My TR181 eats rotor bumpers for a living

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My TR181 eats rotor bumpers for a living

Postby tbathras » Thu Mar 24, 2016 4:36 pm

My TR181 has a bit of design flaw.... the rotor stop arm peg hits the stop bumpers right in line with the edge of the bumper holder. So with every trigger actuation, it basically shoves the rubber into the metal edge and cuts it a little. See image below - the problem area is circled in red and the blue dot is where the stop arm hits). Though I've only shown one bumper, all four suffer from this.

I've tried stock Holton bumpers, round bumpers (the stop peg ends up just slipping by the bumper) and cutting my own (the ones I have on there now I cut from a large diameter piece of rubber and these have held the longest, clocking in at about 3 months)

I need something more permanent than this and I feel like it's going to take either new bumper saddles or modification to the existing.

Ideas?

Image
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Re: My TR181 eats rotor bumpers for a living

Postby Burgerbob » Thu Mar 24, 2016 4:54 pm

You could get a new horn... :D
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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Thu Mar 24, 2016 5:13 pm

You know.... not a half bad idea!

But I'd need money for that and a trip to Dillon's.
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Re: My TR181 eats rotor bumpers for a living

Postby Bonearzt » Thu Mar 24, 2016 5:31 pm

Hi Tim, Those look like Bach cork stop plates, not Holton. Holton plates are bent & formed from thin metal and don't hold their shape or position well. Probably why they were replaced!

So that may be part of the problem. The arc of the stop arm is larger than the center of the bumper.

An idea would be harder neoprene or a larger diameter cord and cut in such a manner to have more material covering the edge.
Unfortunately, this would make the valves louder when they hit.

Not sure what else might be a better fit.

I'll think about it.


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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Thu Mar 24, 2016 7:06 pm

I did indeed do the use-larger-stuff method and yes it was loud, but it eventually got worn through.

I'd be willing to take the actual Holton saddles if you think they'd last more than a few months... This horn is only 2 to 3 years old... Odd it would have swapped out parts.

Wonder if it came from the factory this way... They make more Bachs, so perhaps they just used a plentiful part?

This is driving me nuts.
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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Thu Mar 24, 2016 7:12 pm

I wonder if I could fashion some stop plates from some hobby metal supplies from the hardware store... I can solder, so maybe some flat brass sheet stock with some cut open hollow brass rod - basically duplicate what's there but have it be the right radius... ??

Might be a lot of work where maybe just modifying another manufacturer 's part might be better.
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Re: My TR181 eats rotor bumpers for a living

Postby Bonearzt » Thu Mar 24, 2016 8:45 pm

Trying to make one is a LOT of work!!

I've been trying to repair a Bach plate with one of the half-rings broken. NOT an easy thing to make.
Not that I'm a whiz machinist or anything, but trying to drill & form that "C" is tough!


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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Thu Mar 24, 2016 9:21 pm

Vowtatool has holton replacements in stock for $16 each. I've ordered myself a pair.

I'll let you all know how they work out.
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Re: My TR181 eats rotor bumpers for a living

Postby Sliphorn » Thu Mar 24, 2016 9:51 pm

I agree, you should sell the horn.

To me.
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Re: My TR181 eats rotor bumpers for a living

Postby Bonearzt » Thu Mar 24, 2016 10:00 pm

Sliphorn wrote:I agree, you should sell the horn.

To me.



NEXT!!!
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Re: My TR181 eats rotor bumpers for a living

Postby MrPillow » Thu Mar 24, 2016 10:40 pm

As if you lot would know what do to with a Holton.... :twisted:
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Re: My TR181 eats rotor bumpers for a living

Postby Burgerbob » Thu Mar 24, 2016 10:48 pm

There's Holtons, and then there's the TR181...

IMO of course.
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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Thu Mar 24, 2016 11:14 pm

I've been eyeing the used AC551BH for sale at Dillon's.... But even if I sell the holton, I'm a few too many k short and also have no idea if I like the courtois. I'm kind of done buying horns sight-unplayed.

So, sorry Slip, this one's not for sale until the one that replaces it is my hands.

I'm willing to sink the $32 for a possible fix.

But yeah, I've got some other gripes about the 181 but at the end of the day, it gets the job done.
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Re: My TR181 eats rotor bumpers for a living

Postby najataagihe » Mon Mar 28, 2016 9:07 pm

There is a fix, but most techs hate it.

Just saw it in half, giving you two independent rotor stops.

You can put a bit of blue Loctite on the screw threads, if you want, but I have never found it necessary.

My Bach 36 had this setup for a couple of decades until I finally found a replacement part that fit.

It allowed me to align the rotor ports precisely with the rotor casing, which was not possible with the stock rotor stop.


Good Luck!


