shrinkage calculations

[jerolim 7]

Hi,

Has anyone done (documented) sewing shrinkages for :
- Legstraps
- Risers
- MLW
- Lines (spectra, vectran, dacron, HMA).

For example. 4 point box pattern (8 cm long, folded 3 times) for type VIII would be ?? millimeters.
Or when building mini risers, different lengths of zigzags or bartacks would result in shrinkage of ?? millimeters.

Also would be useful if someone has shrinkages for different bartacks for different line types, and shrinkages due to fignertraping length.

[JerryBaumchen 1,371]

Hi jerolim,

Quote

(documented) sewing shrinkages

You are dealing with a soft product; webbing. With hard products ( wood, metal ) it is easy to do.

There are many variables, the most important IMO is the amount of tension that the particular machine is setup with.

I have never done any measuring regarding this. I doubt that the difference on a 75 mm ( 3 inch ) 4-point stitch pattern on Type 8 would vary more than 5 mm ( 3/16 inch ). That, however is just an opinion.

Practice is your friend.

If you are really wanting to know, I would suggest setting up each machine as you want them to perform, sew at least three examples ( in which everything is exactly the same ) and then compare/measure.

Jerry Baumchen

PS) When doing a harness repair I sometimes will get the exact webbings and do a practice repair/stitch pattern to see if I can get close to the finished dimensions of the original.

[ChrisHoward 8]

jerolim

and shrinkages due to fignertraping length.

I've always used 1-10. Seems pretty accurate for most line types.

[jerolim 7]

1 cm for 10 cm of fingertaped portion ?

[ChrisHoward 8]

jerolim

1 cm for 10 cm of fingertaped portion ?

Yep.