Proper Gap For Olds Standard ???

[Abraxas]

Greetings. Sorry for hogging the Forums these last few days but new horns bring new problems.

I got a '47 Olds Standard and while I'm initially impressed, more time with it allowed for more scrutiny.

I noticed i was blowing a lot more air into it than I'm used to but dismissed it as probably just a bigger bore. Then I noticed a mouthpiece was clicking at the gap.... I mean bottoming out there before being fully gripped by the receiver taper. Then I noticed all my mouthpieces, including 2 Bach, a Mt Vernon and regular bach 7c's were able to wobble a bit and too were also bottoming out.

When i play this on a tuner, notes using the second valve are sharp and I can't pull that slide out enough to bring them down and into tune. I don't know if this too is a symptom of my receiver being on the lead pipe too far.

Anyhow, it's going back in the shop to I guess pull that receiver back. The receiver was butting against a patch on the outside of the lead pipe.

Can anyone tell me what a proper gap distance should be and any experiences they have had with gaps (or lack thereof) affecting tuning ?

[Andy Cooper]

I guess it's kind of good news that your gap problem is "too little" gap.

https://bobreeves.com/blog/tag/gap/

The "paper trick" can help you get an approximation of what your gap should be with a particular mouthpiece.

You will then need to do this with all of the mouthpieces you will probably use and write down the results. You will probably find an appropriate gap for you with a specific mouthpiece and a specific trumpet. We don't know what it will be.
Good news, Reeves, Stomvi, Frost and Jim New all have backbores that allow the gap to be increased or decreased.

I think this is the video that shows intonation changes
https://www.youtube.com/watch?v=Pn58rtyZRtQ
Clicking below will download a PDF file. It shows how changes in the shank size affect the amount of gap with different brands of trumpets.
http://stomvi-usa.com/wp-content/uploads/2015/06/annulus-gap.pdf

[huntman10]

Up until serial number 189,611 (1956), all Olds cornets required a larger shank mouthpiece, and later Olds cornets could be ordered with the older shank. This is a common problem for collectors. Alan Rouses excellent Olds Central explains it here:

http://rouses.net/trumpet/cornetmpc/cornetmpc.htm

I own several Olds cornets, and I have found Jet Tone cornet mouthpieces fit older receivers, as well as some Holton cornet mouthpieces, and any Olds cornet mouthpiece made before the date. You can get a Warburton backbore with the Olds specification if you have a few tops, and I have found several old Bach cornet mouthpieces with an "O" on the shank that fit. I also acquired a Schilke mouthpiece with the Olds shank that I like on my Super Recording. But the dollar bill trick does work fairly well in a pinch.
_________________
huntman10
Collector/Player of Fine (and not so fine) Brass Instruments including
Various Strads, Yammies, Al Hirt Courtois, Schilkes,
Selmer 25, Getzen Eternas, Kanstuls (920 Pic, CG)
Martin Custom Large Bore, Lots Olds!, Conns, etc.

[A.N.A.Mendez]

[Bill Ortiz]

Abraxas, there is no one correct gap that someone can advise you to use. It varies from player to player based on your horn and set up, how you play and what works best for you. The only way to find out the ideal gap is by trial and error. I'd advise you to get a copy of your mouthpiece and have it fitted for sleeves by Bob Reeves and try different sleeves until you find one that works for you best. I personally like the Reeve sleeves over the Stomvi ones because you can get them in 1/4 sizes from Bob while with Stomvi you can only get 1/2 sizes. 1/4 sizes make a difference in my experience. Good luck with it.
_________________
'56 Martin Committee Deluxe #2 trumpet
14B Schilke mouthpiece
Couesnon Paris flugelhorn
Bob Reeves Sleeves and PVA

[Abraxas]

Just to be clear, this is a trumpet, not a cornet. I am aware of that Olds cornet irregularity on the older models.

I can actually feel the mouthpiece end tapping on solid metal as it goes in. What fooled me at first is that the MPC taper coincidentally just poorly engages at the same point, so it's not like it's falling out. I can however, with very little effort wiggle it back and forth from side to side (not in and out).

I can't imagine that i am NOT getting air leaks around such a poor fit or engagement. I'll take it into the shop today to see what the man says.

This lead pipe has a couple of patches on it and one is right at the joint of the receiver and lead pipe so it appears to me to be a poor job and the repair shop just soldered the receiver where it got jammed against the patch. I think i just need the receiver pulled back whatever you folks think should be a proper gap. Maybe say a 32 nd or 0.020 ?? I don't know and it's what I'm asking cause the gap is zero right now. The mouthpiece end is tapping on the lead pipe apparently.

