Endpin hole revoicing tools

[j. condino]

A friend has asked me to take some mass off the braces of a mandolin that used to have a great voice but was re-braced by someone who apparently only works on upright basses or railroad bridges and went way overboard on the size (not me; some other bass dork!); the mandolin subsequently lost all of its power and voice. He's pretty committed to doing this, so I'm helping him out rather than letting someone else hack up a nice mandolin at the local electric guitar shop.

I'm pretty sure I can work through the endpin hole, but I'll need to craft up a specialty tool or two to get the job done well and efficiently. Rather than re-invent the wheel myself, can folks post a few photos of gadgets that they've made in the past to successfully do this? A straight tool won't cover everything, so I'm envisioning some sort of multiple angle articulation with a cutting blade on one end.

Thanks for the help.

j.
www.condino.com

[Loudloar]

J.,
I have tried various techniques. The end pin hole is way too small to work through. You didn't say whether it is an F-hole or oval hole instrument, but I'll assume it has F-holes. Other than removing the back, I've only found one way that really works. In the picture you will see a paint roller handle from the hardware store that's been re-bent, with coarse sandpaper taped to the far end. You can slip it in one F-hole and sweep it back-and-forth to sand the opposite tone bar. Then repeat the process on the other side. It will fairly quickly reduce the height of the tone bars. It will leave them with a flat (squarish) profile, but who cares. It reduces the stiffness of the top so it's closer to where it should be, and that's the goal. It made a huge improvement to the responsiveness of Kentucky in the picture.

Steve

http://www.mandolincafe.com/forum/attachment.php?attachmentid=74274&d=1310437570

[FL Dawg]

Nanotechnology.

[Dale Ludewig]

If I can link this properly, you might be able to do it with a hook tool, normally used in woodturning.

http://azwoodturners.org/summer_2005_basichooktool.pdf

[Larry Simonson]

Those hook tools in the Dale's link remind me of dental tools. Maybe you could ask your dentist for advice on this.

[sunburst]

I was hoping this thread would bring up some creative ideas.
Steve, I can envision bending different angles on the business end of a tool like the roller handle so that the braces could be tapered again after cutting them lower if the flat tops were objectionable.

[MikeEdgerton]

I'm looking for some old threads and can't seem to find them. I think there were some pictures of some home made tools to do this.

[amowry]

I use a riffler with the handle cut off, then duct taped to a long 3/16" rod. I can bend the rod a little when necessary to access difficult spots. The riffler removes wood pretty fast, but leaves a rough surface. I stick some PSA sandpaper to the face of the riffler at the end to smooth things up a little.

[HoGo]

I don't have pics but I made hockey stick shaped tools out of thin but stiff steel wire (approx 1-1.5mm thick). I took 15" of the wire and bent it to half. On the bent end I left the wires go parallel for 1" and then twisted them all the way to the end to create stiff but thin handle that I wrap in tape to meke it safer and give it some grip. I shaped the bent end to slight curve not really hook, something like 1/8"or less crown on 1" length and cut small piece of VERY aggressive high quality thick sandpaper (1"x 1/4"+ wide, Norton 60 or 80 grit, used for large industrial beltsanders, new cuts almost without pressure) which I glued with CA gel directly to the wire (larger beads of glue will cover the wire and hold perfectly).
I bend the working end to resemble hockey stick and shape the handle as necessary so I can insert it through f hole and sand along the bar. The slight curve helps it not to fall from bar and slight pressure is all that is necessary to get it cutting. I can sand 3" of bar with one shape of the tool and reshape slightly to move to other part. I have two of these one for bass side, one for treble so I don't have to rebend the bend at working end. If you shape your tool correctly you can easily get nice rounded shape of tonebars. Just take care not to damage f holes (masking with protective tape).
I hope this helps.

[the padma]

Yo, grandcanyonminstrel, (what a handle non the less)

In my most humble opinion this thread is a perfect example of a 'broken wanter'

Our society wants this that and the other.
They want it now, new, modern, gassed up, with the keys in it and ready to drive off the lot.

