Sunday, December 10, 2017

DIY Saxophone Neck Tenon Adjustment

A couple of preliminary items.  I chose to adjust my own tenons because I like to mess around with things.  It might not be feasible for some.  The petal adjuster that I bought costs $75, including shipping.  That's about what a technician would charge you for a late Martin or Conn 10M saxophone that has the double tenon.  Those models are difficult to adjust because they usually required the tenon to be removed and re-soldered.  I had three saxophones that could use adjusting, so it penciled out for me.

Also, things can go wrong.  If you are nervous about working on your own saxophone, or have difficulty with a can opener, this blog is not for you.  In fact, I would urge you not to continue reading this blog (or any blogs on this site, for that matter).  For those of you willing to try this, I would recommend the "rule of 10."  Figure that it will take 10 adjustments to get the proper fit.  Insert the swaging tool, close the handles until resistance is felt, and then take the neck off and try a fitting.  There should be no change at all.  That's the goal on the first try.  Try again with a little more force.  If not better or perfect, try again with a tiny, tiny bit more force.  There is no going back with this tool (not really), so spend an extra 20 minutes and be careful.

So here is the weapon I used.  $70 on Ebay with 2 day shipping.  You can also rent these at some large rental shops, but the fee was $25 a day and there wasn't anybody close by that had one.  I could drive an hour to a rental place, and an hour back the next day, or I could have FedEx drop it at my door and then resell it on Ebay if I wanted.  I chose to get a brand new one.  


It is called a "petal" expander because the slim cone on the end of the unit is forced into the 6 "petals" (the pie-shaped anvils), causing them to expand.

This tool is actually for use with copper plumbing pipe.  Instead of using expensive couplings, this allows you to form a bell on the pipe and simply insert the same size pipe into the newly formed bell.  That means a couple of things.  Each expander fitting only changes the inside diameter approximately 1/8th inch.   That's plenty for our purpose, but you may end up "in between" sizes and have to start with one and finish with another, as was the case for my Martin tenor.  Also, this is for thicker rigid-walled copper pipe, which is much more difficult to expand than thin brass.  Go easy!


Here is the tool with the 7/8" expander inside the neck tenon of a Conn 6M.  You can see that the expander would insert just short of the neck tenon ring, which is fine because we don't need to go there.   I would recommend that you remove the pip key because it will just be in the way as you fit and refit the neck 10 or more times.


Don't try to "free style" with the tool, meaning holding it out in front of you like a professional wrestler and mashing the handles together.  Place one handle on the floor and from a kneeling position use a little bit of your body weight until you feel slight resistance.  Rotate the neck 30 degrees, feel some resistance, rotate again, press, and then check the fit.  You should have no change the first time.  Perfect, now a little more pressure.  Make sure that when you rotate the neck, the petals on the expander do not rotate (they can), leaving no change to their position relative to the neck.

There is also some preparation that you can perform on the body tube.  On a classic neck receptor, there is a slot with a thumb screw to secure the neck from rotating.  We want that loosened up.  As that area of the receiver is adjustable, it isn't too important that we get a perfect fitting there.  We are interested in an airtight fitting below the neck slot.  We could remove the screw and pry the top of the receiver open like this.

This might just spread open one side or the other.

But I think that there is a better way.  First remove the octave pip actuator from the body if it is in the way.  Then, with the screw snug, pick the expander that best fits the receiver.  We are going to use a little pressure with the expander to do two things.  First, using our slight pressure, we are going to go 30, 30, 30 degrees to make sure that the receiver is round.  These can get out of round, especially if the neck was sloppy.

Then we remove the neck screw and put the expander in, making sure that it is inserted well short of the depth of the slot.  Instead of using a screwdriver as shown above, we are going to push open the slot a tiny bit using the expander tool, thus ensuring that the receiver remains round.

On this sax, the petals could be inserted plenty far even with the pip actuator left on the body (visible at the bottom of the receiver).  You could do this with just the screw loosened but still in place if you think that you might over-expand.  It doesn't take any real force.

Now we are ready to work on the neck to get it to fit snug in the now perfectly round receiver.  <script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-5462135008989626"
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Another issue you may encounter is that the neck inserts snug, but right as seats when completely inserted, it becomes looser.  Tightening the neck screw can keep the neck from rotating, but it still wiggles a little.  It feels as if the diameter is right at insertion, but then looser when seated.  Or maybe it is the neck tenon has expanded at the bottom but not at the top.  For this situation I have found that a wrap of cellophane tape (i.e., Scotch tape) around the start of the expander anvil is enough to expand the neck tenon a little more further in.  Basically, you are either making sure that the expansion is truly cylindrical or even tapering the expansion so that the neck gets tighter the further it is inserted.  Again, CAREFULLY. 

