Best method for cutting driver holes?

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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.

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.
when I start building my subs I'll definately be buying one of these...,43000,43001&ccurrency=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...

I just noticed... max. cutting diameter of 7.5inches...
there is another jig they sell which can make extremely large holes.,43000,43001&ccurrency=1&SID=
It looks like it could be reverse-engineered pretty easily.
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.

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.
Rotozip + Attachment?

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.

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Thatch_Ear said:
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.

Cutting holes

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!

I have yet to see a Jasper circle cutting jig, but, according to a guy at Home Depot, the only thing securing the blade is a wing nut that may come loose with vibrations during use. He said this happened in a shop class of his once and the blade went sailing across the room and embedded itself into a wall. It seems like one should be able to avoid a tragedy by simply being aware of this and watching the wing nut, but, Home Depot no longer sells the product because of the danger it poses. So maybe there's something more to it? If not, it seems like it would be the ideal tool, provided your drill has enough torque.

I'm off to Home Depot shortly. Will come back with plenty of wood and hopefully something to cut it with.

Cutting Circles

I've used the Jasper Circle Jig Model 200 several time and it works
great. You have to start by cutting the flange first then cut the speaker whole.

You should be using a 1/2 shank plunge router and a solid carbide
dual fluted spiral up cutting bit, DO NOT use a Highspeed steel
bit it will dull quickly in MDF. Take you time when cutting the speaker whole, take three passes lowering the bit 33% each pass. Of course you can't make a contiguous circle cut because you need leave the center supporting the jig. You finish the cut with a Jig Saw. This will leave you with a much cleaner circle cut than a jig saw. Remember to get the chuck on the router tight.

Check out Woodcraft or Woodworker Supply 1-800-645-9292 sales the bits and the Jasper jigs.

Good Luck

I finally saw a picture and article of the Jasper Model 200. It's not at all what was described to me by two different hardware store employees. I have yet to see it an action, but it doesn't look dangerous at all. In fact, it looks like it would work very well. If the local Woodcraft store is open today, I'll pick one up and post my experiences.

Thanks again.

I have seen pics of both the rigs from Jasper and I dout they are any more dangerous than any other rig. I like a hole saw and a rotery rasp for small holes. The rasp is very dangerous because I use it in a Roto Zip. Once it gets hot if you hit a hard place the shaft will bend and the centrifical force at 30K rpm plus can have things flying off at tremendous velocities. All part of the fun. I sculpt very hard woods with this setup and have a deadman switch. I also dress for the occasion, as pieces of wood or MDF imbedded in your skin is not pleasant. Just remember as you work if the metal gets hot and cools slowly it will be soft and more apt to break. These machines are great time savers but they can kill you. Then your old lady will sell your system in a garage sale for $10. Which is a bad thing unless I am 1st to show up at the sale.
Jasper Circle Cutting Jigs Are

a very good thing. I bought a Porter Cable 693 "kit" today - motor, plunge base, fixed base and case from Woodcraft. I also bought a carbide dual flute spiral upcut bit (for cutting holes all the way through the board), a carbide 1 1/4" straight (or mortisse) bit (for cutting the shelves/notches in which the driver flanges will rest). and a Jasper Circle Cutting Jig Model 200. A number of problems meant that it took me from 9am until 7pm to get a working router and the proper collection of clamps, double-sided carpet tape, bits, etc., BUT I did get to cut three holes and a mortisse with the Jasper Circle Cutting Jig and I have to say it was one of the most satisfying experiences of my life. It was smooth, easy, fun and 100% safe.

At the time I made my original post, I was under the mistaken impression that a Jasper jig involved a post of varying length with a blade at the end that rotated around in circles. This was what was explained to me by the local Home Despot employee with whom I spoke. Obviously incorrect.

Sorry if my posts caused any confusion. I would highly recommend the Jasper jig to anyone looking to make perfect circles without a fuss. Be aware that it only works with certain routers, however (unless you drill holes in the bottom of your plunge router for the Jasper base plate).

Just finished using the Jasper Model 200 to cut 4 x 6.5" woofer cutouts recesses and baffle back cutaways + 2 x 3" tweeter holes - the best $39.95 I have ever spent on a tool. I found nothing dangerous about the jig. It's secured by two fine thread stainless phillips head screws to the bottom of your router and if you follow their directions it's easy and accurate. Watch out for the formula in Appendix A for cutting holes with a bit other than 1/4" though - it's incorrect in my version of the manual. I haven't emailed them a heads up yet
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