They want the short cut, fast, cheap and dirty.

Lord help us.

In mho the way to deal with this fix is to pull the back, do what ever needs to be did done with and move on.

Now if you don't wanna pay the loofer his price to fiddle around and do the job properly cuz it is too costly in $ or time, then may I direct you to ebay where you may freely purchase a disposable copy of just about every instrument ever made for $199. in just about any colour you want, with free delivery to your door, ~ case included.


Ok...let me put it to you like this...

How would you like some Dr. poken around up your "arsk~me~no~questions" with jimmied up MacGyver tool tryin to fix what the last Dr. frigged up? Hmm?

Ya see grandcanyonminstrel, it all depends on what you want and were you place your values.

Me has been building for a long time and when asked to do the repairs I offer the right way or the high way...simple eh. You would be surprised how many of the broken "wanters" choose the highway and then have the balls to ask for directions to ebay.

:disbelief:

is true...me no lead you down the garden path...well maybe to smell the roses.

blessing
duh Padma



Hear in endith another rant by the Padma ~ all donations to the

Mandolin cafe Vacation Fund
are graciously accepted.
Please give generously.

[Dale Ludewig]

Padma, I suggest you look a little further into what Mr. Condino does for a living and his background and his instruments.

[George R. Lane]

Padma, You may have been building instruments for a long time, but not friendships.

[Charles E.]

Padma, you no not who you talk to. Get straight.

[Ron McMillan]

Padma contributes precisely nothing to a thread that was otherwise interesting.

[Pribar]

Nevermind

[j. condino]

Rough crowd out here on the world wide waste of time.....Some good ideas being offered; thanks to the positive contributors.

Thanks to Mike ( I'll presume) who corrected my spelling errors in the thread title after it was too late .

I'd estimate that 85% of the repair work I do is damage control correcting prior work that was substandard on what are now very, very ( sometimes even very, very, very) valuable vintage instruments going as far back as the late 1700s. In this case we're talking about a structurally sound vintage F5 that has undergone many major repairs over the decades but currently has no issues, hence no need to do major invasive surgery by pulling off the back. I don't think it would be out of line to say that I have a reasonable understanding of tonebars and voicing. I generally feel like the likelyhood of damaging the top of the instrument is higher by working through the F holes than the endpin hole; through the F holes requires a less positive lateral motion rather than a more positive push / pull motion in line with the tonebars through the endpin hole.

Over the years, I've watched almost every great builder I know get REALLY frustrated and never return to the 'cafe because of what seems to be the norm when a very experienced builder basically is asking for a little intimacy from a select group of their professional friends and peers, "Hey- how'd you do it???" and 95% of the time some novice who just finished their first campfire mandolin kit starts giving them advice on how to build #325. I've banned myself from here several times bevause of this. While I often disagree with and there is one egotistical a$$ around here (not in this thread) who absolutely infuriates me on a regular basis, I think it is great that someone is comfortable coming home from work, taking seven huge bonghits, and exhaling all over their keyboard on a public forum. It keeps things spicy and the crusty crusty, whole lotta' nothin' folks alert...;););)

Keep the tool specific replies a comin'.

j.
www.condino.com

[the padma]

Dear Mr. Condino

Sorry but this is not "tool specific reply"
It is an apology for the uncalled for crusty attitude I unleashed at you and your question.

Apologies really never fix anything. However they do serve to illuminate the apologists own errors of drunken folly meant as humour.

Non the less and from the heart, please sir, forgive this old mans ignorant comments to you.

I also believe an apology to this forum is also in order. Sorry guys. Perhaps one day I will learn to keep my mouth shut.


Padma

[Kerry Krishna]

Grandcanyon, I was puzzled by what happened to the original bracing? How did it come about that it got rebraced in the first place? Thanks!

[j. condino]

Above everything else, lets be very clear on one thing: Mr Condino is my father!

No need for anyone to apologize to me for anything, but the intent is understood and appreciated.

