Compare Our Drilling Jar Models
Not sure which jars fits your well program? Match your drilling condition to a model below, then request a spec sheet for the exact tonnage and connection you need.
Mechanical Drilling Jars (Type JZ)
Best for: Standard wells, budget-conscious projects
Key advantage: Field-adjustable trip force, no hydraulic system to maintain
View JZ Specs
Full-Hydraulic Drilling Jar (Type QYⅢ)
Best for: Deep wells, HPHT conditions, precise tonnage control
Key advantage: Stepless up/down tonnage adjustment, rated to 180°C
View QYⅢ Specs
Hydro-Mechanical Drilling Jar
Best for: Wells needing both mechanical reliability and hydraulic precision
Key advantage: Double-acting design, combines both trigger mechanisms
Request Spec Sheet
Email: info@apidrillpipe.com
WhatsApp: +86 18615995257
Already know your BHA design and stuck-pipe scenario? Send us your well data and our engineers will recommend the right tonnage and stroke length.
API 7-1 Drilling Jars Dimensional & Performance Specification Chart
| Jar Outer Diameter (OD) | Tool Joint Connection (API) | Inner Diameter (ID) | Max. Operating Tensile Load | Max. Allowable Overpull | Upward Stroke Length | Downward Stroke Length | Recommended Operating Temperature |
| 3 1/2″ (88.9 mm) | NC26 (2 3/8″ IF) | 1.500″ | 180,000 lbs (800 kN) | 60,000 lbs | 18.5″ (470 mm) | 6.0″ (152 mm) | Up to $200^\circ\text{C}$ |
| 4 3/4″ (120.6 mm) | NC38 (3 1/2″ IF) | 2.250″ | 380,000 lbs (1,690 kN) | 120,000 lbs | 21.0″ (533 mm) | 7.0″ (178 mm) | Up to $200^\circ\text{C}$ |
| 6 1/2″ (165.1 mm) | NC50 (4 1/2″ IF) | 2.812″ | 750,000 lbs (3,336 kN) | 250,000 lbs | 24.0″ (610 mm) | 8.0″ (203 mm) | Up to $200^\circ\text{C}$ |
| 6 3/4″ (171.5 mm) | NC50 (4 1/2″ IF) | 2.812″ | 800,000 lbs (3,558 kN) | 270,000 lbs | 24.0″ (610 mm) | 8.0″ (203 mm) | Up to $200^\circ\text{C}$ |
| 8″ (203.2 mm) | 6 5/8″ REG | 3.000″ | 1,200,000 lbs (5,338 kN) | 380,000 lbs | 26.0″ (660 mm) | 9.0″ (228 mm) | Up to $200^\circ\text{C}$ |
| 9 1/2″ (241.3 mm) | 7 5/8″ REG | 3.500″ | 1,600,000 lbs (7,117 kN) | 500,000 lbs | 28.0″ (711 mm) | 10.0″ (254 mm) | Up to $200^\circ\text{C}$ |
Main Types of Drilling Jars
Hydraulic Drilling Jars
A hydraulic drilling jar uses an internal hydraulic delay or metering system before release.
During operation, controlled overpull or set-down weight allows energy to build in the drill string. The jar releases after the internal hydraulic sequence is completing.
Hydraulic jars may be selected when the drilling program requires:
Controlled release
Repeatable upward or downward jarring
Surface adjustment through applied load
Directional or horizontal drilling compatibility
Reduced dependence on a fixed mechanical trip setting
For quotation, provide the jar OD, bore, connection, action, stroke, expected operating load, mud system and temperature.
Mechanical Drilling Jar
A mechanical drilling jar uses a mechanical latch, detent, spring or release mechanism.
Depending on the design, the release setting may be adjusted before the tool is run.
Mechanical jars may be considered when the operator requires:
A defined mechanical release setting
Operation without hydraulic delay
Specific upward or downward action
Straightforward workshop maintenance
Replaceable latch, spring or release components
For quotation, provide the required release-load range, jar OD, connection, stroke, temperature and quantity.
