Jump to content
Sign in to follow this  
alex_holden

Buttons With Delrin Core And Metal Caps

Recommended Posts

I've read that some modern makers produce buttons that have a nickel-silver or brass cap over a Delrin/acetal core. How are the caps made, is it a drilled rod or deep-drawn from sheet?

Share this post


Link to post
Share on other sites

Steve Dickenson uses a dedicated tool, which came amongst all the tools that he had when he bought up Wheatstones. This tool turns disks of a softish nickel based alloy into dome shaped caps and crimpes them onto the plastic cores. The original cores were wooden, as will be found in many vintage Wheatstones.

I don't personally like dome shaped key tops and much prefer flat tops.

Inventor.

Share this post


Link to post
Share on other sites

Steve Dickenson uses a dedicated tool, which came amongst all the tools that he had when he bought up Wheatstones. This tool turns disks of a softish nickel based alloy into dome shaped caps and crimpes them onto the plastic cores. The original cores were wooden, as will be found in many vintage Wheatstones.

I don't personally like dome shaped key tops and much prefer flat tops.

Inventor.

Thanks Inventor, that's interesting.

 

Did you see Henrik Mullers buttons made out of Rotring pencil caps with wooden inserts.

That's a resourceful idea!

Edited by alex_holden

Share this post


Link to post
Share on other sites

Using the Rotring pen caps was a saved-by-opportunity thing - they ARE good, but veeery expensive.

 

Much later - now, that is - I have changed my opinion about cap diameter.

In the beginning I had fantasies about caps/buttons more than ¼ "/6.35 mm...

 

Then I made #2 (inspite of great look-and-feel still a work in progress, when it comes to reeds) and used buttons from Jürgen Suttner. Ooh - very good, lovely feel.

 

Then I made #3 - yes, I WILL update my web site ;-) (Wheatstone reeds, pan and bellows frame, with new bellows) with my own user interface = end box/action and used Suttner buttons again. A peculiarity (for many) of my user interface is the fact that the buttons go all the way down to the bushing. This time they stopped - because of a small misunderstanding with myself - 1 mm before.

 

No good... hmmm, aha! I removed (my own) felt stoppers under the buttons since they were exactlt 1 mm. What a difference! ;-).

 

Anyway, this instrument has been played a couple of 100 hours, and I am convinced: I want the small ones (Jürgens) - they are 4.8mm. In contrast, the oul Rotrings are 5.8. Two different worlds!

 

It goes to show how different preferences are -

 

/Henrik

Share this post


Link to post
Share on other sites

Very interesting and well described article Alex.

 

One point; do you think 0.5mm sheet Nickel Silver might be too thick for the job ? I imagine the wall thickness of Wheatstone button caps to be a lighter gauge.

 

Geoff.

Share this post


Link to post
Share on other sites

Very interesting and well described article Alex.

 

One point; do you think 0.5mm sheet Nickel Silver might be too thick for the job ? I imagine the wall thickness of Wheatstone button caps to be a lighter gauge.

Thanks Geoff! The original Wheatstone sample has walls that are uneven but pretty close to 0.5mm. It's hard to be sure exactly what thickness it started as, but I doubt it was less than 26SWG (0.4572mm).

Share this post


Link to post
Share on other sites

I am more than happy with the nickel silver buttons of my Anglo. What is the supposed advantage of buttons made of other materials but only capped with metal ?

Share this post


Link to post
Share on other sites

I am more than happy with the nickel silver buttons of my Anglo. What is the supposed advantage of buttons made of other materials but only capped with metal ?

Weight reduction. Solid nickel silver is pretty heavy.

Share this post


Link to post
Share on other sites

Thanks Alex. The weight of the buttons is probably of little significance to those of us who always play seated....but I only have experience of the one instrument.

Share this post


Link to post
Share on other sites

The weight of the buttons is probably of little significance to those of us who always play seated....

 

"Weight" is proportional to inertial mass. A heavier button will require more force to get it moving. While I doubt that the difference between button types will be significant in comparison to the force of the spring and the inertia of the lever and pad, it would be good to hear whether anyone has made such measurements.

Share this post


Link to post
Share on other sites
Posted (edited)

The weight factor is perhaps more to do with the movement and inertia , the ' un-sprung weight' during the action of playing... I am not sure I could tell the difference anymore after 50 years of hard work with my hands BUT the wooden based button is potentially quieter than the solid metal one. The slight click of the location spigot against the wood of the action board and any deficiencies in the felt bush magnified with the all metal button.

 

Cross posted with Jim.

 

I am not sure when the metal capped wooden button was first used at Wheatstones but certainly during the victorian period when the competition between them and Lachenal was at its height and the development of new models with superior playing qualities was happening.

Edited by Geoff Wooff

Share this post


Link to post
Share on other sites

About ten years ago a friend and I weighed every button type in his workshop; a great number of different styles. The lightest was a Wheatstone wooden stemmed button. Very close behind was a titanium single piece. Delrin buttons were light but were typically thick and so beaten by other materials. The heaviest was nickel-silver. There were disparities in thickness and length so hardly a scientific test but the point was made and I have used titanium ever since, mainly because it was one part to make rather than two which need to be fitted to each other. Titanium is also unlikely to erode in the spigot and will only need a polish once.

 

I suspect the point at which inertial mass becomes important for speed is not so much when you are pressing the button with a strong finger but when the spring is returning the button to the up position. It will take longer, especially if the springs are light. The force needed for a fast start may also make it hard to ease off before the button is completely depressed, leading to harder banging of the

button on the actionboard. These things may seem too subtle to matter but when making concertinas you need a reason to do or not do something and it is probably good policy to base it on something tangible as you will have a basis for changing it if it does not do what you thought. Factors such as availability of materials, cost of materials, complexity of machining and durabiliy in service all play a part.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×