Nubie question.. routing pine.

[DH82C]

Hi, I am building a guitar amplifier cabinet and have some questions about making the joints. I am not doing finger/dovetail joints yet.. just using kind of a butt joint.

Looks like this _ _____________________ A |_______ _ - - B - | | C |___________

The top is .. well the top. There is a notch in the top that is 3/4 in deep (B) to take the side of the cabinet There is a lip that covers the top of the side (A) that is 1/4 inch wide. Since the plank is 3/4 wide (C=1/2 inch.. therefor A+B=3/4

Anyway.. Ideally this would be done with a dado.. but I dont have one. I do have a router and table and that is where the question comes in.

I have to do the cut in mulitple passes. I can only take off about 1/8 of an inch at a time. When I am cutting I am noticing that in addition to sawdust there are curls of wood (as if I was using a plane) I can only cut about an inch every 4-5 seconds. When I cut across the grain there is a considerable amount of buring.

Is this normal? I am assuming I am doing something wrong.. just dont know what. Burning when crosscutting? Curling when cutting? Cutting 1/8 deep by

1/2 inch at a time?

I really would appreciate any help. I have looked through several woodworking books and havent found anything pertinent to this situation.

Thanks

Drew I had cleaned any gunk from the bit before I started routing.

[Robatoy]

Off the top of my head... is the bit sharp? Carbide?

[Morris Dovey]

With a sharp bit, you should be able to cut at least the diameter of the bit deep with each pass, and you should be able to feed at least 1-1/4" per second.

This sounds like you're cutting with non-overlapped passes. Try overlapping adjacent cuts by 50%.

Burning is the result of cutting with a dull bit or feeding too slowly. It is the wood chips that carry heat away from the bit - not the air as might seem reasonable - and if you feed too slowly the heat will build up in the bit until it's hot enough to burn the wood (and soften the cutting edges).

It's not abnormal, but neither is it desirable. I'd be inclined to retire that bit and find a really sharp carbide bit - they cost more but last enough longer to be worth the expense. (FWIW, I use carbide end mills).

Try turning that around - cut 1/2" deep by 1/8" at a time and keep that bit moving.

[Scott Cox]

Buy a new high quality carbide bit. You'll be amazed at the difference.

[DH82C]

The router and bit set was a gift (a 50 piece set and I dont think they payed THAT much for it) I will pick up a decent bit tomorrow and try it. I figured a) I was being unreasonable in how much I could cut in one pass and/or b) I had ruined the bit some how. ( I know I have set off the smoke detectors in the house a couple of times with the router so maybe I toasted the bit.

Will let you know how it goes:) Thanks for the help.

[Limp Arbor]

You already got good advice about the cutting problem but you may want to rethink your material. I'm pretty sure speakers and amps are usually made out of something else like MDF. Methinks the Pine would rattle. I think there is a group that focuses on building speakers and such I just can't remember what it is...

[k]

As an option, I have lots of dull bits, to minimize burning on the last pass I will only take about .020 of a inch off. Just a light skim to clean it up and it will get rid of most of your burning. A new bit would be ideal but I'm cheep.

[DH82C]

I am building 50s Fender style amps. and these are usually (almost always actually) 3/4in pine with 1/2 plywood baffles. The difference is that they dont rattle but they do resonate and that colours the tone.. this is a good thing for some guitar amps. This is a bad thing for most stereo speakers. There are many many companies that use MDF now for their cabinets. Nothing wrong with it.. just doesnt sound quite the same.

Working with 5/8 birch plywood for the baffle I used the same router bit.. same problem.. burning and not much progress. Just for a larf I slowed the router down from 21000 RPM to 13000 (approx based on the owners manual) Worked MUCH better on the plywood baffle. Too tired to try pine tonight but I will try tomorrow along with Morris' recommendation to cut deeper with each pass instead of wider. Will post the results tom or wed night. Thanks again all.

Drew

[sheldon.mandel]

shavings is right - it means the bit is sharp. If all you get is sawdust, the bit is dull. 1/8 an inch is ok too. Speed up a little to avoid burning, maybe use a blade lubricant.

shelly

[sheldon.mandel]

Just had another thought - is the bit 1/4 o1/2 in? what is the hp of the router?

[whit3rd]

(about rabbeting a corner joint)

Your router is being asked to turn a lot of cubic inches of wood into sawdust. If you could use a table saw with a narrow kerf blade to do this in two cuts, the work would go faster.