Pedal Rods – Specific Material Question

[Sebastian]

Hello everyone,

I got a broken pedal rod on a L&H23. I am looking for a new rod (I have the tools and knowledge to cut the threads etc).
What specific material are the pedal rods made of? Is it stainless steel (1.4301 / Europe: X5CrNi18-10 / US: AISI 304)? The material has at least the highest tensile strength and bending stiffness at ~3mm / ~3/32 inch. The old rod was magnetic, which in turn could also indicate non-stainless steel.
Does anyone here in the forum know anything more about it?
Thank you very much for all the valuable tips!
Many greetings

[carl-swanson]

Why do you want to make the rod yourself? Are you someplace where it is difficult to order one from Lyon & Healy? How old is the harp? The threadings will probably be different on an older 23 than on a newer one, since the newer ones use Salvi pedals and I’m assuming Salvi rods.

The rod itself is common drill rod. It is dead soft (18 or so on a Rockwell scale). You don’t want a hard material, and certainly not stainless steel. The rod needs to be flexible. The weakest part of the rod is the threadings, and that is where they always break when they do break, on the threaded part. Are you able to re-use the old pedal coupler? In other words, were you able to get the broken part of the rod out of the coupler?

If the harp is an older instrument (20 years or more) then the threadings are probably what Lyon & Healy has used throughout their history, which is 4-48 at the top end, and either 4-48 or 5-48 at the bottom end. If your harp is newer and has a Salvi pedal assembly, then the threadings on the rod are probably Salvi threadings, and I don’t know what those are.

[Sebastian]

Hi Carl-Swanson,
Thank you for your prompt reply.
It’s a about 40 years old Style23 and it has a No.4 – 48 UNF threading. I know the newer models of L&H and Salvi have metric M3 (3mm diameter (3/32 Inch) – a little bit more than US 14/125inch UNF threadings – easier for Europeans 😉 ).

I couldn’t re-use the old rod – it broke exactly at the transition from the thread to the solid material.
Getting the rest out of the coupler wasn’t a problem – a slotted screw was milled with a Dremel, then you could just unscrew it.

Ordering the rod from L&H is not the problem. The nearest L&H Technical Guild member is approximately 300km/186mi away. In most cases, another service call must be on the way for the technician to be able to schedule such a repair. Then there are the travel costs, which are almost the same amount, in addition to the service flat rate.
That’s why I’d like to be more flexible and (if necessary) be able to trim the rods myself. I know several harpists around here – they all know the problem.
Of course I could also order the pedal rods from L&H, I’m only interested in the material itself.

Thanks for the tip about the Rockwell scale.
However, HRC 18 is even closer to the tensile strength of stainless steel (AISI 304: 18 HRC ~ 212 HB ~ 714 N/mm2). Plain steel (AISI 1020) as a non-hard material has a property of 350 N/mm2 ~ 105 HB ~ not even on the Rockwell scale. The flexural rigidity is similar.
Unfortunately, the technician from L&H couldn’t tell me what material the rod is made of either.
If you compare the selling price of a new pole with the material value, I would be interested in the secret of the material. 😉
I’ll do more research and post the result here in the forum if there are other DIY’er out there.

[charles-nix]

Seems to me that if a steel rod, either plain steel or tool steel, broke at the point where it is repeatedly flexed, stainless is one of the _last_ materials I would look at for replacement.

Tensile strength and hardness are pretty much irrelevant–brass would be strong enough. Lack of work hardening is what matters.

Why does it matter that the L&H technician is 300km away? Won’t they just ship the rod directly to you? They come with both ends threaded and ready to go.

If you’re not in the business of repairing harps, it will be hard to justify the tooling cost needed to thread the rod smoothly, accurately, and to the correct thread fit class.

But if you wanted to do it anyway, Carl says above that the material is drill rod.

[carl-swanson]

Sebastian- I agree with Charles. You should be able to just order a rod from Lyon & Healy and install it yourself. If you have my book, A Guide for Harpists, there is a chapter in there that takes you step by step through the process of installing a new rod. Just be sure that, when you get the new rod, you compare the length with the old rod. Lay the old rod, with the piece that broke off, on a table or the floor to show the full length of the original rod, and lay the new rod next to it. Better yet, measure the full length of the old rod so that, when you order a new rod, you can tell the people at Lyon & Healy the exact length of the old rod. I’ve heard stories of people ordering a rod bay name (an A rod, a B rod, etc.) and receiving something that is too short. You should also have the 4-48 die too so that, if you have to add more threads, you have a way to do it.

[billooms]

When threading drill rod, be sure to use the harder HSS die (not the cheaper carbon steel). You can get them at McMaster Carr online (item # 2602A134).

[Tacye]

.120″ drill rod according to Pratt’s 1964 Affairs of the Harp, which of course predates your harp.

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