Making your own climbing harness??

[Moondog55]

Any-one here done it?/

I have a roll of 32mm Polyester webbing here and I was thinking of running up a riggers belt, using a small seat belt 3-bar buckle from an old set of racing harness.
Can any-one tell me how many rows of stitching I need to get the correct 1400 Kg rating using M40 or M20 bonded nylon thread?/
I have reels of both here made by Venus, but I am having trouble finding the tensile strength of the thread.

My stitching is good and I have never had a sling break so I think I can handle the technicalities for my own use, NOT for sale or use by others

[Son of a Beach]

I made my own harnesses when I first started out using seat belts from a car wrecker. No stitching though, just the classic single loop tied with a figure 8, passed around the back and through the legs and joined with the carabiner.

Not much help I guess, but they lasted well even for youth group abseiling days down into one of the cave sink holes near Caveside. I don't think that sort of thing would be permitted these days.

[Bush Walker]

[quote="Son of a Beach"]I made my own harnesses when I first started out using seat belts from a car wrecker. No stitching though, just the classic single loop tied with a figure 8, passed around the back and through the legs and joined with the carabiner.[ /quote]

I took some a simple tape harness for use by some less confident members of my group in the Western Arthurs last time I was there. The harness is recommended as being lightweight and suitable for climbing down a steep slope, possibly wearing a medium weight pack, but is not designed for use where there is a high risk of fall as the webbing is too narrow to be comfortable in a fall and could possibly cause body damage. If you are going to wear a pack then an additional chest harness is necessary in case you tip upside down and fall out .

It works with a simple prusik knot on the main rope, with the other end attached to the karabiner

The components are

karabiners x 1 ($13.76)
25 mm tape 3m ( chest harness) + 3m (waist harness) ($9.36)
1 x 2m 7 mm cord for prusik attachment to 11mm rope ($3.44)

Prices from 2005

[durks]

Can any-one tell me how many rows of stitching I need to get the correct 1400 Kg rating using M40 or M20 bonded nylon thread?/
I have reels of both here made by Venus, but I am having trouble finding the tensile strength of the thread.

Sounds interesting. I've never done it but, if I were thinking about it, I'd probably email DMM or Troll or similar for some (informal and non-binding!) advice.

Googling around just now, I found a document at saumavel.com/Portals/5/Baeklingar%20tvinni/Coats-nylbond.pdf which gives the average strength of Coats bonded nylon M40 as 4.3kg, and M20 as 8.6kg. So maybe that helps.

Good luck. My mate made his own micro-wires once - I think we were all too scared to use them!

[michael_p]

Tie your own:
http://www.animatedknots.com/harness/index.php?Categ=rescue&LogoImage=LogoGrog.jpg&Website=www.animatedknots.com

[Moondog55]

Oh I've tied Dulfers and nappy slings often, and I carry a sewn tape loop for backup. I always have a krab or two on me. I just considered $90- for a riggers belt (Plus postage of course ) over the top.

I searched all over, a quick back of envelope tells me I need "X" times 8.6 = 1400, but the quoted figures for the strength of the thread do not say under which test conditions the breaking strength is derived from.
M-40 has a breaking strength of 4.8kg
M-20 9kg
M-13 14kg

My machine will handle M20 but the heavier thread wont feed.
32mm webbing is rated at 1400kg because it is thicker than usual for this width.

Years ago I was told by a parachute harness maker that the web is what gives the strength, not the stitching, but other makers of safety harness always say the stitching is stronger than the webbing.

My old climbing harness (Whillens) used a flag tack on major stress points and was sewn with M-13 but unbonded thread.

With a stitch length of 3mm and the assumption that each stitch of M20 holds 9kg then 32/3=10 stitches, so a basic flag tack using double stitching at the end and a diagonal of 50 stitches; 150 stitches at 9kg = 1350kg I think I am in the right ballpark.
At least I think so

[tele-whippet]

Any-one here done it?/

I have a roll of 32mm Polyester webbing here and I was thinking of running up a riggers belt, using a small seat belt 3-bar buckle from an old set of racing harness.
Can any-one tell me how many rows of stitching I need to get the correct 1400 Kg rating using M40 or M20 bonded nylon thread?/
I have reels of both here made by Venus, but I am having trouble finding the tensile strength of the thread.

My stitching is good and I have never had a sling break so I think I can handle the technicalities for my own use, NOT for sale or use by others

Harnesses are made from nylon NOT polyester which is REALLY weak and totally not abrasion resistant.
Don't do it with polyester----you may DIE, IMO

[ollster]

Any-one here done it?

Unless you're absolutely sure you know what you're doing... why would you? And if you were sure, you wouldn't need to ask.

Harnesses are cheap. You can get a reasonable harness for ~$100, very nice harnesses for $200. Climbing is not a place to penny pinch or experiment.

[Bush Walker]

Tie your own:
http://www.animatedknots.com/harness/index.php?Categ=rescue&LogoImage=LogoGrog.jpg&Website=www.animatedknots.com

The sit harness I used was a Dulfer and that went with a Parisian Baudrier chest harness, which have been around for "centuries"

The reason I would make such a harness is that it is much lighter and less bulky than a commercial harness and is suitable for occasional use.