I believe the top was "revoiced" at some point and carved a little thin. It collapsed a few years later and anther person removed the back (second time, possibly the third) and put in some BEEFY tonebars, but choked it considerably. I think we can find a middle ground where it will still hold up, but sound a bit better. In this case, damage control is me stopping my friend from just blindly going after it with a bent exacto knife and hacking away out of frustration....

[Loudloar]

Well done Padma.


In response to several comments in this useful discussion:

I certainly have removed backs to shave tonebars. This also allows some regraduation of the top if needed. The downside is that the repair is never completely invisible. It also requires a fair amount of labor, a body-mold, and spool clamps. Frankly some inexpensive instruments don't warrant the effort.

We all know that most inexpensive mandolins have tone bars that are too heavy, among many other shortcomings. The manufacturer can't take the time and still make them cheap enough. I know that no amount of effort will make that Kentucky 675 sound like my 1924 Lloyd Loar, but a couple hours sanding down the tone bars did dramatically improve the responsiveness.

I started out with a desire to nicely shape the tone bars. I have tried various sorts of cutting tools and shaped sanding blocks. The problem is that it takes significant pressure for the tool to cut wood, plus these tools need to be moved back-and-forth along the length of the tone bar. I couldn't find a way to make that motion along the length of the bar while maintaining good pressure. Another issue is that you need to avoid accidentally sanding or cutting the top next to the tone bar. If anyone has had success in doing this I'd be interested in photos of the tools and specific instructions. Andrew, you mentioned a riffler. I'd like to see pixs. Is this a gun-stock shaping tool?

In the end I was satisfied to find an efficient way to cut down the tone bars to about half their original height. Functionally, we care about stiffness and mass. The cross-section shape being square or rounded is mostly aesthetics. (I care about aesthetics but you have to pick your battles.)

In the spirit of full disclosure I have to say I semi-borrowed my idea. I saw someone else who used a smaller bent paint roller to sand the tone bar nearest the f-hole. I modified this approach by using a full-size paint roller to sweep back and forth to sand the tone bar on the opposite side of the instrument.

I found this method can be done with no damage to the sound holes. You have to carefully slip in the sandpaper-covered end of the tool. Then, as you can see in the photo above, I hold the shaft of the tool stationary with the fingers of one hand, and pivot the tool from there. With the other hand I pull up firmly and sweep back-and-forth to sand the tone bar. The shaft of the tool where it's pivoting is nice and smooth yet doesn't even need to touch the edge of the sound hole. With reasonable care there should be no damage. The tool puts my hand directly above the sanding contact point and I can pull up firmly to create good pressure, plus the sweeping motion will reach more than half of the tone bar. So when I'm done sanding the lower part of the tone bar I move the tool to the other end of the f-hole and sand the upper part of the tone bar. With the pressure and several inches of sweep the tool will cut rapidly.

I can't say this is the right approach for the OP, since we don't know too many specifics. But hopefully the discussion is useful to others at the least.

Steve

[Tavy]

Over the years, I've watched almost every great builder I know get REALLY frustrated and never return to the 'cafe because of what seems to be the norm when a very experienced builder basically is asking for a little intimacy from a select group of their professional friends and peers, "Hey- how'd you do it???" and 95% of the time some novice who just finished their first campfire mandolin kit starts giving them advice on how to build #325. I've banned myself from here several times bevause of this.

Just to say: please don't ban yourself, we like having you around, and this campfire builder has learned an awful lot from yourself and other experienced folk around here!

[Ron McMillan]

Just to say: please don't ban yourself, we like having you around, and this campfire builder has learned an awful lot from yourself and other experienced folk around here!

I'm with Tavy, except I've only built campfires, not instruments :)

[Marty Jacobson]

James,

There is a whole class of surgical tools designed for working through a 5mm - 8mm tube. Some of the tools available are long thin rods with forceps on the end (laparascopic graspers (https://www.google.com/search?q=laparascopic+grasper&sugexp=chrome,mod%3D15&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=oU2_UNOcH4G-9QTbnIC4DA&biw=1920&bih=1032&sei=3k2_UMa6F4WQ9gTM24HYCA)). These could be used to hold a piece of razor blade or any other cutting edge. The cool thing is that there is a knob at the end allowing you to rotate the tip without changing your grip orientation.

