Assuming the drilling is done by a professional with at least five years of experience.

An Easy Way

1. Upgrade the machinery. (Upgrade from a 1.5-metric-ton class drilling rig to a 2.5-metric-ton class drilling rig.)
　　　　Drilling Power (Machine Power) – It really gets the job done!

2. Change the bit. (If it’s too hard, switch to a softer bit; if it’s too soft, switch to a harder bit.)
　　　　If you're not sure, go with the double conical for now.

3. Increase the pump size (increase the volume of drilling fluid)
　　　　Pumps that are easy to use for standard drilling include the MG-5 through MG-10 (with inverter).

4. Try using compressed air. (About 50 horsepower is sufficient.)

Things to Try (For Advanced Users) *This is too difficult for beginners.

1. Cementing Drilling (Mixing cement into the drilling fluid)
　　(Washing Instructions for Each Area)

2. Mud-water drilling (using mud as the drilling fluid)
　　(Do not use from the attachment section; ensure the hole is thoroughly cleaned)

3. Super Coat Drilling (Add a small amount of Super Coat to the drilling fluid)
　　(Borehole cleaning and borehole wall cleaning are essential)