Router bit suggestion

[Dotay]

I received my new router (3 1/4 HP Hitachi M12V) yesterday and my Jasper Jig will be arriving sometime this upcoming week so it looks like I'll finally be able to start building the enclosure for my 15" Avalanche sub next weekend. This will be the first time I've used a plunge router for cutting circles so I'm a complete newb. My dad is a carpenter however so I'll probably be enlisting him for some help if needed although I'd like to to stay fairly true to the Y in DIY.

OK, so the last thing tool wise I can think of that I need is router bits. My enclosure is going to be a sonotube design and I am trying to stick as closely to design Thomas used in the Tubezilla project. I have read that I'll need a flush trim bit to do the cuts and a roundover bit to do the...rounding over. I'm not sure what kind of bit is used to do the flush mounting so I'll need some help there. I don't have any other projects lined up at this moment but at the same time if I can spend a little extra to get a lot more quality I'll go in that direction for potential future use.

I read back through some of the old posts and someone suggested MLCS Woodworking as a good place to buy bits. They have a 15 piece anniversary set on sale for $34.95. This seems like a pretty good price and it has a flush trim and a 3/8" roundover bit. Does this seem like a good deal and would it have all the necessary bits to finish this project? Ideally I'd like to stay around $50 for bits but I'd be willing to spend more if I felt there was adequate value in it. I also found this Grizzly set on Amazon.com. It has two flush bits and 4 roundover bits for $24.95 but I know nothing about the quality of Grizzly products.

Naturally any help will be greatly appreciated. :T

[JonMarsh]

Congrats on your Hitachi- they're great routers, I have two of them. (like to leave things setup in one configuration).

I buy stuff from MLCS, but a "collection" is only a good deal if you're likely to use most of the bits. Besides the flush trim bits, I find myself using large 45 degree bevel bits, and larger roundover bits than 3/8", plus straight fluted 1/2" and 3/4" for driver cutouts. Might be better just to get those. My favorite bits are Bosch, though Rockler has some good house brand stuff at their stores. If you have a Rockler store in your area, check them out, too, besides the big box stores.

~Jon

[cjd]

I've heard some not so good things about the Grizzly bits, so I dunno.

My collection keeps growing, but I have found it worth purchasing bits as you need them instead of sets - you may pay a bit more, but you may also not end up with lots of bits you never use.

For starters, unless it is not possible, I suggest *always* getting 1/2" shank.

For flush-trim, I would suggest a 1/2" on a 1/2" shank. You'll need a bit with a cut length longer than whatever you wish to flush-trim. I have 1 1/4" and 2".

For round-over, what radius? 1/2" is often considered "small" on larger speaker projects. 3/4" is common, and you've enough router to swing the 1 1/2" round-over and make many of us quite jealous. :P

For most driver cutout work I use 1/4" spiral upcut bits. If I'm cutting through a final veneer layer, I do one pass with a 1/4" spiral downcut bit to a depth of no more than 1/8". In this case, you may wish to pick up a 1/2" or larger straight-bit (or spiral) for the driver recess (for flush-mounting), though you can simply take multiple passes with a 1/4" bit. I really prefer spiral cut when I can use it for working with ply, and MLCS even has spiral cut flush-trim bits (though not in the 2" length).

Some people like to get rabbet bits for doing driver recesses (this can be helpful if you veneer after you do the cutouts).

For smaller projects, 45 chamfers are helpful for driver relief on the back of baffles. With a chamfer, the larger bits can always do a smaller bevel but the smaller bits can NOT do bigger. So i just got the biggest I could get.

Go ahead and ask more if you're still lost.

C

[Paul H]

Chris posted some great advice there. I personally have a large aversion to cheap router bits spinning at 10 to 20 thousand rpm just a few inches from me. For that reason mostly, along with durability and smoothness of cut, I only buy high quality "brand-name" bits.

Have a look here : http://www.leevalley.com/wood/page.a...168,46171&ap=1
They are not the cheapest - but their quality and service is in my experience excellent.

Paul

[ThomasW]

I'm cheap, sleezy, old, and have no fear. So I buy the low-buck Oldham Viper bits from my local Home Depot and they work fine ......:wink:

I use the solid carbite 1/4" spiral cut up twist bit to cut the outside edge of the rebase, then plow-out the rest with a 3/4" flat bottom bit. I then finish of the remainder of the driver cutout with the spiral bit.

