Guys check this site for some real good Caliper Gauges The LA3 look the best for surfboards http://www.peacockozaki.jp/e_sub01_32_photo3.htm
Peter
Precision looking tools. But be careful if you use those on foam as it easy to dig right into the blank that’s being shaped or scratching the gloss coat on a finished board.
can’t you tape or attach rubber (or foam insert your best soft material here) to the ends . . . to prevent butching the foam or your glass job? You might lose some precision, but if you precision measure the guards . . . and compensate for them . . .
Then someone’s going to post that you can make your own, and you don’t need to be that precise. Then another one is going to follow that you can build your own. Then someone else is going to post a pic of their calipers.
I’m of the opinion of that whatever tool you need to do a good job, go for it.
Quote:
Then someone’s going to post that you can make your own, and you don’t need to be that precise. Then another one is going to follow that you can build your own. Then someone else is going to post a pic of their calipers.
I’m of the opinion of that whatever tool you need to do a good job, go for it
Yep, it’s happened before and could happen again. Good call.
Fine calipers for sure, but we have to decide wheather we’re engineering space ships or handcrafting surfboards. Nothing more pleasing than a nice handmade all wood caliper. You gotta enjoy the ride!
Y’know, Richard, you and Paul are probably working to tolerances at least as close as anyones - and let me throw this one out in general:
Given foam, fiberglass and resin and the natures of them all, for the most part done with or at least finished with non precision hand tools, what lind of precision are we talking about here?
Within 1 or 2 mm or about 1/16" or so, or are we talking less precise, on the order of 1/8" plus or minus that somebody is happy to come within on things like thickness, overall width, getting the curve to match the curve drawn from the template, that sort of thing. I don’t mean getting it smack on on one board, I’m thinking more about an average, lets say over 10 or more boards, and specificly excluding hollow wood boards as a special case.
just kinda curious, what with an inherently imprecise material set like foam and fiberglass, I kinda wonder if in fact anybody can get much closer than around 1/8" or so
doc…
Quote:
just kinda curious, what with an inherently imprecise material set like foam and fiberglass, I kinda wonder if in fact anybody can get much closer than around 1/8" or so
doc…
Well said, Doc. Hearing one of France’s top pro shapers say that he’s shaping within a 1mm margin makes me laugh… (That’s 1/25,4th of an inch, isn’t it?)
Hi Balsa,
You’re exactly right, that’s 1/25" or 0.04", call it a little more than the thickness of a matchbook cover or biscuit-box cardboard.
These days…without my reading glasses… I know I can’t cut that close on a piece of wood that’s marked with a very fine, sharp pencil. Heh… more like ‘take the mark or leave the mark?’.And that’s just getting it right in one dimension; length, with a precise measuring system, a relatively stiff material and tools capable of cutting that close. In three dimensions? With imprecise tools like a power planer or sandpaper? With no reference marks beyond occasionally checking against a template? And a material that compresses, bends and twists on the shaping rack just from the weight of the tool?
Being lazy, I haven’t done it, but it might be interesting to see just how much a planer compresses standard foam from it’s weight alone, ignoring any pressure put on it by the guy who’s actually using it. Or how much the blank bends, etc. Even with a machine shaped blank, held down to the shaping machine with a vaccum clamping system - hey, it has to bend a little from the tool and the clamping and I’ll bet it springs back some when the vaccum clamp is let go.
Don’t get me wrong - I’m not saying unkind things about anybody, but as far as I can see, anyone shaping foam who gets within 5 or 6 mm ( about 1/4" or 0.25" ) on all the dimensions and does it consistently, that’s downright amazing.
doc…
An early version of what I use…
Ah- I looked at those and said to myself, yeah, but there’s one little thing…and then I looked closer and I saw how these were made and saw that Paul had it figured from the start. Know what that was? Hope you don’t mind me using a piece of that picture to illustrate this, Paul -
Two cuts, a rabbet and a dado, in the fixed arm of the calipers to get the bottom edge of the fixed caliper arm as close as possible to the ruler mounted on the movable arm assembly. That’s important, and here’s why:
If you have the fixed arm at some distance from the ruler surface, it becomes imprecise. Depending on where you’re looking at it from, that edge will line up differently with a different mark on the ruler, as you can see above. But the closer that bottom edge of the fixed arm is to the ruler surface, the more precise it becomes, no matter where you’re looking from. The edge is right there, every time.
