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Tearout Troubles
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Author:  meddlingfool [ Mon Nov 23, 2009 3:48 pm ]
Post subject:  Tearout Troubles
Greetings,
I've been having trouble with tearout while tapering my fingerboards. I cut the treble side taper with the FB facedown starting at the nut. Then I flip it and cut the bass side taper. I'm doing it on a tablesaw ala the Sylvan jig I saw here. I'm using a standard 42 tooth blade. I always end up with a bit of tearout on the slotted surface, requiring each board to be routed for purfling to clean it up. Which is OK in a way 'cause purfling looks nice, but I would like to do some guitars with no fb binding at all. Should I be using a different blade? Cutting in the other direction? Does anyone know the solution to this?
Thanks
Author:  matthewrust [ Mon Nov 23, 2009 3:56 pm ]
Post subject:  Re: Tearout Troubles
Can you just clean it up a bit with a block plane? That is what I do and I have never had any issues with tearout.
Author:  Daniel Minard [ Mon Nov 23, 2009 4:14 pm ]
Post subject:  Re: Tearout Troubles
For what it is woth...
It's probably overkill, but when I am tapering my fingerboards, I scribe the exact line with a sharp blade, saw close to the line & finish the cut with a plane & shooting board.
The scribed line shows clearly when you plane down to it.
I wouldn't expect any saw blade to give the finish or accuracy needed.
Just one more way...
Author:  Zach Ehley [ Mon Nov 23, 2009 5:33 pm ]
Post subject:  Re: Tearout Troubles
I do it similar to Todd. I rough cut with the bandsaw (don't have a table saw) then clean up with my jointing plane. I don't have any special jig or hold down. Just use the old shooter board. Makes a nice clean straight edge and you can come up on the dimension without having to make a exact cut.
Author:  Haans [ Mon Nov 23, 2009 5:36 pm ]
Post subject:  Re: Tearout Troubles
I just bandsaw them close and bump 'em up on the ole 6 X 89 sander.
Author:  meddlingfool [ Mon Nov 23, 2009 7:55 pm ]
Post subject:  Re: Tearout Troubles
Thanks Folks!
Author:  Bob Garrish [ Mon Nov 23, 2009 7:55 pm ]
Post subject:  Re: Tearout Troubles
Todd's got a good solution there. The principle is simple when you're talking about avoiding chipout: don't give the chip anywhere to go.

If using a saw, then have something underneath the edge that's being sawn (sacrificial board), and same deal with drilling. If the chip can't 'exit' the workpiece, then the chip doesn't happen. The same principle applies to routing: if the cutter is pushing the chips into the work (climb cutting) then the work can't split.
Author:  Link Van Cleave [ Tue Nov 24, 2009 12:42 am ]
Post subject:  Re: Tearout Troubles
You can do it and still use you same jig. Just don't cut all the way through. Make a very light scoring cut, say about 1/16" deep and then raise your blade and cut normally. Tear out free.
Link
Author:  Jeff Highland [ Tue Nov 24, 2009 5:51 am ]
Post subject:  Re: Tearout Troubles
I do similar to Todd BUT I don't use a fence
Instead I have a runner fixed to the bottom of the base board which can run in a mitre slot or in the case of my ancient table saw, against the edge of the table.
No holding against a fence and no way for the workpiece to move to far into the blade
Author:  woody b [ Tue Nov 24, 2009 8:30 am ]
Post subject:  Re: Tearout Troubles
My jig is alot like Todds (but his looks better LOL). Since the blade's cutting down through the board (slots up) there's no tear out. I cut them 1/16" wide and take 1/32" off each side on my jointer. I taper them, then bind them (if they're going to be bound) before radiusing.

I've thought about putting stops on my jig, but like Todd I use a bunch of different tapers. I am capable of measuring wrong. :!:
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