Changer center supports

[Bent]

Scott, I say have the drill rod hardened to to tool steel hardness aka drill bits. Here is what I found on cobalt drill hardness:
"Cobalt bits are not coated, they are cobalt steel through and through. At the end of manufacture a cobalt bit is baked in an oven to turn the surface color of the steel a dull gold color. This is done primarily for easy identification by color. If the gold wears off or is ground off in sharpening on a cobalt bit, it is still solid cobalt steel. Our cobalt drill bits are made of M42 cobalt steel which has 8 percent cobalt content. The Rockwell is approximately 65.5 to 67 Rockwell"
That is cobalt mind you

My engineer buddy explained to me that a drill rod hardened to Rockwell 60 will break before it bends. So I would say shoot for 60 and you should be ok.

[Bent]

Bent, the original anchoring on a Dekley is what it is - not much, but I had already replaced all that with my rigid, floating, neck and the original axle gave and caused audible detuning. Once the axle was replaced also, the detuning was no longer audible.

Yes, I realize you did a big beef-up job on yours and that was great. I was just surprised to see the big solid aluminum frame and everything and then this puny changer deal. But I suppose it was sufficient in its day. BTW..have you found out the year of manufacture for this D10 Dekley?

[Georg]

I know nothing about hardening and such. I simply took the original axle with me to a producer of various metal parts for the auto industry etc., told a chief engineer that I wanted an axle with same dimensions that was so hard/rigid that it would break before it gave measurable when using their finest instruments.
After a study he told me something like that the best axle I could get there would give/bend before it broke, but that it would give/bend less than 5% as much as the original (Dekley axle) for the same amount of stress. I found that acceptable - still do.

That axle and the new pillow-pieces did cost me what today would be around US$400, so I wasn't surprised that it lived up to my simple "specifications". A little less would probably have been "within range", but the original Dekley changer axle was no good and should never have been put on a PSG. The MSA (around 1980 model) S12 changer axle doesn't look any better.

[Georg]

BTW..have you found out the year of manufacture for this D10 Dekley?

No ... haven't really bothered to look for such details. If its parts fit my S10 (when bellcrank axles are cut to size), and it is otherwise in reasonably good condition, then that D10 will probably end up as an S10 modified to meet my "specifications" anyway - far from what it was manufactured as.

[Jim Smith]

Georg, I think the axle wasn't the main problem with your original Dekley. To me it looks like the anchoring underneath is way too weak. #8 machine screws thru some thin aluminum. From what I have seen without taking things apart, that is the main problem.

Where are these #8 machine screws you're talking about? There are two #10 flat head machine screws that hold a steel plate to the bottom of the Dekley changer shaft pillow blocks, but they are not structural. They just hold the changer together as a sub-assembly before assembly into the guitar. The changer was mounted to the body with four 1/4" machine screws through the body and into the pillow blocks.

As for the changer shaft, we didn't have any fancy test equipment back then, and I don't recall what kind of steel we used for it. I thought it was drill rod, but it was hardened at least somewhat and of some alloy that wouldn't rust.

[Bent]

Jim,
I was obviously wrong and I stand corrected. I did write "without taking things apart, it looks like..." I was too hasty in my assessment and should have kept my trap shut

[Georg]

Jim and Bent,
the original changer mounting in itself was pretty good on my Dekley. The weakest point on mine was that the changer was mounted on what I would call a "tone-flip" on the top plate - the end of the top-plate could vibrate freely within the groove in the frame. Although this "tone-flip" gave my Dekley a very distinct and pleasant tone, it was visibly flexing with stress-variations on/over the changer. This resulted in quite audible detuning when pedals were pushed.

I did a lot of testing over several years of how this "tone-flip" affected tone and detuning, since I wanted to keep the Dekley-tone but eliminate the detuning. I ended up with what amounts to an around 26 inch long "tone-flip" - the changer-carrying floating neck, which doesn't flex at all. Bent can judge the resulting "tone" and "detuning" for himself in a few days, when we get to compare an original Dekley with a modified one in his workshop.

The original changer axle was flexing visible/audible, and early on I tested it with an improvised center support. This sort of solved the problem, but so did a much better axle so I settled for that.

[Jim Smith]

Very interesting, Georg. Dekley's original goal was to build a more stable pedal steel by using Pakkawood instead of maple. As we learned about its machinability problems and limitations, we decided to hide the edges in "the groove in the frame", as you call it.

Because of its size, the top piece was the most troublesome. As time went by, we experimented with, and eventually moved to solid maple tops. We were more interested in the tone, and didn't notice much difference between the two, but it could have been that the Pakkawood tops were more stable.