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Bridge Removal Level up... http://luthiersforum.com/forum/viewtopic.php?f=10101&t=48304	Page 1 of 1

Author:	meddlingfool [ Wed Sep 21, 2016 2:43 pm ]
Post subject:	Bridge Removal Level up...
So, from time to time, mistakes are committed. The mission was to make a 2 1/4" spaced bridge. I carefully made my bridge using the marking on the stew Mac bridge ruler, having a hinky feeling the whole time. Checked, and double checked. Anyway, glued on the bridge, set the guitar up, and was mystified as to why the strings ran so close to the edge this time. Turns out I used the end mark as the start mark and the spacing was closer to 2 3/8". Children would have learned some fun new words when I figured that out. In the past, I've paid someone else to remove the bridge who has a lot more experience. But, they've never turned out absolutely perfect, so I figured I can achieve that myself. After filling in the holes in the bridge plate with the very handy stewmac tool for that job, it came time for the bridge. I was going to order the stewmac tool for that, but it was 50$ plus shipping. Then I noticed my roommates cookie flipping spatula, and had an aha moment. So I zipped down to the Gourmet Warehouse and acquired one for myself. Sanded the leading edge from 220 to 2000 grit to get it nice and smooth, ground down the welds, and covered them with thick self adhesive felt. Less than 20$ and ten minutes. Since I wasn't trying to salvage the bridge, I routed it all across to about 1/8". Made a cardboard protector, and used 1" aluminum barstock as a heat conductor, and had the bridge off perfectly clean with absolutely no tearout in less than 5 minutes. Hopefully, the rest of the task follows suit... routed to 1/8"... top protector... barstock and spatula... the treated leading edge... the thick felt... the result... Anyway, thought the spatula gadget might be useful for others too...

Author:	meddlingfool [ Wed Sep 21, 2016 2:46 pm ]
Post subject:	Re: Bridge Removal Level up...
And since it's HHG, I don't even need to scrape the old glue off!

Author:	Colin North [ Wed Sep 21, 2016 2:49 pm ]
Post subject:	Re: Bridge Removal Level up...
Sweet!

Author:	SteveG [ Wed Sep 21, 2016 3:57 pm ]
Post subject:	Re: Bridge Removal Level up...
Maybe you deserve one of these: http://www.lmii.com/products/tools-serv ... -drill-jig The time you spent on this one will pay for it, perhaps. cheers

Author:	bcombs510 [ Wed Sep 21, 2016 4:31 pm ]
Post subject:	Re: Bridge Removal Level up...
I don't want to hijack your thread, but how does the string spacing ruler work for bridges? Obviously you wouldn't use the same set of marks as for the nut. Do you do the same as the nut and measure in from each edge and then find the set of marks on the ruler that line up? Sent from my iPhone using Tapatalk

Author:	Chris Pile [ Wed Sep 21, 2016 6:03 pm ]
Post subject:	Re: Bridge Removal Level up...
Just like Alton Brown - you've found the right multi-tasking tool for the job in a place you wouldn't suspect.

Author:	meddlingfool [ Wed Sep 21, 2016 6:55 pm ]
Post subject:	Re: Bridge Removal Level up...
Steve, That looks handy. I'm not sure if they're spaced equidistant, or gradually spread like the stewmac ruler. Brad, The ruler has two edges, one side seems to fit nuts, the other fits bridges. Super handy tool. Chris, Alton Brown the food guy?

Author:	Terence Kennedy [ Wed Sep 21, 2016 9:38 pm ]
Post subject:	Re: Bridge Removal Level up...
Along the lines of bridge pin spacing and drilling, Tony Karol posted a great jig here years ago that I copied and it has been excellent and adaptable to any spacing. For the pictures I used a bridge that already had the holes drilled but imagine it does not have holes. It consists of a bridge holder angled the same as the saddle slot. About a 1/8" setback over three inches, a drill press base board, and five spacers with thickness corresponding to the desired space between pin holes. I also made an insert for the saddle slot and a spacer to mark the distance the holes will sit behind the saddle slot. The spacer has a centerline mark and a mark for the center of the first and sixth holes for different string spacings. It has the advantage of putting the holes parallel to the saddle slot which I like. You start with a bridge that has the saddle slot cut and mark the center of the slot. Then put the insert in the slot and push the spacer up against the insert and line up the centerlines. Draw a line along the edge of the spacer and mark the first and sixth string centers. Next you put the holder on the drill press table board, insert the five spacers, and line up a 3/16" brad tipped bit with the sixth string hole mark. Remove all the spacers and make sure the bit lines up with the first string hole mark. Then put the spacers back in and drill each hole removing spacers as you go. I figured the width of the spacer blocks and ran a piece of wood through the sander until it was right with the calipers and cut it into 5 pieces. You can have a set of spacers for standard spacings and easily make some for custom.

Author:	meddlingfool [ Wed Sep 21, 2016 10:33 pm ]
Post subject:	Re: Bridge Removal Level up...
Normally, I use this jig. Slips into the saddle slot. This allows me to use a jig for locating the bridge based off the saddle slot and gets the string path right every time. It wasn't so much a problem drilling the holes as it was that I marked them totally wrong.

