[clarnibass]

Hi

I need to make a neck tenon expander roller for a tapered Conn tenor. Does anyone have suggestion on what's the best way to get the most accurate angle?
It's not like it has to be accurate to a micron or anything close to that. The tools and sax tenons themselves are not made to this accuracy in the first place. But it has to be close enough.

Any method other than measuring the thickness and calculating based on distance?
Unsoldering the tenon and putting it on the lathe to get the angle from the tenon itself is not possible in this case.
Holding the neck itself with the tenon parallel to the bed is tricky.

Another option I though of was to machine some kind of plastic plug and very gradually reduce the angle, starting with it touching at the inner end and checking with a very thin feeler at the outer end of the tenon. Then stop once it is grabbing.
Or something similar using paint (not really paint... forgot the name... but it's that "paint" you use to find part touching, etc.).

If someone here just knows the angle, I guess I can try to get it as close as possible, but I don't have angle blocks close to that so not sure I could use it.

Thanks

 

[valjeanmeister]

 

[clarnibass]

Thanks. That comes out to 2.694°. Obviously it doesn't need to be accurate to the second but what would be a good way to set that (approx) without angle blocks?

Edit: I calculated as if it was 0.850" between the 1.060" and 1.020" diameters, but now I see that there might be a slight overlap, not sure from the drawing if it's more and the 0.850" distance is to slightly below where the diameter is 1.020".

 

[saxoclese]

Might there be a way to expand the tenon using a "petal" expander rather than a "can opener" type. I have not tried that---just thinking out loud.

 

[lostcircuits]

That's going to be interesting, especially given the different wall thickness as you go up (or down). The only way I can see this work would be a wedge (conus) with a thread at the top portion that can be used to pull it through (up) from the bottom by turning a crank. I don't think you want to expand the top jog as well so that might work. I was just looking at the different collet chucks and I have one that looks close enough with respect to the angle but it is too small. It shouldn't be too difficult to machine something like this.

 

[blaine hoopes]

I'd guess the trick is going to be getting a tapered tool to stay in place and expand the tapered tenon instead of wanting to squirm out of the tenon as the tool expands. Maybe leaving the lathe machining marks on the tapered surface of whatever tool you make will give it enough grip?

 

[1saxman]

Have you actually tried a roller expander? How have guys done this over the last 100 years? In order to use a wedge type, you would have to take the tenon off and do it backwards. Obviously you don't want to have to do that, so you're left with the roller.

 

[clarnibass]

Might there be a way to expand the tenon using a "petal" expander rather than a "can opener" type. I have not tried that---just thinking out loud.

I've done that. It worked ok and was extremely slow, with tiny increments, for a tenon that was just very slightly loose. In this case it's way to lose to consider that.

Re the other issues mentioned, yes, because of the different thickness it would have be done in "layers", kept in place, then moving to the next, etc.
This wouldn't be necessary if the rollers covered the entire length of the tenon, but that doesn't seem possible and would require too much pressure for the tenon rollers. Maybe some kind of industrial quality metal rolling machine could be made to work that way. A friend has a very high quality metal roller but the rollers are attached at both ends, so not possible.
There's also an advantage to be able to expand only parts of the length of the tenon.

 

[turf3]

You can slip the tenon over a piece of heavy steel rod tightly held in a big bench vise (that's just smaller than the ID) and slowly gently tap all round with a ball or cross pein hammer to expand it. You'll have to check fit to the receiver frequently with Dykem (or the poor man's Dykem, a Sharpie).

If you have good manual dexterity you can expand a piece of tubing quite precisely this way, but it's REAL SLOW. I have done this very operation to more than one (but not more than three) sax tenons in my life with good results. You MUST work slowly and check both with OD mike and fit check to the receiver very often.

 

[clarnibass]

Yes I've done that before. Hope to save time and the roller would work for this one and others in the future.

 

[clarnibass]

I ended up coming up with a different method that wasn't mentioned here, maybe worth posting. I first set the compound to the approximate angle (as much as possible using the scale) and turned the part. I then held the tenon itself against it (tenon over it) and checked if it was straight. I was half calculating and half guessing by how much I need to move it. In the end I got it more than accurate enough. It seems like the tenon was worn enough, and probably not made completely accurate in the first place, so any higher accuracy of the tool than what I got wouldn't make any difference anyway.