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@ragnkja4 ай бұрын
Fun fact: the shape you get with the curve bow is not a circle arc, or even a parabola, but a catenary, which is the shape that minimises the forces of tension and compression, making it stronger than any comparable curve. Bonus fun fact: the domes of the Sagrada Familia were modelled upside down by hanging a lot of chains with weights attached at specific points to represent additional loads on the structure.
@RexKrueger4 ай бұрын
Wow! I had no idea. Thank you for an actually helpful comment!
@patrickstrasser-mikhail68734 ай бұрын
Fun fact corrected: What you get is a sinus, the solution to the Eulerian Column Buckling problem with two free ends, with beding stress over the whole length. The catenary is what you get when you hang a rope or chain, with weight pulling in one direction (presumably down). If you need a circle, also a string with two loops at the end, a pin, and a pencil will do.
@vittocrazi4 ай бұрын
Your comment IS cool. But the part about the pin and thread i dont like, because its actually pretty hard to keep the pen properly aligned😊@@patrickstrasser-mikhail6873
@ragnkja4 ай бұрын
@@patrickstrasser-mikhail6873 Thanks, I didn’t know they were different, since the catenary is also the strongest shape an arch can have because in that case it minimises the forces of compression. In any case, the shape this bow naturally “wants” to take is inherently a strong one.
@Maker_of_Things4 ай бұрын
I remember explaining this to a funiture design student when I was still teaching. He couldn't work out where the centre of the circle would be for the curve he drew with a bow! I had to show him the flattened ends of the bow curve to explain how the radii changed the further you got from the centre of the bow curve. Important to know if you want an arc, or just an aesthetically pleasing curve. There is a model at the Segrada Familia with weights and strings showing that upside down design process.
@wyssmaster4 ай бұрын
"[This antique compass] may be hard to find" Not true! I know exactly where one is. Now if I could just convince you to sell it...
@davidbroadfoot18644 ай бұрын
Theft is an option.
@samuelmellars78554 ай бұрын
@@davidbroadfoot1864 Strategically Transfer Equipment (to) Another Location
@MK-lh3xdАй бұрын
@@davidbroadfoot1864You mean borrowing for a little while like 20 years? You guys know better than to steal.
@derbestimmer1148Күн бұрын
You can build that circle out of wood.
@notreallymyname37364 ай бұрын
I know it's more for small curves, but there's also the classic "grab whatever round container you can find and fudge it a little bit" method. Half the curves I saw my dad lay out were done with a 5 gallon bucket, a sour cream tub, a coffee cup, or a Copenhagen can.
@zwicker55854 ай бұрын
A string and small nail also works great for any size!
@mthielssalvo4 ай бұрын
i thought from the thumbnail that you were just going to use the string to draw a circular arc (by pinning one end to the tabletop & tying the pencil at the other). the curve bow is neat but because it relies on tension it doesn't generate a circular curve but a catenary curve.
@bakerzermatt4 ай бұрын
Those are two different tools to draw two different shapes. Both shapes are useful, but those tools aren't at all interchangeable.
@louisvictor3473Ай бұрын
Not entirely interchangeable, but in practice often yes. Often you don't need a mathematically precise circle section as your curve, just a symmetric arc between two points and "about this wide", so the difference is non significant
@kalijasin12 күн бұрын
I’ve seen woodworkers and artists who can draw circles and half-circles freehand and near perfect. It’s some crazy stuff. 😮
@georgeb.wolffsohn304 ай бұрын
The curve bow creates a parabolic arc. The compass, a circular one.
@awoogagoogaloo28894 ай бұрын
Not parabolic catenary
@vincentroux15104 ай бұрын
The "antic compass" is actualy realy simple to make. Just need to pieces of wood, a bolt and nut, a nail to make the pin and a piece of tape to hold the pencil. Even the roughest build will do a perfect job.
@spitandprayers4 ай бұрын
Nice, I just used a slim cut-off the other day to make a curve, but had to have someone hold the ends while I traced. The introduction of the string is genius!
