polkat Posted January 8, 2012 Report Share Posted January 8, 2012 How deep are you folks cutting the neck mortise into the top block on new violins (or top block replacements)? I have seen them anywhere from 3mm deep to 7mm (7mm seems rather excessive to me). Also, I have seen a few that were deeper at the bottom of the block, which I guess was a way to get more neck angle. Mostly what I see is about 3 or 4mm throughout the cut. Is that about average? Thanks! Quote Link to comment Share on other sites More sharing options...
Jose Catoira Posted January 8, 2012 Report Share Posted January 8, 2012 IT does taper a bit, I make my neck stop 130mm and then add 6.5mm for the mortice. You could check out Ray Schryer's website, he has a fabulous article there about neck fitting. Ray's articles. He makes the impossible look so easy... Quote Link to comment Share on other sites More sharing options...
jacobsaunders Posted January 8, 2012 Report Share Posted January 8, 2012 In the violin making school/s one learns to make the neck 13cm from nut to belly edge + 7mm for the mortice. I consider this to be too much. My father allways let the neck into the block even further, which makes it absolutly impossible to karate chop out, if need be. It can’t be the object to build a violin like an indistructable brick shit-house, rather so, that a future repairman can get it to bits without destroying it. I have violins in my cupboard from 1800 and before who's necks were not let into the block at all, just glued onto the rib, and they haven't fallen apart yet. With repairs, when I have made a new top-block, I make the neck 13cm + however much the gap for the neck mortice in the belly was already. Quote Link to comment Share on other sites More sharing options...
Doug Marples Posted January 8, 2012 Report Share Posted January 8, 2012 When discussing neck mortise depth it would be helpful if everyone were taking the measurement in the same way (which is not probably the case). Since we measure the neck length from the top edge of the belly plate (at the side of the mortise) then that's probably the logical place to measure mortise depth, too. How deep the mortise is back by the button, or down the front midline of the instrument (projected to the imaginary arc of the belly edge-which isn't there now) are other issues that could cloud the issue. Measuring at the side of the mortise to the edge of the belly (treble side is my custom) I typically use 6.0 mm for new violins. Quote Link to comment Share on other sites More sharing options...
Brad Dorsey Posted January 8, 2012 Report Share Posted January 8, 2012 How deep are you folks cutting the neck mortise into the top block on new violins (or top block replacements)?... I think that the mortise is not generally planned to be a certain depth. Rather the depth is whatever results from several other measurements and angles: The fingerboard surface of the neck is made a certain length from the nut; the end of the neck is cut off at a certain angle; the fingerboard is made with a certain width, edge thickness, scoop and radius; then, finally, the neck mortise is cut to whatever depth is required to achieve the proper neck mensure, fingerboard projection and angular alignments. If all of these other measurements, angles and alignments are standard, the resulting mortise depth works out to be about the same each time (deeper at the back than at the top), but I never measure the depth when I'm setting a neck -- the depth is just whatever it turns out to be. Quote Link to comment Share on other sites More sharing options...
polkat Posted January 9, 2012 Author Report Share Posted January 9, 2012 Well, give me a sec to get behind something before people start throwing stuff at me. I learned fiddle making from my Grandfather, who made stringed instruments in the deep backwoods Blue Ridge mountain style (which is basically do whatever works--think fiddles from the old Foxfire books). So I apologize if this is poorly explained or simply sounds strange. For cutting the mortise, he would measure the top of a finished neck (with the nut but sans fingerboard) from the back of the nut out 130mm and make a mark where the plate edge would touch. We used inches back then, but I’ll use millimeters here so it hopefully makes more sense. The 130mm mark represented where the neck met the front edge of the top plate. Anything left over was how deep the mortise was. In other words, if the full length of the neck (back of nut to the back end of the neck) was, say 137mm, then the neck sat 7mm into the mortise (from the edge of the plate to the back of the mortise). So if the overhang was, say 2mm, the neck would sit in past the outside surface of the ribs about 5mm (including rib thickness). Make sense? See attached drawing. Further, if the neck was made exactly to standard dimensions, with the button surface 90 degrees to the end (heel back), and heel back to fingerboard surface about 87 degrees, and with the top block properly angled to the violin body, then the mortise could be cut to a uniform depth overall while still maintaining the proper angle of neck to body. But this would sometimes be adjusted depending on the arch height. I raised this question as seeing the different mortises I explained above got me to wondering if I’ve been doing it wrong. No doubt I’m wrong about some of this (me and my country ways!). Or am I? Mortise.bmp Quote Link to comment Share on other sites More sharing options...
Doc Eastman Posted January 9, 2012 Report Share Posted January 9, 2012 I think that the mortise is not generally planned to be a certain depth. Rather the depth is whatever results from several other measurements and angles: The fingerboard surface of the neck is made a certain length from the nut; the end of the neck is cut off at a certain angle; the fingerboard is made with a certain width, edge thickness, scoop and radius; then, finally, the neck mortise is cut to whatever depth is required to achieve the proper neck mensure, fingerboard projection and angular alignments. If all of these other measurements, angles and alignments are standard, the resulting mortise depth works out to be about the same each time (deeper at the back than at the top), but I never measure the depth when I'm setting a neck -- the depth is just whatever it turns out to be. I was taught and to measure 7 mm in from the top edge (so neck from lower edge of button to top end of neck is 137 mm), measured in the midline. If overhang is 2.5 and rib 1.2, then the cut extends 3.3 mm into the block at the midline, less at the edges depending on the curvature of the top. I was also taught to cut the angle of the neck root at 5.5 degrees, which meant that the mortise was a little deeper at the button, in order to achieve the correct neck angle/projection onto the bridge. I now cut the angle at 6.5 degrees and the mortise is about the same depth top to bottom, but do whatever it takes to get the neck angle right (per H. Strobel I use the projection of the fingerboard top onto the bridge rather than the height over the arch at the end of the fingerboard as the metric for setting the neck angle). Quote Link to comment Share on other sites More sharing options...