[JayKosta]

A gap of about 1/8 inch seems to be often mentioned for Bach mouthpieces.

If the end of the shank is a fairly 'tight fit' in the receiver, but the fit at the outer end of the receiver is loose, that probably means the overall taper of the receiver is slightly off.

Just reaming the end of the leadpipe to increase the gap, might result in there still being a poor fit of the shank in the receiver (because of taper mismatch).
_________________
Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.

[Andy Cooper]

[Abraxas]

[Andy Cooper]

Note my edited reply above.

I have shortened mouthpieces to fit receivers. They played OK after i chamfered the inside end of the shank. However, you then have mouthpieces that will only play well with that horn.

[Richard III]

So you have a horn that plays poorly and has more than one patch on the leadpipe. Any thoughts that before you spend more money on the horn to just cut your losses and get another horn?
_________________
Richard

King 1130 Flugabone
King 12C mouthpiece

[Bogey Factory]

IMHO you should at least try the paper trick before modifying your horn or mouthpieces. I've had better luck using plumber's tape than paper.

Replacing the receiver would be a safer bet than modifying your horn or mouthpiece.

As far as gap numbers go for early Olds horns go I don't know. I have a few Fullerton Era horns and they all gap larger than normal. I don't have them in front of me but going from memory they gap somewhere around .2" and .25". I'm confident my Super and Recording are in that range. I'm fairly certain my Mendez is as well.
_________________
Justin Shaw

[Abraxas]

[cheiden]

Trying to use a drill to shorten the leadpipe where it enters the receiver and sanding mouthpieces are both options I'd try really hard to avoid. First I'd have a trusted shop determine if the receiver is to spec (not worn) and that it's attached to the right depth on the leadpipe. And if it then needs a vintage mouthpiece, possibly with a different taper that can be solved without threatening the horn or existing mouthpieces.
_________________
"I'm an engineer, which means I think I know a whole bunch of stuff I really don't."
Charles J Heiden/So Cal
Bach Strad 180ML43*/43 Bb/Yamaha 731 Flugel/Benge 1X C/Kanstul 920 Picc/Conn 80A Cornet
Bach 3C rim on 1.5C underpart

[Abraxas]

[JayKosta]

Page 39 of this document shows dimensions for Bach mouthpieces, I think the taper for trumpet is based on Morse #1.

https://www.bachbrass.com/application/files/4614/8521/7763/AV2BA901_Original_1889_web.pdf
_________________
Most Important Note ? - the next one !
KNOW (see) what the next note is BEFORE you have to play it.
PLAY the next note 'on time' and 'in rhythm'.
Oh ya, watch the conductor - they set what is 'on time'.

[Abraxas]

[Abraxas]

It appears the folks at Yamaha are saying no gap is preferred, but they and others are designing for 1/8 inch. I take for the sake of safety and to lesson the burden that comes with tight tolerances in brazing.

Having a zero gap is pretty odd though as that would imply the taper is perfectly mated at the very point the mpc makes contact with the lead pipe. Maybe then my trumpet is in actually awesome shape as it is so close now that trimming a 64th should achieve that nirvana.

https://hub.yamaha.com/winds/brass/advanced-instrument-design-and-maintenance-the-mouthpiece-gap/

I'd still LOVE to know what Olds intended for design and manufacturing specs. I take when they auctioned the plant off in '79 either documents weren't part of it or nobody acquired them due to disinterest. maybe they never kept up with engineering records also.

[JoeLoeffler]

I only read that Yamaha article once, but it seemed to me that Tanabe was very much in favor of a gap. That gap is a huge part of how a Bach or a modern Yamaha (trying very hard to copy Bach playing characteristics) plays.

It has been long time since I have looked at the mouthpipe of one of these very old Olds designs but I do not believe that they have a well-defined ledge at the front of the leadpipe taper. I believe that they have a blended reverse taper or some kind of a smoothed transition out of the receiver. That makes the placement of the Venturi and a "gap" difficult to quantify. Experiment with some shims (or tape) along the side of the shank to reduce the insertion depth or have a mouthpiece cut for sleeves to do your experimentation - remember, this seems just a fishing expedition to see if it helps the instrument. Anything else is asking for problems. (regardless of what tools you have at your disposal.)

[Abraxas]