I use a 3/4" round-over for most everything else

Note that if you're going to copy one of my tube sub designs you'll need to use a 1/2" to 1/4" adapter to get enough plunge depth. And occasionally it will be necessary to start at cut from one side of the panel and complete it from the other, given that the thickness of some pieces is 3 layers of 3/4" material.

[dawaro]

I use a lot of bits from Rockler. They even have discounts based on quanity. I have also used the MLCS bits. I have some very large bits for cabinet making that I got from MLCS and I have had nothing but good results from them.
If you plan on using them in the future I would say get either a spiral flush trim bit or this bit from Amana . It uses blades that can be replaced rather than replacing the entire bit.
Also be careful when using smaller bits. With a large router it is very easy to push the bit to hard and break it.

[Dotay]

I use the solid carbite 1/4" spiral cut up twist bit to cut the outside edge of the rebase, then plow-out the rest with a 3/4" flat bottom bit. I then finish of the remainder of the driver cutout with the spiral bit.

Is there a particular reason you use the flat bit to do your cutting instead of just using the 1/4" spirall? It would seem to me that I would be able to make my entire cut through with the sprial bit, but then again I'm a n00b when it comes to woodworking.

Note that if you're going to copy one of my tube sub designs you'll need to use a 1/2" to 1/4" adapter to get enough plunge depth. And occasionally it will be necessary to start at cut from one side of the panel and complete it from the other, given that the thickness of some pieces is 3 layers of 3/4" material.

So do you glue up the layers together ahead of time and do all the cuts at the same time? If so how do you get the larger bottom layer if they are all glued together?

As far bits go I guess I was thinking that the flush trim bit would be what I would need to make the actual cut but it looks like you guys are recommending a 1/4" spiral upcut. So this is what I'm thinking I'll need based on your recommendations I'll need a 1/4" spiral upcut, a 3/4" straight/flat bit, a 3/4" roundover, and the flush trim bit would be unnecessary. Assuming I would order from MLCS which of these spiral upcut bits would you recommend, #5146 or #903? Should I get the #7779 straight bit or the #7755 plunge style bit? The roundover I'm looking at #8656.

Thanks again for the help here. I'm getting really excited about making some sawdust. :T

I'm also planning on taking lots of pics of the process to help out future n00bs like myself.

[Dotay]

Oh, and how are the roundover bits measured? Is 3/4" the depth it cuts or is it something else?

[ThomasW]

Is there a particular reason you use the flat bit to do your cutting instead of just using the 1/4" spirall?

It takes a LONG TIME and a ton of pin settings to plow out a recess for flush mounting a big woofer using a 1/4" wide bit. With the 3/4" bit you can use one diameter setting, take out small amounts of material at a time, and the bottom will be nice and flat.

So do you glue up the layers together ahead of time and do all the cuts at the same time

Actually it's been so long I don't remember. If you look at the pic below.



You can see a router mark (vertical nick) in the middle layer thats not in either other layer. That means the layers were cut to the outside diameter then assembled. I probably glued up two layers, cut them to size, then added the 3rd layer and evened the layers with a trim bit

Is 3/4" the depth it cuts or is it something else?

It's the radius of the arc it can cut

[Dotay]

It takes a LONG TIME and a ton of pin settings to plow out a recess for flush mounting a big woofer using a 1/4" wide bit. With the 3/4" bit you can use one diameter setting, take out small amounts of material at a time, and the bottom will be nice and flat.

OK, I misunderstood what you were saying. So you use the 1/4" bit to make the outside of the flush mount, use the 3/4" bit to make the actual flush mount, then move the router position to make the inside cut and it's this cut that actually cuts all the way through to the other side (assuming I had enough router depth to cut all the way through). That makes sense as I was wondering what the best sequence of cuts would be used to be the most effecient.

How deep would you recommend making the flush mount recess for the 15" avalanche without the rubber stripping?

[Marzen]

Also be careful when using smaller bits. With a large router it is very easy to push the bit to hard and break it.

So true, having to throw away a 1/4" bit & your underwear can ruin a Sunday afternoon ops: . . I 'generally' don't plunge any deeper than the diameter of the bit shaft for each pass, & for as deep a cut as you're planning I would go with a larger shaft size to reduce runout & increase safety. I have mostly Rockler bits, but hey, they're on my way home.
Looking at Thomas' photo reminded me - a little masking tape on the top of the jig allows you to mark your pin locations. As to using duct tape for a dust shield; well, that's downright cheap & fearless. I could find no evidence of sleeze in any of the photos however.