Nice work
doc…
Quote:
SNIPDon’t get me wrong - I’m not saying unkind things about anybody, but as far as I can see, anyone shaping foam who gets within 5 or 6 mm ( about 1/4" or 0.25" ) on all the dimensions and does it consistently, that’s downright amazing.
doc…
Aloha Doc
I know several shapers who can shape consistently at 1/16" tolerances or even better if need be. I haven’t worked hand on hand with any of them lately though and with shaping machines etc it may have effected their skills! But even if it has, it probably hasn’t degraded them down to 1/4" latitudes.
I remember years ago, Munoz shaping a soap box derby racer and when it was measured they couldn’t find any place that was off by even a 1/16". Least that was what witnesses said. Common customers generally don’t require that kind of precision these days so maybe that level of skill is a waste of time to some people. But I don’t think so, though it certainly requires wisdom as to when to use it.
The best shapers are a combination of…
Artist
Designer
Engineer
Craftsman
Perfectionist
Psychologist
Few shapers bring to the table all those skills rolled equally into one. Those who do though are fast, accurate, productive and make beautiful boards that consistently work at the highest levels of customer satisfaction and don’t go crazy doing it.
Of course, to complicate things more, shapers lacking in some of these gifts can still be hugely successful. So my term “best shapers” doesn’t necessarily mean; most famous, popular, rich, etc.
Among those who regularly perform an art or craft, especially for their economic survival, there is usually a recognition among them as to who the real masters of that art or craft are. Among those masters, 1/16" tolerances if required, are not unusual and are often everyday occurrences.
1/8" tolerances are a breeze. Repetition with a high attention to detail, brings an extremely precise level of skill to one’s craft. I remember back in 1973 when I was helping Al set up things at Channel Islands, that we got Andrini to try laminating a board blindfolded just to see if it could be done - the board came out fine. (Kirk, do you remember that one?)
Mister Jensen,
those be mighty fine calipers you have there. Living in a country built without any apparent knowledge of calipers (or french curves for that matter…) I will be taking the liberty of copying your very fine device… swaylocks rocks! I tried the scissor type but you know, the lever action makes precision reading a problem, a mm increase in measure doesn’t translate to a mm on the guage to so you end up having to hand measure all the points out … gat gat gat…
Muchos thankos for your post.
Paul nice set of calipers! Here’s a set I made on my shaping machine when I had some free time. Similar concept different approach. With the button head tips they work great no marring/scratching.
Quarter inch here, quarter inch there? I guess close is relative.
Quoting Bill:
The best shapers are a combination of…
Artist
Designer
Engineer
Craftsman
Perfectionist
Psychologist
If you think about it, that pretty much nails it. I had a crazy experience
last week. I was doing a ‘specialty board’ as precisely as possible to given
CAD drawings. Once the shape came off our machine the bottom contours
were within .020" (not a typo) of the drawing. (A 16th is .0625) Also, I
recently calibrated our machine and dial indicators show axis tolerance to
within .002 (that’s two-thousandths) throughout the work envelope. This
is not the cutting tolerance, just machine movement.
I was laughing as the guy measuring with his tool could crush the foam if he
didn’t use special contact pads. He took numbers at 5 stations along the
bottom and it came out spot-on. I hand finished and tried really hard not
to touch any of the cuts at their deep points. Took longer than a regular
hand shape. “His numbers” were still good.
After glassing, the thing was (relatively speaking) ‘totally shot’. Ha!! Still
looked good to me. The laps change the bottoms quite a bit. My sander
(also grinds and hotcoats) has a habit of taking out about .050 of tail rocker
in the last 2 inches. Pretty consistently.
I don’t want to tell neither my laminator nor my sander to change. I now plan
to “shape to the glassing” if that makes sense, to see what happens.
I REALIZE this is all moot, the board will flex while being ridden (we managed to
measure this) to around 1 inch static and over 2 inches in moderate turns.
Also, I’ve ridden boards with repairs and duct tape all over them that rode unreal.
I just want to see what I can do with a minimum of shaping adjustment.
I guess certain Marine Architects like to do things this way, but as an engineer,
I like TLAR.
That Looks About Right
It was/is a good learning experience though.
Just use two wooden coat hangers, attached together at the ends or the good old paint stir sticks method. Coast = free.
