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my first attempt at saddle slotting
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Author:  Ken Jones [ Mon Dec 03, 2007 6:33 am ]
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Hello all --


I thought I would put up a couple of shots of the saddle slotting jig I came up with, and hopefully get some feedback on how I could improve the next one. It didn't take very long to build, so for now I'm resigned to just building a dedicated jig for each new bridge design I might come up with. I built in a 10 degree back angle, based on some info from other threads, and used a .125" downcut spiral bit from StewMac in my Dremel. Got some chatter, but that was expected, given the size bit relative to the little dremel. I did get some slight stepping with the consecutive passes, which I can't quite figure out, though I just chalk it up to whimpy tool runout.


One thing that occurred to me halfway through the process is that lowering the action once the guitar settles might be a bigger challenge due to the angled saddle. I suppose if I needed to shave down the saddle, I may just have to either alter the compensation of the exising saddle, or just replace it with another. Does anyone have any experience with this? I'm hoping that the 1/8" width will give me enough leeway to address this down the road.


Anyway, let me know what you think.


Ken
Author:  Ken Jones [ Mon Dec 03, 2007 6:36 am ]
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Here's one more shot:
Author:  JJ Donohue [ Mon Dec 03, 2007 7:59 am ]
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Nice jig but the sooner you can switch to a more powerful router or lam trimmer the better off you'll be. Those dremels are woafully underpowered for such an operation.

Also...those steel bolts so close to the spinning bit make me nervous. I hold my bridge in place with 2 wooden wedges. Or at least use brass bolts...just in case!

I also have incorporated the back angle and like it a lot.
Author:  Mike Mahar [ Mon Dec 03, 2007 8:11 am ]
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One of the explanations I have heard for the back angle was to automatically compensate for a higher or lower saddle. The higher your saddle the more compensation you need so the back angle will actually help. I have no idea whether 10 degrees will give you the right amount or make any meaningful difference.

Author:  David Collins [ Mon Dec 03, 2007 8:18 am ]
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Dump the Dremel. You'll have a hell of a time ever trying to get a clean
cut with the Fisher-Price bearings and housing on those things. That,
plus the fact that though the StewMac base can be great for some things,
plunging and consecutive passes would not be amoung them. It just
doesn't have any guides to keep it in the same plane as you drop it.
That's where your stepping is coming from, and it's not going to go away
unless you get a cutter with a decent plunge base.

As to the angle, I'm not sure which angle you are referring to. Is it the
compensation angle set back between the bass and treble, or are you
talking about the saddle being tilted back from perpendicular to the top?
If the latter, I'm not a big advocate of that, though many other folks here
like it. And if that's the angle you're talking about, 10 degrees is huge. I
think those who use it successfully stay closer to the 3 or 4 degree mark.
Author:  Hesh [ Mon Dec 03, 2007 8:37 am ]
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Nice Job Ken!

Don't listen to these laminate trimmer snobs (even though they are right).  I have used a Dremel to slot bridges a number of times and they work fine.  Just go slow and take many graduated passes.  Of course with a Laminate trimmer it would be much faster.  Perhaps these guys that hate using Dremels are trying to compensate for some other short coming.....

I do the counter sync holes in the pin holes and then use bolts without washers that sink below the top surface of the bridge.  This would help to some degree an errant router bit hitting the bolts.
Author:  Bill Greene [ Mon Dec 03, 2007 10:29 am ]
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David:

Can I ask why you're not a fan of the backward tilt? I didn't do it on my most recent guitar, but was thinking seriously about it on my next.

Thanks in advance for your time.

Bill
Author:  Ken Jones [ Mon Dec 03, 2007 11:04 am ]
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Thanks all for the responses. That left bolt is definitely a little too close for comfort, though with the base locked in to the jig on all four sides, there's really no way to come in contact with it...famous last words. 


Actually, if I was still at the U of Arizona, I'd have cut the whole thing out on the cnc, though I enjoy the hands on process much more. And realistically, I probably would've taken more time drawing it in Rhino, generating toolpaths, fixturing , and cutting anyway. I have a big ol plunge router as well as a laminate trimmer, though it doesn't plunge. I will probably use that next time. I did underestimate the tenacity of the ebony, and its tendency to grab the bit, even making very shallow passes.


David, I based my 10 deg back angle on info from a previous post, though I'm not sure who put that number forth. Those of you who do this, do you feel 10 deg is too much? That worries me.


Thanks, y'all -- spaghetti's ready...


Ken
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