My experiment is to see if I can induce deformation in the heel with a shim. The problem is that it will probably take in excess of 10 years to see any deformation if there is any at all. I will probably give up before then.
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Getting the Facts about Ski Jumps
- Thread starter Turnaround
- Start date
In your experiment, how much deflection did you see when you tightened the screws up to full load? Did the heel area bend at all, that you could measure? If not, then you aren't loading the wood enough to make it stretch, no matter how long you wait and watch.
Thanks Bruce. I couldn't measure any deflection so I thought I would leave it a while and then tighten the screws some more, thinking that over time I might be able to deflect it. At least that was the plan. So far I haven't been able to budge the screws after a year and a quarter, so I don't believe this is going anywhere. Every once in a while I run into the neck in the corner of the shop and check it again and attempt to tighten the screws. Really I should just give up but it's not taking any effort to check every once in a while, and it's in an unused corner of the shop.
I suspect that there is more chance of compressing the maple shim than deforming the neck heel.
The big "but" now is that I am cutting way back on my business and I will probably end up decluttering the shop. That test neck may well be one of the things that gets turfed.
I love reading this correspondence. It's like a good series. From time to time, a plot appears with little action and tension. You have main, good and bad characters as well as unimportant ones. And as with all good series, you never know what the end will be 
A mystery has been committed. Stay tuned.I love reading this correspondence. It's like a good series. From time to time, a plot appears with little action and tension. You have main, good and bad characters as well as unimportant ones. And as with all good series, you never know what the end will be
I love reading this correspondence. It's like a good series. From time to time, a plot appears with little action and tension. You have main, good and bad characters as well as unimportant ones. And as with all good series, you never know what the end will be
When we Luthiers battle, we sling engineering terms and anecdotes of experience! And we mostly fight with smiles and respect. All of us just want to figure out what's going on.
If it's any help I have a 62P with a shim (a bit of cereal box) that has been in there since about 1970. I just checked it with a straight edge and it is dead flat above the shim. As far as I remember I cranked the neck screws pretty hard. (I was a teenager at the time).
Ah, yes.
I've been following this thread since it's inception, albeit, a bit loosely.
I remember you starting that test.
Another point I remember you saying, is that WRT shims, business card stock is ok, but if you're the one doing the job, it's either a full pocket shim, or milling a back angle into the pocket, as you feel it's more elegant.
To reflect what others have said, it's an invaluable resource having @Bruce Johnson and @Turnaround onboard to provide us with so much knowledge.
I myself, can be a bit steadfast in my opinions, unless there's reasonable explanation and experience that proves otherwise.
One example being, you should detune your strings, or bend the neck, or only adjust 1/8 turn at a time, when adjusting the truss rod.
I figured you should be able to adjust it, without aid, because that's what it's there for, right?
Bruce and Richard both pointed out that the TR can act as a crutch sometimes, due to warpage, twists, etc.
Knowing this, now, I feel more forearmed wrt making TR adjustments on future basses.
I myself, can be a bit steadfast in my opinions, unless there's reasonable explanation and experience that proves otherwise.
One example being, you should detune your strings, or bend the neck, or only adjust 1/8 turn at a time, when adjusting the truss rod.
I figured you should be able to adjust it, without aid, because that's what it's there for, right?
Bruce and Richard both pointed out that the TR can act as a crutch sometimes, due to warpage, twists, etc.
Knowing this, now, I feel more forearmed wrt making TR adjustments on future basses.
Hey guys, thanks for this thread!
i’m on the fence of buying a 64 p-bass, a luthier friend of mine said i should look out for ski jumps. I’ve sent him these pictures but according to him it’s difficult to see on the pics. Anyway, maybe you guys could shed a light on this.
Does this look like a ski jump? It looks and feels pretty straight to me, action is low enough, no buzz whatsoever. Only get a sliight fretless mwah on the very last two frets on the d an a string.
On the two pics without the yellow card i’ve put a capo on the 12th fret.
i’m on the fence of buying a 64 p-bass, a luthier friend of mine said i should look out for ski jumps. I’ve sent him these pictures but according to him it’s difficult to see on the pics. Anyway, maybe you guys could shed a light on this.
Does this look like a ski jump? It looks and feels pretty straight to me, action is low enough, no buzz whatsoever. Only get a sliight fretless mwah on the very last two frets on the d an a string.
On the two pics without the yellow card i’ve put a capo on the 12th fret.
To my eye it looks like a ski jump, but a mild one. Assuming your action is adjusted, then A & D only buzz isn’t too bad. My ‘61P is much worse but with a major/minor fret dressing it’s been perfectly playable for the last 20 years. I’d say ya could do good! ...but then we have actual skilled luthiers on this thread so I’ll defer to them.
Yes the action is right where i would want it to be and i don’t have any issues with the slight buzz at all. Should i avoid buying this bass bc of this ‘mild ski jump’?
I have determined that the '72 neck on my '63 P has a slight ski jump. However, it doesn't cause a problem until it's played above the 12th fret, which is territory I don't use. At least for now, I don't think it's worthy of any concern.
Hold the string down at the first fret and the last fret and see if you can find where the gap between string and fret is the largest. If it's close to the 12th fret, you have a classic ski jump. If so, the question is how bad is it?
Is there any rule of thumb that would help me determine if filing some "fall away" will cure, or at least improve some classic "ski jump" on an MIM P bass I'm rehabbing? Using a fret rocker, I identified a couple minor partial high frets that I spot leveled, which has yielded a playable bass below the 12th fret, but above the 12th I get a lot of buzz in the D &G strings. I have set relief at .012" at the 8th fret, and 5/64" string height at the highest fret, so I don't think it's an overly low action. Is there a way to quantify if fall away would work in this scenario?
i’ve just checked, and the largest gap is around the 8th/9th fret. Does dat mean there is no ski jump?
No, but it means that if there is one it is mild. I don't think you need to be worried.
I'm shimming a neck with pieces of sand paper cut to fit about an inch of the rear of the neck pocket. If I use two pieces in the rear could I possibly avoid a ski jump if I used one piece before those in the middle of the neck pocket making more of a ramp?
Or, could I avoid this by adding some full pocket pieces, then a half-pocket piece, and then one or more 1/4 pocket pieces? Would this form sort of a ramp?
