PSG body

[Bay]

Do I need to make top on PSG with 1/2" wood or would 3/4" be better.
how long should changer be with either way




Thanks...Bay

[mac639]

Hi Bay....
Didn't you send me an email a couple of days ago inquiring about my PSG book? Anyway.....3/4" wood is the norm. Most boards that are commonly available are 3/4". I've done other things though. The last guitar I built was 1/2" regular maple with 1/4" birdseye laminated to it. I had this 2+ inch thick plank of birdseye maple 8 feet long. It was too beautiful I thought to resaw into 3/4" boards so I resawed a 1/4" slice off it to use.

[Bay]

yeah Mac that was me emailing you, and am going to get your book,but how close are you to updated version...Thanks for the reply that helps

[azureskys]

Mac, im enterested in that book also .Bay i play a MSa classic and i believe the top deck is over an inch thick i cant get to it to measure but its thick plus the neck is an inch or better. Russ

[richard37066]

Bay -

Mac's post reminded me of something that I fully intend to do when I get around to building my "masterpiece". (HA!)

I intend using maple die board as a substrate and laminating a 1/8" piece of some exotic wood to it. The die board is, for all intents and purposes, a high-density plywood without internal gaps and which should not "move" with time - neither warp nor cup. The only hangup is having a large enough dead-flat surface upon which to press the two together while the epoxy sets. (Got a good table saw?) Yeh - I said epoxy - and not the five-minute variety. These space-age concoctions are much better than the best of wood glues. My last bottle of the best wood glue that money can buy dried up in the bottle in favor of a modern witches brew. To each his own.

Oh - as an afterthought. The width and breadth of the sides and internal aluminum side rails are more important than the thickness of the top. Don't skimp in any of those areas.

My best of luck to you.

Richard

[Bent]

Richard, regarding your remark about side rails I would like to add what my engineer friend told me (the guy who gave me the milling machine). He said that the side rails have very little structural importance the way I have them on my current steel guitar..they stop an inch or so short of the inside end plate extensions.
He said that the side rails have to be fastened to those extensions either by welding or bolting. There is your structure and strength. Now you can start cutting down the wood to lighten overall weight. The aprons can now be made say 1/2" thick instead of 3/4".

[richard37066]

Bent -

You are absolutely correct! In essence, and by fastening the aluminum side rails to the end plate structure, you are approaching the configuration espoused by myself and at least one other, namely Georg. That is, to construct a braced-frame structure to which all of the hardware is attached and which is so rigid as to make the dreaded "cabinet drop" a concern of no consequence. None of the constituent parts would move relative to one another.

Bay didn't elaborate on the overall construction of his cabinet -asking only for the thickness of the top - so I took the liberty of assuming that his design would be more "traditional" than forward-thinking. In the "traditional" sense the depth of the side rails offer the bulk of the resistance to bending of the entire structure. A thin and puny strip of aluminum screwed to the side rails to support the cross-shafts offers little by way of structural rigidity. Remember the "cross strap" on some Emmons guitars? Helps to keep the aprons from splaying outward under pressure. Perhaps I should have asked him for more particulars instead of just making an assumption.

In another thread and post, Georg referred us to a guy who makes the "WBS Ultimate" in Germany. Upon first viewing the photos, I immediately realized that it was the embodiment of all of the ideas that had been floating around in my head as to how one would make a PGS that was mechanically "right" in all senses of the word. And this guy had been doing it all along!!!! So, what else is "new", Richard? Georg has also related to me the fact that the very last thing to be mounted was the cabinet, itself. In my view, it doesn't get any better than that.

To carry that thought concerning the cabinet to an extreme, it then becomes "window dressing" and not a structural component. It also allows me to relax the dimensions of my maple die-board/exotic wood lamination.

Sorry for the misunderstanding. Hope this tends to rectify the thinking.

