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tear out when routing top for inlay

Posted: Mon Dec 29, 2014 3:26 pm
by jartzh
I had tearout on the spruce top when I flush trimmed the top .
I am concerned that the router will do similar damage when I rabbet it for the binding and pearl inlay.

How do I prevent it? If I am going to use lacquer for a finish, then should I lacquer it first ?

Re: tear out when routing top for inlay

Posted: Mon Dec 29, 2014 5:25 pm
by Monkmusic
How much of an overhang are you trimming? If it's more than a few mm's than I usually make a few passes trimming a little at a time. Once you get the spruce down to 1 or 2 mm's then you can push the bearing up against the side.

I'm assuming you're cutting in the correct direction.

Maybe your bit isn't sharp enough.

Lacquer is no match for a router bit.

Re: tear out when routing top for inlay

Posted: Mon Dec 29, 2014 5:39 pm
by tippie53
If your router bit is as sharp as it can be,
then you need to address feed speed, feed and cutter direction.


This is the 1st in 3 part series
You have to be cautious of the feed. It won't hurt to coat the top with a few coats of sealer first.
You need to be aware of the climb and rout cut.
The weakest points on the top most prone to tearout are the extreme points of the waist and the bouts.
This is covered in the binding videos.

Re: tear out when routing top for inlay

Posted: Mon Dec 29, 2014 5:56 pm
by  
This should tell you all you need to know as far as router direction.
Works the same for both top and back.
rout direction.jpg

Re: tear out when routing top for inlay

Posted: Mon Dec 29, 2014 6:22 pm
by tippie53
tommys pic is a good example of how to cut the channels.

Re: tear out when routing top for inlay

Posted: Mon Dec 29, 2014 7:21 pm
by jartzh
Thanks, you are correct . it was the feed direction that got me.
Glad I asked before I tackled the binding cutting.

Thanks guys.

Re: tear out when routing top for inlay

Posted: Wed Dec 31, 2014 12:13 am
by MaineGeezer
Another thing you can do is use a down-cut router bit, if you aren't already. It won't prevent grain tear-out caused by going the wrong direction to the grain (see the direction diagram previously posted) but it will prevent tear-out of the top surface.

StewMac sells 'em.