Wobbly legs: What's the fix?

[Ross Shafer]

The problem starts with the leg's mating surface on the aluminum endplates getting slightly domed from side forces. The shoulder of the legs threaded steel plug does this. Once no longer square, the leg pretty much needs to be overtightened to not have any wobble...in time this leads to worn threads in the softer aluminum endplates. Which leads to severe wobble-itus.

The two square shoulders that create the mating surfaces are not adequate to support the side loads from knee levers especially since one side is much softer than the other.

Sierra's now use a tapered interface much like those used to hold cutters in machine tools...which are specifically designed with high sideloads in mind.

[Fred Treece]

So, would a metal washer be better than the rubber o-ring idea?

[Dave Magram]

So, would a metal washer be better than the rubber o-ring idea?

Fred,
I've been using the O-rings for at least 20 years on my 50-year old Emmons D-10 PSG and they work very well.

I should explain that I never had a problem with wobbly PSG legs.
I had read on the SGF about professional players who did, and had drilled holes in the endplates of their great old guitars so they could insert bolts to keep the legs from wobblying.

My PSG legs stayed tight, because when I bought my guitar (used), I cleaned the threaded segment of the legs and applied a thin coating of molybdenum disulfide grease to prevent the steel threads from grinding down the aluminum sockets.

The coating worked. The grinding never happened and the legs would thread so tightly into the sockets that I had to carry a little 5" square section of the mesh used as an anti-skid pad under carpets to loosen the legs after gigs.

It was then that I came up with the idea of using plumbing O-rings.
............................................
What Ross is describing above is the gradual wearing away of the area around the leg-sockets from the hundreds of tiny sideways movements caused by using the pedals and knee levers.

That has not happened on my Emmons. I suspect the O-rings are acting as tiny cushions or shock absorbers between the legs and the leg-sockets--in addition to working very well as lock-washers, helping to keep the legs firmly in place, but easy to remove at the end of the gig.

Quite a bargain for four 25-cent O-rings, wouldn't you agree?

- Dave

[Fred Treece]

Thanks Dave. And Ross. My Carter was a road warrior for a touring friend of mine. It has no doubt been set up and torn down a couple thousand times, and taken many thousands more knee lever jabs, so your assessments are probably spot on. Heading over to Ace tomorrow to give the o-rings a shot.

[Ron Shalita]

I never let anyone move my steel.. because i have seen people drag them on the floor..

[George Kimery]

I'm with John. The steel legs are not the problem, it's the aluminum threads worn down.They need to be built back up. You might try coating the inside threads with JB Weld or Liquid Steel, then threading a 1/2"-13 bolt in and right back out and let the whole thing harden a couple of days. The worst that could happen is it might work too well and it would be hard, if not impossible to screw the legs back in. This would be a simple fix, just use a bottom tap and re-tap the threads.

[John Drury]

The threads on most legs have a chrome plating, hard surface, they thread into aluminum, soft surface. It wears every time you put the legs in.
I use a strip of black electrical tape around the thread, not too much or it won't screw in.

That makes a tight fit and it also stops the wearing out of the internal threads.

I tried the plumbers teflon tape wich also works, but doesnt last very long.

[Ross Shafer]

"What Ross is describing above is the gradual wearing away of the area around the leg-sockets from the hundreds of tiny sideways movements caused by using the pedals and knee levers."

Correctomundo David. I started a video and embarrasingly long time ago about machining my leg mounting bits. In it is a demonstration of how quickly this wear starts. It's and eye opener, for sure. I need to dig into my video stuff and finish that one.

[Charlie Hansen]

Why wouldn’t the spring action of a proper sized lock washer apply enough back pressure to keep the threads tight somewhat like the robber O rings.

[Dave Magram]

Why wouldn’t the spring action of a proper sized lock washer apply enough back pressure to keep the threads tight somewhat like the robber O rings.

Hi Charley,

Here are five reasons I would never use a metal lock-washer between the PSG legs and leg-sockets:

1.Most metal lock-washers are designed to bite into the metal of the surfaces they are locking together and leave a small gouge. I do not want my PSG leg-sockets to be damaged with hundreds of small gouges in them.
● A neoprene O-ring will not damage my PSG guitar.

2.Metal lock-washers are designed to require a good deal of force to loosen the bolt from what it is threaded into. I wanted something that could be loosened by hand, not a pair of Vise-Grips.
● A neoprene O-ring keeps the PSG legs firmly locked into the leg-sockets while I am playing, but is easily loosened by hand when I’m done—just what I want.

3. Metal lock-washers have a fixed inside diameter and would fall off the PSG leg when you removed it, unless you glued or welded them to the PSG legs.
● The stretchable neoprene O-ring easily slides over the threaded section of the PSG leg, fits neatly into the large groove below the threaded section on the PSG leg--and stays there for years.

