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Bridge Slotting Fixture

Posted: Thu Jun 14, 2012 10:53 am
by woodrat
Hi All, This is fairly self explanatory with the pics but I thought that I would show the luthier brethren here as it may be useful to someone. It is basically a wall to slide down to keep it true to the vertical axis. A set of stops controls the length of the slot and a wedge secures it tightly. I put a shim under the bridge to angle it back ~10 degrees from vertical to give a slight back slant to the saddle. The trimmer base is secured by screws to a piece of aluminium angle to register on the "wall" of the jig.
Anyway I hope that it is useful to someone....I find that it works well for me.

John the Woodrat :)

Re: Bridge Slotting Fixture

Posted: Fri Jun 15, 2012 11:22 am
by EricDownunder
I like that simple and effective

Re: Bridge Slotting Fixture

Posted: Fri Jun 15, 2012 4:45 pm
by woodrat
Yes Eric, The "wall" is nice and high and the 100 x 100 al"oo"minum angle is large enough to give a nice feeling of control as you plunge the trimmer. Yes simple is good!

John

Re: Bridge Slotting Fixture

Posted: Thu Jun 21, 2012 7:40 am
by woodrat
I have just made a variation of this jig to be able to slot on the guitar. The "wall" makes the whole thing very controllable as the vertical axis is easy to control and you know you are not going to tip it at entry. I made the jig to do the on instrument slotting for my first attempt at nut and saddle compensation. I didnt use stops this time just white lines on the bridge. The two battens are to stiffen up the whole arrangement so it will span the length of the guitar. There would be a couple of degrees of back slant to the saddle as well as the jig sits on the end of the fingerboard and is clamped there.
Again I hope this is useful to somebody.....:)

John
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Re: Bridge Slotting Fixture

Posted: Thu Jun 21, 2012 8:39 am
by Nick
I see this very nice easy setup is for an uncompensated saddle John, if you need compensation do you swivel the whole jig or will you have a seperate jig with slanted guides, and what sets the slot length, does the Aluminium angle on your router run into the two uprights or do you rely on eyeball stops?

Re: Bridge Slotting Fixture

Posted: Thu Jun 21, 2012 9:19 am
by woodrat
Hi Nick...you can do either...I am just having a go at my first nut and saddle compensation guitar hence no angle on the jig. On my other jig....the one I posted first...I rout the slot off the instrument...it has compensation angle built in as this is for saddle only compensation...I have stops on that one. I didnt put stops on the on instrument one and found it easy to work to a couple of white pencil lines. My router has LED lights too which makes that easier.

John

Re: Bridge Slotting Fixture

Posted: Thu Jun 21, 2012 10:35 am
by woodrat
....Nick, this set up is actually for a compensated saddle but it is as per the Trevor Gore/Gerard Gilet book. The compensation is over a 5mm wide saddle instead of a slanted skinny one.

Re: Bridge Slotting Fixture

Posted: Thu Jun 21, 2012 11:47 am
by Nick
woodrat wrote:....Nick, this set up is actually for a compensated saddle but it is as per the Trevor Gore/Gerard Gilet book. The compensation is over a 5mm wide saddle instead of a slanted skinny one.
Thanks John for explaining :wink: I still use a 5mm saddle even compensated, I use the Somogyi idea (although I'm not sure he's the one that originated it, I just saw him use it so associate it with him) of a decent radius behind the string break point so the string 'rolls' off the saddle.