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 Post subject: Bridge slotting
PostPosted: Sun Oct 18, 2015 3:39 pm 
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First name: Brian
Last Name: McDonald
City: Okanagan Centre
State: British Columbia
Zip/Postal Code: V4V2H6
Country: Canada
Focus: Build
Status: Amateur
Did a quick search here, not really finding what I want.
Just about to string up a new dread, and I remember from some previous posts that slotted pegs are bad juju.
So, should I have slotted this prior to attaching the back and bridge?
What is the best method on an assembled instrument?
Are the slots gauged?
How deep?
Straight up and down or angled toward the plate or the bridge?
Any info or links are appreciated, thanks

B

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 Post subject: Re: Bridge slotting
PostPosted: Sun Oct 18, 2015 3:43 pm 
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Koa
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Joined: Mon Jul 11, 2005 5:17 am
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Location: United States
City: Tyler
State: Texas
I just use a jig saw with a blade that I made skinny enough to fit in the hole with a belt sander. I do this after attaching the bridge to the closed box. One of my last steps. I don't angle or anything, just make it enough for the string to fit.


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 Post subject: Re: Bridge slotting
PostPosted: Sun Oct 18, 2015 5:47 pm 
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First name: Don
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Stew-Mac sells a little saw that looks a lot like the saw that came with my pumpkin carving kit. It is like a skinny jig saw blade set in a wooden handle. They also sell some files that are gauged for the strings.

Since you want the slots to be through the whole "top, bridge, bridgeplate" sandwich, you should wait until the bridge is glued on to cut them.


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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 7:16 am 
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Brian: Something I got from Mario Proulx......proper slotting should let you pull the pins at full string tension and not effect the string. In other words the string ball is fully captured by the bridgeplate and does not move.
Tom

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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 7:53 am 
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First name: Ed
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Country: United States
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I am not an expert, but I have had success with 2 widths of slot - 3 narrow and 3 wider. I have forgotten where I got these tips a couple of years back, but I use saber saw blades in 2 thicknesses of metal and with fairly aggressive teeth, and they are mounted in handles. One is a standard blade thickness, and the other is a thinner one:

https://www.flickr.com/photos/ruby1638/ ... 776959267/

These handles are boxwood from a neighbor's re-planting. Notice that the blades are angled back off the centerline of the handle. This is so you can get your eye directly over the hole you are working on and the handle won't get in the way visually while you saw. The blades have to be narrower to fit in the pin holes. Takes all of 4-5 minutes to get the job done.

Ed


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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 8:02 am 
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First name: Dennis
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Good for you going unslotted :) Yes, the slots should be cut on the finished instrument. Put a paper towel or something inside to catch the dust.

I use the keyhole blade on the Zona saw from LMI, followed by needle file to smooth it out and fine tune the width. The gauged StewMac things would be convenient, but are by no means necessary. I do match the slots to each string width. If the guitar can handle mediums, make sure to cut the slots wide enough for those. And if you buy gauged saws/files, remember that strings have an extra wrapping before the ball end, so the slots are wider than the main portion of the string. The depth just needs to be enough that the pin goes in without wedging on the string. Slots generally go straight up at first, and then have an angled section as they exit to get the string past the skirt on the pin head. You can also deepen the angled section to move strings' exit points forward individually, to make the break angle over the saddle equal for all strings even if the pins aren't in a straight line.


Last edited by DennisK on Mon Oct 19, 2015 9:21 am, edited 1 time in total.


These users thanked the author DennisK for the post: James Orr (Mon Oct 19, 2015 11:40 am)
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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 9:06 am 
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Brazilian Rosewood
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Joined: Tue May 13, 2008 10:44 am
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Location: Virginia
I've got the little jig saw blade Stew Mac tool and have had it for 15 years or so. I don't think I would like the look of gauged ones preferring them to be all the same but YMMV. I use the little jigsaw tool to rough it out then follow it up with a diamond file.

For those who use an actual jigsaw well... You must have a very steady hand and or are a lot braver then I am :D


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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 9:53 am 
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Brazilian Rosewood
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Location: The Woodlands, Texas
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The new saw blades that Stew Mac supplies are much nicer than the old saber saw blade style.


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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 11:45 am 
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I have the Stew-Mac set-up, but need to get a few of the larger files.
http://www.stewmac.com/Luthier_Tools/Types_of_Tools/Saws/Bridge_Pin_Hole_Slotting_Saws_and_Files.html

I used them for the first time a few months ago and ran into the issue of the slot not being wide enough for the wrapped portion of the string. When I ordered the files, I probably I tried to match them to the string gauge (like nut files), not realizing the wrapped portion is that much wider.

