Choosing a router bit for plywoods

[cloudniner]

I'm new into speaker building. Are there any specialized router bits for plywood routing? Can I used regular router bits?

[badman]

As far as I know, you use the same bits regardless of what (normal) material you use. Keep them clean, oil the bearings, and sharp.

You definitely want the biggest bevel(chamfer) and/or roundover bits you can get (and your router can swing), as well as a flush trim bit and a spiral upcut bit. Rabbeting bits are also helpful for cutting driver recesses and doing joinery, though it's usually better to cut the recess with a circle jig at the same time you do the driver through-hole. Do the recess first then adjust inward and do the through-hole. Take care when the circle falls not to lose control.

[leadbelly]

Some issues with technique when routing plywood:

1) Take precautions against tearout at EVERY corner. Remember that the plies alternate orientation.

2) Do not use bits with an aggressive convex profile. They may tear the plies apart.

[VictoriaGuy]

Originally posted by badman
Do the recess first then adjust inward and do the through-hole. Take care when the circle falls not to lose control.

Clamp the workpiece to a large scrap of mdf or similar and drill the center pivot hole through both pieces. Then the router will be under control after the disc is cut loose. This also allows for making the hole/recess a bit larger if you have cut it too small, as long as you keep the scrap and the workpiece clamped together.
The scrap also helps a bit in controlling splintering.

(I learned this the hard way.)

Also, spiral bits are definitely smoother cutting- both in wood and in your wallet.

Cheers
John

[VictoriaGuy]

Originally posted by cloudniner
I'm new into speaker building. Are there any specialized router bits for plywood routing? Can I used regular router bits?

If by 'regular' you mean the cheap carbide bits most of us use, the answer is yes- fine for plywood.
HSS (steel) bits (from the olden days) will not last long cutting the glue lines in plywood.

Cheers
John

[Brewboy]

John is correct, the glue used in plywood is very abrasive and will dull lines in a steel bit fairly quickly. MDF in its make up is glue and dust thus it to will dull steel tooling fairly quickly also. Quality carbide bits and blades are your best choice not only for composite materials but for all around quality, in all materials.

[R-Carpenter]

Down cutting solid carbide spiral bit to cut driver recess holes. ¼ inch diameter will do fine and will work with Jasper jig. I'd stay away from HSS bits. Carbide tipped bits aren't much more $, safer to use and will last longer. Carbide can also be resharpened a few times.

[johngalt47]

I use Whiteside solid carbide bits. They received the highest rating in a test done by a woodworking magazine. They have the least tear out and last the longest.

[trusound]

I cannot stress rough cutting when all possible to keep the bits happy...

I personaly use whiteside or amana bits...

[cloudniner]

Very useful info. Thanks a lot!