ACME Threaded Rods
01-02-2015, 12:52 PM
#1
ACME Threaded Rods
The problem:
The threaded rod and threaded block that moves the power seat on my Expedition has issues. There is a fair amount of play that is a concern. From what I understand, the threaded rod is an 'ACME" thread (trapezoidal cut). My thought is that I can get a thread repair kit and just drill the block and install the inserts. What I do not know is how these threads work, how the kits work and what the sizes are. From what i can tell, until I get it completely apart, the outer diameter is about a 1/3 of an inch, and the inner diameter is about 1/4 of an inch. I think the rod is threaded at 13 threads per inch, but can only find a reference on the web to 12 per inch. It sucks measuring through the little slot.
If it were a finer thread, i would say helicoil. But these look special and I need a really coarse thread at a relatively small diameter.
This is also not something I know a damn thing about. Any machinists, machinery or mechanical engineers out there?
Thanks in advance.
The threaded rod and threaded block that moves the power seat on my Expedition has issues. There is a fair amount of play that is a concern. From what I understand, the threaded rod is an 'ACME" thread (trapezoidal cut). My thought is that I can get a thread repair kit and just drill the block and install the inserts. What I do not know is how these threads work, how the kits work and what the sizes are. From what i can tell, until I get it completely apart, the outer diameter is about a 1/3 of an inch, and the inner diameter is about 1/4 of an inch. I think the rod is threaded at 13 threads per inch, but can only find a reference on the web to 12 per inch. It sucks measuring through the little slot.
If it were a finer thread, i would say helicoil. But these look special and I need a really coarse thread at a relatively small diameter.
This is also not something I know a damn thing about. Any machinists, machinery or mechanical engineers out there?
Thanks in advance.
01-02-2015, 06:40 PM
#3
You gonna eat that?
iTrader: (1)
Hey, sorry, had a busy afternoon.
I'm not familiar with acme threads.
The threads I make are usually measured in inches, like 8"or 10", not fractions.
Are you sure it's not metric?
Sounds like it could be 8mm-1.00.
I'm not familiar with acme threads.
The threads I make are usually measured in inches, like 8"or 10", not fractions.
Are you sure it's not metric?
Sounds like it could be 8mm-1.00.
01-03-2015, 01:34 AM
#4
Thanks for the response.
i actually got it apart and got more detail. The end result is that a stupid little plastic piece fell apart. I will post some pictures. There are 2 pieces of steel, one in a U, one that fits inside the U. The threaded piece is the ones inside the U. The whole assembly is only 2 inches long. There is a small piece of plastic that keeps the metal pieces from hitting each other. Well, that was a stupid choice of materials. With the plastic gone, the metal parts are free to move a bit and bang into each other. Good news is that it is safe, there is no danger of the seat moving more than 1/8 inch. Bad news is I have to fabricate a new plastic part.
Again, thanks for the response.
i actually got it apart and got more detail. The end result is that a stupid little plastic piece fell apart. I will post some pictures. There are 2 pieces of steel, one in a U, one that fits inside the U. The threaded piece is the ones inside the U. The whole assembly is only 2 inches long. There is a small piece of plastic that keeps the metal pieces from hitting each other. Well, that was a stupid choice of materials. With the plastic gone, the metal parts are free to move a bit and bang into each other. Good news is that it is safe, there is no danger of the seat moving more than 1/8 inch. Bad news is I have to fabricate a new plastic part.
Again, thanks for the response.
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