• 1.  Action Rails

    Registered Piano Technician
    Posted 02-02-2022 15:41

    Hi All,

    Curious as to opinions. What do  you all think the advantages or disadvantages are Re wooden action rails (say, Renner) vs. non-wooden (say Yamaha). We can leave Steinway tubular rails out of the discussion, unless someone can't contain themselves:-). What about hybrids?

    Usual responses will likely center around ambient induced changes to wood rails (in fact to all wooden parts), but if the piano lived in a reasonably decent year-round environment, how serious would any concerns really be? Or is it that pianos typically never really live in year-round decent environments, hence the popularity of Dampp-Chaser Systems.

    is there a tonal component to wood vs. metallic rails, a noise component? etc.

    Put another way, if you had your druthers, what would be your ideal action rail?

    Thanks --- Nick G

    Nick Gravagne, RPT
    Mechanical Engineering
    Nick Gravagne Products
    Strawberry, AZ 85544

  • 2.  RE: Action Rails

    Registered Piano Technician
    Posted 02-02-2022 20:10
    Brother, you got too much time on your hands   Miss you!


  • 3.  RE: Action Rails

    Registered Piano Technician
    Posted 02-03-2022 09:32
    Hi, Nick. 

    Good questions. 

    I am very fortunate to have a humidity controlled situation with almost all 
    fairly new inventory. Steinway grands are D, B and A with a few Boston 193
    grands in the mix along with a C2 and a C3 grand. 

    Uprights are mostly K52s with a number of Boston UP126s and UP118s
    and a few Yamaha U3, U1 and P22. 

    If I cast my memory back to private practice, there is no question that metal
    rails were more stable over time, whereas wooden rails needed seasonal service. 
    I find the same is true here on campus, to a lesser extent. 

    It's hard to judge tonal characteristics between the two as metal was in
    mostly Asian pianos, with wood being prevalent in American and European
    brands except those that originated in Asia and were finished up in 
    some European countries, but this still points back to Asian tonal preferences. 

    I think replacing wood with metal and metal with wood might be the better
    way to find out empirically if tonal characteristics are affected. 

    Hope this helps,


  • 4.  RE: Action Rails

    Registered Piano Technician
    Posted 02-03-2022 10:10
    Hi Nick,
    Ok, I like both WNG and Renner, but I think you're asking the wrong question, or maybe not enough questions.  I'd ask; What's the best action bracket?

    We commonly build new stacks in our shop, one of three types; Steinway, Renner or WNG. I dislike the Renner brackets for some smaller grands because the feet stick out so far towards the player and they make the key doglegs more severe.  The Steinway brackets can at least be bent out of the way.  But Renner, all you can do when making a keyset is move the back square-off forward, or cut the front foot shorter (and re-drill for an angled screw).

    With the WNG bracket (Bruce Clark is a genius) there is no foot forward toward the player. The forward screw is contained in the action. So no interference with the keys is ever an issue.

    That said, I do like Renner action rails, especially the repetition rail which so has many laminations that it's super stable.  The Renner quarter sawn beech hammer rail works fine, but I'd rather see it laminated.

    For a 7' or larger piano it's unlikely that the Renner brackets will be in the way in any case. Only for smaller pianos or pianos with short keys is this an issue.

    If I was designing the perfect action stack though, I'd probably use WNG brackets, Renner rep rail and build a custom laminated hardwood hammer rail.

    I do prefer the wood hammer rails since they seem to regulate a little better. But we do use WNG rails and complete stacks quite often and they work fine.

    Best regards,

    -Dean Reyburn, RPT

    Dean Reyburn, RPT
    Reyburn Pianoworks
    Reyburn CyberTuner

  • 5.  RE: Action Rails

    Registered Piano Technician
    Posted 02-03-2022 11:43
    From a service standpoint, metal rails and plastic flanges mean a lot less service. It isn't only the flanges swelling and shrinking seasonally that causes loose parts, the rail also contributes to the crushing of flange wood (I guess perhaps the rail wood gets crushed a bit as well). 

    With Kawais (metal rail and plastic flanges), the flanges are tight forever until you loosen the screw. Flip side of that, especially for the uprights, is managing to avoid stripping the hole when replacing the screw. Because of the jack limiting rail, it is impossible to get a vertical purchase on the screw head with the screwdriver, so aligning the screw to be vertical to the rail  and making the first turn correctly is very tricky to do. 

    Backing off the screw makes no difference unless you can have the screw very nearly vertical during the backing operation You'll get the click, but it will still cross thread. I had to repin flanges on a few USTs, which drove that home pretty firmly. That could be solved pretty well by a small bevel in the rail and a treadless extension on the screw, as used on other makes.

    A contrary service component is that a stripped hole is a lot easier to repair on a wooden rail.

    I can't see a significant tonal component, assuming everything is tight.