Sunday 24 July 2011

Stainless-steel Tee Nuts (T-nuts), Matice od nehrdjajuceg zeljeza

Ovakve matice od nehrdjajuceg zeljeza (T-matica), ne znam gdje mozete kupiti u domovini. Svakako morate nabaviti slicne matice jer kako bi inace pricvrstili vezove za dasku?
Matice koje sam uspio dobaviti izgledaju ovako:

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T-nuts or similar are needed for the foot pads on our kite surfing board. This is the item I've got from the nearby shop:





Kao sto se moze vidjeti, matica na desnoj strani ima velike "trnove" koji prodiru duboko u drvo i time ucvrscuju maticu na mjesto. No, za ovaj projekt kite surf daske, trnovi su svakako preveliki i prosli bi kroz bambus sperplocu. Tako da sam jednostavno skratio trnove kao sto se vidi na lijevoj matici. Problem rezanja metala je taj sto je matica relativno mala i vijak koji vidite drzi maticu na mjestu, jer je ucvrscen stegom (nazalost, nemam puno alata pa se snalazim:).

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The T-nut has got quite long pins, like you can see on the right side. This pins will definitely go through the bamboo ply so I've needed to shorten all pins on all nuts, like on the left hand side one. The problem while doing it was that the T-nut is relatively small and the bolt is fixed in place with the clamp so the nut doesn't move while cutting the metal (I don't have a proper tools for everything:).





Iduci problem je duzina matice koja je prevelika i time bi virila iznad daske. Za taj sam dio koristio kuhinjsku dasku za rezanje:), par malih stegi i moj univerzalni uredjaj koj ima najvecu upotrebu po kuci dok "pilim" - Dremel. Kako vidite, za skratiti matice potrebno je malo inventivnosti jer to nikako ne zelite raditi "iz" ruke.
Dremel je ucvrscen sa par malih stegi, dok je desno na slici dascica ucrscena stegama koja "vodi" drugu dasku sa maticom na kraju. Tako da nista ne diram preblizu! Jos mi trebaju prsti...

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The next problem is T-nut height which is to high and would go over the board. For this task I used a kitchen board:), a few small clamps and my much loved Dremel tool. Like you can see, a little "work bench" is needed and the Dremel is fixed in place with some clamps, the cutting fence as well and the nut in place with the same bolt from the above. So, I do not go near with my fingers! Still need 10 tho...





Sve super...Zavrsen posao za "pet" minuta! 6 perfektnih matica, dvije za drsku, ostalo za vezove...

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All good and finished in "five" minutes! 6 perfect T-nuts, yes, I might put a handle...




Zasluzeni odmor, odoh na Bali...

I'm off to Bali...

Sunday 17 July 2011

Bambus kiteboard gornji sloj - Bamboo kiteboard top layer

Razmisljao sam koristiti dva sloja sperploce, "marine" tipa, da dobijem  krivulju rokera i konkave. No tada sam dobio sperplocu od babmusa 5mm debljine i odlucio ju iskoristiti. Bambus se moze lijepo "smirglati" brusnim papirom da dobijemo tanke krajeve. I vrlo je cvrst u jednome smjeru te se dobro savija. Izgleda da je sperploca "marine" tipa teska za savijanje i jos ce je biti teze savinuti u 3D smjeru (tri dimenzije).
A bambus? Sto da kazem?
Dvije su vrste bambus sperploce (ili bilo kojeg lijepljenog bambus proizvoda), horizontalno i vertikalno zalijepljeni. Za ovaj projekt izrade kiteborda, odlucio sam se za horizontalni, jer ce se savijati bolje po duzini daske (manje) i nesto manje po sirini daske od vertikalnog.
Receno mi je potpuno suprotno za vertikalno ljepljeni bambus (probao sam, previse je savitljiv).

Napravio sam probu! Zalijepio sam dva komada sperploce prije 10 dana (razlog kasnjenja novog clanka). Ovo je izmjereno od "sredine" konkave i iznosi 11 milimetara!
No, malo sam i iznenadjen! Sto se desilo: Nakon sto sam savinuo drvo i zalijepio, ostavio da se susi i nakon 24 sata otpustio stege, nije bilo konkave skoro uopce. Tako da sam zaboravio na to:)
No 7 dana kasnije pogledao sam ponovno - 11 mm konkava! Kako? Ako je bambus bio suh (da, mora se osusiti prije lijepljenja), mozda je pokupio vlagu i rasirio se? Kako ce to djelovati na dasku? Vidjeti cu.

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I was thinking to use two layers of marine plywood to get the rocker and concave nicely shaped. But than, I got some bamboo plywood 5mm thick and decided to use that instead. Bamboo can be sanded well to get the thinner board tips. It is very strong in one direction and will bend well. Looks like the marine plywood is hard to bend and it will be even more difficult to bend it in 3D (three dimensional).
But bamboo? What to say?
There are two versions of bamboo ply (or any glued bamboo product), horizontally and vertically glued. For this kiteboard project, I went with horizontally glued, since it will bend much better (less) with the board length and slightly less in the board width direction than vertically glued product.
I was told exactly the opposite for vertically glued bamboo (tried it myself, too flexible in my opinion).

Let's test it! I've glued two peaces of ply 10 days ago (hence the delay of this writing). This is measured from the "middle" of the concave and it's 11mm!
But, I'm confused. What happened is: I've shaped the concave when I glued this, left it to dry, and after 24hrs released all clamps. There was almost no concave at that time. So I left it and forgotten about it:)

7 days after, I've checked and there it is - 11 mm concave! How? Was the bamboo dry (yes, I did dry it), and now got the moisture and bent? How will this work on my kiteboard? Time will tell.


Gornji sloj daske od bambusa je ispiljen i spreman za brusni papir (kojime cu stanjiti vrh daske).
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The top bamboo layer is now cut and ready for sanding (to thin the tips).




I konacno, skoro svi dijelovi su spremni za vakumsku pumpu. Tema za iduci clanak...
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Any finally, I've got almost all parts for the vacuum pump. More about this some other time...