Author:	Hesh [ Thu Sep 22, 2016 4:53 am ]
Post subject:	Re: Bridge Removal Level up...
Nice going Ed. Some things that might help you. 1) Heat lamp is faster and gets the wings hotter way easier than something that has to conduct heat through contact when there is no contact. If you go the heat lamp route never, never, never leave the lamp on and unattended and don't even answer the phone if it rings........ D-35's don't smell to good with wake-n-bake...... 2) We remove the old glue anyway and clean up the bridge patch and the bridge bottom on the belt sander, know your platen. This facilitates reexamining the fit of the bridge to the top without any old glue holding anything up. We clear to expand the gluing foot print when possible. 3) We make a masking tape "well" that the bridge can be slapped down into with the HHG applied preventing the bridge from wandering before the glue jells. 4) In the repair world we read the runout of the top too before attacking the bridge with the spatulas and this tells us what direction to insert the things without lifting fibers. 5) Our clamps are already in place and partially closed too so that when we slap the bridge on and the HHG is.... well.... hot we can snug the clamps without having to position them since they are already prepositioned in only ten seconds, likely less. 6) We've been preheating our bridges in the microwave trying to not have it sit in Hesh's glob of cheese he left in there after his corned beef brisket on swiss sandwich. I preheat for about 15 seconds with a wimpy 600 watt microwave. This extends open time of the HHG but we really don't need it with the clamps prepositioned and partially closed.

Author:	JSDenvir [ Thu Sep 22, 2016 6:18 am ]
Post subject:	Re: Bridge Removal Level up...
Hey Hesh, what kind of heat lamp do you use? Steve

Author:	Hesh [ Thu Sep 22, 2016 6:29 am ]
Post subject:	Re: Bridge Removal Level up...
JSDenvir wrote: Hey Hesh, what kind of heat lamp do you use? Steve Hey buddy. For my corned beef brisket sandwich or to remove a bridge? We use a GE (but of course.... ) 250 watt heat lamp in an inexpensive hardware store clamp on lamp holder. I hold the lamp just 1/2 an inch or so off the bridge and alternate from the wings to the center to the wings, etc. Lately I've been heating longer and slower thinking that it takes time for the bottom of the bridge to be as hot as the top. The shield must fit well and I often use the reflective HVAC tape around the edges for additional insurance. The tape tends to stick to the shield so no problems removing the shield and seeing what we have with the spatulas. I'll usually heat for a few minutes (keeping it ALWAYS attended.... ) and then try it but I usually will heat at least twice and maybe more. After reading runout there is a feel that you want to feel with the spatulas. It should feel like goo giving way with moderate pressure working the spatulas back and forth being mindful of runout. If you feel more resistance than give it's not hot enough (or some Bozo used the wrong glue...). If you hear cracking STOP, you are lifting fibers. The risks of removing bridges are smoking the surrounding finish, lifting top fibers, chipping surrounding finish, and burning yourself. It's not unusual to get the bridge hot enough that oils start running and it starts to stink and/or smoke. Valium is helpful at times too.

Author:	Colin North [ Thu Sep 22, 2016 7:02 am ]
Post subject:	Re: Bridge Removal Level up...
Quote: Valium is helpful at times too.

Author:	Woodie G [ Thu Sep 22, 2016 7:08 am ]
Post subject:	Re: Bridge Removal Level up...
It seems like you got a very good outcome! Congratulation on a great rescue! Your aluminum caul idea was a good one - we have a few of those cauls in 1/2" material for bridge plates, but use a cartridge style heater inserted in the caul to allow us to position the tool and clamp in place while cold, then sense and control heat. For bridges, use of a heat lamp was already mentioned, and a silicon bridge blanket would be a third choice if you decide to do much of this sort of work. After seeing how fragile the 1938 00-21S's finish was on a recent bridge reglue, we opted to use extremely low tack tape (Stewart MacDonald now carries a similar white paper tape, but any sign maker's supply will have it in various widths) with a plain white butcher paper paper mask about 1/4" outside the bridge footprint going down first for our tape 'dam' or well as mentioned by Mr. Breakstone for precisely and quickly positioning a warmed, hide glue prepped bridge. Once the super low tack tape is applied, regular blue tape can be used to build the additional layers needed to form the dam (or well...I wonder if there are other terms for it as well!). When marking out pin spacing, we lay out the bridge centerline and the first and sixth string pin centroids, rechecking the first-to-sixth spacing, then either using a divider to walk out five even divisions or using the Stewart MacDonald nut and saddle layout ruler for a proportional layout. I love the jigs in the thread that allow quick drilling of preset spacing patterns, but we do so many different spacings that we tend to just do careful layout with a 0.5mm tip pencil, mark the holes with a sharp awl (and surgical loupes...where did my very sharp, youthful, contacts-free 18 year old eyes go?), and drilled with good German-made brad point bits to just shy of the bottom surface (less squeeze-out into the pin holes). Most art supply stores like Michael's carry small stainless steel palette knives in a variety of shapes and sizes, and we've found the most useful for bridge removal are the 2-1/2" x 1-1/8" or so rectangular versions...all buffed to a high shine and burr-free as suggested. Larger knives may need to have the thickness of their blades reduced and edge recontoured and buffed before use - especially if the bridge will be installed in a stepped pocket in the finish. Good luck on the rest of your project, and please post some pictures!

Author:	Terence Kennedy [ Thu Sep 22, 2016 7:31 am ]
Post subject:	Re: Bridge Removal Level up...
I like that pin hole jig Ed. Another thing I started doing that has helped verify the string lines prior to glue up is to tape the bridge in place where I think it should be and then lay a long straight edge from the first fret (inset the amount the string will lie) down to the centers of the high and low E pin holes. Then measure the inset at the 12th. This will confirm your string runs are proper and you can make small adjustments before gluing. Seems like I always have to adjust it a little. I usually inset about 1/16" from the edge of the bevel at the first and usually wind up around 5/32 at the 12. Do any of you setup experts go for different insets for the high an low E's?

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