Pedal Stops

[sheffield steel]

Hi Guys,

What I'm about to say may not be new? But I got to thinking last nite and it hit me like a ton of bricks (as they say).
Well most of the pedal stops that I've seen are located on the inside of the front apron so when the pedals are pressed we are adding to the downwards force on the body of our already stressed psg's, thus creating more cabinet drop. So why not put the stops on the cross shaft 180 degrees oposite and put an adjusting screw on the stop so that it will stop on the underside of the body instead of the front apron thus creating an upwards force with the downwards pedal movement, a kind of simple counter force. I do hope that I've explained this theory ok and I've attached a simple drawing which may help and as they say every little hepls.

Dave.

[Bent]

Dave, Yes, that only makes sense. even if it don't work as much as intended maybe, at least we are using the process of eliminating doubt Emmons uses it on PP and they have very little cab drop. Who knows, that may be one of the reasons.

[Georg]

What's the preferred software for opening your file? Can't see drawings in my regular choice for ".doc". Anyway, your description seems clear enough, so I'll comment on it.

Correct me if I have misunderstood you, but...
If the stop-arm is "turned around 180" to the other side of the axle and thereby stopping in top position, the downward force applied via the pedal rod gets transferred from the stop to the axle itself.
The result will be no change in downward pull on body-frame, and the axle and axle-bushing will have to take the entire downward force. So, such a solution won't have a positive effect on body-drop, and may wear down and/or misshape the axle and bushing faster than normal.

AFAICS, there is no way to reduce the downward force/effect of the pedal-pull on the body-frame. A more rigid body-front-inside that will take up the load without bending, is possibly best if one wants to reduce the body-drop effect.

One can remove the downward force from the frame itself by constructing a dual-frame - an independent inner-frame for the mechanics that loads all forces onto the end-pieces and legs and leaves the body unaffected.
Think most builders will see such a dual-frame solution as "over-engineering" though - same as some see my "floating neck" that has the same effect.

[sheffield steel]

Hi Georg,

You should be able to open it with "word".
Like Bent has said Emmons P/P uses this method, which I was not aware of, so one would assume that after all these years it is a tried and tested method that works?


Dave.

By the way Georg, I love over engineering things, that way they are built to last.

[Bent]

Yes, Georg, the theory is right... there are two counter-acting forces here...one downward from the pedal movement, and one upward with the stop pushing against the deck, thereby canceling the deck dropping or bowing.
As it is now, with most stops being sideways, the cross rod and its bushing/bearing take the same force as always, but sideways instead. So the force is the same but the direction of the force is sideways. I know we are grossly exaggerating here trying to cover all scenarios. But in the real world, the force on this mechanism is indeed quite light compared to other mechanisms. I believe that the force is quite strong only on the cabinet bowing.

But that's why we safe guard by using bushings that can be renewed and so on.

Yes, a more rigid body front is a sure thing to work into your plans. You (and your Dekley) convinced me that a thinner front apron is warranted if my side rail on that apron is bolted to the inside end plate extensions. So, cut down on wood weight by using, say a 1/2" thick apron instead of 3/4", and have a 1/4" side rail go thru and bolt on to both end plates. An engineer told me that the way I have those side rails now (2" short of the endplates) means that they have little or no structural value. Makes sense?

[Bent]

Emmons P/P uses this method, which I was not aware of, so one would assume that after all these years it is a tried and tested method that works?

Exactly, Dave. Those have been tested thru the last 35-40 years

[mac639]

I don't have endplates on my guitars, it's a 3/4" maple open bottom box. the ends are 3/4" maple and screwed and glued to the aprons all around. The aluminum ends are 1/8" aluminum plate and mostly cosmetic.I really don't have cabinet drop problems at all.....maybe a cent, not much more.
Cheers,
Mac

[Georg]

Dave, ain't got Word, but thanks, OpenOffice opened it just fine, of course

Sorry, but I still can't see a change in downward force on the body, only that it gets transferred to/through the axle/bushing instead of just pulling down on the inner rail directly. I can't see or deduct much counterforce from what is described and drawn either, although the drawing does indicate that the center of the body will be held/pushed back up a little as the front gets pulled down - provided the inner rails and the axle are strong/rigid enough to provide base for the push.

Not that I think the solution will hurt in any way - as long as all involved parts can take the transferred load, but I don't think there's a noticeable positive effect. All in all just more parts for no gain, IMHO.


Bent, yes, that engineer was right: your 2 in. too short rail just stiffens up the apron a bit. The inner rail must load everything onto the front legs in order to offload the apron and top-plate properly.
The weight of aluminum is the same or less than that of the wood you use for same mass, so I would suggest you bolt the most rigid front-rail profile you can accept and work with to the end-plates, and make the wood-apron as thin/light as you possibly can.
I would of course do the same for the backside, resulting in a rigid frame covered "loosely" with wood.

I know probably all of you like the traditional wooden PSG bodies - for looks and tone, but if you also want stability and relative low weight you shouldn't rely on a wooden body. Only the top-plate has to (more or less) be "all wood" to get the "wooden tone" you seem to want, and the front and back apron just have to cover the rails and mechanics well enough to make it all look good.

[Georg]

I don't have endplates on my guitars, it's a 3/4" maple open bottom box.

Sounds good...
I expect well-built "all wood boxes" to be at least as rigid as most "wood and aluminum" constructions.

Same goes of course for "all aluminum boxes", like my blue CarpSteel which also show next to zero body-drop tendencies. My Dekley's bodyframe isn't quite as rigid as that of the CarpSteel, despite the fact that it weighs in at nearly twice that of "the little blue wonder"

[Pat Comeau]

The guitar that im almost finished with...has the pedal stops on the pullrod bellcranks and it works fine