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Reconfiguring horseshoe on rotary valve

PostPosted: Mon Jul 08, 2019 12:41 pm
by roweenie
Ok, so I'm going to have to change the travel of the wing on this rotary valve, necessitating repositioning of the horseshoe.

Dilemma - when putting it where I want it to go, one of the holes in the horseshoe falls halfway in the path of one of the existing tapped holes in the valve. If I use that hole as is, the valve is out of alignment.....

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Any suggestions?

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Mon Jul 08, 2019 12:53 pm
by windshieldbug
Braze it in and drill/tap a new one in the casing.
Alternatively, start with a new 3rd hole completely elsewhere in the “horseshoe”...

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Mon Jul 08, 2019 8:40 pm
by roweenie
Good idea 'bug, thanks.

I was thinking of putting a screw in there, securing it with Loctite red, cutting the head off, and then drilling it - does that seem doable? Brazing can sometimes get kind of "messy"......

(Believe it or not, that's actually the technical term the Germans use for that part - "Hufeisen")

https://shop.voigt-brass.de/B2B/ZYLINDE ... m=Hufeisen

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Tue Jul 09, 2019 3:16 pm
by bloke
nomenclature: cork plate

To braze the original holes shut (though you could use one or both to oil the rotor), screw some very short brass threaded material in those holes to
just above the surface, put a dot of paste flux on there, and braze those threads into the undesired holes. Clean it up with a small file or
(if you dare) a Dremel tool.

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Tue Jul 09, 2019 4:56 pm
by roweenie
bloke wrote:nomenclature: cork plate

To braze the original holes shut (though you could use one or both to oil the rotor), screw some very short brass threaded material in those holes to
just above the surface, put a dot of paste flux on there, and braze those threads into the undesired holes. Clean it up with a small file or
(if you dare) a Dremel tool.


Excellent idea, I hadn't thought of leaving one of the holes open for a bonus oiling port....!

The other hole, unfortunately, is half-way in the way of a new hole, so filling it in and re-drilling it will be mandatory.

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Tue Jul 09, 2019 10:41 pm
by bloke
You may not have an impressive-enough box of spare junk, but you could put a different cork plate on there that has holes located in different places.

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Wed Jul 10, 2019 9:19 am
by roweenie
No other cork plates available, I'm gonna have to work with what I've got :cry:

I think it will go ok - I've got a tap with the same thread and pitch (M2.5 x 0.45) on order, and some nice brass cheese-head screws to match.

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Wed Jul 10, 2019 10:32 am
by bloke
To avoid all of the heat and deep discoloration of a precision part (rotor casing), you might (simply) consider
plugging the holes with flush-fitting threaded brass and epoxying or Loctite-ing them in place.

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Wed Jul 10, 2019 1:10 pm
by roweenie
If I were to use Loctite red and a stud in one of the holes, would I be able to re-drill a new hole into part of that stud? One of the new holes is going to encompass part of that area. I'd prefer not to make a new hole in the cork plate - I think that would look too "honyock"....

(I suppose I could use the original hole, and cut the rubber bumpers so that valve is in alignment, but I think that would look kind of lousy, too....)

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Wed Jul 10, 2019 5:50 pm
by bloke
Miraphone will sell you some nice never-drilled cork plates for very reasonable prices...and they'll even look through their selection
and come as close as they can to matching the i.d. of the interior curve (to fit around the rotor bearing).
Further, I'd bet they have both brass and nickel silver...though I'm not certain about that.

Christian N. is a very nice man.

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Sat Jul 13, 2019 5:46 pm
by Dan Schultz
Some manufacturers are not as good at making their parts all alike and are not very good at marking their parts at assembly. Have you tried switching the bumper plates around to see if they work better in one location than the other?

I've seen the lack of orientation so bad that I've had to either oversize the holes in the bumper plate a bit (or slot them).

Also... I don't get too concerned about one bumper being thicker than the other. I've seen some so bad that the stop pin actually enters the hole where the bumper goes.

Are you certain you aren't dealing with a twisted rotor stem? I've had to mess with those before, too.

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Sat Jul 13, 2019 7:56 pm
by roweenie
Dan Schultz wrote:Some manufacturers are not as good at making their parts all alike and are not very good at marking their parts at assembly. Have you tried switching the bumper plates around to see if they work better in one location than the other?

I've seen the lack of orientation so bad that I've had to either oversize the holes in the bumper plate a bit (or slot them).

Also... I don't get too concerned about one bumper being thicker than the other. I've seen some so bad that the stop pin actually enters the hole where the bumper goes.

Are you certain you aren't dealing with a twisted rotor stem? I've had to mess with those before, too.


Thanks for the thoughts, Dan - actually, the valve is brand spanking new, and this manufacturer's quality and workmanship is above reproach, so nothing is out of order, functionally. Because of some stupid miscalculations I made before I ordered the valve, the eventual necessity of two different sized bumpers seems inevitable. Trouble is, if I use one of the already supplied holes to reposition it (as pictured in the second) it then magnifies the problem even more in the new position.

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Thu Jul 18, 2019 10:49 am
by roweenie
Update - Loctite red worked just fine for this application.

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I waited for it to cure, then just drilled and re-tapped it.

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Re: Reconfiguring horseshoe on rotary valve

PostPosted: Thu Jul 18, 2019 11:09 am
by windshieldbug
You go, guy!
8)

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Fri Jul 26, 2019 10:15 pm
by roweenie
Thanks, windshield bug - the valve is now configured to its best advantage.

Sometimes, I have difficulty in envisioning how a rotary 5th valve linkage should travel, especially when I don't have the parts in place for me to see what is the best way to go.... :oops:

Re: Reconfiguring horseshoe on rotary valve

PostPosted: Tue Jul 30, 2019 11:01 pm
by bloke
An alternative would have been to cut off the existing bumper pin from the stop arm,
filing that area smooth/round (for looks) and brazing on a new bumper pin 90 degrees away from the original.