Texatdurango
Member
I'm working on a "button filler" pen and need some assistance from you "metal smart people" out there!
To be clear as to what I am up against and need, here is a little background.
A "button filler" uses a sac to store the ink and there is a pressure bar which when depressed and released, sucks ink into the sac.
The button fits into a hole at the base of the pen and is pushed in to bend the pressure bar which in turn collapses the sac.
The button needs to "snap" into the hole but has to stay in, once in and that is where I am having trouble.
The button is designed to where the ridge at the end is larger than the diameter of the hole it goes into but due to some saw kerfs, it collapses when pushed in and collapses when pulled out.
So far I made one from delrin and it works fine but I don't think will stand the test of time. I also made one from brass and it works perfectly BUT the brass really doesn't want to return to it's original shape once compressed and I think it's just a matter of time that one or more of the "legs" will just snap off.
My question....
What type of metal would be best suited for making the button? It needs to be "springy enough to withstand numerous compressions over the years. I think copper would be softer than the brass so I haven't considered it yet. This must be a metal that I can work on my small metal lathe.
I made a prototype from clear acrylic so I could see what's going on inside as I make the components. Below are some shots of the prototype pen showing the button, the button next to an original, and how the button fill actually works.
To be clear as to what I am up against and need, here is a little background.
A "button filler" uses a sac to store the ink and there is a pressure bar which when depressed and released, sucks ink into the sac.
The button fits into a hole at the base of the pen and is pushed in to bend the pressure bar which in turn collapses the sac.
The button needs to "snap" into the hole but has to stay in, once in and that is where I am having trouble.
The button is designed to where the ridge at the end is larger than the diameter of the hole it goes into but due to some saw kerfs, it collapses when pushed in and collapses when pulled out.
So far I made one from delrin and it works fine but I don't think will stand the test of time. I also made one from brass and it works perfectly BUT the brass really doesn't want to return to it's original shape once compressed and I think it's just a matter of time that one or more of the "legs" will just snap off.
My question....
What type of metal would be best suited for making the button? It needs to be "springy enough to withstand numerous compressions over the years. I think copper would be softer than the brass so I haven't considered it yet. This must be a metal that I can work on my small metal lathe.
I made a prototype from clear acrylic so I could see what's going on inside as I make the components. Below are some shots of the prototype pen showing the button, the button next to an original, and how the button fill actually works.