Repair And Restoration
TO ADD FORUM POST USE THE DISCUSSIONS TAB OR ADD NEW TOPIC IN THE SIDE BAR
Organizer:
- Organized by
-
-
Local builder mandolin neck reset
-
Local builder mandolin neck reset
A friend of mine gave me his locally built mandolin for a neck reset. The glue in the dovetail has started to fail, and left a large gap at the bottom and a separation from the fingerboard and body. I’ve taken my brownstone and tried to heat the joint up enough to soften things up, but to no avail. I have no idea what type or where the joint is exactly. There are some indicators that this instrument was built with several flaws in the construction and finish, so I’m not entirely sure what I’ll find. At this point I think drilling holes for foam cutters is out, and possibly removing the fingerboard would be the path forward. Any tips or two cents would be appreciated.
-
17 Replies
-
It looks like it has interesting spacer blocks under the fingerboard extension. Maybe try to separate and remove the block (#2) nearest sound hole from the fingerboard extension and top, as it looks like it’s separate from the block towards the heal (#1) and loose? Then you may be able to see if block #1 goes across the top of the dovetail, locking it in. If it does, you may be able to remove that block as well by separating the fingerboard over that, installing heat probes into that block into the vertical joints from the fret slots above the joint, four probes total, and taping out sideways with pine and cork punch so as not to mar. If this works, you can use the same probe holes to remove neck. I watched a vid where the spacers went over the dovetail. Repair person cut fingerboard not knowing that. Still had to remove all the pieces and rebuild. Was a mess. But, in the end, may be easier anyway. If you try though, and do get top of dovetail clear, then probes should get the neck off.
-
Something to think about is this may not be a dovetail joint. Some people use a locking joint method which was coined by Roger Siminoff. Basically the heel and block are cut is a V shaped mortise and tenon and the neck is “locked” in place by two dowels in the back of the neck block. If that is the case I would say that the standard methods of heating a neck joint wouldn’t ever break it loose. From what I am seeing in the pictures, I wonder if the heel block has come loose from the back of the mandolin. As Tony pointed out, those spacer blocks look uneven. It also looks like there may be a small crack along the fingerboard extension. If this came in my shop, I would probably pop off the fingerboard so I could get a good look at what all was going on underneath it. Just my two cents though.
-
Eddie, yes excellent. Have watched vids of guitar and Mando heels with dowels. I’ve been thinking about the application of using an oscillating cutter as a way to tackle that problem. There are very thin, narrow blades available now. Fein makes one that is 0.25 ( which is only a couple of thou wider then most standard fret slot of 0.23) thick and 3/8″ wide. It only cuts 1-1/4″ inch deep but could be extended by welding extra blade length on. My thinking is to cut through fingerboard at 15th (or whatever fret is next after body end fret) fret on center. This would be a nice, neat cut instead of total heel cut. This could also be used if fingerboard off and doweling (0r screws? Blade will cut steel as well) has been determined. Much less intrusive then cutting and chopping using hand tools. I guess what we’re trying to find is the easiest, least impactful way of finding out how the heel is attached. I would certainly use your idea and take off fingerboard before cutting it off although still wouldn’t tell us if doweled but would foster easier access. I would still be hopeful to try and take blocks out first though to see if that would lead to discovery of how heel is fastened. If it shows slotted joint, I’d go for cutting slot through fingerboard in anticipation of dowels. The slot would be fairly unobtrusive and would be covered by fret. At any rate, I’m going to build a mock up of the dowel situation and put the oscillating saw technique to the test.
-
I really like taking the fingerboard off. Especially if you cant get intel on the joint from the luthier.
-
Granted, you guy’s have so much more experience then I. Just basing my thoughts on my experience so far. I didn’t mention that the binding looks crumbly/fractured in the photo’s and I was thinking I’d be worried about mangling the fretboard binding during removal process. That’s why I was thinking you could possibly find out the nature of the joint in stages. Since you’d separate the fingerboard from those blocks anyway, I was thinking you could stop there, remove the blocks (they look loose), and have a gander. If joint type discovered, great, if not proceed with complete fingerboard removal. I’m really interested in this one because every vid I’ve seen on mandolin neck resets have been disasters, fingerboard removal or not. So having fun hearing from the experienced and following along. I’m sure you guys have dealt with crappy binding and all. I’ve only dealt with removing fingerboards with fairly good binding intact. I hope KT that you post the event? Thanks, Tony
-
I just revisited this video. The assembly around the heel looks a lot like yours. https://www.youtube.com/watch?v=4r7EsAzVvMw
-
Okay, update time. Finally carved out some time to heat the neck off. Unfortunately it didn’t give me much evidence as to the cause of the neck releasing. At this point I’m suspicious that the neck block could’ve come loose perhaps, however I’ll admit at this juncture I’m beyond my expertise to diagnose. Amy ideas from you mandolin people would be awesome.
-
Pretty straight forward mando dovetail. Have you ever done one ? How expensive is the instrument ?
-
I have not. It’s a fairly expensive instrument in cost, but not necessarily in quality. Local builder who has since passed away. It belongs to a friend of mine, and he was pretty adamant about having me do the work.
I was thinking to drilling a couple holes for my foam cutters to see if I can break it loose. My biggest fear at this point is dealing with a bad neck block.
-
Foam cutters might be a little underpowered. If you struggle getting it off let me know and I’ll cook up some larger resistance heaters.
-
Much appreciated. Might just skip straight to the heat stick and soldering iron then.
-
-
-
-
-
-
It works great. It will heat those joints as hot as you want. The advantage is you can put multiple probes in heating all the joints and the whole assembly up at once from one controllable heat source instead of having multiple foam cutters and having to move a single point heat source back and forth, losing heat. I’ve used six probes on a single 80w soldering pen. A 60w with four probes works great. And the pen stays stable. You can pull and twist and even turn the instrument upside down, and the pen will stay in place. I use four probes now minimum. I want heat everywhere. I’d use four probes on that joint. I’d use 14 gauge copper wire and matching wire size drill (you can get them on McMaster/ Carr in 3″ lengths.
-
That looks like a sexy way to handle LP’s/other set neck tenons! Lots of heat up and down and all around.
-
That Dimmer switch thing is the bomb, just ordered one off Amazon.
-
I’m not clear how he’s checking the temperature. IR of the wire before inserting?
-
-
Laser temp gun. I check the wire but mainly the whole heel temp on outside and figure about ten degrees of heat loss from inside to out on guitar heel. Mandolin heel much smaller so if outside about 145 to 150F should be good to go figuring that most pva and hide glues soften at around 150F according to manufactures specs.
Log in to reply.