Do it Yourself Valve Alignment Question

MF Fan · Posted: Sat Dec 06, 2003 10:42 am Post subject:

I have a LA Benge that I've been tweaking in the way of valve alignment. So far I've adjusted spring length to increase valve travel slightly, which has been an improvement. During this process I noticed that the inner valve casing (sleeves) could stand to be lowered and/or rotated (ever so slightly) to better align with the outer valve tubing. Am I correct in assuming the inner sleeves are simply pressed in? And if so, should be moveable with the proper tool and technique? I don't want to start playing with them if they're held in by something other than their close tolerence to the outer casing. If that's all there is to it I'd be using a wood rod of the proper diameter to lightly tap the casing vertically. I assuming twisting will require a tool that engages in the valve guide slots that can then rotate the inner casing.

Any other suggestions or warnings from other do it your selfers? I'm very hand mechanically and know I can do this, assuming the inner sleeves aren't held in by something other than having been pressed in.

DavesTrumpet · Posted: Sat Dec 06, 2003 4:28 pm Post subject:

If anything needs adjusting vertically, it's a matter of the proper thickness of cork and felt (or synthetic washers). You do not unassemble the spring barrel from the piston for this type of alignment. Occasionally some machining is required, perhaps on a valve stem, but that's rare.

And occasionally (but rare too), it is necessary to reposition the spring barrel for proper radial/axial alignment but this is not a "do-it-yourself" project and most technicians offering "high tech" alignments do not address this type of alignment and many others do not correct it.

Dave M

DavesTrumpet · Posted: Sat Dec 06, 2003 4:31 pm Post subject:

PS -

The inserts are most likely soldered in. They have a notch registration that keeps them from being able to rotate. Any rotation (in my experience) would come only from the piston (the spring barrel) not the inside of the valve casing and they're soldered too.

Dave M

trumplyr · Posted: Sun Dec 07, 2003 3:01 am Post subject:

I can't imagine how adjusting the spring length would affect the travel at all. Different length stems or pad thickness would change travel length.

This is not a do-it-yourself job. If you think your valves need alignment, pay the money and have a qualified repairman save you from turning that trumpet into a lamp or wall hanger.

Marty

plp · Posted: Sun Dec 07, 2003 4:08 am Post subject:

I do my own 'redneck' valve alignments while replacing felts as part of my cleaning of newly acquired used horns. I went to a fabric store and got 3 different thicknesses of heavyweight felts. I first look at the old felts, guess what comes closest to that one, and cut one felt to size by laying the old felt on it and going aroud the perimeter with an Exacto knife. Then I replace the felt on the 2nd valve. After I reinstall the 2nd valve, I pull the 2nd valve slide and shine a penlight into the tube and visually check the alignment by depressing the valve. If it is either high or low, I go to a thicker or thinner felt to adjust. When it is right, I cut that same arrangement for the other 2 valves.

This is not as good as a PVA, but the price is right, and so far I can't tell it hurts anything. Between this, replacing corks, a good soaking and cleaning, and a good polishing, almost all these old horns play better than they did when I got them.

BTW, a quick note about valve springs. On the bottom springs, such as those found on most old Conns, I made my own alignment tool to make sure the springs are centered. It is a small aluminum rod mounted on a flat base. I set the lower valve cap on the base with the rod through the hole in the cap, and then fit the spring into the cap. By rotating the spring inside the cap, you can change the 'seat' of the base of the spring. When it is right, the spring should be centered at the top and bottom, and neither should be touching the rod. This assures the force pushing the valve back up is at the center of the valve, and the spring is not contacting the inside of the valve casing, which will wear the spring out, in some cases creating minute shavings, which make the valves stick.

_londonhusker · Heavyweight Member Joined: 13 Oct 2002 Posts: 658

Hi everyone,

If the goal is to improve playability on a horn with known alignment problems, there are some things you can do yourself to get the ports reasonably well lined up in both positions. Please keep in mind that a professional will do a far more exacting and long-lasting job, getting the tolerances to between .01 and .001 of an inch. But if your valve ports are off from your slides by anything you can see, the following would definitely help.

Get yourself a thin measuring instrument accurate to at least 1/32 of an inch. This can be anything from a metal rule to a micrometer. Remove any compressible felts, corks and washers. Select a valve to work on, and remember that you will have both an up and a depressed position for each valve. Depress the valve. Measure the distance from the bottom of the casing to the bottom of the valve (call this A). Remove the valve in question. Measure the distance from the bottom of the valve to the top of the lower valve slide port (call this B). Finally, measure the distance from the bottom of the casing to the top of the lower valve slide tube (call this C). A+B should equal C. If it is off by anything you can measure with your instruments, you should make adjustments.

Similar measurements should be taken for the up position as well. In the up position, measure the distance from the bottom of the casing to the bottom of the valve (call this D). Remove the valve. Measure from the bottom of the valve to the top of the lower valve port that bypasses the slide... in other words, the port that carries the air when the valves are not depressed (call this E). Finally, measure from the bottom of the casing to the top of the lower tube that carries the air when the valves are not depressed (call this F). D+E should equal F. Again, if a discrepancy is measureable by your instruments, it's big enough to spend some time fixing.

Get yourself some loose-leaf reinforcements. I prefer the mylar variety, as they do not compress like the paper ones do. These go in one of two places. Put them up under the finger button if your valve travels too far when depressed... if A+B<C, this condition is present. Put them under the upper valve casing cap at the base of the valve stem if your valve travels too far when it returns to the up position... if D+E>F, this condition is present. (On a side note, if the valves do not travel far enough, this is a mechanical fault and would need a pro to rectify it.)

Install reinforcements one or two at a time until A+B=C, and D+E=F. Then play your horn a lot. If you use paper reinforcements, expect to have to replace them more regularly than with mylar. It's a good idea to keep a record of how many go where in each valve, so in a year or two, the process takes a few minutes to get into the ballpark.

Hope this helps you. It can make stuffy beginner horns sound much better, and fine-tune a better horn so it sounds like a million bucks!

Regards

Dave
londonhusker

_Japle · Posted: Sun Dec 07, 2003 5:07 am Post subject:

Ferree's Tools has all the felts and corks you'll ever need.
http://www.ferreestools.com/
_________________
John
Cape Canaveral