The process starts with a bar of steel which the bladesmith "Nai Tao" collects form many sources.Sometimes,they'll combine a legendary iron called "Lek Nampee" which is very rare today,Furthermore,they claim that a sword with Lek Nampee is extremely excellent blade.Master Sakorn Asaisuk said "The good blade must be made of Leek Nampee.But,if you want to cut a nail,the sword made of general steel can also cut it easily"(In Thailand,the swordsmiths usually used a nail as a target for cutting test of a sword).
Another material which they combine in the ancient weapons is "Lek Lai".This material is quite mysterious,magical and find much rarer than Lek Nampee.Some said Lek Lai can melt,when it is burned with only candle.

After Nai Tao cut the prepaid steel into a desired shape,he'll heat the steel in the forge.Next,Nai Tao will use a pliers to grip heated steel over the anvil all the time,and lets his 3 assistants"Kontee Panern" hammer into roughly shaped blade.This process is called"Larb Lek".
When Nai Tao get a shape blade.He cleave the edge side of the blade to embed harder steel which is called "Lek Kla",and Kontee Panern will hammer it until the steel is welded enough,then Nai Tao will heat steel to the verge of melting and hammer again quickly to make 2 kinds of steel welded tightly.This process is called "Merg Lek".

After that,the blade is adjusted with a hammer.This process is "Tee Tang".The process that comes after is called "Koon Meet" in which the blade is forged further, last process is "Sum Meet" or "Fork Lek" in which the blade is shaped into the final shape with a small hammer,and Nai Tao will leave the blade until it's cold.

The later process is "Tee Kent".Nai Tao takes a cooled blade and adjust it carefully with a small hammer until the blade is flat.The adjustment with a hammer in this process is called "Lam Riab" or "Hai".AfterNai Tao finish Tee Kent,he will apply the blade with a special liquid made from cjay.This liquid is called "Kee Tom Gaur".

The most important process is "Karn Shoup Lek".The process starts with adjusting the temperature in the forge.The sword blade is heated at the optimum temperature depends on each smith's tech Especially,only the edge of the blade must be heated until it's red,and then quench in water smoothly.Master Sakorn said"The blade is good or not ,it depends on the type of steel,but the heart of making blade is Karn Shoup Lek which requires much experience of the smith".

After Karn Shoup Lek,the blade is sharpened by the bladesmith with rough and fine whetstone.During this process,the smith whitens the blade by the coconut husk.Then he make a handle and scarbbard.For the handle ,the smith said when he put the tang into prepared handle,he will use special liquid made from vinegar to prevent loose tang. 

source :http://www.muaythaionline.org/disciplines/sword.html