They can be had affordably on ebay or similar sources, under $200 (http://www.dotmed.com/listing/o-r-instruments/snowden-pencer/laparoscopic-grasper/565032). They are beautifully made, you would appreciate the craftsmanship that goes into making them.

[sunburst]

Functionally, we care about stiffness and mass. The cross-section shape being square or rounded is mostly aesthetics. (I care about aesthetics but you have to pick your battles.)

Yep...

[amowry]

Andrew, you mentioned a riffler. I'd like to see pixs. Is this a gun-stock shaping tool?


Steve

Here are two examples-- I didn't say they were pretty :) The short one is the end of a riffler, and the longer one is a needle rasp. They have similar teeth and both cut pretty fast.

[multidon]

Over the years, I've watched almost every great builder I know get REALLY frustrated and never return to the 'cafe because of what seems to be the norm when a very experienced builder basically is asking for a little intimacy from a select group of their professional friends and peers, "Hey- how'd you do it???" and 95% of the time some novice who just finished their first campfire mandolin kit starts giving them advice on how to build #325. I've banned myself from here several times bevause of this. While I often disagree with and there is one egotistical a$$ around here (not in this thread) who absolutely infuriates me on a regular basis, I think it is great that someone is comfortable coming home from work, taking seven huge bonghits, and exhaling all over their keyboard on a public forum. It keeps things spicy and the crusty crusty, whole lotta' nothin' folks alert...

Sorry to not have any tool specific recommendations except to say that Andrew's look really cool. Necessity is indeed the mother of invention.

I really did want to chime in and say that I understand the frustration. I am not a professional builder but I would like to point out that, according to the site's description, this area is for those with "an interest" in building or repair. That's me. I have built several kits and done some repairs for myself and friends. Never attempting anything that I thought was beyond me. Like Dirty harry says, "A man's got to know his limitations". But I think the most important thing I wanted to communicate is that I think I speak for many who would agree that the really wonderful thing about this area is that the interaction between professionals and amateurs/hobbyists/enthusiasts/student/whatever. And I wanted to take this opportunity to say a HUGE thank you to the professional builders who offer their advice freely and generously. I can't count the number of times I have seen the best builders in the world patiently walk someone through a problem they are having with their first kit build. So again, thanks to the professionals. You are the reason the Builder/Repair forum rocks!

[Folkmusician.com]

I made something for sanding braces a few years back..

I took some copper tubing and spring steel, attached a small sanding block to the spring steel, ran the steel through the tubing, and chucked the other end in my jigsaw. I now have a power sander that can be used through the F hole. It actually works pretty well. :)

[Perry Babasin]

James, I have greatly appreciated, and viewed your video (many times) on hand-staining a mandolin sunburst. It is one of the best practical step-by-step illustrations of mandolin finishing that I have found on the internet. Thanks very much for sharing your talents.

Perry

[dunwell]

J.,
Sorry to come in so late, I've been trying to find a source for a tool I use for this sort of thing. I got what I think are referred to as "sanding foil" strips, metal backed thickish foil pieces that have carbide coarse grit on them. I thought I got them from Harbour Freight but now I can't find them there. I did find this (http://www.harborfreight.com/carbide-grit-oscillating-multi-tool-finger-rasp-68956.html) which looks to be made of the same stuff, just a small piece though. I use these for roughing out in the scroll slot to smooth it down after band-sawing in there. You can bend them around for different curvatures, I made up about four different ones.

I'll keep looking and post back up if I find a URL with the goods, but maybe someone else knows what I'm blathering about and has a link.

Alan D.

