[CAUT] practice rail

[Fred Sturm]

Hi Ron,
	Thanks for the detailed instructions. What do you use the short  
length of 1/8"x3/4" material for? The cable bracket?  Are choke cables  
still readily available? It's been decades now since I had a car with  
a manual choke. Bicycle brake cables might substitute, if you came up  
with a knob, which wouldn't be too hard. What do you use to glue the  
felt to the aluminum? In any case, this seems less flimsy than what I  
am imagining the Jansen and Schaff alternatives to be (I've seen one  
or two over the years, though it's a vague memory).
	I'll consider the alternative of making an aluminum one.
	As I've been thinking about this, the Steinway upright I am facing  
probably has the extra thick pressure bar. Maybe a rod that swings  
won't work because it can't clear the pressure bar. I'll have to look  
at the piano. The guy just emailed me this morning, to set up a tuning  
and, by the way, could I install a practice rail. I will temporize,  
tell him I need to have a look-see first.
Fred
On Nov 5, 2009, at 9:56 AM, Ron Nossaman wrote:

> Fred Sturm wrote:
>>    A customer has asked me to install a practice rail (muffler  
>> felt). I haven't done this retrofit before. I see Jansen has one.  
>> Are there others? Any advice, comments?
>
> The easiest way I've found is this. Get a 6' length of aluminum bar  
> stock, about 1/8"x1/2", a short length of about 1/8"x3/4" steel or  
> aluminum (or a 3/4" length of 1" angle), and an automotive choke  
> cable. Measure and bend the ends so it will fit into the piano. Trim  
> the ends as necessary, and drill holes for the pivots. You can drill  
> a series of spaced holes for the cable wire so you can find the most  
> workable leverage ratio by trial and error after everything else is  
> in. The nice thing about aluminum is that you can dogleg it around  
> the bass overstring offset to keep the felt as close to the string  
> as possible. Put whatever padding you want on the action brackets.  
> Install the felt, trim to the right length (depth), and locate the  
> pivot points with icepicks, or small nails acting as temporaries.  
> For the pivots, the damper lifter hanger pins (fluted on one end)  
> driven into the side of the case work great, and the punching won't  
> fall off the pin and roll under the piano like it does when the pin  
> is in the muffler rail arms. Adjust the spread of the arms so it  
> doesn't slop around. Make a bracket for the choke cable, mounted  
> under the bass end of the keybed. Fit the cable in the bracket and  
> determine the length of  wrap needed. Pull the wire, cut the wrap,  
> and push the wire back in. The wrap can be held to the case side by  
> a couple of Dampp-Chaser wire clips, or simply three 1" sheet metal  
> screws, two on one side, and one in between on the opposite side.  
> Push the choke knob all the way in, prop the muffler rail up to  
> clear the hammers, and make a right angle bend in the wire (toward  
> the treble), a little above the hole where you think you'll want it.  
> Another right angle bend, about 1/4" past the first, making a "Z",  
> gives you a connection to the rail. Take the rail out, tip the  
> treble end up, feed the wire into the appropriate hole in the bass  
> end, and reinstall the rail. That's it. If the choke cable won't  
> hold the rail up, kink it gently until it will.
> Ron N

Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu