sanding string grooves in pot metal changer fingers ?

Jim Palmer · Post by **Jim Palmer** » 24 Sep 2011 11:56 am

have 78 sho-bud with pot metal changer fingers, would like to know if i can sand out the string grooves the same way as you would the aluminum fingers. Thanks in advance.Jim javascript:emoticon(':(')

Jason Hull · Post by **Jason Hull** » 25 Sep 2011 4:00 am

James Morehead · Post by **James Morehead** » 25 Sep 2011 9:24 am

Jason Hull wrote:Yes, you can! I did it on my Fingertip and they look brand new. The pot metal parts will sometimes have pits or "rocks" stuck in them, but the fingers seem to be small enough to have avoided those problems. Good luck!

Don't mean to contradict, but fingertips did not have potmetal fingers. Jim's fingers are likely pot metal, and they will be plated. You do not want to sand through the plating--------------------

Jim, I would polish them rather than sand them. Jagwire sells a polish that has a very mild grit. I use a dremel with a felt pad. You have a wider "margin of safety", so you do not cause permanet damage over sanding.

Loren Morehouse · Post by **Loren Morehouse** » 25 Sep 2011 9:29 am

Exactly what James said, you do not want to take the chrome off the fingers!! Loren.

Jim Palmer · Post by **Jim Palmer** » 25 Sep 2011 11:29 am

Thanks Guys, learned a good lesson today.

Jason Hull · Post by **Jason Hull** » 26 Sep 2011 2:49 am

James Morehead · Post by **James Morehead** » 26 Sep 2011 5:41 am

Jason Hull wrote:

Thanks! I didn't know that

Because, according to your avatar, You are from Mars!!

You might be confusing cast aluminum with the lessor quality "potmetal". I've yet to find potmetal on a fingertip.

Jason Hull · Post by **Jason Hull** » 28 Sep 2011 2:44 am

James Morehead · Post by **James Morehead** » 28 Sep 2011 5:08 am

Check this out, Jason.

http://en.wikipedia.org/wiki/Pot_metal

Jason Hull · Post by **Jason Hull** » 28 Sep 2011 5:35 am

James Morehead · Post by **James Morehead** » 28 Sep 2011 6:12 am

Jason Hull wrote:Quoted from Wikipedia:

There is no scientific metallurgical standard for pot metal; common metals in pot metal include zinc, lead, copper, tin, magnesium, aluminium, iron, and cadmium. (italics added)

And your point? I didn't say pot metal didn't have some aluminum in it. I said there's a huge difference between cast pot metal and cast aluminum. That's all.

Paul Gavic · Post by **Paul Gavic** » 28 Sep 2011 12:13 pm

This is a timely topic. I have a 74 Sho Bud and have been noticing the "sitar effect" on my fifth string. Last night the string broke and there is an ugly groove on the finger. So what do I do if I can't sand it out? Just polish it?

James Morehead · Post by **James Morehead** » 28 Sep 2011 12:22 pm

You should be ok to polish with a dremel and felt pad, and if that does not get it, a little sandpaper carefully applied will help. You want to keep your radius correct, and don't round over the edges. The pot metal fingers are what you want to be extra careful about. '74 should be aluminum.

Jason Hull · Post by **Jason Hull** » 29 Sep 2011 1:43 am

Ken Metcalf · Post by **Ken Metcalf** » 29 Sep 2011 4:10 am

Pot Metal is crap and Aluminum is BS.
I notice even within brands different grades of metal in the changer.
My ZB has no grooves after 40 years.
Some newer steels will cut grooves with the 1st set of strings and then the another steel of the same brand may not.

James Morehead · Post by **James Morehead** » 29 Sep 2011 6:26 am

Jason Hull wrote:
James Morehead wrote:And your point?
My point is: How do I tell the difference between cast aluminum and cast pot metal?

Sorry, I didn't see a question in your comment. That's why I asked--------------------

Pot metal used in shobuds has a lighter weight to it, than aluminum. If you had an equal SIZE piece of each in your hand, you would feel the difference. Potmetal is usually zinc plated to give it a finished appearance, or can be polished, as in endplates, etc., at least it was in shobud applications.

Hexagon era 'buds were full of potmetal. The hex shafts themselves are steel, and the mounting brackets to mount the hex shafts to the wooden body are aluminum. The pullers and knee brackets,and straight knee levers and finger radius, keyheads, changer housing, and endplates are pot metal. The pedal bar is aluminum channel, the narrow pedals are pot metal.