[thylantyr]

Good bits and a variable speed 3+ horse router is a
winning combo.

I use Whiteside bits.

http://www.routerbits.com/

MDF:
The SC21 is my workhorse bit, not cheap @ $23 but
I do one pass cuts because I hate multiple passes and
when the bit gets worn, I throw it out and get another.
/lazy

I try to treat the $100+ bits with more respect so they last
longer, but I've been able to use the Whiteside 1.5"
roundover bit on 1.5" thick MDF and do that cut in one
pass with ease. Get a variable speed 3 horse router.

[Hank]

I'll put in a plug for the MLCS bits. I've used them more than any other brand for several years and none have failed or worn prematurely. They are a quality bargain. I use 1/4" solid carbide upcut spiral bits for my circle cutting (Jasper jig). The advice to plunge only 1/4" at a time is sound. I use a 3/4" roundover bit on my cabinet front vertical edges for regular bookshelf and tower cabinets and a 1/2" roundover on my BozeBuster cabinets. I've also got a big 1 1/4" roundover mother that I'll use some day on some super-thick baffles. A 2-flute flush trim bit will do your veneer trim nicely. Be sure to wear a dust mask and try to vacuum the dust as you make it. Ask your Dad if he can rig up a dust collection tube attached to your router so you can hook your shop vac to it to try to suck up as must dust as possible as you route.
Practice on several pieces of scrap to get the feel and appreciation for the router.
Hint: use a couple of pieces of double-sided carpet tape to temporarily stick your baffle to a scrap backup board, making sure the tape covers part of what will become the scrap discs as well as the baffle piece. That way, the disc won't move and cause you to cut a notch into the side of the driver cutout as you complete the circle cut.

[Lex]

ok, here's my router "bit". what did the router table say to the 1/4" round bit? Let's have an Ogee?

Lex

[Dotay]

OK, I went ahead and bought the 1/4" upcut spiral, the 3/4" flat bit, and the 3/4" roundover from MLCS this afternoon. Thanks everyone for your suggestions and advice thus far. :T

Hint: use a couple of pieces of double-sided carpet tape to temporarily stick your baffle to a scrap backup board, making sure the tape covers part of what will become the scrap discs as well as the baffle piece. That way, the disc won't move and cause you to cut a notch into the side of the driver cutout as you complete the circle cut.

I'm not quite sure what you are describing here. Do you have any pictures that show visually what you are describing?

[PMazz]

This is one of my favorites for making the driver recess since I always make templates of my baffles and route after assembly.



I use the 3/4" version and jigsaw out the middle for the driver.



Pete

[jdybnis]

Interesting technique. What are the benefits of routing after assembly and using templates?

[cjd]

Interesting technique. What are the benefits of routing after assembly and using templates?

Perfection. Zero gap. The ability to go back and take out just a LITTLE more depth to get the perfect flush-mount (assuming you trial-fit the driver without removing the template, which is *quite* simple to do).

C

[Evil Twin]

Pete and Chris are true perfectionists... a most admirable trait. And clever, too.

[jdybnis]

Ok, now I'm really curious. Let me see if the process I'm visualizing is correct. You make the cutout with the jigsaw before routing out the recess so that you can drop in the driver to check if the recess is the right depth. And you get zero gap because you can experiment with templates without blowing the real baffle.

-Josh
Perfectionist in Training

[PMazz]

1) Being able to veneer before making cut-outs with no tearout.

2) Making a full baffle template also insures you have it right before sacrificing the enclosure. The last set of enclosures I did I used pre-veneered MDF and mitered everything. Sure saves time not having to veneer. Making a full template once and just clamping onto each enclosure seems to go faster using this bit and a jigsaw.

Pete

[cjd]

You don't even have to do the center cutout. It's a lot simpler to mess with the driver when you put it face-down - no getting stuck! But it's best if you have the through-cut though IMHO.

The template work I've done uses a standard template guide not a bearing-guided bit, so it's actually 1/4" larger all around than the driver cutout should be.

C

[Dennis H]

I'm with Pete and Chris on not doing the rabbets until after the veneer. Another way is to do the driver through-holes, but not the rabbets, before the box is assembled. That will let you do things like open up the backside of the holes in a thick baffle with a chamfer bit and will also give you access to the inside of the box during assembly. After you veneer it, you can use a rabbeting bit to cut out for the driver flange. The trick is to adjust the size of the driver cutout slightly (usually not a critical dimension) so a standard-size rabbeting bit will give you a good fit for the flange.