In defense of TAR (Was S&S retrofit rails ?)

[Ron Nossaman]

>In defense of TAR
>
>I think the tubular action rail (TAR) works well and serves a definite
>function. I believe the rails were designed to virtually eliminate wood
>movement problems. This design dates from the 1870 and if you are
>familiar with the wood rails used in the Steinway grand piano before
>this time you can appreciate what a huge improvement they were. The
>brackets on the earlier wood rails were glued to the key frame. The new
>design allowed for easy access to the keys and the removal of the upper
>part of the action as a subassembly. The old wood brackets and wood
>rails exhibited undue wood movement that effected the stability of
>action regulating. The new tubular rails eliminated wood movement
>between the rails. They also were rigid and would maintain alignment
>when removed from the key frame. Tubular rails are at least as stiff as
>these earlier wood rails.

* It's interesting to me that those who defend this rail configuration do so
by comparing it to what it replaced as if this were a recent innovation. The
real point here is that the TAR is the archaic system in comparison to a
modern wood rail. You are probably right in believing that the TAR was
designed to eliminate, though I would be happier with 'minimize', wood
movement problems, but I haven't found seasonal regulation problems to be
any worse with a good modern wood or aluminum rail design than with the TAR.
Have you?


>Maybe another aspect can be seen in how the new rail shape brings the
>action centers closer inline along the grain to where the flange is
>screwed to the rail. This will reduce the amount the flange centers will
>move in relation to the rails. Also the rail profile allows the flange
>screw to pass through less wood. The thickness of the Renner Steinway
>hammer flange is less than 6mm. The same measurement on an average flat
>rail flange is 8mm. The Steinway design reduces the stresses on the
>flange due to wood movement. 

* Excellent point. No one has brought this up yet, but, again, does this
actually translate to better regulation stability than a more standard
modern system? I haven't found that to be the case. BTW, the average flat
rail hammer flange is often counter bored to recess the screw head. The
Steinway flange isn't, so the net gain in clearance above the rail surface
is nothing.


>There are other factors as well such as
>allowing for a lower string height and less room needed at the breaks
>for the rail to fit. Ever notice how hard it is to access the front
>screws on smaller M&Hs and how much the keys have to be altered to
>accommodate the flanges.

* I trust you are talking about the vertical dimension of the wippen and
flange rails here rather than that 2mm less flange height. Yes, a shorter
stack is possible with this system, at the expense of rigidity. I don't see
what you mean about the rest of this. Please explain.   



>Here are some pointers on working with TARs.
>1. Use the pre-glued felt sold by Steinway under the hammer shanks. This
>will help the shanks stay adjusted.
>2. Use shanks that have screw holes larger than the screws to help with
>spacing. Renner parts come this way but some others will need to be
>re-drilled.
>3. Use high quality cut thread hammer flange screws. Cost more but will
>reduce hole stripping.
>4. Do not over twist shank flanges to space. Instead travel the shanks
>in areas were the string pacing is to close together or erratic. The
>hammer should be evenly space at rest but may travel a little to hit the
>strings.
>5. Space the strings to the hammers in the De-capo area.
>6. For fine spacing get the spacing tool Renner sells. Grind the sides
>to fit between the flanges better.
>7. Either set up to replace action rails or find some one to do it for
>you. 
>
>John Hartman
>Beacon NY
>Rebuilding Steinway piano with minimum re-engineering since 1979.
>

* Everything listed here is a work around to sidestep the deficiencies of
the design. You shouldn't have to drill out flanges, compromise the string
line between bridge and tuning pin, miss travel shanks, buy another tool
that is only used on this particular action type (and modify it so it will
work), and accept the premise that you are going to have to set up to
replace these rails on a regular basis just to get acceptable performance
out of a system that has been superseded by something better but is so
encrusted with an aura of mythology and mystique that it becomes a sacrilege
to modify it. I think a little re-engineering is definitely in order.

Regards,
 Ron