Symmetric Casing

The Symmetric Casing Drilling System consists of three parts: central pilot bit, casing shoe and symmetrical ring bit. The central pilot bit drills away the center part of the hole and guides the drill string, incorporated with a sacrificable symmetrical ring bit make a full face drill bit. The casing shoe is welded or threaded to a casing pipe, which is pulled down by the impact of the DTH hammer and central pilot bit. The symmetrical ring bit and casing shoe assembly is locked into central pilot bit with a hammer shank, and the ring bit is to drill the segment the casing to advance down the hole. The pilot bit’s upper shoulder engages the shoulder of the casing shoe. DTH hammer’s impact energy is transferred through the pilot and ring bits, crushing rock, part of impact energy advances casing. On completion of drilling and casing, the drill string with pilot bit is retrieved by a slight reverse rotation to unlock the bayonet coupling. The ring bit stays in the hole, and can be recovered only if the casing is retrieved. Drilling continues to the desired depth in the bedrock using a conventional drilling.

Drilling through loose, unconsolidated material such as soil, clay, silt, sand, gravel, and boulders is the so-called overburden, which is often problematic due to the tendency of the earth to cave in behind the drill bit. The Symmetric Casing Drilling System is just to drill in rock formation where contains some such ovals and fractures, and it represents the latest technology in simultaneous overburden casing drilling systems.

Superdrill  Symmetric Casing Drilling System is designed to drill holes of many sizes, ranging from 108 to 863mm (4 1/4 to 34 in), at any angle (including horizontal), to any depth (beyond 100 meters) through unconsolidated formations simultaneously with casing. The internal flushing grooves together with the built-in casing shoes gives a good seal to the button of the drilling hole, and thus minimizing the disruption of the surrounding of the drill hole. It makes the casing follow easy and the equipment and operation simple, and is recommended to a multitude of applications, such as micro-piling, underpinning, anchoring, marine work and horizontal drilling etc..

Symmetric Casing Drilling System Features and Advantages:

Stable and reliable working performance

Full face head design for faster penetration and straighter hole

Less torque is required than eccentric drilling

Can drill in vertical, horizontal or any direction

Minimize disruption to the drilled hole

Effective cuttings removal

Unlocking-relocking easily

Easy to operate and system security

Varied ring bit diameters to suit different casing requirement

The less vibration of drill rig

Casing Tube OD		Ring Bit OD		Min. Casing Shoe ID		Pilot Bit Diameter		Hammer Shank Style
mm	inch	mm	inch	mm	inch	mm	inch
108~127	4 1/4 ~ 5	118~134	4 5/8 ~ 5 1/4	78~101	3 1/16 ~ 4	77~92	3 1/32 ~	DHD3.5, Cop34, Mission 30
							3 5/8
140~146	5 1/2 ~	150 ~156	5 27/64 ~	94~117	3 45/64 ~	105~124	4 1/8 ~	DHD340A, SD4, QL40, Mission40
	5 3/4		6 1/8		4 5/8		4 57/64
168~178	6 5/8 ~ 7	178~195	7 ~ 7 5/8	121~150	4 3/4 ~ 5 7/8	125~156	4 59/64 ~	DHD350R, SD5, QL50, Mission50
							6  9/64
194~219	7 5/8 ~	203~234	8 ~ 9 1/4	148~190	5 5/8 ~	150~203	5 7/8 ~ 8	DHD360, SD6, QL60, Mission60
	8 5/8				7 1/2
219~325	8 5/8 ~	235~348	9 1/4 ~	190~284	7 1/2 ~	165~306	6 1/2 ~	DHD380, QL80, SD8, Mission 80
	12 3/4		13 11/16		11  3/16		12  3/64
244~406	9 5/8 ~16	273~440	10 3/4 ~	210~364	8 1/4 ~	190~340	7 1/2 ~	SD10, Numa100
			17  5/16		14  5/16		13 25/64
406~558	16 ~ 22	419~590	16 1/2 ~	328~514	12 27/32 ~	340~440	13 25/64 ~	SD12, DHD112, Numa120, Numa125
			23 1/4		20 1/4		17 3/8
508~762	20 ~ 30	526 ~798	20 45/64 ~	412~716	16 1/4 ~	470~685	18 1/2 ~	SUP205
			31  7/16		28  3/16		26 31/32
609~762	24 ~ 30	637~798	25 ~	513~716	20 3/16 ~	540~685	21 1/4 ~	SUP245
			31  7/16		28  3/16		26 31/32
863	34	900	35  7/16	815	32  3/32	785	30 27/32	SUP325

How to order?

Casing Tube Out Diameter & Inner Diameter + Ring Bit Diameter + Hammer Shank Style + Pilot Bit Diameter