:D
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Re: My TR181 eats rotor bumpers for a living

Postby Bonearzt » Mon Mar 28, 2016 9:31 pm

najataagihe wrote:There is a fix, but most techs hate it.
Just saw it in half, giving you two independent rotor stops.
You can put a bit of blue Loctite on the screw threads, if you want, but I have never found it necessary.
My Bach 36 had this setup for a couple of decades until I finally found a replacement part that fit.
It allowed me to align the rotor ports precisely with the rotor casing, which was not possible with the stock rotor stop.
Good Luck!:D


Actually not a bad idea IF you can lock down the pieces so they won't move when you actuate the rotor!

Whatever works!


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Re: My TR181 eats rotor bumpers for a living

Postby boneagain » Mon Mar 28, 2016 10:24 pm

Bonearzt wrote:
najataagihe wrote:There is a fix, but most techs hate it.
Just saw it in half, giving you two independent rotor stops.
You can put a bit of blue Loctite on the screw threads, if you want, but I have never found it necessary.
My Bach 36 had this setup for a couple of decades until I finally found a replacement part that fit.
It allowed me to align the rotor ports precisely with the rotor casing, which was not possible with the stock rotor stop.
Good Luck!:D


Actually not a bad idea IF you can lock down the pieces so they won't move when you actuate the rotor!

Whatever works!


Eric


How about soldering a sliver between the cut pieces? At least one screw hole will have to be filed into a slot, but if the two pieces were soldered together, there would be good bumper anchors AND good spacing...

I don't think my torch technique is up to such finicky work, though!
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Re: My TR181 eats rotor bumpers for a living

Postby Bonearzt » Mon Mar 28, 2016 10:45 pm

That idea depends on the material of the stop plate.
Not a bad idea, but yes a little touchy.

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Re: My TR181 eats rotor bumpers for a living

Postby blast » Tue Mar 29, 2016 3:25 am

Looks like an Elkhart (Bach factory) built horn. I have only blown one, but that one was pretty poor. A shame those plates are the wrong size .... as Eric said, the later Holton plates were dreadful, cheap items. Now we see a better, solid plate that is the wrong size.... bravo Conn, Selmer, Bach, Holton, King, Steinway, whatever or whoever .... progress ????
50 shades of loud....
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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Tue Mar 29, 2016 9:29 am

yeah, so I ordered replacement plates - they came in and they fit exactly the same - no improvement.

But now I have a set of "spares" that I can attempt to modify or use as a template to fashion some new ones.

The horn sounds good enough and it's not holding me back. If I lived closer to Dillion's, I might trade it in, but I don't, so I have to live with it for a while. Most people seem to like the sound that comes out the bell, so it can't be all that bad.
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Re: My TR181 eats rotor bumpers for a living

Postby Bonearzt » Tue Mar 29, 2016 10:06 am

Try just cutting a notch on the inside curve & spreading the "wings" a bit to match the stop arms.
You will have to file the screw holes a bit for clearance, but leaving them connected gives a LITTLE more security.


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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Tue Mar 29, 2016 10:16 am

Oh, brilliant! That sounds easy enough. (famous last words, right??)
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Re: My TR181 eats rotor bumpers for a living

Postby Bonearzt » Tue Mar 29, 2016 10:18 am

I'll be on alert.........8^P




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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Tue Mar 29, 2016 10:54 am

Bingo! That did it. The holes on the "originals" were already large enough.

What I did was cut a small slit with dremel cut-off tool on the inside and outside of the curve, then pressed the inside of the curve into the non-cutting part of a drill bit that was larger than the original inner radius in a vice, then using the cut-off tool again, I smoothed out the inner curve on the stop plate so it would set far enough up so the swing distance on the stop arm was correct.

Thanks, Eric!

No thanks, Conn-Selmer-Bach-Holton conglomerate.
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Re: My TR181 eats rotor bumpers for a living

Postby Bonearzt » Tue Mar 29, 2016 11:08 am

Glad to help!

My bill is in the mail......8^P



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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Tue Mar 29, 2016 11:57 am

So here's a quick pic of what I tried to describe above in case anyone else with a TR181 feels the need to do this...

The two red circles show where I cut the notches (you can't see the upper notch because I had already smoothed it out) and the blue line shows where I smoothed the inner radius out so it would seat correctly against the outer casing of the rotor bearing.


IMG_1076.JPG
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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Tue Mar 29, 2016 12:02 pm

Also, I was going to put a link to this topic on TTF - but the thread over there is locked? I wonder why.
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Re: My TR181 eats rotor bumpers for a living

Postby blast » Tue Mar 29, 2016 2:50 pm

No idea why it was locked...unlocked it.
50 shades of loud....
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Re: My TR181 eats rotor bumpers for a living

Postby tbathras » Tue Mar 29, 2016 2:57 pm

Thanks, I've posted the link back to here over there.
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