[George Roberts]

James, I am definitely a novice, but the problem of working through the endpin hole is intriguing.
There are Exacto blades that are labeled as "SMALL ROUND ROUTER," but they are more like a miniature scorp. They are meant to be used with the red plastic Exacto saw handles, and have the same type of round attachment. The steel is very hard, and when I tried to flatten the attachment section it shattered. Next I put a 1/4 brass rod in the cutting part of the tool as a heat sink and heated the stem up red hot and flattened it on the anvil. Then I drilled and tapped the end of a 3/16 brass rod for a tiny screw (I used a 4-40) and cut a slot in the rod at right angles to the screw hole. The slot needs to be long enough and wide enough to hold the flattened shank of the "scorp." A clearance hole is then drilled through 1/2 of the tapped portion of the slot.
I believe that the rod could be put through the end pin hole with the small screw in place, the blade added to the rod through the F-hole, and the screw tightened to hold it in place.
The brass rod can be annealed to allow changes in curvature.
Admittedly I have not tried this on an instrument, (I don't have any F-hole mandolins) but it is a reasonably cheap and easy approach.
George9495994960

[MikeEdgerton]

...Thanks to Mike ( I'll presume) who corrected my spelling errors in the thread title after it was too late ...

You are welcome.

[Dale Ludewig]

This is slightly off topic, but not that much. Has anyone tried one of those camera type things that you insert into a cramped space (like a mandolin) and then the image travels a fiber optic channel and winds up on a little screen? They're not cheap but you could actually see what you were doing while doing the tone bar work. Or reinforcing cracks.

[Pribar]

This is slightly off topic, but not that much. Has anyone tried one of those camera type things that you insert into a cramped space (like a mandolin) and then the image travels a fiber optic channel and winds up on a little screen? They're not cheap but you could actually see what you were doing while doing the tone bar work. Or reinforcing cracks.

They are cheap and they do work, I use one to check the guts of anything that comes into the shop just as a preventative measure. I use this one:

http://www.amazon.com/gp/product/B007ROP3FO/ref=s9_simh_gw_p421_d1_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=180S0GFSG1FNKX0D3868&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846

the first one I got was bad but the replacement has held up for 8 months now

[Steve Hinde]

I have one of these little cameras. Use it o my day job to see hidden spaces or inside safe areas too. http://www.4ucam.com/ Look down the list for the wireless remotes.
Steve

[j. condino]

Lots of good ideas here. Thanks again for everyone who contributed. I'll go through a few trials and see which one works out (hopefully) and then post a few images in a couple of weeks when I tackle it.

j.

[David Houchens]

When I do work through sound holes I use #4 copper ground wire. The end can be hammered to flat paddle shapes to pallet glue under braces or attach adhesive sandpaper to sand unreachable places. The flatten ends can be curved to almost any shape. Using through endpin hole it is very easy to add curve as you get closer to the tailend of the instrument, but stiff enough to apply good preasure to the sanding end.
I like the exact scoop shown, but be very careful for grain runout in the tonebar.

[George Roberts]

Good point Bryce about the grain runout. The Exacto "scorp" can be turned around in the slot so it works on a push stroke, but I would probably consider using 1/4 inch brass rod in that case. With a flathead screw countersunk into the rod, it should still make it through the endpin hole.
George

[George Roberts]

James, I was talking to a good friend about your particular problem with the tonebars. He is a former violin maker, furniture designer, wood carver, and general renaissance type of guy. He suggested drilling multiple holes in the tonebars to decrease the mass and hopefully not diminish the strength. I have seen examples of this with bridges, but am unaware of its use with tonebars. He even recommended a small air driven flexible cable drill. It seemed like a reasonable idea to me, but, then again, I am certainly a novice.
George

[Tavy]

James, I was talking to a good friend about your particular problem with the tonebars. He is a former violin maker, furniture designer, wood carver, and general renaissance type of guy. He suggested drilling multiple holes in the tonebars to decrease the mass and hopefully not diminish the strength. I have seen examples of this with bridges, but am unaware of its use with tonebars. He even recommended a small air driven flexible cable drill. It seemed like a reasonable idea to me, but, then again, I am certainly a novice.
George

I've seen that done on guitar braces (deliberately during construction, not after the fact though), been meaning to try it out...