Joe Christian Posted January 9, 2012 Report Share Posted January 9, 2012 Polcat, What you're doing is fine. As Brad said, the mortise depth should end up being whatever is needed to get a neck length measurement of 130mm. When you're laying out the neck you account for the mortise depth as you're describing. This gets you close enough, but the thickness of the fingerboard and angle of the neck throw things off a tiny bit. 6 to 7 mm mortise depth is a good range. When I attended NBSS in the early 90's the school spec was 7mm for mortise depth. Not sure what it is now. Currently I use 6mm but I'm not sure it makes all that much difference. Being able to work with the students at the school for another 5 years after graduating, it seemed like the deeper end (7mm) was used for a few reasons. A little extra strength isn't a bad thing at the beginning when mortises might not fit as well as they should. Students tend to be timid when mortising the neck and will probably end up a little shy anyhow. It's good training to have to remove more wood. --Joe Quote Link to comment Share on other sites More sharing options...
polkat Posted January 9, 2012 Author Report Share Posted January 9, 2012 It's polkat with a k, based on an old college nickname, but that's okay! Thanks guys! Making more sense to me now. Doc, when you say 6.5 degrees, you are of course referring to the angle from the very back of the root (that butts into the back of the mortise) to the fingerboard surface (I'm a bit shy of the actual terms). Right? [PS: I can't seem to insert images into the text. There's a window for it that pops up a tiny box, but it doesn't make sense!] angle.bmp Quote Link to comment Share on other sites More sharing options...
Brad Dorsey Posted January 10, 2012 Report Share Posted January 10, 2012 ...Doc, when you say 6.5 degrees, you are of course referring to the angle from the very back of the root (that butts into the back of the mortise) to the fingerboard surface (I'm a bit shy of the actual terms). Right?... The angle between the fingerboard surface and the end of the neck couldn't be anything close to 6.5 degrees. A casual glance will tell you that it's somewhere close to a right angle (90 degrees). I forget the exact angle -- is it 86-87 degrees or something like that? I have no idea what angle Doc was talking about when he said 6.5 degrees. Quote Link to comment Share on other sites More sharing options...
captainhook Posted January 10, 2012 Report Share Posted January 10, 2012 6.5 degrees in this case is also equal to 83.5 degrees (6.5 degrees from square). That gives a neck root close to parallel to the ribs. Quote Link to comment Share on other sites More sharing options...
Doc Eastman Posted January 10, 2012 Report Share Posted January 10, 2012 6.5 degrees in this case is also equal to 83.5 degrees (6.5 degrees from square). That gives a neck root close to parallel to the ribs. Correct. This was difficult for me to grasp when I started! I was taught to express this angle as 6.5 rather than 90-6.5, but have seen it both ways. I set the protractor at 83.5 however. Expressed either way, when the neck is fit to the block the face of the neck (may not be using the correct terminology) is usually about perpendicular to the ribs. As mentioned previously, I do not use this angle to fit the neck, using the projection of the fingerboard onto the bridge (fit to the top and in the right position)to determine the angle of the mortise. Once I make the cut in the top 7mm from the top edge I don't touch this finish cut. The mortise may actually deviate a little from perpendicular one way or the other depending on the arch. Before I fit my first neck I made up a mock violin neck end with a replaceable block and fit a neck about 10 times. Practice helped in getting good joints. Quote Link to comment Share on other sites More sharing options...
polkat Posted January 10, 2012 Author Report Share Posted January 10, 2012 Yea, I mentioned 87 degrees in my second post. 83.5 then makes sense, but sounds like a lot compaired to 87. But I'm also hearing just to set the angle with a simple inclination jig and adjust from there. But if it measures off, then it means reshaping either the mortise back or the neck heel, so I assume 6.4 can be a good starting point. I think I have enough for now. Thanks all! Quote Link to comment Share on other sites More sharing options...
NewNewbie Posted January 10, 2012 Report Share Posted January 10, 2012 The depth of the mortise is not a stand alone number, and is connected with the neck root angle. So for example a 137 mm neck length and a steep neck root angle like 87 degrees will result in a large amount of neck root being buried into the neck block. This will get your name removed from most repair person's Christmas gift list! Michael Darnton has dealt with this question of Mortise Depth and so doing a search for his name will be most fruitful, as do most searches with his name since he has about the most posts on the violin and so has covered all of the subjects. How deep does the neck go into the block? Neck question These were just the first 2 posts that I looked at, but here at Maestronet there are also posts to be found. Quote Link to comment Share on other sites More sharing options...
polkat Posted January 10, 2012 Author Report Share Posted January 10, 2012 Yep, I understand the root angle importance. In fact, it's what I'm now trying to determine. However, a 137mm neck, with a 2mm overhang and ribs 1.2mm thick would result in an average depth of about 3.8mm in the block itself. Doesn't seem too deep to me. But yes, I'll check out those posts. Quote Link to comment Share on other sites More sharing options...
Joe Christian Posted January 11, 2012 Report Share Posted January 11, 2012 It's polkat with a k, based on an old college nickname, but that's okay! I apologize for spelling your name wrong. --Joe Quote Link to comment Share on other sites More sharing options...
LinkMan Posted January 11, 2012 Report Share Posted January 11, 2012 Quote Link to comment Share on other sites More sharing options...
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