Fin measuring

[Ethan]

I am trying to set my 2022 vapour pro fin back to stock measurements, I have calipers but not the slotted ones.. 

In having a hard time getting accurate measurements for the DFT, each time I close the calipers it seems to be a different number, does anyone have any suggestions?

[Horton]

Does this help?

@mike_mapple any comments you your Dad's technique?

 

Below is how I do it. The thumb pressure is the key.

Without my thumb driving the edge of the micrometer toward the bottom of the ski  the rocker of the tail of the ski makes the measurement extremely inconsistent.    

 

[Ethan]

kinda, still getting different numbers each time... maybe it's worth investing in some proper calipers 

[Horton]

I have the expensive Mitutoyo calipers but a 8" set of Harbor Freight calipers would work just as well. 

https://www.harborfreight.com/hand-tools/measuring-marking/calipers-micrometer/calipers/8-in-digital-caliper-63712.html

Do NOT get the 6". You need 8"

I personally prefer the dial over the digital but I know not everyone agrees with me on that point. Looks like Harbor Freight only has the digital in 8" for now - for $35 you can't go wrong.

[Ethan]

ok thank you, ill look into getting one. 

[Mastercrafter]

On the bright side, the tail shape of the Vapor is the easiest ski to measure. Along with pressure flat to the bottom of the ski, you can roll the calibers side to side a bit to find the smallest (straightest) measurement. Some stand the ski on the nose, some do it laying down.. you’ll get a feel for it. 

[mike_mapple]

On 8/3/2024 at 3:39 PM, Horton said:

Does this help?

@mike_mapple any comments you your Dad's technique?

 

Below is how I do it. The thumb pressure is the key.

Without my thumb driving the edge of the micrometer toward the bottom of the ski  the rocker of the tail of the ski makes the measurement extremely inconsistent.    

 

I always set a fin standing, i cant use ski docs or anything, he was the same way. 

[foxriverat]

@Ethan I try to line one side of the caliper up with one side of slot for fin and keep it straight with that line, then hold down with my thumb. I find if I line up fin on middle of caliper any slightest angle when remeasured will give a slightly different reading.

[BraceMaker]

 

On 8/3/2024 at 3:55 PM, Ethan said:

kinda, still getting different numbers each time... maybe it's worth investing in some proper calipers 

I don't think anyone on here is getting DFT 3x in a row to the thousandth.  Nor should they when the published numbers are rounded to the nearest .005 just take 3 measurements and give it an average in your head.  Every time you do it you'll get more comfortable.  Ditch the digital for a dial it just gives you meaningless numbers.

 

[Justin_C]

If the tail of the ski has a flat spot, sometimes you can almost measure in reverse. Set the calipers on the flat spot and then push it in until it hits the fin then use your thumb to apply some pressure like the others have said. Obviously this doesn’t work if the tail is rounded

[skialex]

@Justin_C it’s called “needle”

standard is “head” 

[EM_]

On 8/5/2024 at 12:48 PM, BraceMaker said:

On 8/3/2024 at 3:55 PM, Ethan said:

 

I don't think anyone on here is getting DFT 3x in a row to the thousandth.

…. you’re not?

[Deanoski]

The only way I can get consistent DFT Is to put the tip down Andy maple technique.  I can hold it with my thumb and constant measurements using this method 

I find the Goode skis to be the hardest ski to measure DFT

plus every caliper will give a different dft

I have 3 calipers and all of them give me a different dft. I use the pr that gives me the middle ground 

Then I adjust dft on feel if the fin needs to go forward or back  depending on. Gate pull out width  turning to hard or not turning onside or offside 

I find tip the depth to be consistent caliper to caliper 

 

 

my 2 penny’s

[Mastercrafter]

This may be panda-worthy or already tried and failed but.. 

What if there was a caliper-like device actually built for measuring true DFT, not distance to some random tangent on some random radius that varies with thumb pressure and the moon's gravitational pull?

We'd have some larger baseline numbers but it seems like it would be way easier to measure and adjust accurately. 

Yes? No? Has it been tried?

 

Edited August 22 by Mastercrafter

[thager]

Let's call it a slot caliper...

[Mastercrafter]

14 minutes ago, thager said:

Let's call it a slot caliper...

Yes, certainly easier but still varies based on bevel and thickness of caliper. Probably good enough though. 

[dchristman]

@Mastercrafteranything you might think up has probably already been thunk... it's no longer available, but:

 

[BGrow76]

For DFT the digital slot caliper is a great tool, I can measure three times and never be more than 0.001" different regardless of the shape of the ski behind the fin.

https://goode.com/products/digital-slot-caliper

https://slotcaliper.com/
 

If you don't have a slot caliper measure like Andy Mapple shows in the above video, still tricky depending on the shape of the ski behind the fin. Since the caliper head thickness can vary from caliper to caliper sharing your DFT measurement with a standard caliper is not very useful.

 

[BraceMaker]

3 hours ago, EM_ said:

…. you’re not?

No I am not (and no one who uses a digital caliper is either even if they think they are) because the depth rod of the tool simply isn't capable of measuring that number on a really nice mitutoyo caliper that spec is =/- .002.  If you showed what you wanted to measure to a machinist they'd make a jig that sat on the top deck of the ski with a block on it that sat square to the top edge of the ski and a micrometer depth gauge.

But play a game here.  If you think you are getting that number flip the caliper backwards so someone else is reading the number and tell them when to write it down when you feel right.  Maybe have Steve measure while you look at the number and then you measure while he looks at the number.  Say when write it down.

There is no difference using the tool while you can see the number vs. when you cannot see it other than your own ability to influence the reading.

 

You can get really extremely accurate numbers by putting a machinist square over the back of the ski pressed against the fin which gives you a solid flat surface to measure off of but that is a meaningless number when it comes to a chart made by someone using a caliper off the curved surface of the bottom of the ski.

[EM_]

21 minutes ago, BraceMaker said:

flip the caliper backwards

But that would change a constant to a new variable? Is the goal to find a consistent way to measure DFT or make things as complicated as possible? 
 

I only chimed in because, second to boots, DFT is probably the most important number to get dialed in first. 

[DW]

EZfin tool:

What is the definition of ‘tail’, this tool allows measuring from the physical tail of the ski.  Number is significantly different from what is the current standard way of measuring for most skis.

Edited August 22 by DW

[aupatking]

2 hours ago, dchristman said:

@Mastercrafteranything you might think up has probably already been thunk... it's no longer available, but:

 

Cool tool but had its own issues. Just like the “fin tool” it’s measuring from the top sheet, which may be longer than from the bottom of the ski. Also, you have to find the right spot on every ski to tighten the clamp to get repeatable numbers. 
Then, you still have to measure with calipers to figure out what the difference is in each measurement, caliper to axiom, to translate in order to set to whatever numbers you are chasing. 
it was best for when you just wanted to isolate one measurement change without effecting the other two. Overall, the calipers were just easier. 
you do get better with them. Unless you’re one of those people who doesn’t, I guess. @EM_kinda does this for a living, so I have a feeling she hits the same numbers pretty often. Also, use the head, not the rod

 

[ColeGiacopuzzi]

You should definitely be able to get the same DFT measurement 3x in a row. It is the trickiest measurement of the three yes; but consistency is key.

Try placing your caliper in the same spot every time.

for ex. line up the back edge of the fin with the top line on the edge of the caliper. (see photo) OR measure in between those two lines. as long as your consistent you should be able to duplicate your number. 

Also DFT should be your first measurement you want to hit when changing a fin.

Practice and patience are required.

caliper photo.pdf