As you slowly approach a tight fit, you may want to use oil or cork grease when test fitting the neck to ensure that you don't, despite using great caution, jam the neck into the receiver having expanded it a little too much.  If you do over expand, you have no choice but to use some kind of a lapping compound to reduce the diameter of the neck (or admit defeat and take it to a technician that has a reduction collet).  

Lapping has its own problems.  The coarser the grit, the faster it reduces the diameter, but it causes the neck to bind and can cut too much.  Also, if you use a water based mixture (toothpaste, chrome polish, etc.) you will generate a little heat and the water will evaporate out, causing the neck to bind.  I use both oil and water mixed in my lapping compound (usually jeweler's rouge, tripoli, etc.) and am very careful not to get the neck stuck to the point where I'm using too much force to rotate it in the receiver.  If you need to lap, be very careful to not twist the neck in the receiver using the cork end.  You can twist your neck into a pretzel.  Keep your hand as close as possible to the "crook of the crook" so to speak.  You can also examine the neck and possibly see the "tight spot" based on what is being polished by the lapping.  Carefully lowering those high spots with fine emery paper glued to a tiny sanding block (I used old reeds) can get the neck fitting perfect.

Despite your best efforts, the nature of the petal expander will cause an expansion that is not perfect.  In fact, most any expansion won't be perfect.  (I leave claims of perfection to those who make a living at saxophone repair and need to justify their fees.)  Here is what I mean by not perfect.



The little lines shown in this neck tenon (right to left, not those round and round) are from the 6 petals of the petal expander despite taking great care.  They quickly lapped out and, in fact, I didn't completely get rid of them because the fitting was air tight.  Although I can see them upon close inspection under magnification, the fitment before I started was also not perfect, probably from the original manufacturing, so I'm not going to let it bother me.  

Having gotten used to loose necks for so long, and having taken "quick and dirty" measures like this to make my Martin neck seal properly (second picture), it is a little unnerving to have the neck actually fit tight.  What if it gets stuck?  Bummer.  Oil and cork grease tend to get thicker and lose their lubrication.  That makes it spooky to leave the neck sit in the receiver for any length of time (meaning like over night).  What I have found is that Dr. Slick cork grease, which is water based, seems to give the best results and actually reconstitutes from the moisture in the horn when played.  It is also possible to use heat to free a stuck neck (maybe not the double tenon type), but that's only if it's on the workbench.

So far, no problems with my new tight fitting necks.  And it seems to have fixed a little bitty problem that I've had with a lot of old horns (10Ms especially).  Second G is always the least stable note for me (and many other players).  I've always wondered if a slight leak at the neck tenon is acting as a ghost vent at just the right spot to cause trouble for that one note.  Several times a tight neck seal has cleaned up that problem for me.  

I can no longer blame leaks in my horn for my performance issues.  Since I now use synthetic reeds, I can't blame my reeds.  I'm running out of scape goats.  I'll have to start blaming my ligature for any performance problems.

3 comments:

  1. Heya! Would you mind placing the link where you got that petal expander? Thanks a bunch!

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    1. Just type in "Plumbing Pipe Expander" on Ebay and you will see a bunch of them.

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  2. Outstanding blog Thank YOU ! I was eyeballing these expanders recently ( but unsure if it would work ) when I was quoted 200$ to expand my original neck/tenon because the shop recognized the horn was a Conn Trans ( pre 10M) 1932 and thought I had no choice or other options. I've rebuilt several Conns and the neck has been the one sticking point I haven't been able to find a reasonable tool for. I have several other horns that could use a swagging on the neck and this could go a long way towards getting those little ghost leaks nailed down. Great article ! Thanks for posting ! For oThers with some DIY skills- beware of the dudes out there in sax repair land with ghostly grey hair and narrow spectacles who make their living telling the rest of us why we cant do things like this without them. I've had good success made most of my own tools - LousisVille Slugger nipped the handle for a mandrel for taking out sax body dents, steel scrap rod with a ball bearing from amzn welded for dent removal,tone hole leveler from brass discs and 500 grit sandpaper you name it. Great posting and again ,thanks for this !

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