Richard

[Pat Comeau]

In my opinion and experience with building PSG...i would use 3/4" thick for the top plate and for the front apron, i've read about people complaining about the weight and others complaining that their steel guitar is moving all over the place when they use the knee lever...i'd rather have a steel that is alittle heavier and does'nt move from side to side everytime i use my knee levers, also with 3/4" thick maple screws goes in real tight and holds better than 1/2" , now about the bearing rail plate... from the pictures i have of other professional PSG's and from what i can see ; Sho-Pro seems to use a 3/16" or 1/8" by 1x1 steel angle from 1" to endplates and Mullen seems to use a 1/4 thick aluminum flat bar and is about 3" or more from the changer end plate side and about 2" or more the keyhead side endpate, and Emmons seems to use a 3/8" thick aluminum flat bar and the're also not welded or screwed to the endplates, i have other pictures of Franklin and Carter PSG and they also don't have the rail welded, so my question is... if this was a big issue i think those builders who's names has been around for ages would be doin' it differently than the're doin' it now, there's other ways to minimize the cabinet drop like...the right pedal bar design ,pedals ,cross shafts and the right changer and axle, those are the key parts in my opinion to minimize cabinet drop, i should make one and weld the rail to the endplate to see if there is a big difference .

i have pics from those PSG's i've mentioned if someone would like to see.

Pat C

[richard37066]

Pat -

One word in your post above triggered recollection of a post on the SGF concerning the diameter and material of axle shafts. At the time, I was turned off by the widely differing opinions concerning the same, and especially since no one offered any sort of mathematical proof to support their claim(s).

When I read the word "axle" in your post above I recalled the SGF post, got a big bug up my butt, and decided to research it just a little. Here's what I found.

Axle diameter on my GFI appears to be approximately 3/8 to 13/32". Can't get my calipers in there for an accurate measurement. Material? Don't know.

Calculated the tensions on all of the strings for a typical E9 setup. The fact that the string diameter of a couple of strings may be off by a thou is of no consequence in the overall picture. Arbitrarily chose the 3*** series of stainless for an axle diameter of 13/32". Plowed through the numbers using accepted data and formulae and found that my axle shaft would bend in the middle by .000647" or .647 thousandths at rest. I arbitrarily raised the 4th, 5th, 6th and 7th strings by a whole tone to sorta unrealistically increase the overall tension and come up with a different average load. Went through the calculations again and found the deflection of the shaft at midpoint to be .0007149". The difference is only .0000697" or .0697 thousandths. Referring to other calculated numbers given in the SGF post, I find that the change in pitch would average approximately 0.1617 percent or much less than one cent.

IF - IF - I did everything correctly, then it would appear as though we needn't worry too much about axle diameter or whether one should use high tensile strength steel or get paranoid about such things. Accepted practice seems to be very conservative. I've saved my numbers as a reminder that I shouldn't get too excited about the niceties concerning the axle when it comes time for me to put something on paper.

The above is meant to be informative and certainly not critical. As I said, I, too, was concerned about the subject and just had to find out for myself. It was worth the effort.

Respectfully,

Richard

[Bent]

Richard, interesting topic and also what you came up with for numbers.
My changer axle is 1/2" 304 stainless. "Just to be sure" type of thing. Like, what's good enough for Emmons is good enough for me.
Lets cancel out the changer axle for the purpose of this discussion.

Now, on to another aspect. Remember the old Sho Buds with their 5/16" axles and a spacer built in to the changer housing between each finger. There is no way that that axle would bend. Therefor, there has to be other factors at play that made the ShoBud get a horrible cab drop.
The way I see it, there can be 3 major things contributing to it then: The housing or anchoring of the housing; the keyhead; the body itself flexing.
I do believe that My keyhead is anchored solidly so for this discussion, lets cancel that. That leaves the changer anchoring. 4 1/4" bolts up thru the body and 5/8 of an inch up into the pillow blocks. That, I dare say is way overkill so we can eliminate that. BUT: Where are those bolt holes located? Very close(too close) to the hole for the changer in the body. A couple are as close to the edge of the hole as maybe 1/8". I believe that is one of my flex problems right there.
Also, my 3/4" hard maple body does flex I believe. Maple is not only hard but also somewhat elastic. So there I have flex. I believe if I get these 2 weaker spots beefed up, it will correct my cab drop by hopefully 4 cents. Right now I have 6 cents cab drop in Red.

As a comparison, the first steel I built has 7/8" hard birdseye maple in it. There I have 2.5 cents cab drop.

Gotta get out to the shop. Working on some bell cranks and roller nuts