Ok I want to get some piano wire for shear pins.. Where do you get yours and what is the part number I am looking for. I went to MCMaster Carr and they have 1065 or 1080 Carbon steel in a .187 size one foot lengths.. Is that what I need.. I have tried every other shear pin material known to man with no luck on my 44's..
Unconfigured Ad Widget
Collapse
Announcement
Collapse
No announcement yet.
Piano wire
Collapse
X
-
shear pins
Originally posted by blueskyracer View PostOk I want to get some piano wire for shear pins.. Where do you get yours and what is the part number I am looking for. I went to MCMaster Carr and they have 1065 or 1080 Carbon steel in a .187 size one foot lengths.. Is that what I need.. I have tried every other shear pin material known to man with no luck on my 44's..
As far as the shear pin issue you are having have you checked the squareness of the prop rear contact area relative to the nut surface when tight. I had some props that were not perfectly 90 degrees relative to the shaft. With this missalignment the pin is put under unequal shear when tight and the prop is slightly off kilter depending on the prop to shaft clearance and degree of out of square the prop contact surface has with the nut.
Also do you use a lock washer and the nut? Is the nut a nylock type. I found the nylock nut alone when about 2 threads of the shaft were exposed at the nut top worked for me. Adding a flat washer acts like a shim and could provide additional bearing on the prop surface if needed but still leave about the 2 thread exposure at the nut top.
The harder pins are a possible solution but they may be so difficult to shear that the internal prop gear pin might go first? Assume that you are using the standard Merc quicki foot.Last edited by ZUL8TR; 05-10-2013, 09:16 AM."Keep Move'n" life is catching up!
No man's life, liberty or property are safe while the legislature is in session.
Comment
-
Shear pin theory
I have been in discussions about this in the past.
I have seen guys torque down a shear pin so hard that it deforms under the load from the prop nut. This is about guaranteed to shear when you run it. Think about what the pin is resisting; the prop motion relative to the propshaft. A pin only has a certain amount of strain it can take before it becomes a three piece unit instead of the single part you put in. Overtorque on the nut uses a percentage of its strength up before you even start the engine. The more propnut torque the less prop load it can withstand.
I put on the prop with just enough to snug the pin in the hole and put a small piece of music wire on the clevis pin. This leaves virtually all the load carrying capability for the prop load.
Even with light nut torque, the 3/16" pin is pretty much maxed out on a good D. I wound up drilling mine to 1/4" and have used the same pin since then. No more one-time use for the 3/16".
Another factor that can make it worse is if there are chips around the shearpin hole in the propshaft. Sometimes this leaves a sharp edge that makes the situation worse.
Just another guys thoughts.
Steve Roskowski
Comment
-
Originally posted by john527 View Postyou ordered the same ones I ordered this morning, you should have no problem with these, when you cut them to length, don't overheat and put a nice chamfer on both ends!Mike - One of the Montana Boys
If it aint fast make it look good
Comment
-
shear pins
Both John 527 and Steve gave excellent ideas and tips. I also have a few new Konig shear pins from Litzell I will give you to try if you like never sheared these when I ran. Years ago the late Doc Collins gave me shear pins he had they were allen bolts. I bought some and I may still have them not sure I dont remember what grade though but they held up on a merc 6 cyl and my 44. They had a small locknut as well
Just some thoughts for ya
Todd
Comment
-
Originally posted by 1100-one View PostBoth John 527 and Steve gave excellent ideas and tips. I also have a few new Konig shear pins from Litzell I will give you to try if you like never sheared these when I ran. Years ago the late Doc Collins gave me shear pins he had they were allen bolts. I bought some and I may still have them not sure I dont remember what grade though but they held up on a merc 6 cyl and my 44. They had a small locknut as well
Just some thoughts for ya
ToddMike - One of the Montana Boys
If it aint fast make it look good
Comment
-
Pins
http://www.aircraftspruce.com/catalo...ispinsgrid.php
We have been using MS aircraft pins with a 3/16 hole for years. Never shear them and you can put a small cotter pin in the hole that extends through the prop and you will never throw them. Another aircraft hardware option is the 3/16 NAS bolt with a GB series nut.
AlanAttached FilesLast edited by OldRacerBU; 05-10-2013, 01:09 PM.
Comment
-
Originally posted by Bill Huson View Postoh yeah, cut the wire with a Dremel 409 disk - nickname "dangerous disk" `cause they would self destruct if you got a hand twitch.Mike - One of the Montana Boys
If it aint fast make it look good
Comment
Comment