MWF FEED
23rd December 2017, 11:00 PM
Hi Guys,
Interesting problem.....
This is the part on my prosthetic leg that should shear if/when something nasty happens. I have been informed that they are supposed to shear at 10 Nm, although I don't know if that is true or not ,as have fallen a few times and all that has happened is that my leg has twisted my hip to buggery....and did not shear....anyway.
This a new part....It has just cost me $600. The last one was free but only lasted 6 months. I'm guessing there are no more 'free ones'......
No NDIS in WA yet.....Don't know when its getting here.....
My pins appear to be wearing away over time.....The bushing I am using now only has one pin left. If they both go, my alignment is lost and my gait goes to the pack.....
These pins are part of the whole bushing...not separate. The whole thing is CNC machined out of one piece of s/steel.
I was wondering if if it may be possible to modify said part to use 'replaceable' shear pins...something like roll pins...although I think they would be too hard and would not shear very easily.Temper the pins before I use them?
If one shears, I could drift it out and fit a new one......sounds easy....
I would mill off whats left and drill 2off 2.5mm holes
Pins are 2.5 mm in dia, 3.6 mm high and bushing is 10 mm thick. OD of bushing is 30 mm.
Brass pins? Aluminium pins? Can you buy them? Is there a way to calculate how much torque would shear the new pins?
Thoughts?
Steve
20171223_192338 (Medium).jpg (http://metalworkforums.com/attachment.php?attachmentid=371439&d=1514029524)
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Read the full thread at metalworkforums.com... (http://metalworkforums.com/showthread.php?t=201375&goto=newpost)
Interesting problem.....
This is the part on my prosthetic leg that should shear if/when something nasty happens. I have been informed that they are supposed to shear at 10 Nm, although I don't know if that is true or not ,as have fallen a few times and all that has happened is that my leg has twisted my hip to buggery....and did not shear....anyway.
This a new part....It has just cost me $600. The last one was free but only lasted 6 months. I'm guessing there are no more 'free ones'......
No NDIS in WA yet.....Don't know when its getting here.....
My pins appear to be wearing away over time.....The bushing I am using now only has one pin left. If they both go, my alignment is lost and my gait goes to the pack.....
These pins are part of the whole bushing...not separate. The whole thing is CNC machined out of one piece of s/steel.
I was wondering if if it may be possible to modify said part to use 'replaceable' shear pins...something like roll pins...although I think they would be too hard and would not shear very easily.Temper the pins before I use them?
If one shears, I could drift it out and fit a new one......sounds easy....
I would mill off whats left and drill 2off 2.5mm holes
Pins are 2.5 mm in dia, 3.6 mm high and bushing is 10 mm thick. OD of bushing is 30 mm.
Brass pins? Aluminium pins? Can you buy them? Is there a way to calculate how much torque would shear the new pins?
Thoughts?
Steve
20171223_192338 (Medium).jpg (http://metalworkforums.com/attachment.php?attachmentid=371439&d=1514029524)
Attached Images
http://metalworkforums.com/images/attach/jpg.gif 20171223_192338 (Medium).jpg (http://metalworkforums.com/attachment.php?attachmentid=371439&d=1514029524) (168.8 KB)
Read the full thread at metalworkforums.com... (http://metalworkforums.com/showthread.php?t=201375&goto=newpost)