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Topic: Why those Delrin crossrod support doohickeys? |
John McClung
From:
Olympia WA, USA
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Posted 4 May 2019 10:43 pm |
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Been wondering this for years, are these thingamajigs meant to prevent crossrod bending in the middle?
If so, then why on earth aren't the Delrin "washers" rotated 90° and mounted on a supported axle, so that they roll, don't just rub against the crossrod collar.
Maybe my presumption of what they're for is wrong, clue me in.
Photo from my Rittenberry SD-12 8+5 I'm just getting around to finally re-rodding for my copedent.
My pre-RP Mullen D-12 doesn't use these. My Zum S-12 does. Go figure!
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 4 May 2019 11:12 pm
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Yes, they're there to keep the crossrods from flexing. And when they're properly adjusted, they present almost no extra friction on the rod. That's because the maximum tendency for flexing comes after the rod has hit the stop and it's no longer rotating. (That's when the pulling forces are greatest.) It's just an alternate way to deal with a problem that some builders ignore.
Some feel a center support is necessary, and some don't. |
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Jon Light
From:
Saugerties, NY
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Posted 5 May 2019 4:34 am
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My steel---double-wide body 12 string with pulls spread out across all 12 strings, full apron to apron cross shafts, metal-on-metal bushings (not bearings) at each end in each apron, NO delrin 'bumpers' in the middle. A formula for years of aggravation until I installed some relief myself.
I am neither a physicist, an engineer nor a steel builder so I can only go by my observations. My A & B pedals became very grabby and notchy feeling on slooww pulls. You could not do a slow half-pedal because it would want to stop at every friction point. After much observation I became convinced that as the shaft flexed and bowed on a pedal pull, the shaft ends in the bushings were going out-of-square....I believe there is a word for this ?....and causing friction. My homemade delrin bumper solved enough of the problem to be able to continue playing this guitar. Left a bad enough taste, though, and a steel that is still somewhat challenged. Now that I'm gigging a lot again, a new steel is on its way.
Would an actual rotating bearing in the center be even better than the stationary butting contact? Good enough question.
When I look at my undercarriage and then look at the undercarriage of some of the very highly regarded steels that have always had the bumpers, I wonder why my builder decided that such a thing was not worth his effort. 'If it ain't broke' is fine and good. If it ain't. |
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Patrick Huey
From:
Nacogdoches, Texas, USA
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Posted 5 May 2019 5:07 am
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One plus with delrin rollers is not only do they operate smoothly they don’t require lubricant. I am a mortician and we have several different brands of cots/stretchers at the mortuary. I recently took them all and lubed all the moving parts underneath (the legs are made to raise and lower to different levels) and the legs travel down a long rail underneath. I noticed the two less sturdy, harder/more finicky to operate of the three brands has a small metal roller that rolls against the rail underneath and makes a lot of friction and requires constant lubrication but the better and more sturdy and smoother operating of the three different brands has a large plastic delrin roller just like the one pictured and it’s operation is much more smooth, solid, and doesn’t necessitate the lubrication the others do....nor does it require the initial 30 minutes of cleaning off the old, gunked up, built up sludge left over from prior lubrications. I would say they are a plus and a big improvement mechanically
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Pre RP Mullen D10 8/7, Zum 3/4, Carter S-10 3/4, previous Cougar SD-10 3/4 & GFI S-10 3/4, Fender Steel King, 2 Peavey Session 500's, Peavey Nashville 400, Boss DD-3, Profex-II, Hilton Digital Sustain, '88 Les Paul Custom,Epiphone MBIBG J-45, Fender Strat & Tele's, Takamine acoustics, Marshall amps, Boss effects, Ibanez Tube Screamer, and it all started with an old cranky worn out Kay acoustic you could slide a Mack truck between the strings and fretboard on!! |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 5 May 2019 5:46 am
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| Jon Light wrote: |
...Would an actual rotating bearing in the center be even better than the stationary butting contact? Good enough question.
When I look at my undercarriage and then look at the undercarriage of some of the very highly regarded steels that have always had the bumpers, I wonder why my builder decided that such a thing was not worth his effort. 'If it ain't broke' is fine and good. If it ain't. |
The benefits of a bearing would probably be offset by the added cost. Ball bearings offer few additional benefits because the amount of rotation in this application is so small, and because the bearings would require some additional supporting mechanism. The delrin buttons do the job acceptably.
Different builders have different ideas about what's necessary and what's not. There's still no concensus that center supports are absolutely necessary. |
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Bobby D. Jones
From:
West Virginia, USA
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Posted 5 May 2019 2:57 pm Why those Derlin crossrod support doohickeys
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There is a few guitars that have plastic sleeves on the cross rods that keep the rod from bending. But they are like a puzzle to get the cross rods out of them to change copendent, Or add or remove bell cranks. All that is needed is a slick stop (Derlin) for very little movement, As the cross rod turning brings the strings to tune.
The hole in the doohickey being drilled off center, Would allow the doohickey to be rotated and come in contact with the collar on the cross shaft so there would be 0 flex in the cross rod when the pedal or knee lever was engaged. Then tighten the screw. Causing no binding of the bushing on the ends of the cross rod.