[ninjapuppet]

moondog55 has big b*&%s and is a very brave man.
its good to get into the spirit of DIY, but personally, i wouldnt risk it either if i was a climber.

I saw these climbers even throwing away set of ropes that looked pretty good because they were 2 years old so it appears that the sport of climbing involves throwing away goods past their use by date even though they look perfectly good to a non-climber like me.

My Seatbelts got replaced after a bad accident, and I threw away a $900 perfectly looking motorbike helmet after a little accident so I'm a little risk averse when it comes to these things. maybe its just me though.

[Moondog55]

Wrong, polyester IS the harness tape of preference, because it has no stretch, when it is adjusted it stays adjusted.
Racing cars use polyester seatbelt webbing as well as nylon. In climbing it is the rope that stretches to absorb shock.
Back in the day we used to make our own gear and not worry, if it failed we only injured ourselves so we made sure it was made right, I think this approach is OK but it leads to massive overbuilding and increased weight.

[climberman]

http://www.camp-usa.com/products/harnesses/alp-95.asp

95 grams, around US$50. Tested, rated, scrunches up to a small apples size.

[climberman]

Wrong, polyester IS the harness tape of preference, because it has no stretch, when it is adjusted it stays adjusted.
Racing cars use polyester seatbelt webbing as well as nylon. In climbing it is the rope that stretches to absorb shock.
Back in the day we used to make our own gear and not worry, if it failed we only injured ourselves so we made sure it was made right, I think this approach is OK but it leads to massive overbuilding and increased weight.

Back in the day T-W used to make equipment as well, commercially, he's just too polite to say so. The day wasn't too long ago either.

[Bush Walker]

http://www.camp-usa.com/products/harnesses/alp-95.asp

95 grams, around US$50. Tested, rated, scrunches up to a small apples size.

Thanks for the suggestion.

At 95 g I think this is a better alternative than the self made tape harnesses in term of comfort, safety and most likely lighter. Can you buy it in Australia?

[Moondog55]

TW may have made gear but the blanket ejection of polyester webbing for riggers belts is simply wrong, most fall harness is made from polyester tape and/or webbing.

TW may have thought I was referring to polypropylene tape which is unsuitable.
If I wanted a full harness I'd try and find an old style Chouinard "Alpine Bod" style harness.

[Son of a Beach]

moondog55 has big b*&%s and is a very brave man.
its good to get into the spirit of DIY, but personally, i wouldnt risk it either if i was a climber.

I saw these climbers even throwing away set of ropes that looked pretty good because they were 2 years old so it appears that the sport of climbing involves throwing away goods past their use by date even though they look perfectly good to a non-climber like me.

My Seatbelts got replaced after a bad accident, and I threw away a $900 perfectly looking motorbike helmet after a little accident so I'm a little risk averse when it comes to these things. maybe its just me though.

Yep, I still have two climbing ropes somewhere, but if I ever start climbing again, I won't be using them, even thought they appear to be perfectly fine. I'd be buying new ones (and new harnesses/carabiners too).

I've also disposed of a motorbike helmet that was merely dropped onto carpet and got a tiny chip flaked off on the surface. Very expensive exercise that.

But I was still happy to go climbing in my home made seat-belt harnesses. They weren't terribly comfortable, but did the job until I could afford a proper one.

[Orion]

Wrong, polyester IS the harness tape of preference, because it has no stretch, when it is adjusted it stays adjusted.
Racing cars use polyester seatbelt webbing as well as nylon. In climbing it is the rope that stretches to absorb shock.

Both nylon and polyester webbing are used in commercially made climbing harnesses. Any failure to stay adjusted is going to be due to buckle slip, not stretch.

Back in the day we used to make our own gear and not worry, if it failed we only injured ourselves so we made sure it was made right, I think this approach is OK but it leads to massive overbuilding and increased weight.

But you're asking pretty basic sewing questions on the internet.

[Moondog55]

I wouldn't use an old rope for climbing either, but a rope has a long working life unless fallen on, good rope should last 4-5 years, mine got retired and now are used as snatch straps for the 4X4.

Lets please not get into an argument about the rights and wrongs of making our own gear, that is a decision we each have to make for ourselves and I'm happy to trust my life to stuff I make.

If anybody wants some Troll SupaTape I am happy to send them some, I still have a few dozen meters left.

I used to test my climbing slings by putting them on a rail and loading them until they broke, totally unscientific but it satisfied me and after reading the Mamutt catalogue in the 70s I realised that most gear is totally over the top anyway, only the rope needs to be really strong and stretchy and I dropped from 12.5mm dynamic to 11 and if I was buying no I'd go as small as possible to save weight and money.

If I had the money I'd buy, I'm broke but I have the materiel here so I may as well use it up, I cant sell it as I don't have an ISO paper trail to give to the purchaser.

[Moondog55]

Hi orion, I'm not asking a basic sewing question at all, what I asked is a direct query on determining the strength of a row of stitching by calculation.