@kevinbunting8263 ай бұрын
Thanks. Used this to layout the knees for timber frame
@theromanorder4 ай бұрын
One trick i was taught but usual fail to do, is get a pice of sting the length of your wood, fold it in hafe and hopd it at the center, use your grathit stick at the end of the string and just turn it around
@vinnycruise4 ай бұрын
How has this alluded me I was just needing it too. Thanks
@richardseed82533 ай бұрын
It's a pair of Compasses A compass is for direction finding.
@WiFiJeremy4 ай бұрын
Hey, This is super usable, easy, and NEAT. Thanks
@jeffantonio1627Ай бұрын
you could always use string and something to hold pressure on the centerline of your desired circle
@arloames45173 ай бұрын
The curve you get is a cubic. y= ax^3+bx^2+cx+d. Curves drawn for airplane design were drawn using long thin slats of wood, held in place using weights, called ducks. You can use any number of ducks aling the length, and you get a different cubic curve in each segment. Please, the curve isn't a catenary, which is a solution where force (usually gravity) is applied uniformly along the curve. The cubic is a result of force applied at discrete points, resulting in the cubic curve. B-splines and Bezier curves are different formulations expressing such curves.
@arloames45173 ай бұрын
en.wikipedia.org/wiki/Flat_spline
@arloames45172 ай бұрын
The slats of wood were called splines. Same nomenclature is used for the mathematical ones, also called splines.
@realcolby2 ай бұрын
This isn’t a catenary or a cubic. An immediate tell should be that cubic equations are not symmetric while this curve is. If you look at the differential equations the solution is actually a half-sinusoid. Look into buckling theory if you’re interested.
@erikjones6970Ай бұрын
Just drill a couple holes in a measuring tape and lock it in place with a nail or screw. Works for any size circle.
@Papa-in-Tx4 ай бұрын
You could take that same piece of wood, drill a small hole near one end, and another one at the radius distance from the first hole. Drive a small nail through the first hole and into the wood, and use a pencil in the other hole to draw the circle.
@artimesbabai4 ай бұрын
OH I love you for this You made my life so easy
@garydargan64 ай бұрын
Instead of using knots use a spring-loaded toggle like the ones used to adjust a hoodie. Bend the wood to get the curve you want then lock it in with the toggle.
@kimberlydrennon49824 ай бұрын
I'd be interested in a video about making a beam compass
@pettere84294 ай бұрын
Quick and dirty beam compass: take a sufficiently long piece of scrap wood, a nail and whatever you wish to mark with, predrill for the nail and scribe/pen, and you are done. Even lazier: nail or pin needle, string and whatever to mark with.
@mohamedzaghlool4164 ай бұрын
I use metal 1 meter ruler, by length it's flexible and dependable
@jamiesprout27104 ай бұрын
I made one of those and have been using it for years. Never knew it was actually a thing lol.
@varno4 ай бұрын
Most nicer drafting or mathematics compass kits come with a beam extension which gets you to about 45cm radius. These can be had pretty inexpensively.
@jaywalker5124 ай бұрын
For a circle I just hold one end of a string at the center and attach a pencil at the other end. Then you pull the string tight and draw the circular arc.
@markkieran10044 ай бұрын
I really would like to see you make a beam compass - contrasting woods, shiny brass screws and shinier steel points.
@shermanhofacker44284 ай бұрын
Might be a good idea to flip the bow and draw another line. If the lines are the same; perfect! If not split the difference!
@mrskateslipknot4 ай бұрын
100mm rip of 6mm ply makes this sort of thing really well
@graphzaal43984 ай бұрын
pencil, string and optional nail work like a charm for me, but shapes always needed a proto. the bow is a nice idea... will try
@davidgagnon28494 ай бұрын
The only thing wrong with a curvebow is if you use wood to make it, it may not be an accurate arc, as there are stronger and weaker sections of the wood and it won't bend consistently
@TomsBackyardWorkshop4 ай бұрын
The curve bow doesn't give you a constant or repeatable radius. Its more of a parabola.
