Another Changer Idea

[mac639]

Hello folks!
I've been working on yet another changer design. It's not a new invention, just an adaptation of several other designs, particularly the old ShoBud fingertip. I recently had one of those in for repairs. After getting all the extraneous junk off that had been added over the years and getting it set up properly I couldn't believe what an accurate pitch changing guitar it was. You know what makes the difference? It's that the fingertip guitars, although a pain to adjust with your fingers, once set in the right place make for a really solid "stop" for the changes. Virtually all the "modern" all/pull guitars suffer from one thing I think. The "stops" are way too far back in the pull train, allowing for slack, slop, temp changes etc. to affect the raise/lower/normal string position. I never thought too much about this until I had this old Bud here. Those fingertip "stops" really work!
Anyway here's attached my version that I'm building up to install on the guitar I'm building right now. I'd like some feedback on what any of you think of this. In particular (for you engineering types) what are your thoughts on the effect of shortening the finger a bit and making the "pull" lever a little longer. What effect or advantage/disadvantage would this have. I know it would make a bit more room for rod holes but would make the action a little harder perhaps?? Any thoughts guys!
Thanks so much in advance
Cheers,
Mac

[Bent]

Hi Mac,
Interesting stuff. They really knew how to do things in the more or less infancy stage of pedal steel.

A question: In the drawing it appears that on a raise, the fingertip nut and bolt adjuster slides with the finger and stops against the tail piece. Is this the only stop or is it incorporated and timed with a pedal crank stop as well? If not, I would think that the pedal/KL would get a spongy feel to them.
OTOH, I can't see anything wrong with using both types of stops if one so desires.

[mac639]

Hi Bent,
The Bud I had here had both, a stop on the finger and also on the pedal cranks. It's just my feeling that whether or not you have both, the one on the finger is the one that's most important 'cause the finger position is where the note is actually determined wherever you stop it. One problem is if you raise or lower a string to more than one note, then of course the stop is ineffective for one of them. I was thinking about the pull/release single finger design. On knee levers the stop is the determining position which makes the knee lever kind of nice feeling, You can push it as much as you like (within reason) and the note will lower to the stop, and further pushing of the lever has no effect as the rod and the nylon tuner just goes on a little further with no effect on the note. Some fingertips had springs right on the rods to take up any differences in the two stop positions, but that wasn't too great an idea as it did make for sponginess. I just seem to think that a positive stop right on the finger for raises is going to result in the best note determination however you do it. Guess we'll see.
Hey, Happy New Year to you and the folks at your house!
Mac

[Bent]

Hi Mac,
Happy New Year!. No doubt you're right about the note determination. The one thing I was wondering about was the spongy feeling even on the raise, where you have pulled the note to the finger stop and without any stop on the pedal crank, the pedal would "want to" go further and thereby the spongy feeling. It does depend on how heavy the player is on his feet. After a while he's get a feel for it, likely.

[jcbartee]

is the raise stop attached to the finger? I have never seen a showbud changer, that's why i asked the question

[jcbartee]

what is the attachment just above the raise rod?

[mac639]

Hi,
The black thing above the raise rod on the left is an adjustable raise helper spring. Sometimes you need them, sometimes you don't. The raise stop is a piece of "pull rod" coupled to the raise finger (hinged) and threaded at the other end, and a nut with the plastic insert is screwed on and can be adjusted to stop the finger when the finger (note) is raised. The same goes for the lower stop, which is a screw (bolt) that goes through the endplate with an insert in the hole to make it adjustable but stop it from turning on it's own. The two grey pieces on the right side of the lever are the pivots. Top one for the lower pivot and the bottom one for the raise pivot. Hope this helps you to understand how it works.
Cheers, Mac

[Storm Rosson]

Mac, the raise stop on the finger could be left out I think, as it would create 2 different tuning points that do the same thing if u have a stop on down at the pedal pull bellcrank . I'm thinkin ,like Bent, that the stop adjustments should be farther down the line at the bellcrank/pedal pull or ideally at the pedal itself (this would prolly be a bitch to tune down on the floor lol), to get as much tensile stretch as possible out of the complete pull assembly and reduce as much "sponginess" like Bent said. The lower finger stops would be fine as they would be essentially lower compensaters.I think it could be a pita with 2 different raise stops to get them in sync. JMHO. If I missed something please point it out as I'm a little fuzzy atm.....Stormy ....(ok most of the time) LOL

[mac639]

I haven't actually built the guitar yet with this changer or one with any stop on the raise finger. I have however over the years since 1962 built quite a few steels with pull/release one piece fingers. The lower stop is an integral part of this design and always gives a really accurate lowered note because of it. Look at it this way....where is the last place that the note is determined? The finger of course (forgetting the tuning key). So why not make a stop for the raises there. Mine never did, but most pull/release guitars use the body or a fixed plate attached to the body as a stop for the raises. The "modern" all pull guitars have adjustable stops on the crossrods or pedals etc. This leaves any crossrod flex, sloppiness in the pull rod attachment to the bellcrank, temperature changes affecting the length of rods, slippage or sloppiness where the nylon tuner contacts the finger etc. etc. Like I said earlier, that old fingertip Bud with the raise and lower stops right on the finger worked as well or better than any guitar that's ever come through my shop. Sure some of the old 80 lb. "tanks" work fine with major heavy duty parts, but with the trend today toward lighter guitars I'm just searching for simplicity and accuracy in tuning and stability. Regardless....I can't do much in my shop anyway for awhile until this crazy cold lets up. 25 below zero (-27 for you metrics) plus I've contracted a cold bug and just want to lay low for a few days and keep warm!
Cheers,
Mac

[Storm Rosson]

Mac, thx for the explanation, get well bud.....Stormy