Tools and ideas for cutting kevlar woven cords cleanly

[morgandemarigny]

I am currently cutting it with a diamond wheel on a Dremel tool at varying speeds. I wrap the cord with tape and cut through the tape. works pretty well, but without the tape, the cordage frays badly. I also can't trim. Any ideas? I want to make some finger traps and the fraying is a problem. Thin CA glue stops fraying but wicks impressively, and makes something harder to trim!

 

[Antares JS]

I am currently cutting it with a diamond wheel on a Dremel tool at varying speeds. I wrap the cord with tape and cut through the tape. works pretty well, but without the tape, the cordage frays badly. I also can't trim. Any ideas? I want to make some finger traps and the fraying is a problem. Thin CA glue stops fraying but wicks impressively, and makes something harder to trim!

Look for "kevlar scissors" on Amazon.

 

[morgandemarigny]

I want to attempt a finger trap and realized a clean (semi) non-frayed end is very desirable. I currently use a diamond wheel on a Dremel. Cut it like butter. If I wrap the cord, put it under slight tension and cut through the tape I get a great cut. I have been unsuccessful trying anything else.

 

[morgandemarigny]

Thanks! didn't realize they existed!

 

[dhbarr]

I've used diagonal cutters before, but if they have nicks it won't be very clean.

 

[Donnager]

For smaller kevlar, I put a drop of CA on the cut line. It prevents fraying (while also making it harder to cut). I can usually have a clean end this way.

Cut the glue joint with whatever, dremel, razor, etc.....

 

[cls]

Kevlar scissors, like these

 

[Kane]

I tape the end and use a sharp X-Acto blade.

 

[bjphoenix]

I've only been cutting small cord for shock cords- a sharp hobby knife will do it but I think a slightly rougher edge does better- my sharp pocket knife cuts through kevlar much better.

 

[mh9162013]

I use a sharp x-acto knife blade, then apply white glue or wood glue on the tip to stop the fraying.

I never apply CA to Kevlar I plan on using in a model rocket as a shock cord.

 

[goose_in_co]

Kevlar scissors, like these

View attachment 630503

I got a pair of these for Christmas. Clean non-fraying easy cuts every time.

 

[Ronz Rocketz]

On a side note, I landed a Doorknob on high voltage lines. The electric company just happen to drive by and see it. By the time I got there, they were already setting up. They attached a knife to the end of a pole to try and cut the shock cord. I told them it wouldn’t work because it’s Kevlar. They tried anyways and quickly gave up. They were able to flip the rocket over and landed on the low voltage line which they could grab with gloves. Out of spite, they then dropped it to the ground to see if the chute works. It didn’t.

 

[manixFan]

If you are doing finger traps with Kevlar, the buried end needs to be tapered. If you leave the end blunt, you create a stress riser where the outer cord bends around the buried blunt end, and you lose a lot of the benefits of a finger trap vs a knot.

I learned that the hard way.


Tony.

(Edit: You should be able to run your fingers along the cord with the buried and and not be able to tell where it ends – it should be a smooth taper all the way along. Watch videos on making a Dyneema splice for examples.)

 

[teepot]

I use a pair of Kline Tools scissors. The blades have small teeth. I think they are for cutting wire. I've cut 2000lb Kevlar with them. Goes thru the lighter stuff easy.

 

[Greg Furtman]

I bought these to cutting Kevlar cord and cloth. They work great. Great for cutting fiberglass cloth too. The secret is the serrated blades.

https://www.amazon.com/gp/product/B000VYOISU/ref=ppx_yo_dt_b_asin_title_o08_s01?ie=UTF8&th=1

 

[John Kemker]

These are arriving today.

 

[bjphoenix]

On a side note, I landed a Doorknob on high voltage lines. The electric company just happen to drive by and see it. By the time I got there, they were already setting up. They attached a knife to the end of a pole to try and cut the shock cord. I told them it wouldn’t work because it’s Kevlar. They tried anyways and quickly gave up. They were able to flip the rocket over and landed on the low voltage line which they could grab with gloves. Out of spite, they then dropped it to the ground to see if the chute works. It didn’t.

At a recent launch somebody landed on the lines along the field. The power company came out and messed around for a long time with a long pole trying to flip the payload bay over the line. They finally rigged up the truck, donned the gear and raised the bucket. I asked them if they would like to tape a knife to the end of the pole. They said the pole already had one but they didn't even seem to be trying to cut the cord.

 

[MClark]

Years ago when we launched north of Flagstaff a rocket was hung in the huge power lines. Crew came out with “The Condor Truck" and got it down.
We let them push the button on a few rockets, sandwiches and drink all around and magically we didn’t have to pay to have them come out. Boss man gave us his card to call him directly and keep management out if we did it again.

 

[OZRoc]

I tape the end and use a sharp X-Acto blade.

+1