What is the proper measurement technique for DFT?

[freeski41]

Is this proper technique for DFT measurement?

 

 

 

[gregy]

No, its a mistake.

https://www.youtube.com/watch?v=jzqnDVVE_jU

[freeski41]

Yeah, I didn't think the DFT measurement shown in the image was correct? I got the image from waterski.com from some fin whisperer article.

[skialex]

@freeski41 you are right, picture is wrong.

Best way to measure DFT is "heads",

Ski vertical, tip down, press caliper with the thumb against the bottom of the ski in order to be as straight as possible in all axis. If done right you will always get repeatable numbers that can be shared with confidence.

Ski with rounder ends are more difficult to measure, worp

[DW]

@freeski41 : It depends on what you want to call the 'tail' of the ski. For me, your picture does represent the way to measure DFT since it takes any variation of different calipers out of the picture and is truly the very back or tail surface/point of the ski. Most people seem to prefer, as noted in the two responses above, simply using the head of the caliper thickness to determine what they call the tail of the ski. Different calipers will have different head thickness' so direct comparisons may not be accurate along with the specific curvature of the tail of the ski variation may also influence the result.

[bigtex2011]

Get a slot caliper for dft. It WILL always be different than using a dial or digital but you can consistently get repeatable numbers and work from there. My slot is usually .007 longer than my expensive dial caliper.

[Than_Bogan]

Or get a Denali with a nice flat spot for easy, repeatable DFT with any caliper!

(Invented by @Wish, btw.)

[Wayne]

I always wondered why the ski manufacturers didn't put a spot to aid with DFT measurements. Im glad at least one company has done it.

[igkya]

With the Ez fin tool, that pic would be correct and will provide a very reliable and repeatable way to measure dft. The problem is that most dft measurements don't use this. If you know how to adjust your fin, this could provide a good reference point and baseline.