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Jam Nuts on Rusty's Adjustables?

ty20404

ty20404

NAXJA Forum User
Location
Raleigh/Charlotte, NC
I think I'm going to get some Rusty's adjustable Uppers... What's the advantage to having Locking Jam nuts? I know what they do, but will they make the ride change at all? Reduce Flex? I just need it to ride well, because I'm giving the Jeep back to my brother and I need to attach the front DS...
 
They take the stress off of the threads...

Having said that...there was something on here a while back about the fact that Rusty uses "acme" threads instead of...well, whatever the others are called. Due to me not being able to see pictures b/c the nazi's have them all blocked, I dont know what ACME threads look like off the top of my head. I dont know if they are considered stronger or what.

I think I'd rather have some superflex joints on one end to help with the flex, but I may be wrong. I like the JKS control arms though too because they look like they have some flex to them in the middle (i.e., no jam nutz)
 
without the jamb nut, the arm will rotate/twist and it could possibly weakin the treads.

i have RE supeflex arms that allow for some twisting.
 
Yes, a vice has ACME threads. You'll have a hard time finding Jam nuts in ACME thread at a local place. Plus, I believe a Jam nut would be useless on an ACME thread. It wouldn't tighten up against the arms.

Edit: Thought you were selling it...
 
I just don't like the idea. Acme threads usually don't keep tight tolerances between males and female. Seems like there would be a lot of slop between them. I could be wrong, I've never used the arms.
 
Not selling it anymore... It's going back to my 17 year old brother, so it'll still be in the family.

I ordered a set of Rock Krawler adjustable uppers. My bro isn't a car nut at all, so putting a front DS on would be like him trying to do College level Differential Equations Applications... Haha. I'm sure I'll still be haunting NAXJA even though I'll have moved onto BimmerForums and what not.
 
I'm running Rusty's arms with the jam nuts for almost 2 years now. No problems. The jam nuts do lock down. I have yet to test the flex with them loosened. Acme threads are used in heavy construction for their strength and durability.
 
Acme threads are trapezoid shaped threads used in high stress situations such as building structures (think iron working) and mining operations where the much thicker threads provide greater strength. NC or NF (national coarse or national fine) are both triangular threads. There is another square shaped thread, but the name of it escapes me and you do not find it used very many places.
 
terryd said:
Acme threads are trapezoid shaped threads used in high stress situations such as building structures (think iron working) and mining operations where the much thicker threads provide greater strength. NC or NF (national coarse or national fine) are both triangular threads. There is another square shaped thread, but the name of it escapes me and you do not find it used very many places.
Click to expand...

witworth? or is that the same as ACME?
 
lowrange2 said:
I just don't like the idea. Acme threads usually don't keep tight tolerances between males and female. Seems like there would be a lot of slop between them. I could be wrong, I've never used the arms.
Click to expand...

supposedly you just need to make sure you keep them greased and all is well. Otherwise I hear they make noise.
 
ACME threads are usually used for motion translation (like on lathe beds and mill ways) and for high-strength threads (thicker roots and crests, and a 29* included angle, I think.)

You'll have to look to find nuts for ACME threads - start with McMaster-Carr, I think. Also, you'll need two different threads - they're the same nominal OD and pitch, but should be opposite twists (left-hand and right-hand.)

There are a large number of thread profiles - with three in common use. "Unified V" thread (60* included angle, most common screw thread,) ACME thread (discussed here and previously,) and buttress thread (sort of a one-way ACME thread - something like a 15* pressure angle on one side, and a 60* angle on the other. It's meant as a 'one-way' thread to be used with a "half-nut" - you tighten it like a screw handle, but release by loosening slightly and lifting the screw out of the half-nut. I've seen it on some vices.)
 
I have Rusty's adjustable arms Uppers and Lowers. I do not run jamb nuts. I drive it everyday. I've never had any trouble out of them. I do keep them greased up very very well. Grease, grease and more grease. After that.......more grease. They are not noisy at all.

Hale
 
We just put some of those locknuts on a buddy's XJ with the Rusty's arms, his arm were making alot of noise, clunking over every little bump. The nuts took care of that.

He probably wasn't lubing the old arms enough and they developed play in those threads.
 
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