Two last dumb circle cutting questions... (1 Viewer)

[Brian J Dupuis]

Hey guys,
I finally have all my ducks in a row as far as finishing my first subwoofer project... finally got my router and installed my circle cutting jig, got a variety of clamps (thanks to Hank Frankenberg
for the Merle band clamp recommendation... got 2 of them waiting for the glue up... they look exceedingly useful!) for holding the project together while I glue, got my General Tools precision drill guide for cutting perpendicular holes (thanks Jack Gilvey!), got my MLCS 1/4" carbide spiral upcut bit, getting my replacement 1/2" collet chuck tomorrow for the used (read: rusted) one I got with the router (note to self: Amazon used ain't always what it's cracked up to be). So this weekend, barring any unforeseen screw ups, I may very well have a box put together .
Here's my final two questions for those out there who have used the Jasper jig. Everything I've read concerning router usage tells me to feed the router "into" the work. For interior work, like speaker holes, they thus recommend a clockwise direction. My question is, I've seen project pictures that have a picture of the router sitting there churning away, almost unsupervised, cutting the circles. I really don't remember which page it was, but the fellow was talking about sitting under a tree for 3 hours while the circles were cut. Is this what I should expect? After setting up the Jasper so it's ready to cut, do I simply crank the router up, plunge to whatever cut depth (I currently assume I'm going to do 1/4" depth cuts at a time, until I get the hang of it), lock the plunge and let the router do it's magic without even needing to hold on? Sounds cool, but just making sure. I plan on hacking up some of my scrap MDF with the router to get used to it, of course.
Dumb question number 2: I already have my finish plywood laminated to the front baffle. Perhaps this was a mistake, but let's go with it for now. How do I protect the plywood finish from chipping during the outermost flange routing? Anyone have secrets or tips?

 

[JimHal]

About leaving that router unattended, that is probably a huge no-no. I don't know if you misunderstood that page you looked at or not.

A router can be a pretty scarry tool if not given proper respect. You have a razor sharp bit spinning at 30,000 rpm waiting to cut anything.

If left alone I can see the router grabbing the wood and jumping clear off.

The pager you looked at my have had some sort of special circle cutting maching. A simple jig to cut a circle would not be enough.

Never leave a router on unattended.

As for protecting the wood. You can try simple masking tape on the area you want to cut. I've done this with table saws to prevent chipping.

 

[Pete Mazz]

The two best ways I know for eliminating tearout of veneer are:

1) Set the depth of your first pass to 1/16" and run the router CCW. This will force the cutting action of the bit into the edges of the veneer. Finish the other passes CW to your final depth.

2) More reliable way would be to make a pattern of you front baffle on a scrap piece of MDF, cut the same width of your actual baffle, but longer for clamping purposes. After you make a pattern with all holes for all drivers in exact locations, clamp it onto your baffle, aligning the holes as needed. Change to a top bearing pattern cutter in the router and route away (CW). To do the other baffle, if a mirror imaged pair, simply flip the template over.

Pete

 

[Patrick Sun]

Oh my! Routers are like any power tool, they need constant supervision and hands-on attention during operation. Once you turn on the router, you have to use your hands and arms to guide it, and keep it on the routing path. Make sure you wear a good dust mask (get the thick masks that cost 2/$6 at Home Depot), safety goggles, and baseball cap.

Please do experiment on scrap to get the hang of it.

I've always routed counter-clockwise (that's what the instruction told me to do - with MDF, you don't have to worry about the grain of the wood). So read the manual and find out which direction you should be going with the router. There were be one direction that feels better when you route, that's the right direction.

 

[JonahWicky]

In general, you should feed the router counter-clockwise when cutting a circle. If you feed opposite, the router will tend to 'walk' or pull itself along the material. Picture feeding a piece of wood into a table saw blade the wrong way (just keep everyone and everything out of the path of the flying wood!). It is possible, and sometimes desireable, to 'back feed' at VERY shallow or thin depths of cut, and holding on securely to the router. If you're not experienced with this, don't try it.

Make some practice cuts, and you'll be able to tell which way is easier to control and produces a better cut.

 

[Brian J Dupuis]

Thanks for all the input and good advice, guys. I envision an exciting weekend of experimentation and breakthrough . Hopefully one day I'll turn the tide and answer more questions than I ask here.

 

[Jack Gilvey]

If you never post again after this weekend, we'll assume you decided to let go of the router.

 

[Brian J Dupuis]

Fear not, I've learned my lesson . I enjoy keeping my fingers.

 

[Pete Mazz]

Jack...
Guys, when routing a plunge cut in material, it doesn't matter what direction you travel. When you route an edge, CCW around the piece is correct.
Pete

 

[Brian Bunge]

I just follow the instructions that came with my Jasper Circle Jig and route clockwise when using it!
Brian

 

[Pete Mazz]

That makes sense for a circle jig. The router will "pull" against the center pin when running CW.

Pete

 

[Hank Frankenberg]

Brian D, regarding your second question, this will work (my real experience) on veneered work: use a carbide spiral DOWNCUT bit. I've used one on expensive rosewood veneer and it worked perfectly - the bit slices downward through the veneer as you cut. The reason that we use spiral upcut bits on bare MDF or plywood is that they pull the dust and chips up out of the groove.

BTW, if you find one of those magical routers that allow you to place it on the wood, walk away and sit under a tree, I want one!

 

[Brian J Dupuis]

Brian D, regarding your second question, this will work (my real experience) on veneered work: use a carbide spiral DOWNCUT bit.

You know, this frightens me for one reason... this exact thought actually occurred to me as I was on my way back to work from lunch today. If that means I'm starting to think logically, I have great concerns. Thanks for the tip, Hank.

 

[Jack Gilvey]

Hank's right, I found that when I used an upcut spiral on plywood, it did leave a rougher edge on the top than on the bottom. But, in my case, the edge that will be visible (the one around the recess/countersink,not the one around the through hole) will have been already cut with a 1.25" carbide straight/mortising bit, which gives a nice edge (though the downcut may be nicer still, I've never used one). So I don't worry about the edge made by the upcut since it's under the driver.

 

[Brian J Dupuis]

Hmm... should I consider using a straight/mortising bit for the outermost cut of my flange, then? Would that leave a smoother finish than the upcut?