TromboneChat

What is the diameter of the rotor corks on an 88H? I want to replace mine but I don’t know what diameter to order.
5, 6, 7, or 8 mm?

I suggest you take your calipers and measure the existing ones. .. if you insist on ordering cork.

Also, you can try to use round glue sticks , the kind used for kids warm glue pistols, availabe at any hard ware shop. These are easily shaped with a scalpel, are sufficient hard to not compress, but sufficiently soft to eliminate noise.

Works very well for me. Most important: make sure you cut the bumpers such that valve ports align perfectly, both open an engaged.

marccromme wrote: Sun May 18, 2025 1:13 pm I suggest you take your calipers and measure the existing ones. .. if you insist on ordering cork.

Also, you can try to use round glue sticks , the kind used for kids warm glue pistols, availabe at any hard ware shop. These are easily shaped with a scalpel, are sufficient hard to not compress, but sufficiently soft to eliminate noise.

Works very well for me. Most important: make sure you cut the bumpers such that valve ports align perfectly, both open an engaged.

I’m looking at silicon for this. Not cork.
But the glue stick sounds interesting. I may have to try that.

Driswood wrote: Sun May 18, 2025 1:25 pm I’m looking at silicon for this. Not cork.

Silicone may be too elastic or "bouncy" (depending on the durometer) and cause your valve to sort of double-actuate. This happened on my 88HCL, and was VERY annoying. John Sandhagen diagnosed it and replaced the bumpers with a stiffer rod. Works great now!

Thats why I like the stiffer glue sticks. No double bounce there. ... and easy to obtain

Posaunus wrote: Sun May 18, 2025 1:34 pm Silicone may be too elastic or "bouncy" (depending on the durometer) and cause your valve to sort of double-actuate.

Yeah, I tried silicone for a while and just found it to be irritatingly bouncy. Also, I worried a bit about its compressibility and how uniform the valve action would be. I went back to the usual black rubber ones -- but even those you can get in different hardnesses.

If you need to measure the diameter, measuring inside diameter with a standard caliper is a bit tricky. A good way is to use pin gauges. Of course, if you don't have a collection of several hundred pin gauges, it's hard to cover all alternatives. But drill bit shanks work really well as long as you're confident that you're measuring a pretty standard size, or don't care much if you're a little bit off.