Earlier wide pedals are cast aluminum. Perms, Fingertips and crossovers had cast aluminum pedal bars, keyheads, pulleres, endplates, tail pieces. the Professional era saw the use of aluminum channel for pedal bars, and that carried on through the super pros. Probably the Pro II "CUSTOM" era saw the use of channel with the inside ribbing--to mount the hardware and bracket for the "open sided" volume pedal. The Pro II custom era was when pot metal started to appear. Early roundfront Pro II's still used aluminum. These are just some of the differences I've noticed handling many of these old 'buds. Hope this helps.

Brint Hannay · Post by **Brint Hannay** » 29 Sep 2011 6:42 am

Whoa, the pedals, changer housing and keyhead are pot metal

??? The changer housings on my late-70's LDG and Super Pro as far as I can tell appear to be made from the same material as the changer housing on my '74 LDG (round front, wide pedals, barrels behind two-hole pullers). The endplates have the same relatively dull finish as the changer housing and will not take a shiny polish. Likewise the keyheads and pedals. The pullers and levers and lever brackets are obviously different material. I can readily tell the difference between the aluminum changer fingers on the '74 and the pot metal ones (which are much shinier than the housing they're in), but these other parts?

James Morehead · Post by **James Morehead** » 29 Sep 2011 7:28 am

Brint Hannay wrote: appear

That's the key word. There are different grades of casting quality, by whatever someone wants to mix up. All aluminum castings are not created equal--there are different grades of aluminum, depending upon purity.

The technology of the '60's and '70 is a whole different dimension of today's technology. They did the best they could back in the "day".

Brint Hannay · Post by **Brint Hannay** » 29 Sep 2011 7:33 am

So what is the distinction between different grades of aluminum and pot metal? You've drawn a distinction between "aluminum" and "pot metal." Are you saying some of the parts you've referred to are lesser-grade aluminum as distinct from pot metal?

James Morehead · Post by **James Morehead** » 29 Sep 2011 8:04 am

Here's some interesting reading, Brint. Enjoy!
http://www.wisegeek.com/what-is-pot-metal.htm

James Morehead · Post by **James Morehead** » 29 Sep 2011 8:05 am

And another-------------

http://en.wikipedia.org/wiki/Pot_metal

James Morehead · Post by **James Morehead** » 29 Sep 2011 8:06 am

and yet another another--------
http://en.wikipedia.org/wiki/Aluminium

http://www.ehow.com/about_5164212_casting-aluminum.html

James Morehead · Post by **James Morehead** » 29 Sep 2011 8:17 am

Brint, to know exact distinctions might get you into a deep study of metalurgy. There are different grades and purities. There is probably no info on what formulas Shobud used back in the day. Most likely that sort of work was contracted out.

James Morehead · Post by **James Morehead** » 29 Sep 2011 8:36 am

Here's a Super Pro changer housing someone over polished. We built new replacement housings out of high grade aluminum for this project.

James Morehead · Post by **James Morehead** » 29 Sep 2011 9:03 am

Now, getting into the purity of the castings is a long drawn out conversation and a study of it's own, and what Jason and Brint are really wondering. Could it be a correct observation---"The quality of aluminum castings were a matter of how pure the aluminum WAS, going into that casting. Shobud felt there was more than just a casting going on. They felt that a quality casting had a resonance, contributing to the "voice" of the finished guitar. So what WAS a good material to cast, with musical quality in mind? Well, that might be a whole new can of worms--trial and error? Food for thought.

In otherwords what percentage was aluminum, and what percentage was "other alloys"? How much alloy can be added before you could NOT call it an aluminum casting? What alloys would compromise the integrity of the end result--what % of certain alloys mixed with certain alloys blah blah. Where's the point of no return, where it's enough, yet a smidgen more is to much?

It's my understanding, when the Pro II Custom era came along, through out that generation of guitars on to the Super Pro era, the quality/purity of castings decreased, and the pot metal was introduced more and more, possibly cost driven. Yet I have seen poor castings in some Professionals, in the keyheads, endplates, and changer housings. I have a set of Professional enplates some one was over aggressive with on a buffer. They managed to open up a million pin holes, like the above photos. Poor casting? Yes. Could it have been poor casting technique, or poor alloy mix? or both? not enough of one--to much of another--- Who knows.

Bottom line, boys, Don't over polish your shobud metal, you may regret it. And if you think your guitar sounds good, then enjoy it, because it IS good. It is what it is.