@rottenmeat59344 ай бұрын
Apparently, it's a catenary and typically better for taking loads. As stated by @ragnkja
@bruceswanson28114 ай бұрын
Patternmakers called beam compasses "trammel points". They could be had to clamp on a stick; another version clamped on a ruler. The better ones had a thumbscrew fine adjustment. A big wooden compass is a fun project. A short bolt, two fender washers and wing nut locks the joint. The other ends can use sharpened nails to scratch a line. You can use adhesive tape and a sharpie or be a truer craftsman and rig up a pencil clamp.
@jameshaulenbeek59314 ай бұрын
A similar process is used in the railroad industry for determining if a truck frame (where the wheels are) is bent, twisted, or skewed. It's referred to as "tramming".
@marchess9233 ай бұрын
A beam compass is also known as "trammel points".
@sandytooks4 ай бұрын
I bought a beam compass and made an extension for it.
@mircomuntener46434 ай бұрын
Re: hard to find large compass: Get me a couple pieces of flat scrap about an inch or so wide, a foot or two ling, with a hole in one end, a bolt, couple washers, a wing nut, nail, pencil, and some tape.
@rottenmeat59344 ай бұрын
Hey! You ever used a gouge for chiseling out endgrain? Seems like it would be equivalent to a cambered edge, cutting the edges rather than wedging them out.
@LilyJaneH4 ай бұрын
My teacher always called the beam compass a set of trammel points, so that’s what I’ve always called them.
@WiFiJeremy4 ай бұрын
Rex - I'd like to see a video from you on Ticking Sticks. That seems like it'd be in your wheelhouse
@OctavMandru4 ай бұрын
How about the old string and nail?
@userpandr3 ай бұрын
Bro invented guitar...
@mitch.paulsen4 ай бұрын
I want to get into novice woodworking but i have no idea where to get wood! Where do i go? Near Minneapolis, MN in case anyone is local!
@CrazyCamo4 ай бұрын
Nice
@eus2ks4 ай бұрын
The Sumerians called. They want their tool back.
@parjau45544 ай бұрын
I have this huge Starrett divider/compass that I bought because it was just a lovely piece of formed metal. I'm forever trying to find uses for it so I don't feel guilty for spending all that money on it.
@jimcarter49294 ай бұрын
Just tie the same knot you use for tent stakes and tou can move it where ever you want, no problem.
@yourneurdivergentpiers34574 ай бұрын
Thats a pair of compasses, a compass points north. You're only a chippy though so I guess we can't expect much 🤷♀️👩🏭🔥.
@Helveteshit11 күн бұрын
Meanwhile, I would just take a nail, and scrap Wellpapp and do a hole for a pencil and do a circle xD
@martinpoulsen65644 ай бұрын
Well... probably not as lazy as some would like to think. It takes even straight grain, very even thickness and no knots to get the curve even, without certain sections bowing more than others.
@Tensquaremetreworkshop9 күн бұрын
They are call trammels. Where you get free string?
@Korhanne4 ай бұрын
now can you play rock lobster on one?
@aditya.khapre7 күн бұрын
Bro should learn geometry
@ianpearse44804 ай бұрын
How far does it shoot? LOL.
@7-ten4 ай бұрын
Are you a woodworking teacher?
@fnafplayer64473 ай бұрын
Take of all the rust on that compass. Let it shine
@chopshopchopper4 ай бұрын
Is that a radius, diameter, or a pry bar. lol
@Pierreisking4 ай бұрын
What species of wood can you use for this?
@rojirrim72984 ай бұрын
My guess is pretty much any, provided it's thin enough
@BohumirZamecnik4 ай бұрын
Flexible wood like ash may be a solid choice. It should not break.
@topcat59884 ай бұрын
I love this guy… My wife, not so much! Guess I watch too much…
@CandidZulu4 ай бұрын
I thought the whole thing was a trammel ...nope!
@richardallanhopkins26904 ай бұрын
Sweet ❤😂
@pinballrobbie4 ай бұрын
Don't use this method if you need a true arc for your project, otherwise its good.
@ivymoon50844 ай бұрын
What's the math to work out the angle of the curve?