4. Most metal lock-washers are relatively thick, and to Ross’ point above, would allow even more movement of the PSG legs caused by the action of the pedals and knee levers—wearing out the leg-socket threads even more and increasing the wobbliness of the legs--the last thing I want to happen.
● Because the neoprene O-ring fits neatly into the large groove below the threaded plug on the PSG leg, it does not allow more movement—rather it virtually eliminates movement without damaging the PSG legs or leg-socket.

And finally, Reason # 5:
I have “tested” the neoprene O-rings for many years and they work perfectly.
● And at 25 cents each, you can’t beat the price to at least try them out—wouldn’t you agree?

- Dave

[Tom Vollmer]

Get a good machine shop to do 1/2x 13 helicoil. I think the Emmons angle is 10 degrees.If you decide to do it yourself you should be a decent mechanic as why I would go with a good pro. Kits are available at MSC on line.
If threads in endplates are that bad and are not a canditate for helicoils an extreme fix would be E Z Locs
with an 1/2 x 13 internal thread and 3/4 NC external thread.

[George Kimery]

My wobbly legs are caused by bad knees and being 75 years old.

I would start with the O rings first. You can't beat Harbor Freight for the kit that has an assortment of sizes for experimentation.

[Ron Shalita]

Tom Volmer (spelling ) funny thing.. just before i got this message that is EXACTLY what i was thinking... yes a washer would work but the problem will just happen again ... maybe lock tite the coil in ?

[Fred Treece]

If I am understanding correctly, there are three possible issues - the “doming” effect around the perimeter of the end plate leg socket, worn socket threads. and loose threaded inserts on the legs (which I have discounted because all four of them are tight).

The rubber O-ring fix did not work. I now realize it is probably not meant as a fix, but as a preventive measure (?).

Tightening the legs super tight helps, but not enough. I think the permanent fix is thread-related. It makes sense that the aluminum socket threads would wear out and not the steel leg insert threads. Short of spending machine shop labor costs on the helicoil solution, I will experiment with wrapping the leg threads with something a little tougher than teflon tape. One concern is that wrapping with electrical tape will leave a gummy residue that will need to be cleaned off if I decide to move on to the more permanent JB Weld idea.

[Johnie King]

Get a new Sierra Rose has solved this wobble problem. Or for $10 bucks you can x it.
X factor ::: Couple small turn buckles :: You can tighten tight as dicks hat ban. Takes about same time as attaching a pedal rod.

[Brendan Mitchell]

I don’t have a fix for wobbly legs ( the o ring sounds good ) but I do know of a probable cause : carrying a guitar set up in in a car . I know some players do this , not wanting to set up / tear down all the time but this causes a LOT of wear on the leg joints .

[Fred Treece]

Gobs of teflon tape around the leg insert threads. I did about ten wraps for each leg and the wobble is reduced at least 50%. It’s going add another 5 minutes to setup time, because the tape unwinds when removing the legs from the end plate sockets.

[Brint Hannay]

I have, so far, (knock on wood!) just one wobbly leg that I have clearly established has nothing to do with the threads--the threaded insert is loose inside the leg tubing. I can get a short-term improvement by tapping it in with a rubber mallet to snug it up, but it re-loosens quickly. I have no machine shop background or tools to deal with this. Is it possible to get a machine shop to weld it with care so as to have the leg angle correct? Or do I need to obtain a new leg?

[Ross Shafer]

The new paradigm for pedal steel leg mounting.

[Fred Treece]

Ross, I had a hard time mental-picturing what you were talking about in your earlier comment. The photo tells it all, and what a brilliant design it is. Thanks for posting

[Ross Shafer]

You're welcome Fred, glad its clear now....I gotta remember, one picture is worth.....

[Colin Keyworth]

I successfully used a helicoil kit. It came with the correct drill,tap and inserts,if you use this method check the angle that the leg is at before you drill and try and keep the drill true to that angle. The end result was very solid

[James Quillian]

This is a very low brow solution but it works. II stretch a bungie cord around the back legs. That firms things up enough that it doesn't wobble when I use knee levers.

[Bryan Daste]

Ross's design is definitely the "right" way to do it! But, retrofitting an existing steel with O-rings is a cool idea...I just ordered some to try. Thanks Dave!

[Jon Light]

Ross Shafer -- from day one when you started presenting some of the features you developed for the Sierra I have struggled to decide which is the coolest. This leg cone & pocket design killed me then and remains in the top 27, for sure.

Question re: moly grease -- are we talking about any of a million products that are basically lithium grease with the moly additive or is it in a purer form? I'd appreciate a specific product reference. I'd like to start using this as a long term preventative maintenance thing.