Router / hole cutting question (1 Viewer)

[Todd Stout]

I now have the parts to build my Adire Kit 281s and Kit 81s but I'm not exactly sure how to make the holes in the front baffles. I notice from reading through old posts that most of you use plunge routers to cut out driver openings and to rabbet the openings. I have access to my dad's workshop which has just about everything you can imagine as far as tools go but he only has a Craftsmen fixed base router (that is currently mounted in a table). Will a fixed base router work for this?

I am familiar in the use of most of the tools in his workshop but I have never used a router before. Can you recommend a source for information (hopefully online) on using routers, especially as they relate to cutting holes and rabbeting?

Thank you.

 

[Robin Smith]

If you are adventurous you can make your own circle jig fairly cheaply.

I borrowed mine from a friend. He simply cut a tear drop shape out of perspex with the fatter end being the same diameter as the router base and the skinny pointy end extending roughly 2 feet away.

Then you countersink and drill some holes using the router base as a template and attach the router to the bigger end of the perspex.

You can use the arm extension to guide the router in a circle by drilling a hole through it at the right point.

If you have no idea what I am talking about let me know and I'll try and take a picture of it before I return the router. If anyone has something similar and has a pic of it, post it up as I am sure my description sucks.

Alternately, you can buy a Jasper Circle Jig but they are not cheap. Do a search on the DIY forum for Jasper and you'll get some results.

A Fixed router is fine for routing the circles, the plunge is just a little easier.

Hope this helps

Robin Smith

 

[alan fallert]

Does anybody have any pictures of thier homade circle jig. I need to build one for my router to cut out some endcaps. THANKS.

 

[Jim_Hunt]

A fixed base router will work just fine. A circle cutting jig need not be fancy. I usually make them cheap and throw away rather than a finished project.

Measure your router base and then cut a piece of (scrap) 1/4" plywood 1" wider than the base and about 12" longer than the radius largest circle you want to cut. This is just a simple rectangle. (Why waste time making it tapered and fancy?)

I picked 1/4" plywood since it usually available and close to the thickness of the router base. Since it is the same thickness, you can use the same router base screws to attach the router to the plywood. Sometimes the screws are some weird thread and size so this will save your efforts of finding screws and allow you to focus on more important tasks.

I usually use the plastic router base plate to mark the screw holes on the plywood template. Naturally, you put the base about a 1/2" from the end and center it across the direction. Just eyeball it. Measuring wastes time - really!

Drill the screw holes using an appropriate sized drill bit. Since the screw holes countersunk, you will need to use a larger bit to create countersunk hole. Some router brands, like Bosch, use a small screw and people usually have a larger bit to do the countersunk hole.

If you have a larger base plate screw, like on a Porter-Cable router, I suggest getting a cheap reamer style counter sink from the hardware store.

Put the (straight) router bit in the router. (You know, the one you are actually going to use to cut the hole.) Some routers allow you to separate the base and motor/collet. If this is the case, then you can put in the router bit in later.

Mount the router to the 1/4" plywood. Yes, we have not cut hole for the router bit. No need! Again, it just wastes time and it will make things easier later.

Now you have the router and the plywood base as a unit. Fire up the router and poke the bit through the plywood. You did put on your safety glasses, hearing protection, and dust mask? Now unpoke the bit and turn the thing off and unplug the router.

Turn over the router and measure and see how close you came to center. Close enough! Now measure to center on the other end and then draw a (center) line down the (1/4" plywood) router base.

All that is left to do is measure from the router bit hole to the center point of of your circle. (Don't forget to use the center line as your guide.) Remember which side of the router bit hole to use for your inside/outside edge. It isn't rocket science so I bet you can see what I am talking about just by a quick observation.

No go mark and cut some speaker holes...

Extra info, 1/2" shanks are better than 1/4" shanks. However, you can use 1/4" if you take smaller (shallower) cuts.

If you don't have a plunge router, drop the bit down through the 1/4" plywood base and lock the motor to the base. Do this before the router is turned on. You can then flex the router base up and firmly hold the router (and bit) above the material to be cut as you turn on the router. Slowly drop in the router and you're off.

The cheap, throw away jig I mentioned above can be made in 10 minutes in my shop. I'll give you 20. Also while it seems like I am throwing away accuracy when making the jig, it is just isn't needed. Only critically measuring the center pilot hole from the router bit hole is needed. My jig can usually make holes less than 1/32" diameter accurate which is close enough for almost anything.

FYI: I was a professional wood-worker for 18 years and have done this dozens of time.

 

[alan fallert]

Jim, thanks a lot I am more confident now then ever on building my own. great description on building this circle jig.Thanks a million.

 

[Todd Stout]

Thanks a bunch. You guys have been A LOT of help.

The router I have access to is a Craftsmen fixed base router with a 1/2" shank.

One more question... is it better to cut the holes and then rabbet them or should I do it the other way around?

I'm going to document this project as I progress so I should eventually have photos to share.

 

[Phil M]

Todd:

If you click on my signature link, it will take you to my first DIY project. I went step-by-step and took pictures of each stage. I almost just made my own circle jig, but I found a fairly decent one at Lowes for 19.95 so I bought it. There is a picture of it on my site as well.

Page 7 of my site is where I start routering!

Phil

 

[Todd Stout]

Thanks Phil. I'll take a look for that circle jig next time I'm at Lowe's. I'm still not sure whether of not I'm going to build one or buy one. I had better hurry up and decide though because I'm getting really anxious to hear what these speakers will sound like.

 

[Jim_Hunt]

One more question... is it better to cut the holes and then rabbet them or should I do it the other way around?

A rabbeting bit is made to run after a circle (or any finished edge) has been cut. The bearing rides on the edge and the cutting area is larger than the bearing and will cut the rabbet.

If you don't have a rabbeting bit and want to use the circle jig/straight bit to cut the rabbet, which is not a problem, you will need to do it before you cut the circle. (After the circle is cut, there won't be a center to area to mount the jig.)

 

[Mike Strassburg]

I made my DIY circle jig out of 1/8" pegboard. Worked great!

I also second the: cut out the speaker flushmount first, the cut out the circle to avoid having to use a rabbit bit.

Good luck...Mike

 

[Todd Stout]

Thanks again guys... you have been a lot of help to me.

Time to go make some sawdust! Well... maybe this weekend anyway.