TubeNet

OK. Things went well today. I modified the small receiver on my Conn Eb today. Before the mods, a regular shank mouthpiece only engaged about 3/8". After the modification, the same mouthpiece engaged about 7/8". First, I enlarged the receiver to .531" down to where it meets the leadpipe. (That's the same diameter as the small end of most regular shank tapers.) Next, after MANY revolutions of the Jarno #5 I am satisfied with the mouthpiece engagement. The gap is still quite large. I may go back and open up the receiver a little more to shorten the gap later but for the time being, the horn plays OK. I only opened up the receiver about .025" (.0125" per side) so I am confident that the wall of the receiver has not been compromised.

For those of us who don't have a Jarno #5, what are the specs of a mouthpiece receiver reamer?
(Yes, I realize this is an old thread, but at least I "searched the archives")

Marty - perpetually modifying the BART receiver and inserts

MartyNeilan wrote:For those of us who don't have a Jarno #5, what are the specs of a mouthpiece receiver reamer?
(Yes, I realize this is an old thread, but at least I "searched the archives")

Marty - perpetually modifying the BART receiver and inserts

Marty... the reason why I use a Jarno #5 taper reamer to enlarge tuba MP receivers is because a #5 is .500" diameter at the small end. All Jarno reamers are EXACTLY .050" per inch taper.

Whereas Morse taper reamers are dimensioned at the big and small end and the rate of taper is 'about' .050" per inch. Also... standard Morse reamers are not available in a size that's conducive to enlarging a small-shank receiver to fit a regular-shank receiver.... unless you take the receiver off the horn first.

Ferree's, on the other hand.... will make a reamer with the size small end you want for a fee. An alternative might be to take a standard Morse reamer and shorten the small end by grinding to a diameter of around 1/2".

Officially showing off my ignorance here. Some of this I should just figure out myself but you clearly have a firm grasp of this subject area.

I did some googling at one point but never found what I was looking for:

Seems the morse reamers are standardized at very specific sizes with no overlap(and some gap) between reamer tapers.

Do they make half sizes? Your post above suggests not, why is that? Seems like a sensible thing to have some crossover between reamers for machining purposes.

Are Jarno and Morse 'brands' or a specific rate of taper? Or both?

No there are no Morse "half sizes" available.

Morse and Jarno are just standardized sizes of tools that are available in metalworking. They have very limited use. If you need a special size you can pay a lot to have it made.

It's kind of like asking "Why are tubas only available in Bb, C, Eb and F? Don't they make in-between sizes?"

Doug Elliott wrote:No there are no Morse "half sizes" available.....

+1. Exactly. This is why I use the Jarno #5 when working on tuba receivers. The #5 has a small end of .500" which works with most tuba receivers I've seen. With Morse sizes one is too small while another is too large (don't remember the size numbers).

Doug,

Your answer would probably make perfect sense if I had a machinist background.. in which case I guess I wouldn't have needed to ask?

Reading the wiki articles about tapered reamers I've gathered that they are used to enlarge holes to a consistent size AND those tapers are used in holding tools in place(aka jaws of a drill press have a slight taper).

Which is helpful knowledge BUT doesn't explain to me why there is a gap between standard morse taper reamer designations... which means there are specific hole sizes that are actively skipped over for enlargement. Are those hole sizes not important for a reason similar to why a D tuba isn't necessary? I can't imagine a theoretical reason why such a tool is standardized in such a way.

More specifically, tuba shanks fall in between morse sizes. As a non-machinist, my instinct would be to find a half size reamer to machine receivers. Perhaps that's a terrible idea? Clearly real machinists don't have trouble with this but google has failed me in finding an answer.

Thank you for your time and energy

joh_tuba wrote:.... Which is helpful knowledge BUT doesn't explain to me why there is a gap between standard morse taper reamer designations... which means there are specific hole sizes that are actively skipped over for enlargement. Are those hole sizes not important for a reason similar to why a D tuba isn't necessary? I can't imagine a theoretical reason why such a tool is standardized in such a way.

More specifically, tuba shanks fall in between morse sizes. As a non-machinist, my instinct would be to find a half size reamer to machine receivers. Perhaps that's a terrible idea? Clearly real machinists don't have trouble with this but google has failed me in finding an answer.

Thank you for your time and energy

Morse taper reamers DO overlap in size and cover an entire range of hole sizes. Where the problem comes in is when working with brass instrument receivers when mounted on a horn the small end of the reamer is way into the receiver and causes problems when the leadpipe curves. Most leadpipes only stay straight for a short distance after the receiver.

Ferree's will custom make a reamer with any small end you want. I think they simply cut off the small end of a standard Morse reamer.

The only reason I use the Jarno #5 is because the small end in .500"... the size it takes to enlarge a small tuba shank receiver by .020" or so.

I understand why you like the #5 Jarno. That's pretty awesome for that application!

But I'm still confused about reamers in general. If there is a resource I should be studying rather than posting annoying questions here... please point me in that direction. I really have tried to find it.

http://www.industrial-tool-supply.com/M ... eamers.pdf

I want to defer to your notably greater knowledge on this topic but that chart definitely shows gaps between the small end size of one reamer and the large end of the next. Apparently this doesn't concern machinists or there would be half sizes readily produced.. that confuses me.

Maybe machinists don't use reamers that often... or for the purposes I imagine that they do? I can't imagine it's any more difficult, in this modern era, to produce one spec vs another spec.. so there must be a more fundamental reason for the standards that do exist. I just haven't wrapped my mind around that.

Time for me to stop asking questions and find a machinist friend that will let me annoy him/her in exchange for beer.

The answer is "standardization." Many machine parts are mounted by way of a taper - the same reason brass instrument mouthpieces and trombone slide-to-bell are mounted with tapers. It self-centers, can be assembled quickly and securely, but also disassembled easily. Machine tool parts need to be standardized to be interchangeable, so certain sizes were developed for that reason.

Kind of just like mouthpieces.... and instruments.... why is there no D tuba? Because there's no need for it. Of course you can have one custom made if you have enough money.

AND nobody really uses tapered reamers for much of anything anymore. Parts are made on CNC machines so there's no need for reamers.

Thank you. That took more effort than it should have to click.. but standing here in front of a nice old lathe I see what your are talking about. I was thinking of reamers as something used for machining rather than as a standard for quickly interchanging tools.

Again, thank you.

why is there no D tuba? Because there's no need for it

Ivan Hammond didn't think so.

He never once spoke about reamers though.