George,
You are right, Barnfield’s list of attributes does nail it. I really know what you mean about sanding tolorances. I would always sand my own personal boards, after glassing. I referred to it as the final step in shaping the board. As to shaping tolorances, 1/8’’ is a sleepwalk, and 1/16’'is not that difficult, you just have to pay close attention. As you know. I’m not really sure that tolorances any closer than that, makes a difference in the performance of the finished board. Though I do know that it can make a differance in the mind of a customer with a fixation on a set of dimensions they have fallen in love with.
Hey Guys;
Just had to comment!
With the advent of shaping machines most shapers need to get with the program and talk in industry standard. When Bill says 1/16 tolerance, does he mean + or - a 1/16"? (thats how everyone else says it in industry) or does he mean + or - a 1/32" (1/16 out vrs. 1/8" out)? In my experience when talking tollerances below + or - (I can’t figure out how to overtype here) 1/16" we should refer to “thousands” so it would be + or - .060 or “60 thousands”.
For George:
Marko is making custom blanks that are + or - “20 thousands” or + - .020". This was always industry standard for EPS and a little sloppy in my thinking. When I was molding EPS Apple Computers required their product to be molded at + or - .10! We also custom molded EPS at + or - .005" for a munitions manufacturer and ran a lot of rejects in the process! To far out …and…kaboom!!
For Oak:
Great gauge. If you are really reading a dial indicator (the boards in the background are really sweet as to tolerance!) are you reading + or - .010? This would produce a great product off of the shaping machine.
A story for all:
A few years ago I shaped a longboard for myself with a flat bottom and some stratigical curves and concaves. I took it to a new glasser who hadn’t much experience with glassing longboards but did really good work. When I got it back I cured it up in the rafters and waxed that baby up and paddled out to my favorite “secret” beach break in 2 - 3’ surf. It is still my favorite board and I ride it most the time. It was a “magic” board. I took it back home and put it on the racks and took a straight edge & calipers to it. The glasser had put a concave in the bottom right under my chest and double concaves thru the side fins (I was riding it as a single fin)! The concave was a strong 1/8"!!! I had specified on the glassing sheet where the bottom changed with shading, etc… so, as George said, we need to be aware what everyone is doing as shaping, glassing, sanding, etc. can change board in the gross tolerances we are working with!
Have a good one guys, I’m out of the water for a while as I got stabbed by a big stingray!
BKB
Aloha BKB
When I say “1/16” tolerance"… I mean, that the boards measurement is not more and not less then 1/16" from what was intended at that position. So that would be the + or - 1/16" as you have clearly detailed. I am not sure what others might mean, but thanks for helping clarify this so there can be better communication on these issues.
As you know, I was mostly commenting on Doc’s comment, regarding common tolerances that skilled shapers can achieve.
Another discussion would be whether or not those tolerances are sufficient to properly control performance variables. But that discussion would probably produce too much emotion fueled by too few facts and too many opinion.
Hey Surfteach,
I see where you are coming from, I bet Bill means (+/-) 1/16 inch. Guys
with his experience can see that from across the room in correct light.
I’ve seen it, it’s just amazing. It’s also how they look at it, which comes
from experience.
In the case of my Architect client, it was (+/-) 0.010 which for a milled
blank, was pretty darn decent. I know of quite a few machines in our region
that don’t get better than (+/-) 1/16 inch, this being due to blank fixturing
and spring-back.
For example,
A production run of let’s say 100 6’2"s all made from the same blank
will no-doubt use the same fixture settings. The worker will place each
blank as instructed, but say, some rockers are off by 1/16 someplace during
glue up. The foam gets placed into the same position as the previous job,
maybe forcing it down just slightly. The board gets milled, then released
from the fixture and voila, a “new” rocker, or twist, etc.
There is also the case of inadequate support of a blank, then the blank flexes
in spots when the tool passes over the foam. Shapers do this when their
rack heads are too far apart or a tail is thin and they don’t support it with
their hand.
Also, there is the “post, post-curing” of the foam, once milled, and the stringer,
once freshly exposed, will wreak havoc if not handled correctly.
On the other hand if I was molding, I would expect tighter tolerances than that,
but hey, it’s gonna get shaped away by a person or a machine anyhow 
Take care of that foot, those toxins are nasty for infections!!!