Model JKQ key seat reamer is a downhole tool which is designed to destroy and finally eliminate the key seat formed on the borehole wall.It is connected above the drill collar, At its sliding sleeve surface,many carbide-cutting ridges are built-up by welding, which can ream the key seat effectively. 
Technical parameters and specifications 
 
| Type | 
O.D.  (mm) | 
I.D.  (mm) | 
Connection API 
  | 
O.D. of carbide blade(mm) | 
Stroke of sliding sleeve(mm) |  
| JKQ140 | 
121 | 
38 | 
NC38 | 
140 | 
251 |  
| JKQ187 | 
165 | 
57 | 
NC50 | 
187 | 
300 |  
| JKQ212 | 
465 | 
57 | 
NC50 | 
212 | 
360 |  
| JKQ212 | 
178 | 
57 | 
5 1/2FH | 
212 | 
360 |  
| JKQ308 | 
203 | 
71 | 
6 5/8REG | 
308 | 
400 |    |