If I still had access to a bar-tack machine I'd be using that as a 20mm straight bartack using M-40 is good for 50Kg WLL

[tele-whippet]

Moondog55, yes my bad, polyester webbing can be used for harnesses, IF it is rated appropriately, if not its not just bad but very bad.
Polypropylene defintely not.
BD Alpine Bod harnesses are made from appropriately rated nylon webbing.

[Moondog55]

This is polyester webbing specifically woven for safety harness by AWI in Reservoir, I got a roll as a sample when the mill moved to Dandenong in 2006, I was using it for shoulder straps on day packs but it was way overkill, and I have about 20 meters left.
AWI was the owner ( In Australia ) of the Troll Safety Equipment business and produced among other things fall harness for industry so "Yes!" the webbing is rated.

[Bush Walker]

http://www.camp-usa.com/products/harnesses/alp-95.asp

95 grams, around US$50. Tested, rated, scrunches up to a small apples size.

I've been told by someone who owns one of these and uses it regularly in their emergency kit, that fitting is quite difficult, leg loops seem smaller than waist, and while marginally better than 25 mm tape, they would be very uncomfortable in a lead or crevasse fall

[climberman]

Mine is OK. I wouldn't swap leads all day with falls on rock in it. But I would use it as an occasional harness where the risk of fall was low but the consequence high !

I bought mine second-hand, yet hardly used (maybe not at all, stil had the tags on).

[Bush Walker]

I bought mine second-hand, yet hardly used (maybe not at all, stil had the tags on).

Do you know if they are available in Australia?

[climberman]

I bought mine second-hand, yet hardly used (maybe not at all, stil had the tags on).

Do you know if they are available in Australia?

There is very limited CAMP gear in Oz. I've never got a response from their main website or the US one on who distributes in Oz.

No ideas if avail in Oz. Mine was in Oz, but as I said, s/hand.

[Orion]

Moondog, I don't mean to be overly critical. It's just that this likely falls under the category of "if you need to ask...", especially on an internet forum. It's a red flag that suggests you may not know what you're doing.

As a first approximation one can just multiply number of stitches times two (two threads per stitch) times the tensile strength of the thread, minus a safety factor. The tensile strength of bonded nylon M40 (about 50 N) can be looked up fairly easily.

How will you validate your work? Just saying that you've never had a sling break says little about their breaking strengths.

And where did you get the 1400 kg rating? Is that an Australian standard? CEN specifies 15 kN for climbing sit harnesses.

[Moondog55]

It is a static rating and is actually 1445kg which while slightly lower than 15kn is close enough for a riggers belt which after all is a "Back-up" not the primary.
As I said earlier I never made my slings for sale so never had to have them tested by machine; but I tested the first couple by hanging them off a beam and loading them until they failed. If the sling broke before my stitching I was satisfied.
Thanx for the clarification on the stitching BTW, I was unsure whether you could use the thread on both sides of a lock-stitch, so that effectively doubles the strength of a line of stitching.
Back in the 70s there was so little gear available in Australia that most people I know used tied slings, I got tired of the knot catching on rough Alice Springs rock so I started to make my own, back then we all made our own gear slings and racks, I even sewed my own etriers rather than tie them.

[Orion]

The CEN standard is also a static pull. True, the difference between 15 kN and 1445 kg is not much, especially since you will not be able to determine breaking strength to that level of accuracy. I was just curious where the number came from.

The book "On Rope" devotes some space to sewing your own climbing gear. The authors state that for a zig-zag stitch one should expect a strength of 1.8X (instead of 2X). Craig Connally's "Mountaineering Handbook" also discusses sewing your own slings.

I've sewn my own etriers and gear sling. I used a cheap home machine. But the expected loads are low and these are not life support items. A harness is in a different category, but you say that your homemade harness will not be a primary? Are you planning to wear a second harness or tied swami as well?

Back in the day I tied my own swami belt. But it isn't back in the day now. Are harnesses in Australia that expensive? Or is this just for the fun of it?

[Moondog55]

Not primary because my climbing days are well over, if I ever go back to serious mountaineering I'll buy some new gear.



Mainly just for the fun of it, but I have had one or two occasions in the last few years where I wished I had the ability to tie-in better.
A properly made riggers belt is lighter than 6M of 25mm tubular webbing and you always have it because it holds up your pants.
When I was taking my kids out I carried a full length of safety rope "Just in case" mainly for the kids mental peace of mind, and carried several sewn tape loops for use as Swami belts for the kids. I still have these and usually have one with me. A big D or pear krab always live on my shoulder strap, a habit I won't even try and break, always a screwgate in my survival kit/bumbag too
So if I use the combination of a riggers belt and a set of leg loops there is my harness, no different to the set-up I used when I started climbing in 1974.
Making my own gear is part of the enjoyment, also as I am recovering from a serious illness at the moment I am not yet fit enough to do much else except make and repair gear and prepare for the next trip

[Moondog55]

That 1445 kg is from AWIs own testing, they had to be compliant as they supplied and manufactured safety harness and seatbelt webbing for Safe&Sound and others.
As I said in an earlier post this is 32mm wide but much thicker than normal seatbelt webbing of similar width