Changer Arm finger?....Bent???

[Pat Comeau]

Hi guys, i'd like some opinions on some mesurements for a changer finger, i have some mesurements but just like to know what other mesurements can be made, also on the drawing#1 if the distance is longer will it benefit for a shorter and easyer pull?, the mesurement i have on my changer finger is 2" 1/2 for drawing#1 .

thanks.

[Allan]

Hi Pat,
The longer any lever arm is, the easier it will be to pull. However, that also means that it will have to travel further for the same amount of rotation. My feeling is that if you have a system that works, go with it. Otherwise, you will end up having to redesign the entire chain of movement.
In other words, if it works, don't mess with it!

Allan.....

[Pat Comeau]

Ok, i will have to make 10 new swing arms fingers for my changer to fit in the endplates i got from Scott ....cause the ones i have on the changer are in the wrong side exemple...the holes for the pull rods on the fingers has to be switch side so i'm gonna make some new ones and would like some advice on other mesurements , i'll also have to make the lowering finger longer to rest against the stop plate and for the return springs to attached, right now the hole for the spring is just barely touching the stop plate with a 3/4" deck.

Bent...Bent....i know you have some advice

[Bent]

Well, Pat, you'll laugh at this advice because the thing is, I did not research this at all when I built the 3 guitars. With the first one, I simply took pictures of a Fulawka, blew the pic up to about life size and printed it. Now comes the funny part: I actually cut out the finger parts with a sharp blade and traced it onto the aluminum or galv. steel. I fretted over it a bit throughout the project, wondering if it would work at all, until one day I cried the blues to one Hans Holtzherr from Switzerland, a steel player that I bought some used legs from. What he told me was reassuring, and I will pass this on to you: "The changer mechanism is the most forgiving mechanism in the world" Those words really proved to be true.

Instead of me giving you arbitrary measurements that might or might not fit your project, simply do this:Draw up a cross section of your guitar body. Figure out what you need for height of changer axle to accomplish making use of ALL raise and lower holes(the raise holes closest to the axle are the most critical) Then you determine the length of fingers and scissors needed to accomplish this.
Another thing to think about: Keep your cross shafts as low to the top plate as possible. This will of course help you out when you go to connect a rod to the highest raise hole. And remember: The changer is a very forgiving piece of work

It might also help you a bit to look over the pics on my photo site

[Allan]

Bent, that post to Pat there has just given me the nudge I needed to get back to thinking seriously about the PSG I want to build. I have been agonizing about proportions, lever arms and such. Thanx good buddy!!!!!

[Pat Comeau]

Thanks Bent for the info ,
i heard that GFI's steel has a short and easy throw and that is what i'm trying to figure out with what i have to work with trying to fit a changer in the endplates that Scott sent me, but i have some good mesurments for a MSA style changer that might try.

[Georg]

Pat, the most precise/smooth working changer I've seen/played so far is found in the Infinity. The changer itself isn't shown on Frank's site, but he showed/demoed it in details in Dallas so he may respond positively with the info you need if you email him.

[Bill Ford]

FWIW...I read somewhere that the PP Emmons top (E9) changer pulls were longer than the bottom (C6),so the length should not make a difference in tone, only the distance it takes to achieve a tone change. Make them long enough to have sufficient room underneath to clear everything.

Another interesting point...do the pull rods need to be parallel with the body?? Or is that strictly a geometry thing for proper operation, knowing that geometry plays a firm part from start (changer)to finish (pedal/lever).

Just my nickleworth...Bill

[Bent]

Sure would be nice to learn all those little "Emmons PP secrets" I have heard there are around 50 features that make those guitars sound like they sound.

As for rods... for visual effect, I say its best to keep the rods straight. If you have to bend a rod to negotiate a difficult pull..by all means. I know some people don't agree and couldn't care less about looks. This is of course MO.

For ease of and quiet operation, there is some merit to keeping the rods super straight as well. Magnify this in your mind: The rod is off the straight line to the changer finger, what happens? The rod will be pulling on an angle to the finger and thereby try and pull the scissors sideways so that it rubs against the other scissor bar. This makes for friction and unnecessary noise. Also, rods running on an angle will more likely rub against bell cranks etc creating noise.

Another bad feature with bent rods (especially 3/32") is that some flex is created in the bend. So when you hit a pedal/lever, you can see how some of the energy is taken up by the flexing, thereby creating unnecessary pedal/lever movement and not transferring that energy to the changer finger, and thereby making for less travel possibility for that finger...that's bad when you are trying to make it achieve that high G# lower to F#