There is only one point of force even if the doohickey went 360 degrees around the cross rod, The point of force would only be on one side of the rod. (The side the cross rod it is bending too)
The doohickeys makes it easier to assemble the guitar, But also makes it easier to work on and change copendents or move bell cranks without Having to work cross rods through a cent bearing setup. |
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John Goux
From:
California, USA
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Posted 7 May 2019 5:58 pm
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Hi John.
A Rit SD-12?
Jealous sigh.
I compared my Rit SD-10 for a week with a borrowed Franklin. I don’t think a meticulous steel player could tell the difference in tone and sustain between them.
Happy coped ing.
John |
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Paul Redmond
From:
Illinois, USA
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Posted 7 May 2019 6:33 pm
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These Delrin "snubbers" should always be drilled slightly off-center so they can be fine-adjusted by loosening the screw and rotating the snubber until it contacts the shaft. Or better yet, use a piece of aluminum foil as a feeler gage and set them that way. When the shaft bottoms at the end of rotation, it will just barely hold pressure on the snubber. A smear of oil will make the snubber as slick as a peeled onion.
PRR |
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Jerry Roller
From:
Van Buren, Arkansas USA
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Posted 7 May 2019 10:21 pm
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The guitars with aluminum cross shafts use the support because aluminum will flex much quicker than steel. Emmons used steel cross shaft thus no support is needed.
Some others may use steel but I don’t know. I have Zum’s with aluminum cross shafts with the nylon supports and they are very easy playing and accurate guitars.
Jerry
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http://www.littleoprey.org/ |
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Bob Carlucci
From:
Candor, New York, USA
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Posted 8 May 2019 4:34 am
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HOW in Heavens name did all the players in the 60's 70's 89's 90's ever play a note in tune?.... We need "snubbers" to keep cross shafts from bending",, My Lord, who knew?...
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I'm over the hill and hittin'rocks on the way down!
no gear list for me.. you don't have the time...... |
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Marco Schouten
From:
Amsterdam, The Netherlands
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Posted 8 May 2019 1:09 pm
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| Jerry Roller wrote: |
The guitars with aluminum cross shafts use the support because aluminum will flex much quicker than steel. Emmons used steel cross shaft thus no support is needed.
Some others may use steel but I don’t know. I have Zum’s with aluminum cross shafts with the nylon supports and they are very easy playing and accurate guitars.
Jerry |
My JCH has steel cross shafts and also the delrin supports.
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JCH SD-10 with BL XR-16 pickup, Sho-Bud Volume Pedal, Evidence Audio Lyric HG cables, Quilter Steelaire combo |
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John McClung
From:
Olympia WA, USA
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Posted 8 May 2019 11:12 pm
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Thanks, John Goux. Of late I've been getting to know my Zum S12, Lynn Stafford just set it up with basics of my copedent, still need a bunch more rods for changes and compensators.
The surprise to me is it doesn't fit me very well. LKL is 2 inches further left than my Mullen or my Ritt. So I'm inventing ways to remedy that without actually moving the knee lever, that's a tough job on a single body axe. Bruce Zumsteg told me that with all my levers (6 or 7), I'd be better off with an SD-12, and now I know he's right.
Also I'm not comfy without that back neck or pad. Hoping I can get used to it.
The guitar sounds great and plays well, it's a 1990 model.
The Ritt fell into my lap from a student. It's the only 12-string Gary Rittenberry ever built, as I understand it, and its build quality is equal to the Zum and any other guitar. Hex crossrods and single blade bell cranks, both which I'm a big fan of, coming from the Mullen with the same easy-to-work-on features. Split screws. 3r/3l changer. Pretty deluxe. Wish it had 4 raises, that'll put me in line for a new MSA or Excel at some point, if I fail to conquer GAS.
_________________
E9 INSTRUCTION
▪️ If you want to have an ongoing discussion, please email me, don't use the Forum messaging which I detest! steelguitarlessons@earthlink.net |
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Patrick Huey
From:
Nacogdoches, Texas, USA
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Posted 9 May 2019 4:05 am
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| Bob Carlucci wrote: |
| HOW in Heavens name did all the players in the 60's 70's 89's 90's ever play a note in tune?.... We need "snubbers" to keep cross shafts from bending",, My Lord, who knew?... |
And how they EVER got by without splits I can’t imagine! 😂
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Pre RP Mullen D10 8/7, Zum 3/4, Carter S-10 3/4, previous Cougar SD-10 3/4 & GFI S-10 3/4, Fender Steel King, 2 Peavey Session 500's, Peavey Nashville 400, Boss DD-3, Profex-II, Hilton Digital Sustain, '88 Les Paul Custom,Epiphone MBIBG J-45, Fender Strat & Tele's, Takamine acoustics, Marshall amps, Boss effects, Ibanez Tube Screamer, and it all started with an old cranky worn out Kay acoustic you could slide a Mack truck between the strings and fretboard on!! |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 9 May 2019 4:57 am
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| Bob Carlucci wrote: |
| HOW in Heavens name did all the players in the 60's 70's 89's 90's ever play a note in tune?.... We need "snubbers" to keep cross shafts from bending",, My Lord, who knew?... |
I hear 'ya, Bob. But players back in the '50s, 60s, and '70s were used to playing without "perfect" guitars. There were no half-stops, no compensators, no digital tuners, and steels could be a lot less precise than they are nowadays. Nevertheless, they developed the techniques and skills (and ears) to get around these obstacles and play some great music.  |
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