Torque specs table out there for wire..
questionma1 | Posted in General Discussion on
..rope clips? At least give me a 80% efficiency factor if you can.I need the following specifications;
Diameter, and spacing of clips per inch or mm so I can end up with the recommended 6 times the weight vs. connection torque to be applied to such fasteners. How do I find out the stress factor?
Also I was wondering about the differences between single sling basket hitch’s vs. endless ones. what is a toggle hitch? Thank you in advance. QM
Replies
WTF?
Please rephrase the question in some sort of proper English, and I will try to answer when I figure out WTF you are trying to ask.
An example - for a 26mm diameter wire rope figure on 5 clips spaced 175mm apart, torgued to 25 kg.m and don't saddle a dead horse.
But we don't know your real question - what is the rope holding up? What is it's size, what is it's construction. You're asking about stress factor, sounds like a student engineer to me!
Most rigging books will the number and req'd torque for wire rope clips. But efficiently? In most circumstances overhead rigging is rated with a five to one safety factor, that being said, the original question is still gibberish.
I was looking for a table that gives recommendations for safe maximum assemblies of wire rope, aka "airplane cable". The breaking strengths for the different diameters per weight factor, as well as, torque spec's for the clips to also space them correctly to prevent any slipping or snapping in the crimped areas. I really don't want to go by "yea that looks like it will hold" scenario and have these graphic headers fall down after 2 weeks. Just asking!
Why do designers love to draw things on paper that float in the air ;) QM
aka "airplane cable".
I usually don't post over here, but the previous responses indicate your lack of basic knowledge which can get you into trouble --- better be carefull with your cable application and read some of the manufactureres application notes on various web pages - no I won't do the research for you!
BTW 'airplane' cables do NOT use clips, they use swaged fittings!
I was merely putting it into understandable lingo dude , chill. This has everything to do with Fine woodworking and I disagree with whomever on this board thinks it doesn't. Can anyone here honestly say that hoisting equipment, haulage ropes, wire rope, guys, derricks, various tackle riggings are what you use to move your pieces and secure them properly- isn't a part of Fine Wood working also?
Swaged fittings..?, Would that be crimped or bolted ;) Happy New Year dudes and dudettes.! _/ _/ _/ -/ /
I disagree with whomever on this board thinks it doesn't.
Whoever.
QM
I'm feeling generous. In the context of the loads a furniture maker might encounter:
14mm nylon rope has a mean breaking strength (MBS) of about 3100kg, 14mm polyester rope has a MBS of about 2700kg.some strength reduction factors (SRF) - sharp bends (say < 50 times the rope's diameter) 0.7, knots 0.7, age 0.5 (old) to 0.9 (near new)factor of safety = 6 yes, this is a fudge factor - and no I wont expand on how it is determined. A first principles analysis of a lifting arrangement may allow a lower FoS.
Standard Working Load (SWL) = (MBS/FoS) x SRF1 x SRF2 x SRF3, etc
so for a 14mm nylon rope passing arround a beam and tied to a loadSWL = (3100/6) x 0.7 (sharp bend) X 0.7 (knots) x 0.9 (assume near new rope) = say 230 kg (or about 500 lbs)
If steel wire rope is used similar calculations apply but the SWL depends upon the construction of the rope.
To give you more detailed examples and/or strength data would breach copyright on the rigging data I'm referencing. If your aim is to use as little rope and tackle as possible to achieve a particular lift you'll have to get your own rigging reference and do the necessary calcs.
"This has everything to do with Fine woodworking"
Barely applicable. Nylon straps are the preferred way of all the woodworkers I know to secure furniture. I work for a timber framing company where trusses are easily 2,000 lbs and up. Sure the crane uses cable but poly rope slings are what we use to lift them without damaging them and nylon straps to secure them to flat bed trailers.
Your question has little to do with lifting furniture and more with rigging so a furniture forum isn't the most appropriate place for a wealth of information. Fine Homebuilding would be more likely but even there isn't the best source for your question. For example if a saw tips over and crushes your foot do you go to a woodworking forum because a saw was involved or a doctor?
Alright, alright I admit the question should have been researched a little more by myself, and posted in a more appropriate forum. But understand that I build exhibits and use many different types of materials, although millwork is my main backround. When I log on I go straight for this forum to pick up tips and keep my eye out for tools and machinery. I will keep my future questions in the applicable forums. The straps are great and are used for moving antiques, artifacts, and fine wooden items. Along with blankets and build up pieces they are probably the safest that I have seen. Thanks Rick!
Ian, I will print your information out and look at a little later thanks.
Chester, how are you doing this New Year!
Edited 1/1/2003 1:07:55 PM ET by QuestionMan
OK, now you have provided a bit of detail on the application you will probably find that aesthetics is more important than strength. As an example, at one time I sailed a 16ft catermaran. The main rigging on the mast was a single 5/16 stainless steel wire rope (rated at 2 tonnes) and the trapeze wire was 1/8 stainless rated at about 1/2 tonne. Both ropes were multi-strand multi-lay construction, something like 7 lays with 21 wires in each. As a stress wire within a furniture piece - say cross bracing for a book case (Ikea has/had an example) - either would be suitable visually, but the resulting stress in the wire would be way below the SWL. A steel wire brace in a furniture piece that was working close to SWL would be << 1mm diameter - to my eye this would be far too thin !
What kind of question is that in a furniture making forum? You should be contacting a wire rope manufacturer. They have specs on what the different types of cables are rated for and could point you in the right direction. Almost makes more sense to ask the question in Treads...barely!
While I cant answer your question you should try Hanes Supply Co. in Buffalo NY. They specialize in all types of rigging and wire rope. It's a very big and great company to do business with. Bob
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