BTW, when I searched for that link, I found these instructions:
http://www.stewmac.com/How-To/Online_Re ... tting.html[url][/url]


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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 12:49 pm 
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Joined: Sat Dec 30, 2006 3:20 am
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Location: Powell River BC Canada
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I have 3 jigsaw blades glued into dowels for handles. 2 are metal cutting and the thickest kerf is a wood cutting blade. The thinnest has been made thinner by way of a sander.. I start all the slots with the thin blade and it will do the high e. Straight up and down with a ramp exit to the string and finish with a file to make it look purdy. Call me if you need more. I'm sending this from my phone. [uncle]


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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 4:32 pm 
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First name: Daniel
Last Name: Petrzelka
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Country: United States
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I've made my own, as posted here http://acousticguitarconstructionforum.com/viewtopic.php?f=7&t=2054&p=18801&hilit=slotting+saw#p18801

One of the luthier suppliers sells two saws, the smaller .028" kerf, and the larger .051". I did some very brief research and found a fine tooth Bosch blade that was spec'd as having a .020" kerf, and figured that was a loose number, and close enough for slotting bridges.

1 Pack of Bosch SS5-15PL Scroll Saw Blades
1 wooden dowel for handles - I chose 3/4 oak

#33 drill bit (something close, little smaller, would work)
Thick cyanoacrylate glue - epoxy would be better, use what you've got
Large tin snips (for cutting the saw blades)

Simply cut 3 dowels to length for handles - 4" worked well for me.
Drill a #33 hole centered in the end of each dowel - drill about 3/8" deep.

Cut 3 of the Bosch SS5-15PL blades in half. These will be grouped to get our thicker saw kerfs.

1 blade approximately .022"
2 blades, approximately .054"
3 blades, approximately .76

Not the most beautiful, but they get the job done.

Image

Image

Image

Image



These users thanked the author dpetrzelka for the post (total 3): flounder (Tue Oct 27, 2015 2:19 am) • klooker (Mon Oct 26, 2015 6:28 am) • TimAllen (Wed Oct 21, 2015 12:11 pm)
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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 6:44 pm 
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Brazilian Rosewood
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Joined: Wed Apr 08, 2009 9:34 am
Posts: 3081
I just use my fitted set of nut files that are just ground needle flat files with the cutting edge on the edges. You can hand rout the slots too with a Dremel and finish them out with the nut files.


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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 19, 2015 8:52 pm 
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Brazilian Rosewood
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On my last 2 builds I located the bridge,
drilled and tapered the holes,
slotted with a jigsaw blade held with vice grips.
I did this with the top glued to the sides, and the back off.
Really nice to see what's going on with the string ball fits!
Oh, they are Weiss styles,
so accuracy isn't as critical!
if that matters.


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 Post subject: Re: Bridge slotting
PostPosted: Tue Oct 20, 2015 5:26 pm 
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Bryan Kimsey has some great information and pics concerning slotting and ramping on his website.

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 Post subject: Re: Bridge slotting
PostPosted: Wed Oct 21, 2015 12:06 am 
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Brazilian Rosewood
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Joined: Fri Dec 14, 2007 3:21 pm
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Location: Alexandria MN
Ever since Sylvan Wells described it 6 or 7 years ago I have been using a jig saw. It is safer than you might think.

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 Post subject: Re: Bridge slotting
PostPosted: Sun Oct 25, 2015 8:11 pm 
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First name: Brian
Last Name: McDonald
City: Okanagan Centre
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Zip/Postal Code: V4V2H6
Country: Canada
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Status: Amateur
Thanks for all the replies.
I like to over think things sometimes and this was one of them.
Ended up using a fine jig saw blade, and neatened up the kerf with a diamond cutter from a coping saw for tile.


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 Post subject: Re: Bridge slotting
PostPosted: Sun Oct 25, 2015 10:42 pm 
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Joined: Sat Dec 30, 2006 3:20 am
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Location: Powell River BC Canada
First name: Danny
Last Name: Vincent
Well that's looking nice! Going to Baja with you?


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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 26, 2015 9:46 am 
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First name: Brian
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Country: Canada
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Status: Amateur
DannyV wrote:
Well that's looking nice! Going to Baja with you?

Sure is, maybe I can even find time to practice.
The guitar I took last year, I gave away to young Mexican with a lot of talent and no instrument or money.

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These users thanked the author Bri for the post (total 2): Alex Kleon (Mon Oct 26, 2015 11:52 am) • Bryan Bear (Mon Oct 26, 2015 9:55 am)
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 Post subject: Re: Bridge slotting
PostPosted: Mon Oct 26, 2015 10:06 am 
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Bri wrote:
... The guitar I took last year, I gave away to young Mexican with a lot of talent and no instrument or money.


Very Cool [:Y:] [:Y:]

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