckle:
Larger bits experience less tearout than smaller ones. In general, the largest bit that will do a job is best.

"Are there differences between different fixed base routers if all I do is to route out circles?" Tricky question.

There are big routers and small routers, wouldn't make much difference for this application.
Some have much better bit extension mechanisms than others, again not in this application.
Some run faster than others. Here's a difference, as a faster router gives a better finish for a given feed.
Some routers are simply of, shall we say, less than stellar quality. This I avoid at all cost, not only because I like high quality gear that lasts a long time, but because a machine that spins a heavy cutter at over twenty thousand r.p.m. should be of good quality.

The two fixed base routers I use are the Porter-Cable 690 and the Bosch 1617. Out of the box, the PC is a better machine, due to a bad design on the Bosch's baseplate. With a replacement baseplate, the Bosch is a joy.

But for this application only? Any quality router will do just fine. But are you really only going to cut holes?

Dave<HR></BLOCKQUOTE>

[larliz]

I have two routers. A Hitachi M12V plunge router. Its a 3.25 HP unit. Really big and bulky though. So I bought the Bosch 1617 mentioned above. No complaints here but I would like to know what is the problem with the baseplate. Other than that its a dream to use.

One other note and probably not one for your application but for safety sake. Please be carful to not use a really high speed if you are using larger bits. Most bits have a rating on them about the max speed. The last thing you want is a bit coming out of the chuck at 20k rpm. Very dangerous. Probably not a problem for your application but keep it in mind. Is the router you bought a variable speeed? That is definately a good feature.

[Dave Arbuckle]

Workboy, sorry but I don't know Ryobis...

Ah, the Bosch 1617 baseplate. Solid, with a huge hole in the middle. Some things you don't want to do with this baseplate:

With a bearing guided profile bit, don't route around a corner. With the big hole, you get very little support from the baseplate, wobble is likely.

A lot of my router use is on a dovetail jig (among other reasons, I give classes on the Leigh D4). Don't try the stock 1617 with Bosch's template guides. Once again, there is very little support when you move "out" (toward you) on the jig. As well, since the plate is solid, you cannot see where you are routing. This is a HUGE temptation to look under the plate, routing at face level. This is a potentially deadly activity to be avoided at all cost (should the router bit break, it can expel at your face at tremendous speed).

There are certainly a lot of activities that the stock 1617 will perform well, but with a minor change, it could unreservedly be the best in its category. To see my choice for what that minor change would be, go to Pat Warner's website, http://www.patwarner.com/ , and choose the link "Clear round sub-bases". For fifteen bucks, the base that's drilled for a Porter-Cable guidebush is a dream. With that one addition, the 1617 is my favorite hand-held router. For $25, you can have that and good visibility for larger bits too.

Dave
P.S. Jake....anytime.

[RGad]

There is a fairly neat book called "Router Magic" from which you can learn a lot about baseplates and routing circles (and other patterns). Try Barnes & Noble or one of the web-based booksellers. Full of plans for a number of jigs and gizmos, and well worth the $20 (I think) I paid for it.