Best method for cutting driver holes?

[dc]

Hi all,

I'm hoping to build 5 baffles in the next 5 days with a total of 16 cutouts for drivers, 8 of which need rebates on one side and bevels on the other.

I'm hoping to make perfect circles so the routing of the rebates will go smoothly. I was thinking of using a Jasper circle cutting jig, but a guy at Home Depot told me that they stopped selling them because they are dangerous. Apparently, the blade is not attached very securely and occasionally flies across the room. Somewhat less than ideal.

Second choice, as far as I see it, is a jigsaw with some kind of compass-like attachment. I'm a little uneasy about the circularity of such a circle, but I've never tried it.

Any advice would be greatly appreciated.

brad

[Thatch_Ear]

I built my own jig out of masonite and it works fine Small circles are a pain because the radius is smaller than the diameter of the router base. I use a fairly long piece of masonite shaped like a teardrop whith the router in the round base. The piont works as a handle to easily and smoothly swing it around while cutting the circle out.

[bostarob]

I do something very similar to you, Thatch. I have multiple layers of 1/8" masonite in a teardrop shape. A nut and bolt act as the center pin. This can slide under the base of the router because of mult. layering of masonite.
-andy

[seangoesbonk]

when I start building my subs I'll definately be buying one of these...
http://www.leevalley.com/wood/page.a...urrency=1&SID=
There is a "switch currency" button on the top right corner of the screen if you want to know the US or AUS or EURO price.
There is one of these Lee Valley stores near my house and I've bought some stuff there and the service is good, but I can't vouch for the mail-order. They generally have really great tools, but they are sometimes a little on the over-priced side. You might be able to find this product in store closer to where you live.
Anyways, this seems like the ideal jig...

---*EDIT*---
I just noticed... max. cutting diameter of 7.5inches...
there is another jig they sell which can make extremely large holes. http://www.leevalley.com/wood/page.a...urrency=1&SID=
It looks like it could be reverse-engineered pretty easily.

[Pete Mazz]

I like to make a baffle template and route all the others using it and a top bearing pattern bit. Actually, first I position the template, scribe the holes, and hog out most of the material with a jigsaw. This makes much less dust and I find it's faster. The other plus is you can finish the box off first and then cut the baffles, with little fear of ruining them by a slipup or mis-measurement.

Pete

[Thatch_Ear]

About the dust, I have a talble in the back yard I can use and I have a powerful fan blowing to drive the dust away and wear the goggles, mask and face shield. MDF is especially nast stuff. Oh, and don't forget the earplugs and protectors since you can't put your fingers in your ears while using a router.

[dc]

Thanks for all the input so far. Very helpful.

Is a router the best way to go? I've seen a rotozip attachment made for cutting circles. It's a jig with a center point and an adjustable metal bar that attaches to the rotozip. They must make something like this for a router as well, no?

The router I have access to is 30+ years old and pretty much shot. One of the handles is loose, etc. I think it may be time to get a new router (or rotozip).

Thanks again.

brad

[bostarob]

I have tried roto zips. to cut one hole I went through 2 bits, and cursed horribly. Try it, if you will. The bit heats up very fast.
Just curious, How could that jasper jig be dangerous?
-andy

[planet10]

Originally posted by Thatch_Ear
Small circles are a pain because the radius is smaller than the diameter of the router base

A hole saw works well here -- at least for making the holes. If i need perfect rebates i get Chris to do them (he has a full cabinet shop at his disposal -- including a CNC milling machne). If not i have this really small, really lovely little Rockwell router and enuff practise to do a pretty good job freehand.

dave

[Bose(o)]

For holes 3.5" and smaller i use my Hole saw pieces otherwise I get my drill and jig out. I make five holes, top, bottom, left, right and center. I cut out the pieces so that my circle is cut out by quarters. That's how I do it, it works fine too! Have fun!