Double-Acting Drilling Jars
A double-acting jar can deliver upward and downward impacts.
It may be selected when the recovery plan requires the ability to work the stuck point in either direction.
Confirm:Upward stroke,Downward stroke,Maximum upward operating load,Maximum downward operating load,Tool OD and bore,Connections,BHA position,Bottom-hole temperature.
Fishing Jar
A fishing jar is selecting for fishing and recovery operations rather than routine drilling BHA use.
Fishing and drilling jars may differ in:Tool placement,Stroke,Load range,Connections,Impact requirement,Use with accelerators or intensifiers,Operating procedure.
State clearly whether the tool is requiring for a drilling BHA or a fishing string.
Drilling Jars Usage and Maintenance Manual
Not sure which jar fits your well program? Match your drilling condition to a model below, then request a spec sheet for the exact tonnage and connection you need.
1. Preparation Running the Drilling Jar into the Hole
(1) The drilling jars shipped from the factory or sent to the well must pass ground tests and can be put into use only after passing the test.
(2) Check that the upper and lower jar spindles sit fully loose. Install the mandrel clamp on the exposed mandrel before handling the tool at the rig site. Remove the clamp only after the drilling jar has been made up into the drill string.
(3) When adjusting the shock force of the lower hammer, ensure that the adjusted shock force should not exceed the drill string mass above the jar drilling tool under any circumstances. How to adjust the shock force:
Remove the adjusting ring locking pin and adjust it on the test stand to the designed compression release force, that is, the shock tonnage. When the adjusting ring is turning in the increasing direction, in order to increase the shock force, each time the adjusting ring is turning one hole, the load changes by about 10~30kN. After adjustment, tighten the locking screw plug.
(4)Before running the drilling jar into the hole, check that the oil plugs sit tight and confirm the jar locks in the closed state.
2. Drilling jars and drilling operations
(1) Lift the prepared jar drilling onto the drill floor with a lifting sub-joint, apply sealing grease and connect it to the drill string. Lift the drilling tool and remove the clamp on the mandrel (Keep the clamp in a clean and safe place for future use.).
(2) Lower the drill string carefully while running in hole. Avoid sudden impacts, ledges or restrictions that may unintentionally activate the jar. — that kind of snag triggers an unplanned downstroke.
(3) If a downstroke happens, the upstroke device returns to its pre-shock state on its own. Lift the drill string slightly, If a downward jar is accidentally triggered, slowly pick up the drill string to reset the tool before continuing the operation, and pause the operation for a few minutes to let the upper hammer release. Don’t lift it hard or fast.
(4) During the process of drilling and tripping, Always position the tong dies on the designated wrench flats or tong areas specified by the manufacturer. After drilling, the jars drilling should be in the open state. After installing the mandrel clamp at the wellhead, After pulling out of hole, install the mandrel clamp before breaking out the drilling jar from the drill string. Never allow any clamping and lifting tools to be stuck in the open part of the mandrel to prevent damage to the mandrel.
(5) The jars drilling is always in the fully extending state during raising and lowering in the well.
(6) Once you’re done with the jar, clean the surface, coat the exposed mandrel with grease, and remove it from the drill floor carefully to avoid impact damage.
3.Normal drilling
(1) Drilling with the Jar in Tension.
Under tension, the jar stays open through the entire drilling run, and both mandrels stay stretched. The weight of the drill collar below the jar, the pump pressure on the mandrel, and the flush pipe and scraper sleeve on the striking parts all work together to keep the tool open. The jar performs best this way.
(2) Drilling with the Jar in Compression
You can also run the jar under compression, but keep the pressure on the tool below the pre-set jar tonnage. Reference Figure 7-7 to calculate the pump pressure load on the jar before you lower it into the well.
(3) When you pressurize the jar, the upper hammer may close. Lifting the drill string afterward can cause a slight upward shock from the weight of the string below.
