Few Questions about Router bits

[codyAllen191]

Im about 2 weeks from having to route out a cavity for a kahler tremolo and was wondering what bits would be necissary/good quality. I also have a couple questions:

1. what is the difference between upcut and downcut spiral bits?

2. what is the best size bit for routing a tremolo cavity (about 3.5x4" and about 1/3 to 1/2" deep)



if I think of anymore questions, ill add them later.

 

[SDB Guitars]

The size of the bit you choose has a lot to do with how "pointy" the corner areas if your route are going to be. A 1/2" diameter router bit will, naturally, leave a corner with a 1/4" radius... just something to keep in mind.

I'd take a lot of the "bulk" of any area you are going to be routing with something else, like a forstner bit in a hand drill (or better yet a drill press), as it saves the bit, it won't overheat as bad, and you won't risk breakage on smaller bits as much. Larger bits are good for removing bulk or flattening the bottom or a large area, smaller bits are better for delicate work, like in corners or tight curves.

Spiral bits come in a couple of flavors:

upwards cutting, which is better for dispersing the wood chips and keeping your route clear while working, but with some highly figured or more open grained woods, it can tear out the grain, or leave the top edge of your route "fuzzy" because the bit pulls the wood grain upwards as it cuts it.

downward cutting , which pushes the wood chips down into the area you are routing, which can contribute to bit overheating or binding, but will leave a much nicer top edge to your route, with less risk of tearout.

Most inlay work is done with spiral downcut bits, to my knowledge.

Invalid Link Removed

 

[DanielM]

great explanation SDB! thanks! I was wondering about up and downcut bits myself.

 

[Basschair]

A link to this thread has been added to the FAQ section under Tools: Routers.

Thanks for the info!

 

[codyAllen191]

whoa, thanks for the info SBD, just one more thing if you dont mind.


I have a plunge router, but i have access to a drill press......which would you recommend I use for making the initial hole?


and, I looked up forstner bits, but im not positive on what they're used :router or drill press, what is the advantage of one of these compared to a spiral router bit?

 

[Musiclogic]

You can use Forstner bits or Brad points to remove as much of the excess as needed to make the routing job easier. If you look at my pick-up cover tutorial in the Tutorial thread, you'll understand what a Forstner bit does.
Good Luck

 

[PaleMelanesian]

A Forstner bit is a DRILL bit, not a router bit. Drill press is the best place for them, with a hand drill a distant second.

 

[codyAllen191]

hmm, alright......ill have to remember not to put a forstner bit in my router

 

[PaleMelanesian]

Maybe I overreacted there. I just want to make sure you're careful and safe.

 

[codyAllen191]

thanks for caring....id rather get a intense reply on the internet than have a drill bit fly at me from a router

 

[bass rocks]

do you have to have a forstner drill bit to rout cavitys

 

[Dirk Diggler]

I would suggest a good template and a top bearing straight bit. And agreed about the Forstner bit for hogging out the bulk of the route.
Good luck,
Dirk

 

[Hopkins]

do you have to have a forstner drill bit to rout cavitys

No you don't have to use a forstner bit. You can rout the whole cavity with your router, just do it in multiple passes. Don't try and go to the final depth in one shot.

That being said, taking out the majority with a forstner bit will extend the life of your router bits.

 

[tedsalt]

Whiteside makes good quality router bits. Freud is probably easier to find, and a second choice. Top-bearing router bits work best for template routing, but are harder to find. Router bushing guides and straight router bits will work also (and will last longer; bearings wear out).

Create a good working template from your original template. Routing a working template is good practice for the actual routing of your bass. Then, use a forstner bit in your drill press (or very carefully with your hand held drill) to drill out a fair amount of what you want to route out. Leave 1/8 to 1/4" between what is drilled out and the outer edge of what you want routed out. If blue painters tape does not affect the finish of your bass, use blue tape to protect the surface of your bass body. Use double sided tape to hold the working template to the bass body. Use more blue tape to hold the template down (make sure it is firmly attached and won't move when you're routing). Then use the router in a couple of passes to complete the routing.

You can use top-bearing router bits with the bearing adjacent to the template, or use bushing guides with a straight router bit to guide the router along the template.

As you're not routing very deep, due to the limited sizing of router bits available, the working template you make will need to be thicker (deeper) so that the top bearing or bushing guide rides along the inside of the template with the router bit below this.

Take your time, do plenty of research, and if you don't have (much) experience routing, practice on pieces you can throw away.