(4) Regardless of whether the jar is drilling under tension or pressure, the drill must be fed evenly to prevent the drill from slipping or skipping.
(5) If you encounter a jam during the drilling process, you can activate the upper clicker to release the jam.
4. Freeing a Stuck Drill String
1). Upward Jarring
Lift the drill string to release the jar’s pressure. Lifting tonnage controls the jar’s shock intensity — start with a lower shock force and increase it gradually. Run several shocks at the same tonnage before adjusting further. Never push the shock force past the combined weight of the drill string above the jar and the upstroke device’s maximum release tonnage (see Table 7-2 for the maximum shock tonnage).
2) Downward Jarring
After jarring, lift the drill string 3-5 tons above the string weight sitting on the jar.
5. Precautions
Always run the drilling jars as part of the complete bottom hole assembly (BHA). It is designing to free a stuck drill string and should not be operaingd as a standalone impact tool.
To trigger a downward shock, lower enough weight from the upper drill string to exceed the down hammer’s preset tonnage, and the jar produces a downstroke.
Lower the drill string to seat the upper hammer.
How to Compare Drilling Jar Quotations
Do not compare drilling jars using only tool OD, connection and unit price.
Confirm that every quotation includes the same:Jar type,Upward,downward or double-acting action,Tool OD and bore,Overall length,Connections,Stroke,Release-load range,Maximum operating load,Maximum tensile and torsional capacity,Maximum temperature,Mud compatibility,Testing scope,Spare-parts packageOperation manual,Warranty and repair support.
Also check whether the quotation includes:Mandrel clamp,Lifting or handling sub,Seal kit,Mechanical spring or latch spares,Service tools,Functional test report,Release-load verification,Export packing,Third-party inspection.
Ask each supplier to identify all technical deviations and exclusions in writing.
Fast RFQ Checklist for Drilling Equipment Buyers
To receive a detailed technical data sheet and official factory quotation within 2 hours, please specify:
Outer Diameter (OD): e.g., 6 1/2″, 6 3/4″, or 8″
Jar Type: Hydraulic-Mechanical Drilling Jar or Fully Mechanical
Tool Joint Connection: e.g., NC50 (4 1/2″ IF) or 6 5/8″ REG
Operating Environment: Standard Mud or Sour Service (H 2S / NACE MR0175)
Operating Temperature: Standard (121℃) or High-Temp (200℃)
Order Quantity & Destination Port
Email: info@apidrillpipe.com
WhatsApp: +86 18615995257
Drilling Jars – FAQ
Q1: How do I choose between a mechanical and hydraulic drilling jars?
A: Go mechanical if you want a simpler tool with field-adjustable trip force and no hydraulic system to maintain — it works well for standard wells on a tighter budget. Go hydraulic if you’re drilling deep or high-temperature wells and need stepless tonnage control on both the up and down stroke.
Q2: What tonnage rating do I need for my well depth?
A: Tonnage depends on your drill string weight above the jar, hole conditions, and expected stuck-pipe scenarios — not just depth alone. Send us your BHA design and well parameters, and our engineers will recommend the right jar and tonnage setting.
Q3: Are your drilling jars suitable for $H_2S$ Sour Service operations?
A: Yes. All pressure-retaining components and mandrel bodies can be supplied in sour service metallurgies complying with NACE MR0175 / ISO 15156 standards to resist sulfide stress cracking (SSC).
Q4: What is the difference between a Drilling Jar and a Fishing Jar?
A: Drilling Jars are built with heavy-wall section splines to withstand continuous rotation and torque as an integral part of the BHA during drilling. Fishing Jars are lightweight tools using exclusively for remedial static pulling/jarring after a pipe string becomes stuck.
Q5: Can the drilling jar be supplied with API or premium thread connections?
A: Yes. Standard API connections such as NC, IF and REG are available. Premium connections can also be supplied according to project requirements.
Q6: Do you provide third-party inspection?
A: Yes. Inspection by SGS, BV, DNV, ABS or other third-party agencies can be arranging according to the purchase order.
